[House Hearing, 108 Congress]
[From the U.S. Government Publishing Office]
LUNAR SCIENCE AND RESOURCES:
FUTURE OPTIONS
=======================================================================
HEARING
BEFORE THE
SUBCOMMITTEE ON SPACE AND AERONAUTICS
COMMITTEE ON SCIENCE
HOUSE OF REPRESENTATIVES
ONE HUNDRED EIGHTH CONGRESS
SECOND SESSION
__________
APRIL 1, 2004
__________
Serial No. 108-53
__________
Printed for the use of the Committee on Science
Available via the World Wide Web: http://www.house.gov/science
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______
COMMITTEE ON SCIENCE
HON. SHERWOOD L. BOEHLERT, New York, Chairman
RALPH M. HALL, Texas BART GORDON, Tennessee
LAMAR S. SMITH, Texas JERRY F. COSTELLO, Illinois
CURT WELDON, Pennsylvania EDDIE BERNICE JOHNSON, Texas
DANA ROHRABACHER, California LYNN C. WOOLSEY, California
KEN CALVERT, California NICK LAMPSON, Texas
NICK SMITH, Michigan JOHN B. LARSON, Connecticut
ROSCOE G. BARTLETT, Maryland MARK UDALL, Colorado
VERNON J. EHLERS, Michigan DAVID WU, Oregon
GIL GUTKNECHT, Minnesota MICHAEL M. HONDA, California
GEORGE R. NETHERCUTT, JR., BRAD MILLER, North Carolina
Washington LINCOLN DAVIS, Tennessee
FRANK D. LUCAS, Oklahoma SHEILA JACKSON LEE, Texas
JUDY BIGGERT, Illinois ZOE LOFGREN, California
WAYNE T. GILCHREST, Maryland BRAD SHERMAN, California
W. TODD AKIN, Missouri BRIAN BAIRD, Washington
TIMOTHY V. JOHNSON, Illinois DENNIS MOORE, Kansas
MELISSA A. HART, Pennsylvania ANTHONY D. WEINER, New York
J. RANDY FORBES, Virginia JIM MATHESON, Utah
PHIL GINGREY, Georgia DENNIS A. CARDOZA, California
ROB BISHOP, Utah VACANCY
MICHAEL C. BURGESS, Texas VACANCY
JO BONNER, Alabama VACANCY
TOM FEENEY, Florida
RANDY NEUGEBAUER, Texas
VACANCY
------
Subcommittee on Space and Aeronautics
DANA ROHRABACHER, California, Chairman
RALPH M. HALL, Texas NICK LAMPSON, Texas
LAMAR S. SMITH, Texas JOHN B. LARSON, Connecticut
CURT WELDON, Pennsylvania MARK UDALL, Colorado
KEN CALVERT, California DAVID WU, Oregon
ROSCOE G. BARTLETT, Maryland EDDIE BERNICE JOHNSON, Texas
GEORGE R. NETHERCUTT, JR., SHEILA JACKSON LEE, Texas
Washington BRAD SHERMAN, California
FRANK D. LUCAS, Oklahoma DENNIS MOORE, Kansas
J. RANDY FORBES, Virginia ANTHONY D. WEINER, New York
ROB BISHOP, Utah VACANCY
MICHAEL BURGESS, Texas VACANCY
JO BONNER, Alabama VACANCY
TOM FEENEY, Florida BART GORDON, Tennessee
VACANCY
SHERWOOD L. BOEHLERT, New York
BILL ADKINS Subcommittee Staff Director
ED FEDDEMAN Professional Staff Member
RUBEN VAN MITCHELL Professional Staff Member
KEN MONROE Professional Staff Member
CHRIS SHANK Professional Staff Member
RICHARD OBERMANN Democratic Professional Staff Member
TOM HAMMOND Staff Assistant
C O N T E N T S
April 1, 2004
Page
Witness List..................................................... 2
Hearing Charter.................................................. 3
Opening Statements
Statement by Representative Dana Rohrabacher, Chairman,
Subcommittee on Space and Aeronautics, Committee on Science,
U.S. House of Representatives.................................. 8
Written Statement............................................ 8
Statement by Representative Nick Lampson, Ranking Minority
Member, Subcommittee on Space and Aeronautics, Committee on
Science, U.S. House of Representatives......................... 9
Statement by Representative Roscoe G. Bartlett, Member,
Subcommittee on Space and Aeronautics, Committee on Science,
U.S. House of Representatives.................................. 10
Witnesses:
Dr. Paul D. Spudis, Senior Staff Scientist, Johns Hopkins
University Applied Physics Laboratory; Visiting Scientist,
Lunar and Planetary Institute, Houston, Texas
Oral Statement............................................... 11
Written Statement............................................ 14
Biography.................................................... 19
Dr. Daniel F. Lester, Research Scientist, McDonald Observatory,
University of Texas, Austin
Oral Statement............................................... 19
Written Statement............................................ 21
Biography.................................................... 24
Dr. Donald B. Campbell, Professor of Astronomy, Associate
Director, National Astronomy and Ionosphere Center (NAIC),
Cornell University
Oral Statement............................................... 24
Written Statement............................................ 26
Biography.................................................... 30
Dr. John S. Lewis, Professor of Planetary Sciences, Co-Director,
Space Engineering Research Center, University of Arizona
Oral Statement............................................... 31
Written Statement............................................ 34
Biography.................................................... 36
Dr. Timothy D. Swindle, Professor of Geosciences and Planetary
Sciences, University of Arizona
Oral Statement............................................... 36
Written Statement............................................ 38
Biography.................................................... 41
Discussion
Helium-3....................................................... 42
Solar Energy on the Moon....................................... 42
In Situ Resources.............................................. 43
Possible Return Dates to the Moon.............................. 44
Timeframe for In Situ Resource Development..................... 45
Prioritization of Lunar Science................................ 45
Timeframe for a Human Return to the Moon....................... 46
Other Potential Lunar Fuels.................................... 47
Mobile Solar Stores............................................ 48
Gravity Gradient Stabilization................................. 49
Mobile Solar Stores II......................................... 49
Moon as a Way Station.......................................... 50
The Value of Telescopes on the Lunar Surface................... 51
Amount of Water on the Lunar Surface........................... 52
Additional Data Needed Before a Human Return Mission........... 53
Canceled Apollo Missions as Future Expeditions................. 54
International Cooperation...................................... 54
Our Knowledge of the Lunar Surface Regarding Vehicles on Mars.. 57
Percent of the Moon That Has Constant Light.................... 57
Role of Private Sector......................................... 58
Space Exploration and National Security........................ 59
Appendix: Answers to Post-Hearing Questions
Dr. Paul D. Spudis, Senior Staff Scientist, Johns Hopkins
University Applied Physics Laboratory; Visiting Scientist,
Lunar and Planetary Institute, Houston, Texas.................. 64
Dr. Daniel F. Lester, Research Scientist, McDonald Observatory,
University of Texas, Austin.................................... 67
Dr. Donald B. Campbell, Professor of Astronomy, Associate
Director, National Astronomy and Ionosphere Center (NAIC),
Cornell University............................................. 70
Dr. John S. Lewis, Professor of Planetary Sciences, Co-Director,
Space Engineering Research Center, University of Arizona....... 73
Dr. Timothy D. Swindle, Professor of Geosciences and Planetary
Sciences, University of Arizona................................ 77
LUNAR SCIENCE AND RESOURCES: FUTURE OPTIONS
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THURSDAY, APRIL 1, 2004
House of Representatives,
Subcommittee on Space and Aeronautics,
Committee on Science,
Washington, DC.
The Subcommittee met, pursuant to call, at 1:00 p.m., in
Room 2318 of the Rayburn House Office Building, Hon. Dana
Rohrabacher [Chairman of the Subcommittee] presiding.
hearing charter
SUBCOMMITTEE ON SPACE AND AERONAUTICS
COMMITTEE ON SCIENCE
U.S. HOUSE OF REPRESENTATIVES
Lunar Science and Resources:
Future Options
thursday, april 1, 2004
1:00 p.m.-3:00 p.m.
2318 rayburn house office building
1. Purpose
On Thursday, April 1, 2004 at 1:00 p.m., the Subcommittee on Space
and Aeronautics will hold a hearing to examine current thinking about
the suitability of the Moon for scientific and commercial activities.
The hearing is not meant to focus on whether to go to the Moon, but
rather is intended to examine the suitability of using the Moon for an
extended--perhaps permanent--presence to conduct space science and
resource-extraction activities.
2. Witnesses
Dr. Paul Spudis is a Senior Staff Scientist at the
Johns Hopkins University Applied Physics Laboratory and
Visiting Scientist at the Lunar and Planetary Institute in
Houston, Texas.
Dr. Daniel F. Lester is a Research Scientist at the
McDonald Observatory, University of Texas at Austin.
Dr. Donald Campbell is a Professor of Astronomy and
associate director of the National Astronomy and Ionosphere
Center (NAIC) at Cornell University.
Dr. John S. Lewis is a Professor of Planetary
Sciences and Co-Director of the Space Engineering Research
Center at the University of Arizona.
Dr. Timothy Swindle is Professor of Geosciences and
Planetary Sciences at the University of Arizona.
3. Overarching Questions
1. Is the Moon a uniquely useful site to base deep-space radio,
infrared and optical telescopes or other science instruments?
a. Can space science be conducted using instruments on the
Moon more reliably and cheaply than it could be done from Earth
or using satellite-based instruments? What other fields of
science (i.e., astrobiology, cosmology) would benefit from
using a Moon-based laboratory?
2. Does the Moon contain minerals, isotopes, or other materials that
one day may be commercially exploitable? How much certainty is there
about the presence and quantity of these resources? How readily
extractable are they?
a. What additional technologies, if any, must we first develop
before these resources can be made useful?
4. Background
On January 14, 2004, President Bush announced his Space Exploration
Initiative, putting in motion a major new NASA program to send
astronauts to the ``Moon, Mars and beyond.'' Among other goals, the
plan states: ``The extended human presence on the Moon will enable
astronauts to develop new technologies and harness the Moon's abundant
resources to allow manned exploration of the challenging environments..
. . Experience and knowledge gained on the Moon will serve as a
foundation for human missions beyond the Moon, beginning with Mars.''
\1\
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\1\ ``President Bush Announces New Vision for Space Exploration
Program.'' www.whitehouse.gov/news/releases/2004/01/20040114-1.html
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The Space Exploration Initiative calls for the first launch of a
robotic probe to the Moon in 2008 to begin mapping and reconnaissance
studies. At least one probe will be launched each year thereafter,
either an orbiter or lander, with the goal that the first manned Moon
mission would occur between 2015 and 2020. While the Space Exploration
Initiative establishes a goal of going back to the Moon, it does not
specify what we would do once we get there (i.e., lunar geology, space
telescopes, mining).
The initiative is silent on whether the U.S. would attempt to
establish a permanent human presence on the Moon. But proponents of
such a presence believe the time is ripe to advocate lunar bases--
robotic or human tended--as a logical next step of any U.S. effort to
return to the Moon.
Some members of the lunar science and astronomy communities have
long viewed the Moon as a base from which to operate telescopes and
other science instruments.
The Moon offers several clear advantages--and disadvantages--as a
base for astronomical observatories. Advantages include the lack of an
atmosphere, its ability to shield instruments from radio and thermal
pollution of Earth, lack of a magnetic field, a solid surface, and, in
lunar craters at the poles, the capability of keeping infrared
telescopes operating at optimally cold temperatures.
Disadvantages include dust, the need to install power sources to
run instruments, and the risk of landing payloads safely on the Moon.
Human-tended operations pose challenges that are far greater, such as
assuring a reliable supply of food, water and oxygen; developing a
suitable shelter; high background radiation; the risks of launching and
landing; working in a cold vacuum; and the prolonged effects of
operating in a low-gravity (one-sixth of Earth's) environment.
Some scientists believe the Moon contains large deposits of
minerals and isotopes that one day may be commercially exploitable. Of
most interest is the possible presence of water, and the presence of
helium-3, which theoretically could be used on Earth to generate energy
using fusion reactors.
The attached article from the March 12, 2004 edition of Science
Magazine outlines the debate on possible activities that could be
conducted on the Moon.
5. Issues
How much water is on the Moon and how difficult would
it be to extract? In 1994, the U.S. lunar orbiter Clementine
found indications of frozen water at the Moon's poles.
Scientists disagree on whether water is actually present, and,
if it is, whether it exists in significant quantities.
Obviously, water would be a boon to any human activities on the
Moon because it could be used to sustain human life and to
produce hydrogen fuel and oxygen. If no readily accessible
source of water is found, lunar astronauts would need to
transport their own water, significantly adding to the
logistics burden and possibly limiting the amount of other
materials they could bring along, as well as limiting the time
they could remain on the Moon.
Water can be transformed into fuel (hydrogen) and oxygen,
but exploiting this opportunity requires launching heavy
processing equipment from Earth, safely landing and assembling
it on the lunar surface, and providing power for its operation.
Would benefits of this approach outweigh the costs of simply
launching fuel and oxygen from Earth? Would the lack of easily
extractable lunar ice prove to be an insurmountable obstacle to
long-term human habitation?
Do the advantages outweigh the disadvantages of using
the Moon as a base for astronomical observatories? How does the
Moon compare with other alternatives? Scientists disagree about
the benefits of using the Moon as a site for operating science
instruments that are designed to look into deep space.
Astronomical observatories located on the Moon's far side, or
at its poles, hold many advantages over Earth-based
observatories. Having no atmosphere eliminates a major source
of aberrations common to Earth-based telescopes and it permits
viewing objects at all wavelengths (Earth's atmosphere filters
out ultraviolet, x-ray, and gamma ray wavelengths). The Moon
would also act as a shield against radio and thermal pollution
from Earth sources. Its uniformly low temperatures at the lunar
poles provide an excellent location to site infrared
telescopes.
Disadvantages include the threat of lunar dust settling
on, and obstructing telescope optics. Dust may be kicked up
during landing, assembly, or repair. The risk of safely landing
the telescope is substantial. Providing power to run the
instruments will require construction of solar arrays or the
use of a small nuclear-electric generator at a location far
enough away to avoid interference. Relying on lunar astronauts
to assemble the observatory raises significant risk factors,
especially if they are expected to work at the bottom of a
deep, cold crater.
Some scientists advocate free-flying telescopes (such as
Hubble, the Chandra Observatory, and the newly commissioned
Spitzer Infrared Observatory) as a more cost-effective, less
risky alternative than lunar-based telescopes. With the
exception of Hubble, none of the observatories are designed to
be serviced or repaired, eliminating any need for human
tending. Free flyers can be launched to high Earth orbits or
libration points, removing a large source of thermal and radio
interference. Guidance, pointing and tracking technologies are
extremely accurate, negating any advantage of using a stable
lunar surface.
Is it commercially practical to mine lunar-based
minerals and isotopes? Scientists disagree about the amounts
and types of valuable ores that may be found on the Moon. A
related issue is whether commercial enterprises can overcome
the huge costs associated with launching, landing and
assembling foundries and fabrication facilities to mine and
process any ores, and transport finished products to Earth or
use them to support missions to other parts of the Solar
System. Once again, the availability of lunar ice (water) would
affect the success of such activities.
Harvesting resources on the Moon would also raise several
important legal questions (about which the Committee intends to
hold a future hearing). The United States is a signatory to
four multinational treaties concerning the use of outer space,
two of which expressly mention the Moon. The Treaty on
Principles Governing the Activities of States in the
Exploration of the Use of Outer Space, including the Moon and
Other Celestial Bodies was codified in 1967 and ratified by the
United States, Russia and 96 other nations. Among other things,
the treaty provides that the Moon is ``not subject to national
appropriation.'' The United States is not a signatory to the
Agreement Governing the Activities of States on the Moon and
Other Celestial Bodies (``the Moon Treaty''). Codified in 1979
and ratified by only seven nations, the Moon Treaty states in
relevant part that the Moon is ``the common heritage of all
mankind,'' and that the Moon's natural resources may not become
the property of any person. The treaty further provides for an
international regime to govern the ``exploitation of the
natural resources of the Moon.''
How practical is it to consider extracting helium-3
for power generation facilities on Earth? Helium-3 is a scarce
isotope on Earth but lunar samples returned by Apollo missions
suggests that it is more abundant on the Moon's surface. While
it may more plentiful, extracting large amounts of helium-3
from lunar soil is likely to prove difficult. Physicists
believe helium-3 will one day be used as a fuel for specially
designed fusion reactors on Earth, but development of such
reactors is decades away.
6. Questions to Witnesses
In his letter of invitation to appear as a witness, Dr. Spudis was
asked to address the following questions in his testimony:
What science can be conducted on the surface of the
Moon that cannot be duplicated by Earth-based research or free-
flying satellites?
What minerals, elements and isotopes exist on the
Moon in sufficient quantities that they could contribute to
expanding the reach of human exploration of the solar system?
What is the basis of your estimate and how widely shared is it?
How soon after a human return to the Moon would it be possible
to begin exploiting resources?
How much water do you believe is trapped on the lunar
surface, and what is the basis of your estimates? How confident
are you of these estimates? Based on current observations, is
the water concentrated in various pockets on the lunar surface,
or is it widely distributed?
Do you believe that long-term human habitation on the
Moon is necessary to conduct science and lunar resource
extraction activities? What role would robotics play?
In his letter of invitation to appear as a witness, Dr. Lewis was
asked to address the following questions in his testimony:
What minerals, elements and isotopes exist on the
Moon in sufficient quantities that they could contribute to
expanding the reach of human exploration of the solar system?
What is the basis of your estimate and how widely shared is it?
How soon after a human return to the Moon would it be possible
to begin exploiting resources?
What are the advantages to human exploration of the
solar system by siting fabrication and processing facilities on
the Moon? Can lunar-based fabrication be done more effectively
than using Earth-bound facilities?
How would you characterize the possibility that
extraction of Moon materials may one day be commercially
viable?
In his letter of invitation to appear as a witness, Dr. Campbell
was asked to address the following questions in his testimony:
How much water do you believe is trapped on the lunar
surface, and what is the basis of your estimates? How confident
are you of these estimates? Based on current observations, is
the water concentrated in various pockets on the lunar surface,
or is it widely distributed?
How important is finding water to exploiting the Moon
for scientific or economic purposes?
What kinds of instruments need to be flown on
upcoming lunar probes to try to resolve questions about water
on the Moon?
What other minerals, ores, or elements do you believe
may be present in the lunar soil that may hold interest for
future exploitation?
In his letter of invitation to appear as a witness, Dr. Lester was
asked to address the following questions in his testimony:
What space science can be conducted on the surface of
the Moon that cannot be duplicated by Earth-based research or
free-flying satellites?
Is the Moon an appropriate site for astronomical
observatories? What advantages and disadvantages does the Moon
pose as a base for telescopes?
As NASA begins to launch lunar robotic probes to
survey the Moon's resources, what instruments should be flown
on the probes that can be used to serve the Space Exploration
Initiative as well as inform lunar scientists about the
suitability of using the Moon as a base for long-term science
activities?
What are your views about the practicality of
establishing long-term human bases on the Moon to conduct
science? Will robotics be able to carry out the same science
missions without the presence of humans on the Moon?
In his letter of invitation to appear as a witness, Dr. Swindle was
asked to address the following questions in his testimony:
What are the most pressing questions in lunar
science? To what extent do they require human lunar missions to
be pursued? To what extent can they be pursued from Earth?
What minerals, elements and isotopes exist on the
Moon in sufficient quantities that they could contribute to
expanding the reach of human exploration of the solar system?
What is the basis of your estimate and how widely shared is it?
How soon after a human return to the Moon would it be possible
to begin exploiting resources?
Specifically, how much helium-3 do you believe is on
the Moon, and what is the basis of your estimate? Based on
current observations, is the helium-3 concentrated in various
pockets on the lunar surface, or is it widely distributed? How
much ore would have to processed to refine useful amounts of
helium-3, and how technologically difficult would it be to
accomplish? How long after a human return to the Moon would
production of helium-3 likely be viable? How close are we to
developing technologies that could make use of helium-3?
7. Attachment
``Moon's `Abundant Resources' Largely an Unknown Quantity,''
Science Magazine, March 12, 2004
Chairman Rohrabacher. I hereby call this meeting of the
Space and Aeronautics Subcommittee to order. Without objection,
the Chair will be granted the authority to recess this
committee at any time. Hearing no objections, so ordered.
Thirty years ago, the end of the Apollo era signaled the
beginning of a much more narrow, scaled-back agenda for human
space flight. Unfortunately, President Bush--or should I say
fortunately, not unfortunately. Fortunately, President Bush has
made the decision to recommit this nation to its heritage of
human exploration, and then pushing it beyond, human
exploration of the universe. The question now is not whether we
will return to the Moon, but what things might be done there in
the name of science and economic development. Today's hearing
will focus on the Moon. What are the key lunar minerals and
ores there on the Moon and what is the Moon's potential as a
scientific-industrial laboratory.
And I share the belief that the Moon affords us the
opportunity to pursue exploration, perhaps in the tradition of
Lewis and Clark. The Moon is a way station, that is right. That
is true. But, further than that, it could well be a destination
in and of itself. Some question whether resources on the Moon
are adequate enough to be commercially exploitable, and some
argue whether or not the Moon is a proper destination in and of
itself. Some question the validity of going to the Moon even
for a visit. Measurements made by Defense Department's
Clementine and NASA's Lunar Prospector probes have suggested
the presence of water on the Moon. Now, there is some debate
within the scientific community whether or not the water is
sufficient for sustaining some type of a lunar operation.
Resolving this issue is, of course, one of questions that needs
to be answered.
And NASA's plan to map lunar resources, however, holds the
promise of informing us how people can live and work on the
Moon. In this regard, we must ensure that the technology,
equipment, and instruments that NASA plans to use for mapping
the lunar resources are the right ones for the task. Is NASA's
planned series of lunar robotic missions adequate? What input
from the private sector has NASA received in making the
determinations as to what its goals will be? And, that said, we
have assembled a panel of expert witnesses that will provide us
their insight and analysis on these issues.
I believe that Americans must continue to be the leading
force in exploring space. But we must know why we are going to
be sending human beings on particular missions, and especially
that dealing with the Moon. We must be identifying critical
lunar exploration activities and what they could be and what
they couldn't be. What are our limitations? All this will
determine what role we will play as a country as a leader, as I
say, in the exploration of space.
Mr. Lampson, you may proceed with your opening statement.
[The prepared statement of Mr. Rohrabacher follows:]
Prepared Statement of Chairman Dana Rohrabacher
Thirty years ago, the end of the Apollo era signaled the beginning
of a much more narrow, scaled-back agenda for our human space flight
program. Fortunately, President Bush made the decision to recommit this
nation to its heritage of human exploration beyond Earth's orbit. The
question now is not whether we will return to the Moon, but what things
might be done there in the name of science and economic development.
Today's hearing will focus on the Moon's suitability in these areas for
enabling a permanent human presence on the lunar surface. Utilizing key
lunar minerals and ores is critical if the Moon's potential as a
scientific and industrial laboratory in Earth's neighborhood is to be
realized.
I share the belief that the Moon affords us the opportunity to
pursue exploration in the tradition of the Lewis and Clark expedition.
Exploration of a new frontier then aided our nation in laying the
groundwork for settling the American Northwest. Similarly, the Moon
offers us the potential to establish lunar human settlements in the
future. Some question whether resources on the Moon are adequate or
commercially exploitable. For example, measurements made by the Defense
Department's Clementine and NASA's Lunar Prospector probes have
suggested the presence of water on the Moon. There is some debate
within the science community whether water is sufficiently abundant for
sustaining lunar-based operations. Resolving this fundamental issue is
key for successfully returning people to the Moon.
NASA's plan to map lunar resources, however, holds the promise of
informing us how people can live and work on the Moon. In this regard
we must ensure that the instruments NASA plans to use for mapping lunar
resources are the right ones for the task. Is NASA's planned series of
lunar robotic missions adequate? What input from the private sector has
NASA received in making these determinations? That said, we have
assembled a panel of expert witnesses that will provide us with their
insight and analysis of these issues.
I believe Americans must continue to explore space, but we must
know why we are sending humans there. Identifying critical lunar
exploration activities will have major implications for our future role
as a leader in space.
Mr. Lampson. Thank you, Mr. Chairman. And the only thing
that was wilder than your announcement about the civilization
on the Moon is when I got a phone call this morning from a
local television station telling me that I had been selected by
John Kerry to be his running mate. And the only thing that I
could think of that the only thing that would have been wilder
than that was if it had been George Bush.
Chairman Rohrabacher. Well, there you go.
Mr. Lampson. It is a--thank you very much, both for the
time, and for calling this hearing. I am certainly pleased to
welcome our witnesses today, and look forward to all of the
testimony that you have to bring us. We do have a distinguished
panel of scientists appearing before the Subcommittee, and I am
anxious to hear all of your views.
A return to the Moon by U.S. astronauts is a central
feature of the Space Initiative proposed by the President in
January of this year, and that makes sense to me. I have long
believed, as I know Dana has--Chairman Rohrabacher has, that
the exploration of our Solar system should involve a number of
interesting destinations, including the Moon. However, an
important question is what we will do on the Moon. Will we have
a limited presence there for just as long as it takes to test
the systems and techniques needed for human missions to Mars,
or will we establish a long-term presence on the Moon, using it
for scientific, operational, or even commercial purposes?
So our witnesses will present a range of viewpoints
regarding potential scientific opportunities on the Moon. And
they will also discuss the arguments for and against the
likelihood of significant extraction and utilization of lunar
resources. This hearing will help the Subcommittee understand
just what the Moon has to offer to us as we move out into the
Solar system. And so I hope that we will have more such
hearings, and I hope that we will have a chance to hear from
some of the folks at the Johnson Space Center who have been
working on some of these issues, also, for a very long period
of time. There is a great deal for us to learn, and when we
have the opportunity to hear it from the people who are living
it, it makes a big difference for me, so I come to this hearing
eager to learn from our witnesses.
Again, I want to welcome you, and I look forward to
listening to the testimony.
Chairman Rohrabacher. All right. Thank you very much. Mr.
Bartlett--or Dr. Bartlett, I should say. Excuse me.
Mr. Bartlett. Thank you very much. I look forward to this
hearing. I have never shied away from the President's
commitment to return humans to the Moon and on to Mars. In
addition to the benefits that our society will get from pushing
the envelope to do that, our country desperately needs
something that captures the imagination of our people, and
inspires our young people to go into careers of math, science,
and engineering. Maybe this will do that. When we made that
commitment to put a man on the Moon, that really did that.
We now have our best and brightest students in this country
going into careers other than science, math and engineering. As
a matter of fact, far too many of them are going into
destructive pursuits. They are becoming lawyers and political
scientists. Though we need a few of each of those, and we have
got more than a few of each of those.
For the short-term, our economic superiority is at risk if
we don't turn out more scientists, mathematicians, and
engineers, and for the longer-term, our national security is at
risk. We will not continue to have the world's best military
unless we turn out scientists, mathematicians and engineers,
well-trained, and in adequate numbers. And hopefully returning
then to the Moon and on to Mars will provide the stimulus that
encourages our young people to move into these careers that
keep us the premiere economic nation in the world and the
premier military nation in the world.
So I think that this is an investment that will pay very
well for our society. That is why I look forward to this
hearing, and thank you all very much.
Chairman Rohrabacher. Mr. Feeney, do you have a one-minute
statement? All right. Without objection, the opening statements
of other members will be put in the written record so we can
get right to the testimony. Hearing no objection, so ordered.
I also ask unanimous consent to insert in the appropriate
place in the record the background memorandum prepared by the
Majority Staff for this hearing. Hearing no objection, so
ordered.
We have a distinguished panel with us today to provide
their unique perspectives to these issues. We have asked them
to summarize their testimony to five minutes so that we can get
right to a dialogue, and I have encouraged them to be as
aggressive in promoting their ideas or attacking ideas that
they disagree with, as they see fit.
Our first witness is Dr. Paul Spudis, who is a senior staff
scientist at Johns Hopkins University's Applied Physics
Laboratory. Dr. Spudis is also a member of the Aldridge
Commission, but he is appearing before this committee today as
a recognized expert on lunar science, and his testimony will
represent his personal views and opinions. I understand that he
is not appearing on behalf of the Aldridge Commission, and it
is nice to see you again, and you may proceed.
STATEMENT OF DR. PAUL D. SPUDIS, SENIOR STAFF SCIENTIST, JOHNS
HOPKINS UNIVERSITY APPLIED PHYSICS LABORATORY, VISITING
SCIENTIST, LUNAR AND PLANETARY INSTITUTE, HOUSTON, TEXAS
Dr. Spudis. Mr. Chairman and Members of the Committee,
thank you for inviting me here today to testify on the subject
of lunar science, resources, and the U.S. Space Program.
Recently, President Bush articulated a new strategic
direction for America in space, one that includes a return to
the Moon, and the development and use of off-planet resources.
The value of the Moon as a space destination has not escaped
the notice of other countries. At least four new robotic
missions are currently being flown, or prepared for flight, by
Europe, India, Japan, and China. And advance planning for human
missions in many of these countries is already under way. I
believe that our nation needs to return to the Moon, and that
this return should take place now rather than later.
While you have my full written testimony, in the time
available, I would like to make the following points, and
answers to the questions posed to me by the Committee.
Point 1: the Moon is a unique scientific resource on which
important research, ranging from planetary science to astronomy
and high-energy physics, can be conducted. The Moon is a small
planet of surprising complexity. The period of its most active
geological evolution, between three and four billion years ago,
corresponds to a missing chapter of Earth's history. The
processes that work on the Moon--impact, volcanism, the
deformation of its crust--are the same ones that affect all the
rocky bodies of the inner solar system, including the Earth.
Because the Moon has no atmosphere or running water, its
ancient surface is preserved in nearly pristine form, and its
geological story can be read with clarity and understanding. As
Earth's companion in space, the Moon retains the unique record
of this history of this corner of the solar system,
particularly the history of impacts, vital knowledge
unavailable on any other planetary object.
Telescopes on the Moon possess many advantages over both
Earth-based and space-based instruments. The Moon's stable base
permits the construction of optical interferometers with
multiple-kilometer baselines. Such an instrument could image
the disks of terrestrial planets orbiting nearby stars. The
Moon's environment is well characterized. Dust accumulation can
be controlled, and presents no intractable difficulties to the
establishment and maintenance of service telescopes.
The Moon offers astronomers many environmental advantages
with its far side blocking the Earth's radio noise, dark polar
craters to cool infrared detectors, and a solid mounting base
that requires no pointing gyros as do free-space telescopes.
Point 2: we already know that the Moon possesses the
resources needed to create a space-faring transportation
infrastructure in cislunar space. Cislunar space is the volume
of space between Earth and Moon.
As usable commodities, lunar materials offer many
possibilities. Because of its high abundance, oxygen production
is likely to be an important early product. The production of
oxygen from the Moon involves breaking the very tight chemical
bonds in lunar minerals between oxygen and various metals,
including iron, aluminum, and titanium. Many different
techniques to accomplish this task have been developed. All are
based on common industrial processes easily adapted for use on
the Moon.
The most important use of oxygen in its liquefied form is
to make rocket fuel oxidizer. Coupled with extraction of
hydrogen from the soil, this processing can make rocket fuel
the most important and profitable commodity of a new lunar
economy. Once processing is established, lifting fuel off the
Moon for use in space will be like driving a tanker truck away
from an oil refinery.
Point 3: hydrogen, probably in the form of water ice,
exists at the poles of the Moon in quantity, and can be
extracted and processed into rocket propellant and life support
consumables.
Our current estimate of the amount of water on the Moon
comes from two orbital measurements. The Clementine bistatic
experiment indicates that an area of about 135 square
kilometers of pure ice exists within an observed area of about
45,000 square kilometers, corresponding to a concentration
level of 0.3 percent. This estimate is consistent with
observations from Earth-based radio observatories, including
Arecibo and Goldstone, which show small, scattered areas of
high radar backscatter within the sun-dark regions of the
poles. The Lunar Prospector neutron spectrometer found a
concentration level of about 1.5 weight-percent water over an
area of approximately 12,000 kilometers in extent. Because of
the observing geometry between Earth and Moon, Clementine and
Earth-based radar could only examine about 1/4 to 1/3 the total
dark area of the south pole, while Lunar Prospector in orbit
around the Moon collected data from 100 percent of the dark
area. It is estimated that over 10 billion metric tons of water
exist at the lunar poles, an amount equal in volume to Utah's
Great Salt Lake. We do not know how widely disseminated this
ice is. We must survey the poles from orbit to understand this
distribution in detail.
We have identified several areas near both north and south
poles of the Moon that offer near-constant Sun illumination. An
outpost or establishment in these areas will have the advantage
of being in sunlight for the generation of electric power via
solar cells, and a benign thermal environment, because the Sun
is always at grazing incidence angles. The poles of the Moon
are inviting oases in near-Earth space, easily accessible from
the L-1 Point or polar orbit, both possible staging areas for
lunar missions.
Point 4: by allowing us to travel at will with people
throughout the Earth-Moon system, a return to the Moon to use
lunar resources gives the Nation a challenging mission, and
creates capability for the future. Returning to the Moon to use
its resources will establish a robust transportation
infrastructure, one capable of delivering people and machines
throughout cislunar space.
Make no mistake, learning to use the resources of the Moon,
or any other planetary object, will be a challenging technical
task. We must learn to use machines in remote, hostile
environments, working with ore bodies of small concentration
under difficult conditions. The unique polar environment of the
Moon, with its zones of near-permanent illumination and
permanent darkness, provides its own challenges, but also
offers extraordinary advantages. For humanity to have a future
beyond low-Earth orbit, we must learn to use the materials and
conditions available off-planet. Otherwise, we will always be
mass- and power-limited to only those payloads that we can lift
out of Earth's deep gravity well. Investment in a few robotic
precursor missions would be greatly beneficial and help ensure
the success of our efforts.
We should map the polar deposits of the Moon from orbit
using imaging radar and an advanced neutron spectrometer to
determine the extent, purity, and thickness of the ice in these
dark regions. We can use this information to select sites to
land small robotic probes, conduct chemical analyses of the
polar deposits, and radio the results to Earth. Although we
expect water ice to dominate, these deposits made from cometary
cores may also contain methane, ammonia, and organic molecules,
all potentially useful resources. We need to inventory these
species, determine their chemical and isotopic properties as
well as their physical nature and setting.
Finally, we should land a series of demonstration
experiments designed to test various techniques and methods of
lunar resource extraction. Ultimately, both people and machines
are needed on the Moon to fully realize its potential as an
off-planet logistics and industrial base.
Point 5: this mission will create routine access to
cislunar space, which directly relates to important national
economic and strategic goals. Learning space survival skills
close to home, we create new opportunities for exploration,
utilization, and wealth creation. Space will no longer be a
hostile place that we tentatively visit for short periods,
instead it becomes a prominent part of our world.
Achieving freedom of cislunar space makes America more
secure by enabling and maintaining cheaper assets in orbit, and
more prosperous by opening an economically limitless frontier.
Creating this infrastructure, we will have a system that can
take us to the planets.
Point 6: timing is everything. It is important for America
to undertake this mission now rather than later. Many nations
have recently indicated an interest in the Moon. The possible
collection and use of lunar resources raises some interesting
political and economic issues. Our initial return to the Moon
would be an engineering and scientific research and development
project. We undertake our studies of the extraction of lunar
resources to ascertain the best methods to harvest and use
these materials. Our presence on the Moon does not give us
title to it. However, a strong and continuing American presence
on the Moon can help establish de facto the broad legal
framework and economic paradigm of democratic free-market
capitalism off the Earth. It is not clear that other nations
will be similarly inclined.
America must have a challenging and vigorous space program.
A mission that inspires, educates and enriches. It must relate
to important national needs, yet push the boundaries of the
possible and serve larger national concerns beyond scientific
endeavors. The President's program fulfills these goals. A
return to the Moon is a giant step into the solar system.
Thank you for your attention, and I will be happy to answer
any questions that you may have.
[The prepared statement of Dr. Spudis follows:]
Prepared Statement of Paul D. Spudis
Mr. Chairman and Members of the Committee, thank you for inviting
me here today to testify on the subject of lunar science, resources,
and the U.S. space program.
Recently, President Bush articulated a new strategic direction for
America in space, one that includes a return to the Moon and the
development and use of off-planet resources. Although we conducted our
initial visits to that body over 30 years ago, we have recently made
several important discoveries that indicate a return to the Moon offers
many advantages and benefits to the Nation. In addition to being a
scientifically rich object for study, the Moon offers abundant material
and energy resources, the feedstock of an industrial space
infrastructure. Once established, such an infrastructure will
revolutionize space travel, assuring us of continuous, routine access
to cislunar space (i.e., the space between and around Earth and Moon)
and beyond. The value of the Moon as a space destination has not
escaped the notice of other countries--at least four new robotic
missions are currently being flown or prepared for flight by Europe,
India, Japan, and China and advanced planning for human missions in
many of these countries is already underway. Additionally, at least two
of these future planned missions (India and China) have advanced their
launch dates considerably within the last month, indicating that these
nations recognize both the importance and value of the Moon and the
urgency of establishing a presence there.
The points below elaborate on WHY the Nation needs to return to the
Moon and why that return should take place NOW rather than later.
(1) The Moon is close, accessible with existing systems, and has
resources that we can use to create a true, economical space-faring
infrastructure.
The inclusion of the Moon as the first destination in the
President's new vision was no accident. The Moon is both a scientific
bonanza and an economic treasure trove, easily reachable with existing
systems and infrastructure that can revolutionize our national
strategic and economic posture in space and at home. The dark areas
near the poles of the Moon contain significant amounts (at least 10
billion tons) of hydrogen, most probably in the form of water ice. This
ice can be mined to support human life on the Moon and in space and to
make rocket propellant (liquid hydrogen and oxygen). Moreover, we can
return to the Moon using existing infrastructure of evolved-expendable
and Shuttle-derived launch systems for only a modest increase in the
space budget within the next five years.
The Moon is also a testing ground, a small nearby planet where we
can learn the techniques of the strategies and operations we need to
explore the solar system. The ``mission'' of this program is to go to
the Moon to learn how to use off-planet resources to make space flight
easier and cheaper in the future. Rocket propellant made on the Moon
will permit routine access to cislunar space by people and machines,
vital to the servicing and protection of national strategic assets and
for the repair and refurbishing of commercial satellites. The
availability of refueling capability in low-Earth orbit would
completely change the way engineers design spacecraft and the way
companies and the government think of investing in space assets. This
capability will serve to dramatically reduce the cost of space
infrastructure to both the government and to the private sector, thus
spurring economic investment (and profit).
(2) The Moon is a unique scientific resource on which important
research, ranging from planetary science to astronomy and high-energy
physics, can be conducted.
Generally considered a simple, primitive body, the Moon is actually
a small planet of surprising complexity. The period of its most active
geological evolution, between four and three billion years ago,
corresponds to a ``missing chapter'' of Earth history. The processes
that work on the Moon--impact, volcanism, and tectonism (deformation of
the crust)--are the same ones that affect all of the rocky bodies of
the inner solar system, including the Earth. Because the Moon has no
atmosphere or running water, its ancient surface is preserved in nearly
pristine form and its geological story can be read with clarity and
understanding. Because the Moon is Earth's companion in space, it
retains a record of the history of this corner of the Solar System--
vital knowledge unavailable on any other planetary object.
Of all the scientific benefits of Apollo, appreciation of the
importance of impact (the collision of solid bodies) in planetary
evolution must rank highest. Before we went to the Moon, we had to
understand the physical and chemical effects of these collisions,
events completely beyond the scale of human experience. Of limited
application at first, this new knowledge turned out to have profound
consequences. We now believe that large-body collisions periodically
wipe out species and families on Earth, most notably, the extinction of
dinosaurs 65 million years ago. The telltale residue of such large body
impacts in Earth's past is recognized because of knowledge we acquired
about impact from the Moon. Additional knowledge still resides there;
while the Earth's surface record has been largely erased by the dynamic
processes of erosion and crustal recycling, the ancient lunar surface
retains this impact history. Although other planets display craters,
only the Moon resides in our vicinity of the solar system, records the
same impact flux that has struck Earth over the geologic past and
retains a unique record that cannot be read on any other body. When we
return to the Moon, we will examine this record in detail and learn
about its evolution as well as our own.
Because the Moon has no atmosphere and is a quiet, stable body, it
is a premier place to observe the universe. Telescopes erected on the
lunar surface will possess many advantages over both Earth-based and
space-based instruments. The Moon's level of seismic activity is orders
of magnitude lower than that of Earth, permitting the construction of
interferometers with multiple-kilometer baselines. Such an instrument
can image the disks of terrestrial-sized planets orbiting nearby stars.
The lack of an atmosphere permits clear viewing, with no spectrally
opaque windows to contend with; the entire electromagnetic spectrum is
visible from the Moon's surface. Its slow rotation (one lunar day is
708 hours long, about 28 terrestrial days) means that there are long
times of darkness for observation. Even during the lunar day, brighter
sky objects are visible through the reflected surface glare. The far
side of the Moon is permanently shielded from the din of
electromagnetic noise produced by our industrial civilization. Unique
electromagnetic windows on the sky, such as low-frequency shortwave
radio ( 10-100 m), can be mapped only from the lunar far side. There
are areas of perpetual darkness and sunlight near the poles of the
Moon. The dark regions are very cold, only a few tens of degrees above
absolute zero and these natural ``cold traps'' can be used to passively
cool infrared detectors. Thus, telescopes installed near the lunar
poles can see both entire celestial hemispheres at once with infrared
detectors, cooled courtesy of the cold traps.
Recent suggestions that lunar dust poses unsolvable problems and
difficulties for telescopes on the Moon are incorrect; lunar dust does
not ``coat'' surfaces if left undisturbed. The Apollo astronauts became
covered in dust because in some cases, they fell, knelt, or had to
literally wallow in dust to pick up the samples they wanted to return.
The best evidence that lunar dust creates no long-term problems comes
from the performance of the Laser Ranging Retroreflectors (LRRR), which
were deployed by Apollo astronauts at four different sites. These
passive arrays of glass cubes are used as mirrors to reflect laser
pulses sent from Earth in order to precisely measure the Earth-Moon
distance. After over 30 years of continuous use and exposure to the
lunar dust environment, they show no degradation of photon return
whatsoever.
(3) We already know the Moon possesses the resources needed to create
a space-faring transportation infrastructure in cislunar (Earth-Moon)
space.
The return of the Apollo lunar samples taught us the fundamental
chemical make-up of the Moon. The Moon is a very dry, chemically
reduced object, rich in refractory elements but poor in volatile
elements. The composition of the Moon is rather ordinary, made up of
common Earth minerals such as plagioclase (an aluminum, calcium
silicate), pyroxene (a magnesium, iron silicate), and ilmenite (an
iron-titanium oxide). The Moon is approximately 40 percent oxygen by
weight. Light elements, including hydrogen and carbon, are present, but
in small amounts--in a typical lunar mare soil, hydrogen makes up
between 50 and 90 parts per million by weight. Soils richer in titanium
appear to be also richer in hydrogen, thus allowing us to infer the
extent of hydrogen abundance from the global titanium concentration
maps returned by both the Clementine and Lunar Prospector missions.
As usable commodities, lunar materials offer many possibilities.
Because radiation is a serious problem for human space flight beyond
low-Earth orbit, the simple expedient of covering surface habitats with
soil can protect future lunar inhabitants from both galactic cosmic
rays and even solar flares. Lunar soil can be sintered by microwave
into very strong building materials, including bricks and anhydrous
glasses that have strengths many times that of steel. When we return to
the Moon, we will have no shortage of useful building materials.
Because of its high abundance in lunar materials, oxygen production
is likely to be an important early lunar product. The production of
oxygen from lunar materials is not magical, but simply involves
breaking the very tight chemical bonds between oxygen and various
metals in lunar minerals. Many different techniques to accomplish this
task have been developed; all are based on common industrial processes
easily adapted to use on the Moon. Besides human life support, the most
important use of oxygen in its liquefied form is to make rocket fuel
oxidizer. Coupled with the extraction of solar wind hydrogen from the
soil, this processing can make rocket fuel the most important commodity
of a new lunar economy.
The Moon has no atmosphere or global magnetic field, so the solar
wind, the tenuous stream of gases emitted by the Sun (mostly hydrogen),
are directly implanted onto the dust grains of the Moon. Although this
solar wind hydrogen is present over most of the Moon in very small
quantities, it too can be extracted from soil. Soil heated to about
700+C releases more than 90 percent of its adsorbed solar
wind gases. Such heat can be obtained from collecting and concentrating
solar energy using focusing mirrors on the lunar surface, a readily
available form of energy on the Moon. Collected by robotic processing
rovers, solar wind hydrogen can be harvested from virtually any
location. Additionally, recent discoveries by space probes of the
1990's suggest that special areas exist where this material is present
in much greater abundance, making its collection and use much easier.
(4) Hydrogen, probably in the form of water ice, exists at the poles
of the Moon in quantity and can be extracted and processed into rocket
propellant and life-support consumables.
The joint DOD-NASA Clementine mission was flown in 1994. Designed
to test sensors developed for the Strategic Defense Initiative (SDI),
Clementine was an amazing success story. This small spacecraft was
designed, built, and flown within the short time span of 24 months for
a total cost of about $150 M (FY 2003 dollars), including the launch
vehicle. Clementine made global maps of the mineral and elemental
content of the Moon, mapped the shape and topography of its surface
with laser altimetry, and gave us our first good look at the intriguing
and unique polar regions of the Moon. Clementine did not carry
instruments specifically designed to look for lunar water, but
encouraged by an interesting result from Arecibo radar data that
suggested interesting deposits near the Moon's south pole, an ingenious
improvisation used the spacecraft communications antenna to beam radio
waves into the polar regions; radio echoes were observed using the Deep
Space Network dishes. Results indicated that material with reflection
characteristics similar to ice are found in the permanently dark areas
near the south pole. This major discovery was subsequently confirmed in
1998 by a different experiment flown on NASA's Lunar Prospector
spacecraft.
The Moon contains no internal water; all water is added to it over
geological time by the impact of comets and water-bearing asteroids.
Dark areas near the poles are very cold, only a few tens of degrees
above absolute zero. Thus, any water that gets into these polar ``cold
traps'' cannot get out so over time, significant quantities accumulate.
Our current best estimate of the amount of water on the Moon comes from
two orbital measurements. The Clementine bistatic experiment indicates
that an area of about 135 km2 of pure ice exists within an
observed area of about 45,000 km2, corresponding to a
concentration level of about 0.3 percent. This radar estimate is
consistent with observations from Earth-based radio observatories,
including Arecibo and Goldstone, which show small, scattered areas of
high radar backscatter within the sun-dark regions of the lunar poles.
The Lunar Prospector neutron spectrometer found a concentration level
of about 1.5 percent water over an area approximately 12,000 km2
in extent. It should be noted that because of the observing geometry
between Earth and Moon, Clementine and Earth-based radar can only
examine about a quarter to a third of the total dark area of the lunar
south pole, whereas Lunar Prospector collected data from 100 percent of
the dark region. This difference in part may explain the discrepancy.
In all, we estimate that over 10 billion metric tons of water exist at
the lunar poles, an amount equal to the volume of Utah's Great Salt
Lake--without the salt! Lunar polar water has the advantage of already
being in a concentrated useful form, simplifying scenarios for lunar
return and habitation. Water from the lunar cold traps advances our
space-faring infrastructure by creating the first space ``filling
station'' on the solar system highway.
The poles of the Moon are useful from yet another resource
perspective--the areas of permanent darkness are in proximity to areas
of near-permanent sunlight. Because the Moon's axis of rotation is
nearly perpendicular to the plane of the ecliptic, the sun always
appears on or near the horizon at the poles. If you're in a hole, you
never see the Sun; if you're on a peak, you always see it. We have
identified several areas near both the north and south poles of the
Moon that offer near-constant sun illumination. Thus, an outpost or
establishment in these areas will have the advantage of being in
sunlight for the generation of electrical power (via solar cells) and
in a benign thermal environment (the sun is always at grazing
incidence); such a location never experiences the temperature extremes
(from 100+ to ^150+C) found on the lunar equator.
These properties make the poles of the Moon an inviting oasis in near-
Earth space.
(5) By allowing us to travel at will, with people, throughout the
Earth-Moon system, a return to the Moon to use lunar resources gives
the Nation a challenging mission and creates capability for the future.
Implementation of this objective for our national space program
would have the result of establishing a robust transportation
infrastructure, one capable of delivering people and machines
throughout cislunar space. Make no mistake--learning to use the
resources of the Moon or any other planetary object is a challenging
technical task. We must learn to use machines in remote, hostile
environments, working with ore bodies of small concentration under
difficult conditions. The unique polar environment of the Moon, with
its zones of near-permanent illumination and permanent darkness,
provides its own challenges. But for humanity to have a foothold beyond
low-Earth orbit, we must learn to use the materials available off-
planet. We are fortunate that the Moon offers a nearby, ``safe''
laboratory for our first steps in using space resources. Initial
blunders in mining tactics or feedstock processing are better practiced
three days from Earth than from Mars, located many months of space
travel away.
A mission learning to use these lunar resources is scalable in both
level of effort and the types of commodities to be produced. We begin
by using the resources that are the easiest to extract. Thus, a logical
first product is water derived from the lunar polar deposits. Water is
producible there regardless of the nature of the polar volatiles--ice
of cometary origin is easily collected and purified while molecular
hydrogen on lunar dust from the solar wind can be combined with oxygen
extracted from rocks and soil (through a variety of processes) to make
water. Water is easily stored for use as a life-sustaining substance
for people or broken down into its constituent hydrogen and oxygen for
use as rocket propellant.
Although we currently possess the minimal information to plan a
lunar return, investment in a few robotic precursor missions would be
greatly beneficial. We should map the polar deposits of the Moon from
orbit using imaging radar to determine the extent, purity, and
thickness of the ice in these dark regions. A camera and associated
instrument to make a high resolution global topographic map (e.g.,
radar or laser altimetry) is also needed on this orbital mission to
make high quality maps for future explorers and miners. The next step
will be to land small robotic probes to conduct chemical analyses of
the polar deposits and radio results to Earth. Although we expect water
ice to dominate the deposit, impact deposits from cometary cores are
made up of many different substances, including methane, ammonia, and
organic molecules, all potentially useful resources. We need to
inventory these species, determine their chemical and isotopic
properties, and their physical nature and environment. Just as the way
for Apollo was paved by such missions as Ranger and Surveyor, a set of
robotic precursor missions, conducted in parallel with the planning of
manned expeditions, can make subsequent human missions safer and more
productive.
After these robotic missions have documented the nature of the
deposits, focused engineering research efforts should be undertaken to
develop the techniques and machinery needed to be transported to the
lunar base as part of future human expeditions. There, the processes
and principles of resource extraction will be established and
validated, thus paving the way to automation and commercialization of
the mining, extraction and production of lunar hydrogen and oxygen.
(6) This new mission will create routine access to cislunar space for
people and machines, which directly relates to important national
economic and strategic goals.
By learning space survival skills close to home, we create new
opportunities for exploration, utilization, and wealth creation. Space
will no longer be a hostile place that we tentatively visit for short
periods; it becomes instead a permanent part of our world. Achieving
routine freedom of cislunar space makes America more secure (by
enabling larger, cheaper, and routinely maintainable assets in orbit)
and more prosperous (by opening an economically limitless new
frontier).
As a nation, we rely on a variety of government assets in cislunar
space, from weather satellites to GPS systems to a wide variety of
reconnaissance satellites. In addition, commercial spacecraft continue
to make up a multi-billion dollar market, providing telephone,
Internet, radio and video services. America has invested billions of
dollars in this infrastructure. Yet at the moment, we have no way to
service, repair, refurbish or protect any of these spacecraft. They are
vulnerable with no bulwark against severe damage or permanent loss. It
is an extraordinary investment in design and fabrication to make these
assets as reliable as possible. When we lose a satellite, it must be
replaced and this process takes years.
We cannot now access these spacecraft because it is not feasible to
maintain a human-tended servicing capability in Earth orbit--the costs
of launching orbital transfer vehicles and propellant would be
excessive (it costs around $10,000 to launch one pound to low-Earth
orbit). By creating the ability to refuel in orbit, using propellant
derived from the Moon, we would revolutionize our national space
infrastructure. Satellites would be repaired, rather than written off.
Assets would be protected rather than abandoned. Very large satellite
complexes could be built and serviced over long periods, creating new
capabilities and expanding bandwidth (the new commodity of the
information society) for a wide variety of purposes. And along the way,
we will create new opportunities and make ever greater discoveries.
Thus, a return to the Moon with the purpose of learning to mine and
use its resources creates a new paradigm for space operations. Space
becomes a part of America's industrial world, not an exotic environment
for arcane studies. Such a mission ties our space program to its
original roots in making us more secure and more prosperous. But it
also enables a broader series of scientific and exploratory
opportunities. If we can create a space-faring infrastructure that can
routinely access cislunar space, we have a system that can take us to
the planets.
(7) Timing is everything: It is important for America to undertake
this mission NOW, rather than later.
Many nations have recently indicated an interest in the Moon. The
possible collection and use of lunar resources raises some interesting
political and economic issues. Currently, the 1967 United Nations
Treaty on the Peaceful Uses of Outer Space prohibits claims of national
sovereignty on the Moon or any other object. However, it is not clear
that private claims are likewise prohibited under this treaty. The 1984
United Nations Moon treaty specifically prohibits private ownership of
lunar assets, but the United States, Russia, and China are not
signatories to that treaty, ratification of which was specifically
rejected by the United States Senate.
Our initial return to the Moon would be an engineering and
scientific research and development project. We undertake our studies
of the extraction of lunar resources to ascertain the best methods to
harvest and use these materials. Our presence on the Moon does not give
us title to it. However, a strong and continuing American presence on
the Moon can help establish de facto the broad legal framework and
economic paradigm of democratic, free-market capitalism off the Earth.
It is not clear that other nations would be similarly inclined. In
short, regardless of impressions, we are indeed in a race to the Moon--
not a race comparable to the 1960's Cold War race to the Moon between
America and the Soviet Union, but a race no less important in
establishing future socio-economic stability. History has shown that
our economic-political system produces the most wealth and freedom and
highest quality of life for the most people in the shortest time.
America needs to continue to lead in space, ensuring an open economic
and self-determining, democratic framework is established off-Earth.
(8) The infrastructure created by a return to the Moon will allow us
to travel to the planets in the future more safely and cost
effectively.
This benefit comes in two forms. First, developing and using lunar
resources can enable movement throughout the Solar System by permitting
the fueling of interplanetary craft with materiel already in orbit,
thereby saving the enormous costs of launch from Earth's surface.
Second, the processes and procedures that we learn on the Moon will be
applied to all future space operations. To successfully mine the Moon,
we must learn how to use machines and people in tandem, each taking
advantage of the other's strengths. The issue isn't ``people or
robots?'' in space, it's ``how can we best use the combination of
people and robots in space?'' People bring the unique abilities of
cognition and experience to exploration and discovery; robots possess
extraordinary stamina, strength, and sensory abilities. We can learn on
the Moon how to best combine these two complementary skill mixes to
maximize our exploratory and exploitation abilities.
A return to the Moon will give us operational experience on another
world. Activities on the Moon will make future planetary missions less
risky as we gain valuable experience in an environment close to Earth,
yet on a distinct and unique alien world. Systems and procedures can be
tested, vetted, revised and re-checked. By learning to live and work on
the Moon, we gain both experience and confidence in planetary
exploration and surface operations.
The Moon provides a nearby laboratory and industrial test-bed where
we can hone our exploratory skills and lay the foundations for a future
space-based economy. Human expansion to the Moon will provide new
opportunities and horizons for the American entrepreneur, our
businesses, and our workforce. Developing new technologies has always
led to new markets and increased our general prosperity. Expansion of
the economy is vital to our national health and security. Who will
capitalize on this opportunity and become the next Rockefeller,
Carnegie, Ford, Getty, or Gates?
America needs a challenging, vigorous space program. It must
present a mission that inspires, educates, and enriches. It must relate
to important national needs yet push the boundaries of the possible. It
must serve larger national concerns beyond scientific endeavors. The
President's program fulfills these goals. It is a technical challenge
to the Nation. It creates security for America by assuring access and
control of our assets in cislunar space. It creates wealth and new
markets by producing commodities of great commercial value. It
stimulates and inspires the next generation by example. A return to the
Moon is a giant step into the Solar System.
Thank you for your attention.
Biography for Paul D. Spudis
PAUL D. SPUDIS is a Senior Staff Scientist at the Johns Hopkins
University Applied Physics Laboratory in Laurel, Maryland and Visiting
Scientist at the Lunar and Planetary Institute in Houston, Texas. He
was formerly with the Branch of Astrogeology, U.S. Geological Survey in
Flagstaff, Arizona and the Lunar and Planetary Institute. He is a
geologist who received his education at Arizona State University (B.S.,
1976; Ph.D., 1982) and at Brown University (Sc.M., 1977). Since 1982,
he has been a Principal Investigator in the Planetary Geology and
Geophysics Program of the NASA Office of Space Science, Solar System
Exploration Division, specializing in research on the processes of
impact and volcanism on the planets. He has served on NASA's Lunar and
Planetary Sample Team (LAPST), which advises allocations of lunar
samples for scientific research, the Lunar Exploration Science Working
Group (LEXSWG), that devised scientific strategies of lunar
exploration, and the Planetary Geology Working Group, which monitors
overall directions in the planetary research community. He has also
been a member of the Committee for Planetary and Lunar Exploration
(COMPLEX), an advisory committee of the National Academy of Sciences,
and the Synthesis Group, a White House panel that in 1990-1991,
analyzed a return to the Moon to establish a base and the first human
mission to Mars. He was Deputy Leader of the Science Team for the
Department of Defense Clementine mission to the Moon in 1994. He is a
member of the President's Commission on the Implementation of U.S.
Space Exploration Policy, whose report is due in June of 2004. He is
the author or co-author of over 150 scientific papers and three books,
including The Once and Future Moon, a book for the general public in
the Smithsonian Library of the Solar System series, and The Clementine
Atlas of the Moon, published in 2004 by Cambridge University Press.
Chairman Rohrabacher. Thank you very much. Our next witness
is Dr. Daniel Lester, who is a research scientist at McDonald
Observatory, University of Texas at Austin. Dr. Lester, you may
proceed.
STATEMENT OF DR. DANIEL F. LESTER, RESEARCH SCIENTIST, MCDONALD
OBSERVATORY, UNIVERSITY OF TEXAS, AUSTIN
Dr. Lester. Thank you. Mr. Chairman, Members of the
Committee, I want to thank you also very much for inviting me
to testify before you today. I am an astronomer at McDonald
Observatory, University of Texas, and I am going to use my five
minutes to talk a little about telescopes in space and on the
Moon in particular.
I want to start out by saying that space--the vacuum of
space--is a tremendously enabling place for astronomical
telescopes. We do very well with telescopes on the Earth, but
those telescopes on the Earth, which are much easier to build
and cheaper to build than telescopes in space, look through the
Earth's atmosphere, and the Earth's atmosphere blocks a lot of
the light that we would like to be able to see from the stars
and galaxies beyond.
So the question becomes where do we put telescopes in
space? Do we put them in orbit around the Earth? Do we put them
in orbit around the Sun? Or, perhaps, do we put them down on
the surface of a body that doesn't have any atmosphere, like
the Moon? What we have to ask ourselves at this point is what
the Moon offers to us.
Now, I want to backtrack just a moment and say that 20 or
30 years ago, my community, the astronomical community, was
very excited about the idea of putting telescopes on the Moon.
I, too, invested a lot of effort in going in that direction.
Now, you have to understand that at that time, 20 or 30 years
ago, we had virtually no high-capability free-flying telescopes
in space, and we had people walking around on the Moon. So at
that time, it seemed like a very credible thing to do. We are
going to have people walking around the Moon, thanks to the new
initiative, but we now have a tremendous amount of experience
in making observatories in free space, much like the Hubble
Space Telescope, work very well. A long time ago, we were
worried about whether we could point telescopes in free space--
telescopes floating around. How would we be able to keep them
to track on the stars we were looking at? We now understand how
to do that extremely well using what is now off-the-shelf
technology.
So one can ask what does the Moon have that free space
doesn't? And the way I and my colleagues look at it is that the
Moon has dirt and the Moon has gravity. And so the question
becomes are dirt and gravity enabling to astronomy, and my
contention is that they are not for the following reasons.
Dirt, while we will hear about the use of dirt for lunar
resources, and I think that is a wonderful thing to think
about, astronomers tend to look at dirt as a pollutant for our
telescopes. Dirt that gets on our telescopes, gets on the
optics, prevents the light from getting through them, and
actually, for infrared telescopes which I use a lot of, adds to
the background enormously, reducing the sensitivity. That dirt
has strongly abrasive properties. That dirt will get in gears.
It will get in bearings. And will make maintenance of
telescopes quite challenging on the Moon compared to free
space.
Now, gravity is no friend of telescopes. Gravity--of
course, the Earth has plenty of gravity and we have telescopes
on the Earth and we manage to avoid having problems with
gravity. Of course, the problems that we have are where a
telescope looks in this part of the sky, gravity is pulling
down on it. When the telescope then goes over and looks in this
part of the sky, gravity is pulling down in a different way.
Gravity bends the telescopes. It doesn't bend it very much, but
it doesn't take very much to get the telescopes out of
alignment.
Now, our approach to that for ground-based observatories is
very simple. We make them very stiff and very strong and very
massive. We throw a lot of steel at them. That is not a good
strategy for deciding what to do with telescopes in space. Now,
it is true that the lunar gravity is only 1/6 of the Earth, but
nevertheless--and so it in principle is easier to make
telescopes that will work well on the Moon compared to making
telescopes that will work well on the Earth. But free space has
no gravity at all, and so the kinds of structural complexity
that we need to hold together a telescope in alignment in free
space is very much lower.
Finally, gravity is a risk. When we are sending equipment
to the Moon from the Earth, it has to survive. It has to
survive the soft landing. The retrorockets have to work.
Parachutes don't work. And so we look at that as a risk factor
that we don't have for telescopes in free space.
Now, in conclusion, I would just say that one of the big
advantages that one can look at by having telescopes on the
Moon is that there will be people there. I want to make it very
clear to the Committee that myself and many of my colleagues
look ahead to the new initiative involving humans and
astronauts in astronomical activities is profoundly highly
enabling. We are very excited about that. We are looking
forward to looking into that.
For example, the very biggest telescopes that we hope to
make--telescopes far bigger than Hubble Space Telescope--these
telescopes are too big to be put into a rocket already
unfolded. If I want to build a ten-meter telescope and I only
have a five-meter rocket shroud, I have got a big problem,
unless that telescope is folded up. We fold the telescope up,
we shoot it up, and then we cross our fingers, and the hinges
and motors, then they get deployed, have to work. If they don't
work, we are in trouble. Now, in a situation like this, having
an astronaut there with a screwdriver in one hand and a wrench
in the other hand and the ability to give something a pull
where it needs to be pulled, can be fantastically enabling for
us, so we are really looking forward to that.
I would just like to say in summary that we would very much
hope that the technologies that we develop to put people back
on the Moon, and to the experience that we gain in doing that,
can be used to optimally service and aide astronomy in free
space. Thank you.
[The prepared statement of Dr. Lester follows:]
Prepared Statement of Daniel F. Lester
Mr. Chairman and Members of the Committee, thank you for this
opportunity to appear and give testimony concerning future options for
using the Moon to do science. As a member of the space astronomy
community, I have been asked to express current thinking about the
advantages and disadvantages of the Moon for doing astronomy and, in
particular, whether the Moon is an appropriate site for astronomical
telescopes. The importance of space telescopes both to fundamental
science and to the excitement that the public has about our national
efforts in space, combined with the key role that the Moon plays in the
President's new space initiative, give special importance to this
issue. In summary, and upon careful recent review of lunar observatory
concepts that have been presented over the years, my colleagues and I
find that the opportunities for lunar-based astronomy offer much less
value, compared to observatories in free space, than had been
anticipated several decades ago. While the lunar surface is not a
highly enabling site for an astronomical observatory, development of
the Moon would need many technologies that would substantially advance
telescopes in free space.
Space Astronomy as a National Priority
I want to begin this testimony by reviewing the reasons that we do
astronomy--answering some of the most far-reaching and exciting
scientific questions that challenge our nation. While studies of our
own solar system are increasingly dominated by actual visits by robotic
craft, and soon humans, studies of the universe beyond depend entirely
on telescopes that detect energy coming from it. While our solar system
provides us with clues about the formation of our Earth and the way
that life formed upon it, the universe beyond offers insights into
extremes of the physical world that are impossible to replicate in our
laboratories. We seek to understand the structure and evolution of the
cosmos on both the largest scales, reaching back to its earliest times,
and on the smallest scales, in the vicinity of black holes. We want to
learn how galaxies, stars, and planetary systems form and evolve, their
cycles of matter and energy, and understand the diversity of worlds
beyond our own. We want to search those worlds for those that might
harbor life. Such explorations provide us with not just intellectual
satisfaction and national pride in scientific accomplishment, but with
new understanding that is the foundation for future technologies. By
looking at our universe far away, we better understand the physical
world nearby.
Space as an Enabling Site for Astronomical Telescopes
But why do we go into space to do it? Large telescopes are
ubiquitous on terrestrial mountaintops, and with roads, power lines,
and air to breathe such telescopes are much easier to build and operate
than those in space. For several different reasons, it is the vacuum of
space that is extraordinarily enabling for astronomy. The atmosphere of
the Earth, while essential for life here, distorts and blocks much of
the light that comes from the cosmos. That our atmosphere effectively
blocks gamma rays, x-rays, and ultraviolet light is critical to our
survival, but makes direct studies of black holes and supernovae
difficult. That our atmosphere contains water vapor that blocks most
infrared light makes studies of star and planet formation especially
challenging, though such water is crucial to our existence. In the
vacuum of space there is no such impediment. The sky from space is
profoundly clear, and this clarity has been utilized by the Compton and
Chandra observatories to explore the universe at high energies, the
recent Spitzer observatory in the infrared, as well as the Hubble
telescope for visible light. For infrared telescopes in particular, in
which cryogenic operation offers a dramatic increase in sensitivity,
such operation is impossible in the presence of an atmosphere, which
would freeze out on a cold telescope. So the vacuum of space offers
important thermal advantages.
Astronomical Observatories and the Lunar Surface
Some forty years ago, the Moon was first proposed by astronomers as
a prime site for large telescopes. The lack of an atmosphere offered an
unobscured view of the cosmos, and the lunar surface offered a
``platform'' on which to anchor big structures. At this time, the
concept for observatory operation was strongly human-intensive, modeled
on the operations plan for ground-based telescopes of the era. Humans
would be needed, it was thought, not just to handle the (now obsolete)
photographic plates that were the sensor-of-choice in that era, but to
look through an eyepiece to point and guide the telescope! With a
facility firmly anchored to the lunar surface, astronauts could inhabit
the observatory and go about their jobs without jiggling the telescope.
One or two decades later, with astronauts actually walking and doing
science on the Moon, this idea of lunar telescopes gained credibility
in the science community. Then, and to this day, astronomical
telescopes on the Moon were understood to offer vastly greater
capabilities than they would on the surface of the Earth. If the
surface of the Moon and the surface of the Earth were the only places
able to host large astronomical telescopes, and if cost were not an
object, the Moon would win handily in science potential.
Within the last two decades, however, there has been a revolution
in our capabilities to autonomously deploy, stabilize, and point
satellites in the vacuum of free space. This understanding was gained
from both military and commercial (Earth resources) surveillance
investments, as well as from the communication satellite industry.
Telescopes in free space now track with a precision that is far higher
than can telescopes on the ground. Even for arrays of widely separated
telescopes that are optically coupled, and offer big advantages in
image clarity, implementation strategies have been designed for free
space that offer low risk. Finally, information is now returned
electronically, rather than on material media, such as photographic
plates. While human involvement has been in at least most contemporary
cases unnecessary for startup, the Hubble telescope proved that
astronaut roles in mission assurance and servicing could be highly
enabling for astronomy. Our space program, as well as that of other
countries, has achieved huge successes in astronomy from telescopes in
free space.
Dirt and Gravity are No Friends to Telescopes
In comparison to zero-g sites in free space the Moon, as a
telescope platform, offers mainly dirt and gravity. While dirt has been
viewed by some as providing harvestable resources, it also translates
into serious performance liabilities. Surface dust kicked up by both
meteorites and activity near the telescope (whether blast waves from
rockets or footsteps of astronauts) will degrade optical surfaces. This
will result in a reduction of sensitivity and a sharp increase in
background light that suppresses the faintest infrared light from
distant stars and extra-solar planets. It also dramatically enhances
scattered light that will interfere with studies of solar systems in
the vicinity of bright stars. This dust, the deleterious properties of
which are well understood from Apollo efforts, can be assumed to
increase wear and reduce performance of loaded mechanical bearings, on
which such lunar telescopes would critically depend for precision
motions.
Compared to the weightless environment of free space, even the 1/6g
of the Moon will threaten the precise optical alignment of telescopes
as they move across the sky. In order to achieve the stiffness needed
to avoid such gravity deformations, a lunar telescope will have to be
much more massive, and concomitantly more expensive, than a similar
telescope in free space. Consider, for example, that the six meter
diameter James Webb Space Telescope (JWST), now being designed for free
space, will have a mass of about six metric tons. Similar sized
telescopes on Earth each have about three hundred metric tons of
material that has to move, almost an order of magnitude larger than
JWST when scaled to the lowered lunar gravity. Finally, gravity is
something that lunar surface telescope builders would need to fight.
All parts and subsystems brought from the Earth must survive soft
landing on the Moon, a requirement that involves considerable added
expense and risk. In short, we should ask whether dirt and gravity
offer any general value to astronomy. The answer, I believe, is no.
Concepts for lunar telescopes have been proposed that take
advantage of special properties of the Moon. The orbit of the Moon is
such that telescopes within craters at the lunar pole would never have
sunlight shining on them. These telescopes would naturally be extremely
cold, perhaps 40-50K, and in this respect could offer excellent
infrared performance without expendable cryogens or costly
refrigeration. While noteworthy, this property of the Moon is no longer
particularly enabling, as such temperatures are achievable in free
space, using lightweight reflective shields to block the sunlight. The
Spitzer Space Telescope is at least partly passively cooled using such
sun shields, and the thermal performance actually realized for that
observatory is identical to engineering predictions. JWST will use
shields with more layers, and these models predict achievable telescope
temperatures of 35K. We can do even better. The Single Aperture Far
Infrared telescope (SAFIR) is a cold telescope facility even larger
than JWST, roadmapped as a Vision Mission candidate for the next
decade. I am the Principal Investigator on a concept study for SAFIR.
Our team believes that with lessons learned from JWST, and optimized
shielding, even lower temperatures can be realized passively. The lunar
poles are indeed very cold places but with sunlight properly screened,
free space is as well.
The far side of the Moon is also claimed to be scientifically
noteworthy as a radio-quiet site. On this hemisphere of the Moon there
is never a line-of-sight to the Earth, so the strong human radio
traffic and natural radio emission from our planet cannot interfere
with astronomical observations there. While this is potentially
enabling, the scientific need for such a radio quiet site has never
been entirely persuasive. The potential of this site was discussed, but
never included explicitly, in the Decadal Study of astronomical
priorities by the National Academy of Science. Recent significant
developments in strategies for radio frequency noise mitigation may
also pertain to this.
It's Not Humans versus Robots
A final advantage that has been ascribed to the Moon for space
astronomy is that it is where people will be. I believe I speak for my
community in saying that the involvement of astronauts in space
astronomy has enormous potential. We look ahead even in the near-term
to telescopes that do not fit, fully deployed, into launcher shrouds
(c.f. JWST). Such telescopes need to be packed, unfolded, locked tight,
aligned, and verified, all carrying significant risk if done
autonomously. The advantages of in situ astronauts holding screwdrivers
and wrenches who are there to deploy and assemble large space
telescopes, and rescue these expensive assets in the event of a
technical failure (c.f. HST) cannot be dismissed. But if astronauts are
going to be based on the Moon, and if we believe they will visit Mars,
we will certainly have the capability to put these astronauts to use in
free space to advance astronomy, whether in low-Earth orbit as for HST,
or farther out. For example, the semi-stable Earth-Moon and Earth-Sun
Lagrange (or libration) points in free space are understood to offer
huge advantages to astronomy, and current plans call for a whole
squadron of science missions at the latter site within the next two
decades. No credible discussion of space astronomy can be had without
considering the impressive science potential of these Lagrange points
in the Earth-Moon system. As a result, it would be truly unfortunate if
astronaut involvement in the future of space science was limited to
opportunities with dirt underfoot.
The new space initiative is a bold vision that promises rich
payoffs, and gives our nation a defining challenge. National leadership
to accrue from this vision and the sustainability with which is it
pursued will depend upon careful consideration and strategic pursuit of
science opportunities. Such opportunities are founded in curiosity and
the spirit of exploration, which are historically established parts of
our national heritage and very much key national needs. The Moon offers
many such opportunities, but for space astronomy the real value of
lunar development will come from how well such development serves
observatories elsewhere.
Biography for Daniel F. Lester
Daniel F. Lester is a Research Scientist at the McDonald
Observatory of the University of Texas. His research specialty is
infrared studies of star formation in galaxies. His is the author of
more than eighty refereed papers in professional journals. Dr. Lester
earned his Ph.D. at the University of California at Santa Cruz with the
Lick Observatory, followed by postdoctoral work at the NASA Ames
Research Center, and as a staff scientist at the University of Hawaii
Institute for Astronomy. He worked closely on the conceptual
development of the Stratospheric Observatory for Infrared Astronomy
(SOFIA), and has been active in community strategic planning and policy
development for space astronomy. Dr. Lester is currently Principal
Investigator and team leader for the Single Aperture Far Infrared
(SAFIR) vision mission study, now being funded by NASA. He is active in
K-12 science education and public outreach efforts.
Chairman Rohrabacher. Thank you very much for your
testimony. Our next witness is Dr. Donald Campbell, who is a
professor of astronomy and Associate Director of the National
Astronomy and Ionosphere Center at Cornell University. Dr.
Campbell, you may proceed.
STATEMENT OF DR. DONALD B. CAMPBELL, PROFESSOR OF ASTRONOMY,
ASSOCIATE DIRECTOR, NATIONAL ASTRONOMY AND IONOSPHERE CENTER
(NAIC), CORNELL UNIVERSITY
Dr. Campbell. Thank you, Mr. Chairman, Members of the
Committee, and thank you for inviting me to testify on the
subject of lunar science and resources. I have been
specifically asked to address the issue of the possible
presence of water on the surface of the Moon and how we should
proceed in determining whether it is or is not present in
recoverable quantities.
There is no doubt that accessible, significant, and
recoverable deposits of water on the Moon would greatly
facilitate the setting up of a lunar base. The lunar surface is
rich in a variety of minerals, such as iron, titanium oxides,
and these minerals could provide resources such as oxygen to
sustain an extended human presence on the Moon. However,
recoverable amounts of one vital commodity, hydrogen, needed to
produce water and possibly rocket fuel, are in short supply on
the lunar soil. For this reason, the idea that the lunar polar
regions may have water ice, which was so suggested 40 years
ago, continues to be of great interest.
There are two remote sensing techniques currently used to
look for water: radar and neutron spectrometry. Radar is
sensitive to thick deposits of relatively pure water ice. This
was demonstrated by the discovery by Alpha Earth-based radars
of water ice deposits in the very cold bottoms of permanently
shaded impact craters at the poles of Mercury. Neutron
spectrometers are sensitive to the presence of hydrogen, which
may or may not be incorporated in water molecules. The power of
this technique was dramatically demonstrated with the recent
discovery of large quantities of ground ice on Mars.
Suggestions from radar observations from the Clementine
Orbiter in 1994, that there are thick ice deposits in one
crater at the lunar South pole, were not confirmed by radar
observations using the National Science Foundation's Arecibo
telescope. As you can gather that Dr. Spudis have some
disagreement in terms of the interpretation of those--the
Clementine data and the Arecibo radar data. However, it is
important to understand that both these radars had a very poor
view of the polar region. They had almost identical views of
the polar regions, and looking from a very low angle in the
sky--they are only about six degrees above the horizon, so
there were large areas of the lunar surface which they could
not, in fact, view very adequately, the shadow effect away from
the radar.
The neutron spectrometer--yeah, I don't know--I should say
that this result does not in anyway preclude, because of the
poor visibility, the possibility there may be thick deposits of
ice, although it makes it somewhat unlikely. The neutron
spectrometer on the 1998 Lunar Prospector Orbiter had a clear
view of all of the surface in the polar regions. As reported by
Dr. William Feldman, the principle investigator for the
instrument, and his colleagues--and I should emphasize that I
was not involved in this particular work--there is a general
increase of a factor of about three in the hydrogen
concentration in the upper three feet of the lunar soil in the
polar regions, compared with the equatorial regions. They also
found much higher hydrogen concentrations associated with
several large, permanently-shaded impact craters at the south
pole. At the north pole, the shaded craters are smaller than
the 30-mile best resolution of the neutron spectrometer. It was
not possible to look at individual craters, but there was an
increased hydrogen content associated with groups of small
shaded craters. The hydrogen may be in the form of free
hydrogen implanted into the lunar soil surface by the solar
wind, water in the form of ice, or hydrated minerals in which
water molecules are chemically bound to the minerals.
If all the excess hydrogen in the polar regions is in the
form of water, it would correspond to about two billion tons.
That sounds like a lot, but you have got to understand that the
concentration in the lunar surface would be extremely small,
and it would be so low, it is probably not feasible to recover
it. Of a lot more interest are the high hydrogen concentrations
coincident with the large impact craters of the south poles.
The bottom of these craters are in permanent shadows and are
very cold, acting as traps for hydrogen or water molecules. If
it is in the form of water ice, the enhanced hydrogen
concentration of these craters would correspond to about 1.5
percent water ice, getting up to be a significant concentration
of potentially--would be recoverable amounts of water without
too much effort. It is probably in the form of grains or
crystals mixed into the upper few feet of the lunar soil. The
radar experiments on the Clementine orbiter, or from Arecibo,
would not have been sensitive to that form of water ice, small
crystals and grains mixed into the soil.
Given the size of these craters, this concentration of
water ice corresponds to about 200 million tons of water, a
significant amount if it can be recovered. However, one has to
keep in mind that the craters are deep, very cold, and dark,
and so devising a recovery method will not be easy.
Because of its importance as a resource, we need to settle
the question as to whether there is any accessible and usable
quantities of water at the poles. To do so, a lunar polar
orbiter should be equipped with a suitable set of instruments.
And, as you already heard, you know, those instruments should
include a high resolution advanced neutron spectrometer. It is
my understanding that a 3-mile surface resolution is feasible,
about 10 times better than the 30-mile resolution of the Lunar
Prospector orbiter. That would allow mapping of the hydrogen
concentration of relatively small scales, and looking into much
smaller craters to see if there are concentrations of water
there that may be more accessible than in the big craters.
A mapping synthetic aperture radar system to search for
thick ice deposits possibly buried under the lunar soil. The
SAR would also allow detailed images to be obtained of the
areas at the lunar poles that are in permanent shadow. These
cannot be imaged with normal cameras.
We also need an instrument to measure the altitudes of the
polar terrains, including the depths and wall slopes of the
craters that may harbor ice deposits. This could be an
interferometric SAR as an expansion of the radar SAR system
mentioned in item 2, or it could be a LASER altimeter system.
We would like to know the temperatures at the bottom of
these craters, and so there should be an infrared system for
measuring temperatures in the interior of the craters with
shadowed bottoms.
There should obviously be a high-resolution camera for
investigating suitability of possible landing sites, and for
the part of the route illuminated by the Sun, the ease or
difficulty of access to possible water ice deposits.
And finally, if there is some evidence for water ice
deposits in the shadowed craters, clearly we want in situ
measurements, and probably the most simple way to do that is
to, initially at least, is put penetrators into the surface to
directly examine the composition of the surface itself.
Thank you very much.
[The prepared statement of Dr. Campbell follows:]
Prepared Statement of Donald B. Campbell
Mr. Chairman and Members of the Committee, thank you for inviting
me here today to testify on the subject of lunar resources.
The lunar surface is rich in a variety of minerals such as oxides
of iron and titanium and it is possible that these minerals can be
utilized to provide resources such as oxygen to sustain an extended
human presence on the Moon. Recoverable amounts of one vital commodity,
hydrogen, needed to produce water and possibly rocket fuel, appear to
be in short supply in the lunar soil. Consequently, the idea that the
polar regions of the Moon may harbor ice deposits, first suggested over
40 years ago, continues to be of great interest. In the early 1990s the
idea was given further impetus by the discovery of apparent ice
deposits in the cold, permanently shaded bottoms of impact crater at
the poles of the planet Mercury. The discovery and investigation of
these ice deposits were made using powerful radar systems on one of
NASA's Deep Space Network (DSN) Goldstone antennas and on the NSF's
Arecibo telescope (operated by Cornell University under a cooperative
agreement with the NSF) in Puerto Rico. Ice at low temperatures has
unusual radar reflection properties--it ``lights up'' under the radar
illumination very much like a highway sign at night and the reflected
radar signal has different polarization properties than for rock or
soil--but only if it is in the form of thick, relatively pure deposits.
As can be seen in radar image of the north polar region of Mercury made
at the NSF's Arecibo Observatory in Puerto Rico, the ice deposits stand
out very brightly on Mercury.
Figure: A radar image of the north pole of Mercury showing the bright
radar echoes from what are thought to be thick deposits of ice on the
shadowed floors of impact craters. The circles show the sizes and
locations of known impact craters from images taken in 1974 from the
Mariner 10 spacecraft. The ice stands out so brightly because it is a
good retro-reflector. The radar echoes from the surrounding terrain are
so weak that they cannot be seen. The image was made with the NSF's
Arecibo telescope (courtesy of J. Harmon).
Ice can also be identified by using a neutron spectrometer to map
the properties of cosmic ray produced neutrons that scatter in the top
few feet of a planetary surface with the nature of the scattering being
very sensitive to the presence of the nuclei of hydrogen atoms and,
hence, water ice if the hydrogen is incorporated in water molecules.
The ability of neutron spectrometers to detect the presence of water
ice was dramatically demonstrated by the recent discovery of
considerable ground ice deposits on Mars.
How much water may be trapped on the lunar surface?
Over the past decade there has been evidence from instruments on
lunar orbiting spacecraft suggestive of the presence of water ice in
the polar regions. Results from bi-static radar observations using the
Clementine orbiter--the radar signal was transmitted from the
spacecraft and the echo received by one of NASA's DSN antennas--were
interpreted as indicating the presence of thick deposits of ice in a
crater at the south pole. The interpretation of the Clementine results
has been debated in the scientific literature and, as can be seen from
the figure, imaging radar observations using the NSF's Arecibo
Observatory have not found any evidence for ice deposits on the Moon
similar to those seen at the poles of Mercury. However, since neither
the Clementine nor the Arecibo observations were able to view some or
all of the shaded bottoms of the impact craters at the lunar poles,
these observations cannot be regarded as definitive. While perhaps
unlikely, the possibility still exists that there are thick ice
deposits in the bottoms of some shaded impact craters at the lunar
poles.
Figure: Radar images of the poles of the Moon made with the NSF's
Arecibo telescope. Much of the area close to the poles themselves,
especially at the south pole, is in shadow from the Sun and cannot be
seen in optical images. The radar on the Earth is higher above the
horizon than the Sun so can ``see'' some of these shaded areas. There
are no bright radar echoes similar to those for Mercury indicating no
thick deposits of clean water ice. Only some of the shaded areas can be
seen with the radar and it is possible that ice may be present in
locations yet to be investigated. (Image courtesy of B. Campbell.)
Measurements from the Lunar Prospector orbiter are not open to this
level of uncertainty. Its neutron spectrometer looked directly down so
could view all of the polar terrain. As discussed above, this
instrument is sensitive to the presence of hydrogen atoms and it
discovered significant concentrations of hydrogen in the lunar polar
regions. Its best spatial resolution on the Moon's surface was about 30
miles. As reported by William Feldman of the Los Alamos National
Laboratory and colleagues, near the south pole there is a small general
increase in the hydrogen concentration compared with the equatorial
regions and there are significant concentrations associated with large
impact craters with shaded bottoms. In the north there is a similar
general increase in the average concentration of hydrogen. However,
most of the impact craters with shaded bottoms are small, so that the
hydrogen deposits cannot be uniquely associated with individual
shadowed craters and it is not possible to say whether there are areas
with significant concentrations. There are definitely higher
concentrations of hydrogen at the lunar poles compared with other areas
of the Moon but both its origin--cometary impacts or solar wind
implanted hydrogen--and its current form--hydrogen, ice or hydrated
minerals--is a topic of considerable discussion in the relevant
scientific community.
If all of the hydrogen at the lunar poles is in the form of ice,
then an analysis of the Lunar Prospector results by Dr. Feldman and
colleagues has shown that the total inventory of water ice in the upper
three feet or so would be about two billion tons. Considering just the
shaded areas at the south pole, where the only economically recoverable
deposits discovered so far seem to reside, they concluded that the
weight concentration of water ice in the upper three feet would be
about 1.5 percent. Taking our best estimates of the total shaded area
at the south pole, this translates into about two hundred million tons
of water equivalent. This water is likely distributed as ice grains or
crystals in the lunar soil and would not have been observable by either
the Clementine orbiter or Earth-based radars. Because of the poor
spatial resolution of the neutron spectrometer on the Lunar Prospector
orbiter, it is not possible to say from current data whether there are
small areas where there may be even higher concentrations of ice.
Is finding water important for exploiting the Moon for scientific or
economic purposes?
Accessible deposits of water on the Moon would profoundly affect
the economics and viability of a human presence on the Moon. Water is,
literally, the stuff of life. For a permanent or reusable base a local
supply would be invaluable both for human needs in the form of water
and oxygen, and for production of rocket fuel. A viable base would
enable both further exploration of the Moon and, as Dr. Spudis and
others have pointed out, has the potential to allow exploitation of
lunar resources.
However, the need is for accessible deposits. Unfortunately, the
only recoverable deposits are likely to be in the polar regions
probably in the bottoms of very cold, permanently dark craters. It is
likely, but not certain, that any deposits are well mixed into the
lunar soil at about the one percent level of concentration. Recovering
water from these deposits will not be an easy task.
Before we spend too much time making plans for exploiting water
resources on the Moon, we should determine whether there are any
recoverable deposits of water, in what form--distributed at low
concentrations in the lunar soil or in concentrated deposits--of what
type--ice or hydrated minerals--and how accessible. To do this we need
to send one or more missions with these specific objectives.
Instruments needed to resolve the water issue.
Detecting water ice in the cold, dark bottoms of impact craters in
the lunar polar regions is extremely difficult especially if the ice is
covered by, or imbedded in, the lunar soil. Two remote sensing
techniques that we have available, imaging radars and neutron
spectrometers, offer the best hope. If the ice is in the form of thick
sheets, then it is possible that a radar system on an orbiter would
detect the associated strong radar reflection properties even if the
ice lies beneath a surface covering of lunar soil. Depending on its
frequency of operation, a radar system could probe many feet into the
lunar surface to search for buried deposits. According to Dr. Feldman,
neutron spectrometers with about ten times the spatial resolution of
the instrument on the Lunar Prospector orbiter appear to be feasible
and would allow searches on about three mile or better scales for those
areas with the highest concentration of hydrogen. In situ searches
would be the most definitive but could only be made in a very small
number of locations. Such sampling could be achieved by using
instrumented penetrators or, ultimately, rovers to investigate the most
likely sites to harbor water based on results from previous searches
using a high resolution neutron spectrometer and imaging radar.
A possible suite of instruments on one or more lunar polar orbiters
would be:
1. A high resolution neutron spectrometer. Three mile surface
resolution appears to be possible, 10 times better than that of
the Lunar Prospector neutron spectrometer, allowing mapping of
the hydrogen concentration at this scale.
2. A mapping synthetic aperture radar system (SAR) to search
for thick ice deposits possibly buried under lunar soil. A SAR
would also allow detailed images to be obtained of the areas at
the lunar poles that are in permanent shadow and, hence, cannot
be imaged with normal cameras.
3. An instrument to measure the altitudes of the polar
terrains including the depths and wall slopes of the craters
that may harbor ice deposits. This could be an interferometric
SAR as an expansion of the SAR system of item 2, or a LASER
altimeter.
4. An infrared system for measuring the surface temperatures
over the polar regions and, especially, in the interiors of the
craters with shadowed bottoms.
5. A very high resolution camera for investigating the
suitability of possible landing sites and, for the part of the
route illuminated by the Sun, the ease or difficulty of access
to possible water ice deposits.
6. Suitably instrumented penetrators on a follow up mission to
investigate locations that the earlier measurements indicate
may harbor water in useful concentrations and directly
determine its presence and form.
What other useful minerals, ores or elements may be present in the
lunar soil?
Many useful materials are present in significant concentrations in
the minerals present in the lunar soil and rocks. Mare basalts have
high concentrations of oxygen, silicon, ion, magnesium, titanium and
the lunar highlands have significant amounts of aluminum and calcium.
The major issue is how to recover these materials or make use of the
minerals themselves using relatively simple automated processes
suitable for use on the lunar surface.
Thank you for your attention.
Biography for Donald B. Campbell
Education:
University of Sydney--BS (Physics); MS (Physics, Radio Astronomy)
Cornell University--Ph.D. (Astronomy and Space Sciences) 1971
Positions Held:
1993-Present-- Associate Director, National Astronomy and Ionosphere
Center, Cornell University
1992-1993-- Interim Director, National Astronomy and Ionosphere Center,
Cornell University
1988-Present-- Professor, Department of Astronomy, Cornell University
1983-1987-- Adjunct Professor, Department of Astronomy, Cornell
University
1981-1987-- Director of the Arecibo Observatory, National Astronomy and
Ionosphere Center, Cornell University
1976-1987-- Senior Research Associate, Cornell University (NAIC)
1974-1976-- Research Associate, Cornell University (NAIC)
1973-1974-- Staff Scientist, Haystack Observatory, MIT
1971-1973-- Research Associate, Cornell University (NAIC)
1966-1971-- Research Assistant and Graduate Student, Cornell University
Professional Societies:
International Astronomical Union
American Geophysical Union
American Astronomical Society and its Division of Planetary Sciences
International Union for Radio Science
American Association for the Advancement of Science
Honors:
1984-- NASA Medal for Exceptional Scientific Achievement
1992-- NASA Group Achievement Award
1994-- NASA Group Achievement Award
2003-- Fellow, American Association for the Advancement of Science
Professional Activities:
1984-1988-- Member of the Radar Investigation Group for the Venus Radar
Mapper Mission
1989-1994-- Co-Investigator, NASA's Magellan Mission Radar
Investigation Group
1992-1995-- Vice President, American Astronomical Society
1993-1996-- Advisory Committee, NASA-sponsored Venus Geologic Mapping
Project
1994-1996-- NASA's Planetary Geology & Geophysics Proposal Review Panel
1994-1997-- Nat'l. Academy of Sciences, U.S. Nat'l. Committee for the
Int'l. Astronomical Union
1995-1999-- Member of the Visiting Committee for the National Radio
Astronomy Observatory
1998-1999-- Chair, Visiting Committee for the National Radio Astronomy
Observatory
1999-2000-- Radio and National Centers Panels of the Astronomy and
Astrophysics Survey Committee's Decadal Review
2003-- Steering Committee for the Canadian SKA Project.
2003-- Member, Executive Management Board for NASA's Deep Space Mission
System
Some Relevant Publications:
Arecibo Radar Mapping of the Lunar Poles: A Search for Ice Deposits,
N.J.S. Stacy, D.B. Campbell, and P.G. Ford, Science, 276, 1527-
1530, [April 1997].
Surface Processes in the Venus Highlands: Results from Analysis of
Magellan and Arecibo Data, B.A. Campbell, D.B. Campbell, and
C.H. DeVries, JGR-Planets, 104(E1), 1897, 1999.
The Topography of Tycho Crater, J-L. Margot, D.B. Campbell, R.F.
Jurgens, and M.A. Slade, J. Geophys. Res., 104, 11,875, 1999.
The Topography of the Lunar Poles from Radar Interferometry: A Survey
of Cold Trap Locations, J-L. Margot, D.B. Campbell, R.F.
Jurgens, and M.A. Slade, Science, 284, 1658, 1999.
Digital Elevation Models of the Moon from Earth-based Radar
Interferometry, J-L. Margot, D.B. Campbell, R.F. Jurgens, and
M.A. Slade, IEEE Trans. on Geoscience & Remote Sensing, 38(2),
1122, 2000.
Icy Galilean Satellites: Modeling Radar Reflectivities as a Coherent
Backscatter Effect, G.J. Black, D.B. Campbell, and P.D.
Nicholson, Icarus, 151, 167-180 [June 2001]
Advances in Planetary Radar Astronomy, D.B. Campbell, R.S. Hudson, and
J.L. Margot, Review of Radio Science 1999-2002, W.R. Stone,
ed., John Wiley & Sons, publishers, Chapter 35, pp. 869-899,
[Aug. 2002]
Measurement in Radio Astronomy, D.B. Campbell, ASP Conference Series,
Proc. of the NAIC-NRAO School on Single-Dish Radio Astronomy:
Techniques and Applications, June 10-15, 2002, Arecibo, Puerto
Rico, Ed. S. Stanimirovic, D. Altschuler, P. Goldsmith and C.
Salter, Astron. Soc. Pacific Conf. Series Vol. 278, 2002.
Radar Evidence for Liquid Surfaces on Titan, D.B. Campbell, G.J. Black,
L.M. Carter and S.J. Ostro, 2003, Science, 302, 431-434, 17
Oct. 2003.
Long Wavelength Probing of the Lunar Poles, B.A. Campbell, D.B.
Campbell, J.F. Chandler, A.A. Hine, M.C. Nolan and P.J.
Perillat, 2003, Nature, 426, 137-138, 13 Nov. 2003.
Chairman Rohrabacher. Very well. There it is. Thank you
very much. Our next witness is Dr. John Lewis, Professor of
Planetary Sciences and Co-Director of the Space Engineering
Research Center at the University of Arizona. Mr. Lewis, you
may proceed.
STATEMENT OF DR. JOHN S. LEWIS, PROFESSOR OF PLANETARY
SCIENCES, CO-DIRECTOR, SPACE ENGINEERING RESEARCH CENTER,
UNIVERSITY OF ARIZONA
Dr. Lewis. Mr. Chairman, Members of the Committee, I will
assume that the remarks by the gentlemen to my right have said
have registered upon your consciousness and I need not repeat
many of the points that they have made, with which I agree. I
would like to cut to the chase and talk specifically about the
space resource value of the Moon, both locally and for external
use.
First of all, let us take the case of local use of lunar
resources on the Moon. The most elementary use is simply to
take lunar dirt and use it as radiation shielding for human
habitats on the surface of the Moon. The radiation environment
is very challenging in space, and indeed, it will be very
challenging on the way to Mars and back. On the surface of the
Moon, we have that unprocessed lunar dirt, ilmenite, available
as a radiation shielding.
We also have the various minerals that contain oxygen on
the surface of the Moon. I would say that it would be actually
quite feasible to design and build a device for extracting
oxygen-bearing minerals and extracting the oxygen from them in
an unmanned lander starting today. The technologies are well-
understood for many of these schemes. I would not pretend to
know which is the best scheme, but I would claim there are
approximately a dozen competing schemes, any one of which may
be made to serve under these circumstances. The extraction of
oxygen from the surface of the Moon would be principally useful
for making life-support materials and rocket propellant for
local mobility on the Moon.
Local mobility, you often think of rovers running around on
the surface of the Moon. I think in terms of devices that have
the ability to hop over obstacles. If you want to get around
anywhere besides on the Mauri bottoms of the Moon, you would
probably need to have that ability to take off and land. Being
able to manufacture rocket propellants in situ on the surface,
the Moon would be a great advantage for that kind of
functionality. Also, that oxygen's available for the return of
human beings and of samples to Earth, and plays a very
important role there.
The urgent scientific goals that Dr. Spudis talked about
concerning the history and evolution of the Moon contain many
issues that could be closely linked to the science we need to
know in order to design these processing and extraction
experiments. The science is urgent. There is much unfinished
scientific business on the Moon, and the best question I could
raise at this point is how can those resources assist in the
developing, understanding, and exploration of the Moon.
Mobility is very high on my list of reasons why local resource
utilization is valuable.
I should also point out that once you have the chemistry to
extract oxygen from minerals, such as ilmenite on the surface
of the Moon, they leave behind a residue that contains ultra-
high purity iron metal. Ultra-high purity iron metal is not
usually thought of as a first generation product, but the, so
to speak, slag from the oxygen extraction process, will contain
many percent by weight of ultra-pure iron, and that ultra-pure
iron has the unusual feature that it has the chemical
resistance, corrosion resistance, and strength of stainless
steel, so it is an ideal material for use in fabricating
anything from wires to habitats on the surface of the Moon.
Now I would like to address the issue of export of lunar
resources to Earth. Many of these resources have been
extensively mentioned, in very different contexts usually with
very little cross-reference. One of these is helium-3
extraction for uses of fusion fuel on Earth. There are a number
of issues involving that characterization of helium-3 that
Professor Swindle will be addressing in his remarks, and I will
tell you in advance, unless he has changed his testimony, I
have read and approve of the remarks that he will make on that
subject and will not duplicate them now.
There are many science issues involved in characterizing
that helium-3 occurrence and in extraction of it. I, frankly,
am quite skeptical whether it can be made to be economical, but
I don't know. We don't have the answers to those questions yet,
and many of those fundamental questions can be answered
relatively inexpensively by cleverly designed scientific
missions in the regions of the Moon that human beings are
likely to visit anyhow, in the Mauri basins of the nearest
sunlight.
Water from the polar deposits on the Moon--let me say that
I am far from convinced that this has any economic significance
whatsoever. Even if we had high concentrations--higher
concentrations of water ice than has been suggested by the
experiments to date, we would find ourselves in the very
difficult position of mining in total darkness at a temperature
less than 100 Kelvin, 100 degrees above Absolute Zero, in
virtually inaccessible places in crater bottoms near the poles.
If something goes wrong there, how do you fix it?
Will something go wrong there? One: mining permafrost under
any circumstances, even here on Earth, is extremely demanding.
The Army Cold Regions Research Engineering Laboratory has books
and books on what you do with permafrost, and piece of advice
number one is if it is there, leave it alone. Mining permafrost
is extremely difficult. We are talking here about a mixture of
abrasive glass particles frozen in a frozen ice matrix that is
so cold that it has the strength of granite or of steel. Mining
that stuff is not easy. Second, the mining equipment we will be
bringing from Earth is made of metal, and metals at 100 Kelvin
tend to be as brittle as glass. So I find this to be an
extremely daunting series of technological issues, and I am far
from willing to endorse the economic potential of lunar polar
ice at this time. On the other hand, I have learned--I think I
learned in kindergarten--that there are things I don't know,
and when new information comes along, I may be willing to
change my mind. Let us go after that critical information. Let
us characterize those deposits. The scientific value of knowing
what is in those lunar polar ice deposits--I say ice here as an
assumption. I think it is probably mostly water ice, but I
can't prove it. The other materials in there are tracers of the
common asteroid bombardment history of the Moon, and may have
considerable scientific interest in their own right.
The third item for import from the Moon is solar power.
This has been discussed by Professor David Criswell of the
University of Houston. He proposes manufacturing solar cells on
the surface of the Moon and beaming electric power from those
solar cells down to Earth. The up-front investment for this is
gigantic and daunting, but it appears that once the system is
installed, it might be economically feasible. And indeed, the
chemical processes needed to manufacture those solar cells on
the Moon seem plausible from present knowledge, and I would
strongly recommend that the Committee think in terms of looking
further at that technology.
The broader significance and utility of lunar resources and
solar system exploration, I would boil down to a three-point
argument here, sort of starting with a left jab. The Moon is
not halfway to Mars. The Moon is not even on the road to Mars.
If we imagine the Dutch sitting around in the 17th Century
trying to decide whether to trade in the East Indies or the
West Indies, they did not decide to go to New Amsterdam and set
up a base for trading with Indonesia. They decided to go to
both places. And I sincerely hope that in the wisdom of this
committee, they will understand that both of these goals are
worthy and they aren't necessarily closely linked.
Further, I should point out that the Dutch, when they went
to New Amsterdam, did not come here to settle and colonize all
of North America. One fact, if you have a vehicle departing
from Earth to travel to either the Moon or Mars, that vehicle
can deliver more payload to Mars if it goes direct to Mars than
it can if it just lands on the Moon, because of the energy cost
of landing on the Moon. The notion of landing on the Moon in
order to refuel in order to go to Mars makes absolutely no
sense.
And I guess the--there are certain common technologies that
I would strongly recommend for exploration that support both
lunar and Mars missions. One: lowering launch costs. This can
be done by using some of the new technology launch vehicles
that are out there on the market. Lowering those launch cost
supports the most innovative segments of the Earth-space
industry, and is a highly desirable thing because it makes the
missions approximately 10 times as affordable as they are now.
Number 2: use local resources locally, and I am referring
here to lunar resources used on the Moon where they are high
utility, and on the way to Mars, near-Earth asteroids, Phobos
and Deimos, Martian satellite resources, or Martian resources
may be extremely useful.
And finally, a great value would be an appropriate
transportation system architecture to provide maximum
accessibility to the Moon and Mars that would involve a
refueling station in a highly eccentric Earth orbit, from low-
Earth orbit ranging out to approximately the Moon and back.
That might serve to be a location where lunar oxygen could be
accumulated for use to service Mars missions, and although I
can't promise that that will work out economically, that is far
more attractive than the other scenarios for staging missions
to Mars from the Moon.
Mars need not wait for the Moon. And the basic science and
the technology testing needed to develop these resource
extraction schemes can be begun immediately without having to
wait for human beings on the Moon. So the possibility that a
commercial oxygen generation plant on the Moon could be there
when the first men land should be considered.
Thank you, Mr. Chairman.
[The prepared statement of Dr. Lewis follows:]
Prepared Statement of John S. Lewis
Abstract
Use of materials native to the Moon can play an important role in
facilitating both unmanned and manned exploration of the lunar surface,
most notably in the form of oxygen extracted from lunar minerals for
use in life support and rocket propellants. Lunar metals may also play
a valuable role in local construction activities.
Lunar resources are of no obvious utility for other exploration
activities, such as missions to Mars. In general, the prospects for
economically sensible export of lunar-derived commodities are limited
by the unattractive composition of the lunar surface and the
substantial energy requirements for landing on and taking off from the
Moon.
The three lunar commercial options that seem most plausible are the
collection and transmission of solar power to Earth, the extraction of
helium-3 as a fuel for terrestrial fusion power plants, and manufacture
of rocket propellants from lunar polar ice deposits. All three of these
schemes require substantial fundamental scientific and engineering
research in the lunar environment before their economic potential can
be fully assessed. At the moment, lunar Solar Power Stations appear to
be the most promising of the three.
Chairman Rohrabacher, Members of Congress, ladies and gentlemen: It
is my pleasure to offer some remarks concerning the role of the Moon
and its mineral resources in the future pursuit of lunar science and
exploration. I shall also address the potential role of lunar resources
in support of wider human exploration of the Solar System, and their
potential economic importance to Earth.
The resources of nearby space can be exploited for two major
purposes; either for local use in space, or for return to Earth. The
most immediate utility of lunar materials lies in their use to support
manned and unmanned activities on the lunar surface and to facilitate
the return of astronauts and scientific samples to Earth. The easiest
such scheme to implement would be that requiring the least-complex
handling and processing. Even raw, unprocessed lunar surface material
can be readily utilized to provide radiation shielding for lunar camps
and base modules.
Most lunar resource utilization schemes, however, entail both the
beneficiation (extraction and enrichment) of specific ores and their
chemical processing. A variety of extraction schemes and target ores
have been suggested. It is premature to select the ``best'' targets for
extraction, but it is already clear that as many as a dozen different
proposed schemes for extraction of oxygen from lunar minerals may be
practical. Oxygen makes up 90 percent of the mass of the high-
performance hydrogen/oxygen propellant combination. Even if hydrogen
propellant for use on the Moon were imported from Earth, the energy
requirements for delivery of propellants to the Moon would be reduced
by a factor of ten. In any return to the Moon, it would be a serious
oversight to ignore the great benefits of lunar oxygen production for
providing both life-support materials for crews on the Moon and
propellants for lunar-surface mobility and return to Earth.
Demonstration, and even practical use, of oxygen extraction
technologies need not wait for human presence on the Moon. Lunar-
derived propellants can play valuable roles in providing mobility for
unmanned missions on the lunar surface (using brief rocket firings to
hop over obstacles) and in returning scientific samples to Earth. It is
possible to envision small processing units, dealing with kilogram
quantities, on automated, unmanned spacecraft carrying out mineral
extraction and processing at a low level of complexity. Such an
experiment might, for example, react hydrogen gas brought from Earth
with lunar minerals containing iron oxides to extract water vapor from
them, leaving behind a residue containing high-purity iron metal.
Electricity generated from sunlight by means of photovoltaic cells
would then be used to separate water into hydrogen and oxygen by
electrolysis. The hydrogen would be recycled, and the oxygen
accumulated for use. Successful demonstration of this process would
encourage scaling the equipment up to ton quantities to serve the need
of a manned expedition or base, and would as a bonus permit recovery of
ton quantities of ultra-pure iron metal from the extraction residue.
That metal, which exhibits the strength and corrosion resistance of
stainless steel, could be used for fabrication of beams and girders,
nuts and bolts, wire and cables, and even the shells of habitat
modules. Technologies for the extraction and purification of iron could
be based on the gaseous carbonyl (Mond) process, which has over a
century of industrial use on Earth.
One especially interesting lunar resource is the sunlight that
impinges on its surface. Prof. David Criswell of the University of
Houston has proposed that solar cell ``farms'' deployed on the lunar
surface could collect vast amounts of solar power, convert that power
into electricity, and beam that power back to Earth as microwave beams.
Criswell argues that the installation cost of such a system could be
slashed dramatically by fabricating its principal components on the
Moon from lunar materials. A variety of chemical schemes for
manufacturing solar cells, wire, and other system components have
already been explored, and small-scale testing of these processes could
be started at an early date. It is my opinion that the brightest
prospect for profitable export of any commodity from the Moon to Earth
is power from such a Lunar Solar Power Station.
Export of actual lunar materials for use elsewhere, especially on
Earth, has rarely been suggested because of two major deterring
factors. First, the overall composition of the lunar surface is
strikingly similar to that of the slag discarded in metal smelting
operations on Earth. Few native lunar materials may be of sufficient
abundance, accessibility, and value to merit their extraction and
export. Second, the gravity field of the Moon, although substantially
less than that of Earth (an escape velocity of about a quarter of
Earth's and a surface gravity about one sixth of Earth's) is still
quite substantial. Given the propulsion requirements for escape from
the Moon and return to Earth, and the complete absence of ready-to-use
propellants on the Moon, the cost of retrieval of lunar materials is
certain to be very high, rendering the return of almost any lunar-
derived product to Earth prohibitively expensive. Of the materials
known or suspected to exist on the Moon, only one appears to offer any
hope of economic benefit: that is the isotope helium-3, a potential
fuel for fusion reactors. I have reviewed Prof. Swindle's testimony on
this subject and concur with his assessment that many questions (such
as the actual abundance, distribution, and recoverability of helium-3
on the Moon and the feasibility of commercial fusion reactors) need to
be answered before we can conclude that helium-3 extraction from the
Moon is economically sensible. A renewed program of lunar exploration
must address these scientific and technical unknowns. Much of the
needed research can be done by unmanned missions.
A second lunar resource, ice from permanently deep-frozen crater
bottoms near the lunar poles, has also sometimes been suggested as
appropriate for export either to the lunar equator or to space stations
or vehicles off the Moon. I regard this suggestion with deep skepticism
because of the immense technical difficulty of mining steel-hard and
highly abrasive permafrost under conditions of permanent darkness, at
the bottom of steep and rugged craters, at temperatures so low that
most metals in the mining equipment are as brittle as glass. Further,
the location of the hydrogen-bearing deposits (almost certainly
dominated by water ice) at the poles is the most remote from sensible
locations for a lunar base of any place on the Moon.
The lunar ice deposits are of great scientific interest for the
stories they can tell about comet and asteroid bombardment of the lunar
surface. Scientific investigation of these deposits need not, and
arguably should not, involve human presence. With such composition data
in hand, and with a greatly improved knowledge of the extent,
concentration, and purity of the lunar ice, a more realistic assessment
of the utility of these deposits could be made.
Specifically, the use of lunar-derived propellants, whether oxygen
extracted from iron-bearing minerals such as ilmenite and olivine or
hydrogen and oxygen made from polar ice, to support expeditions to Mars
makes no logistic sense. The Moon is not ``between'' Earth and Mars; it
is a different destination, poorly suited to function as a support base
for travel to Mars. Water extraction from the martian moons Phobos and
Deimos or from near-Earth asteroids may offer great advantages to Mars-
bound expeditions, more profound than lunar water could even if the
Moon had no gravity to fight. In any location, development of
extraction and fabrication technologies should, like low-cost space
launch services, be conducted as a commercial endeavor.
There are clear advantages to the use of lunar resources in support
of both manned and unmanned activities on the Moon. Direct benefits to
Earth from lunar resource exploitation are certainly conceivable, but
will remain conjectural until substantial further research on in situ
fabrication of solar cells and on the abundance and distribution of
helium-3 and polar ice has been done on the Moon.
Biography for John S. Lewis
John S. Lewis is Professor of Planetary Sciences and Co-Director of
the Space Engineering Research Center at the University of Arizona. He
was previously a Professor of Planetary Sciences at MIT and Visiting
Professor at the California Institute of Technology. His research
interests are related to the application of chemistry to astronomical
problems, including the origin of the Solar System, the evolution of
planetary atmospheres, the origin of organic matter in planetary
environments, the chemical structure and history of icy satellites, the
hazards of comet and asteroid bombardment of Earth, and the extraction,
processing, and use of the energy and material resources of nearby
space. He has served as member or Chairman of a wide variety of NASA
and NAS advisory committees and review panels. He has written 15 books,
including undergraduate and graduate level texts and popular science
books, and has authored over 150 scientific publications.
Chairman Rohrabacher. Well, thank you. And I know there
will be more discussion. And our final witness is Dr. Timothy
Swindle from--he is a Professor of Geosciences and planetary
Sciences at the University of Arizona. Dr. Swindle, you may
proceed.
STATEMENT OF DR. TIMOTHY D. SWINDLE, PROFESSOR OF GEOSCIENCES
AND PLANETARY SCIENCES, UNIVERSITY OF ARIZONA.
Dr. Swindle. Here we go. Thank you. Chairman Rohrabacher
and Members of the Committee, and ladies and gentlemen, thank
you for the invitation to talk about issues regarding lunar
science and lunar resources. Today, I wish to address one very
good science reason to go the Moon, and one proposed lunar
resource that would be very difficult to utilize.
First the science reason: we can go to the Moon to learn
about the environment on the early Earth at the time when life
was forming. Furthermore, much of what we can learn about the
Earth from the Moon, we cannot learn from the Earth itself. One
of the dominant processes occurring on the Moon is--has always
been the impact of comets and asteroids. The large circular
dark features that you can see from Earth without a telescope
are lava flows that fill basins, which were formed by impacts
larger than any that have occurred on Earth in the three
billion years. Surprisingly, the vast majority of Moon rocks
formed by these big impacts are virtually the same age, not
quite four billion years old. We don't know whether that is
because the last one or two or five of these impacts plastered
the limited region that we sampled with Apollo, or whether
there really was a half a billion years before that, where
there were relatively few impacts. There are older Moon rocks,
though not formed by impacts. To solve this puzzle, we would
need to go back to the Moon and carefully select certain rocks
from areas that we didn't visit before. So why is that
interesting?
The last well-dated impacts on the Moon are about the same
age as the oldest rocks of any kind on Earth, which is also the
time when the first evidence for life on Earth appears. Since
Earth has nothing more than fragments of any rocks older than
this, learning anything about what happened on Earth before
then from the terrestrial record will be very difficult.
However, we can learn how many impacts the Moon was suffering
before this, and even something about whether these impacts
were comets or asteroids. And if we know what was hitting the
Moon, we instantly know something about what was hitting the
Earth. Since if the Moon was taking a pounding, the Earth was
getting hit by the same kinds of things, only by more of them.
These could have provided the water or the organic
materials for life, or their impacts could have continually
frustrated the start of life on Earth. Learning about the Moon,
we learn about the Earth. However, we need carefully selected
rocks from the Moon, and by far the best way to do that is to
send humans. During the Apollo missions, the astronauts looked
at far more samples than they brought back, and they
judiciously chose what were almost the best samples they could
have. Robotic technology, unfortunately, is still far from
being able to separate out the subtleties that a human easily
can.
Now, let me switch gears and talk about something very
different, a suggested lunar resource. As Professor Lewis
mentioned, it has been proposed that we should go to the Moon
to mine helium-3 as a fuel for clean burning fusion reactors.
Helium, and particularly helium-3, is extremely rare on the
Earth. Heilum-3 makes up less than one-trillionth of our
atmosphere. It is somewhat more abundant on the Moon. That is
because the solar wind, the flow of particles expelled by the
Sun, includes quite a bit of helium-3. The solar wind hits the
Moon's surface, it gets implanted into the outer ten millionth
of a meter of grains that are at the very surface of the lunar
regolith or the lunar soil.
Small impacts then stir this regolith so that the helium-
bearing grains on the surface get mixed to greater depths. We
know quite a bit about the distribution of helium-3 on the
Moon, but two things we don't know are how deeply those grains
from the surface get mixed down, and whether the fact that the
Earth's magnetic field can shield parts of the Moon's surface
from the solar wind at certain times will make a difference at
some spots. These two rather small uncertainties make a
difference of a factor of ten in our total estimates of the
amount of helium-3 on the Moon.
We do know this, though, mining helium-3 from the Moon
would be a massive, difficult operation. At the most promising
locations, helium-3 makes up no more than about one part in 100
million, and it is almost exclusively found in the upper ten
meters of the regolith, perhaps the upper three meters. Thus,
to mine one ton of helium-3 per year, which one group suggested
as a goal to fuel a working fusion reactor, we would have to
move 100 million tons of dirt, which is comparable to some of
the largest terrestrial mines. It is difficult to imagine this
being a robotic operation. The minimum amount of the Moon that
would have to be mined to match that one ton a year is about
seven square kilometers per year, and it wouldn't take very
many years to mine enough of the Moon that you could see the
Moon--the mine from Earth with binoculars.
I would stress that at present, a full assessment of the
feasibility of mining helium-3 is far cheaper and simpler than
actually trying to mine it. The assessment would include
learning more about the lunar regolith at various depths at
various locations around the Moon, determining the relative
value of helium-3-based fusion reactors, the cost of other
potential sources of helium-3, not to mention developing and
testing mining techniques. Also, I would point out that there
are many other lunar resources for which extraction would
require far less ambitious projects.
So, my three main points: First, the Moon holds valuable
clues as to the early history of the Earth at a time when life
was forming. Second, helium-3 is a potentially valuable
resource, but extracting it from the Moon is a difficult
process. There should be more basic assessment before
attempting to implement anything. And finally, the work I have
talked about will be accomplished far more easily with humans
on the Moon than without.
Thank you.
[The prepared statement of Dr. Swindle follows:]
Prepared Statement of Timothy D. Swindle
Chairman Rohrabacher, Members of the Committee, ladies and
gentlemen: Thank you for the invitation to talk about issues regarding
lunar science and lunar resources. Today, I wish to address one topic
in each. First, we are beginning to understand that lunar science is
important because the Moon contains clues to the earliest history of
Earth, perhaps even of the start of life on Earth. Second, there are
aspects of fundamental lunar science that we need to understand better
to be able to assess whether it would be worthwhile to try to exploit
the Moon for certain resources that might be used on Earth. In specific
example of helium-3, while it is clear that it is a prodigious
undertaking, we need more information to know the real magnitude of the
task.
The first evidence of life on Earth comes in rocks that are
approximately 3.8 billion years old. The evidence is ambiguous, and it
is unlikely that we will be able to use terrestrial rocks to learn much
more about what was happening then, or earlier, because there are so
few rocks this old or older. Could we use the Moon to understand what
was going on on Earth?
The large circular dark features on the Moon that we see from Earth
are dark lava flows that fill basins, which were formed by impacts
larger than any that have occurred on Earth in the last three billion
years. Perhaps surprisingly, analysis of the rocks returned by the
Apollo program showed that the vast majority of impact-derived rocks
are roughly the same age, between 3.8 and 4.0 billion years old. Few
are younger than 3.8 billion years old; none are older than 4.0
billion. Although a number of rocks older than 4.0 billion years were
brought back, extending back to the age of the Moon itself nearly 4.5
billion years ago, none of the older rocks were the types formed in
large impacts.
Two possibilities have been suggested to explain the tight
clustering in ages of the impact rocks from the Apollo collection. One
is that the Moon actually had not had many, if any, large impacts in
the previous 0.5 billion years, and then had a cataclysmic bombardment.
The biggest problem with the idea of a late cataclysm is that we do not
understand where the objects causing the bombardment could have been
stored for that length of time before suddenly being released on the
inner Solar System. The other possibility suggested is that there were
many large impacts all along, but the rocks formed in the earlier
impacts were all destroyed in the final few impacts, the terminal
portion of this heavy bombardment. The biggest problem with the idea of
a terminal heavy bombardment is the difficulty with destroying the old
rocks produced in impacts while leaving intact many other rocks formed
in that same period.
The question of the early impact history of the Moon has important
implications for the early history of Earth. If the Moon suffered
several large impacts in any given period of time, Earth probably
suffered many more, since Earth is nearby (in solar system terms), but
larger. This is probably why we find no intact rocks on Earth older
than the time of the final basin-forming events on the Moon, whether it
was a cataclysm or a terminal heavy bombardment.
Assuming that the lunar basins were only the last in a continuous
string of large impacts, the end of a heavy bombardment, some
scientists have suggested that there was an ``impact frustration'' of
life. Life may have arisen long before the first evidence we find, and
perhaps may have even begun more than once, but was wiped out, or
``frustrated,'' as one impact after another hit the Earth with enough
energy to boil the oceans. In this scenario, life began on Earth
virtually as soon as it became possible.
On the other hand, if there was a cataclysmic bombardment, then
there may have been a long, relatively peaceful period on Earth in
which life could have started. In this scenario, life might have been
more abundant when the cataclysm began, but it could only have survived
in some niches away from the oceans and away from the Earth's surface.
There are some primitive organisms even today that might be suitable
candidates for such survival. In this scenario, it is also possible
that it took hundreds of millions of years of clement conditions for
life to start, reducing the chances of finding life on a planet like
Mars, whose climate was only pleasant for a brief period of time.
These two alternatives provide fundamentally different expectations
about the formation of life on Earth, and its likelihood elsewhere.
There is also the question of where and when Earth got its water.
Water is crucial for life as we know it, but in many models of the
formation of the Earth, the planet formed from material that would have
lacked water because that material came from too close to the Sun.
Hence, the water may have been added at some later time by the impacts
of comets or water-rich asteroids. There are few clues available on
Earth to address these questions, but the Moon does contain clues. The
rocks formed in lunar impact basins often contain rare elements that
can serve as tracers for the bodies that impacted. As we learn more
about the compositions of more of the bodies that impacted the Moon, we
learn more about the bodies that impacted Earth, and hence we learn
more about how much material of what kind was added to Earth, and when
it was added.
Although we continue to try to address these problem in a variety
of ways, we are hampered by the fact that the only lunar rocks we have
from known locations are the Apollo samples, and the Apollo samples all
come from a rather restricted region on the near side of the Moon where
the more recent basin-sized impacts occurred. One of the arguments for
going back to the Moon is to try to decipher the Moon's early impact
history by studying rocks from a variety of known locations that are
not near the latest basins. We can do this robotically, and it would be
a great improvement over the suite of samples currently available, but
having humans present is far superior. During the Apollo missions, the
astronauts looked at far more rocks than they returned, and judiciously
chose what were almost certainly the best samples available. Robotic
technology is still far from being able to separate out the subtleties
that a human easily can.
Exactly how and when life started on Earth is one of the great
scientific questions of the 21st Century. Understanding the history of
the bombardment of the Moon will not tell us how life started on Earth,
but it will tell us far more about what the conditions were on Earth
when life did start. Furthermore, the record stored within the rocks on
the Moon is of times and events whose record no longer exists on Earth.
Going from the distant past to the near future, understanding basic
lunar science is also crucial to understanding whether certain ideas
for using lunar resources are even feasible, much less how to implement
them. As an example, Gerald Kulcinski, Harrison Schmitt, and co-workers
have proposed the use of the rare helium-3 from the Moon as a fuel for
clean-burning fusion reactors.
Helium, and particularly its lighter stable isotope helium-3, is
rare on Earth. Helium is light enough that any atom currently in the
atmosphere is likely to escape from Earth's gravity at some time over
the next million years or so. Earth's atmosphere is gaining some helium
from Earth's interior or by trapping it from space, but it is in tiny
amounts, only about 10 kg per year: helium-3 is less than one part per
trillion of the atmosphere by mass, and extraction is clearly extremely
difficult.
There is, however, a body in the Solar System with huge reserves of
helium-3--the Sun itself. The Sun contains a total of about 1.4
1026 kg of helium-3, a larger mass than the entire mass of
the Earth. Going to the Sun to get that potential fuel is far beyond
our presently imagined capabilities, but the Sun expels some of its
outer layer in a rather steady flow of particles, the solar wind. The
solar wind flux at the distance of the Earth from the Sun is about
0.005 g of helium-3 per km2 per year. The Earth's magnetic
field deflects virtually all of this solar wind, but the Moon has no
magnetic field or atmosphere of its own, so the solar wind is implanted
into the surface of the Moon, except during the portion of the month
when the Moon is shielded by the Earth's magnetic field.
Kulcinski and Schmitt have suggested the possibility of mining the
Moon for helium-3, and have suggested one ton per year as a target
amount. In 1990, I was part of a group at the University of Arizona
that evaluated the potential of this idea. We considered how much
helium-3 the Moon actually contains, how well we know that amount, and
how we might mine it. Although there have been some advances in lunar
science since then that have caused us to revise our estimates
slightly, we still have not been able to learn anything more definitive
about the two most critical parameters, the distribution of helium-3
with depth in the lunar regolith and the distribution of helium-3 with
location on the Moon. Our estimates of the total helium-3 contained in
the lunar regolith (the lunar ``soil'') ranged from 450,000 to 4.6
million tons, based just on plausible variations in these two factors.
The amount varies with depth within the regolith because solar wind
is implanted only 0.1 to 0.2 microns deep (a micron is one millionth of
a meter). Small impacts stir the regolith, so that helium-bearing
grains on the surface can get mixed to greater depths. However, models
of regolith formation predict that the amount of solar wind should
generally decrease with depth, because deeper layers should have fewer
grains that have spent time at the surface. At present, we have no
samples from any deeper than three meters (the depth of the longest
drill core taken by the Apollo astronauts), and the predicted trend is
not really seen. If the abundance changes little with depth to the
bottom of the regolith (typically 10 to 15 meters), then approaches to
mining helium-3 would clearly need to be different than if the helium-3
is concentrated in the upper two to three meters.
The amount of helium-3 varies with location as a result of two
factors, one of which we understand, and one of which we don't. One
factor is the chemical composition: helium atoms are so small, and so
light, that they can escape from many minerals, even if they are
implanted. Some minerals will retain less than one percent of the
helium-3 implanted. By far the best, in terms of retention, is the
mineral ilmenite, which also happens to be the mineral that contains
most of the element titanium on the Moon. Hence, by mapping the
abundance of titanium (something that has been accomplished by orbiting
spacecraft), we can predict where helium might be retained well.
The other factor is the amount of helium received. Since Earth's
magnetic field shields the Moon from the solar wind during part of the
month, the portion of the Moon facing the Sun at that time each month
(the Near Side of the Moon) is exposed to less solar wind than the
portion of the Moon that faces the Sun when the Moon is not within
Earth's magnetic field. But even though some portions are exposed to
more solar wind, we do not know whether they actually receive more--it
is possible (and has been suggested, based on some experiments) that
individual grain surfaces become saturated, reaching a state where no
more can be implanted, even if the surface is exposed to more solar
wind. By far the best way to test this is to analyze samples from a
variety of locations on the Moon, which we cannot do at present.
We also need to know more about the general properties of the lunar
regolith if we are going to attempt to mine the Moon for helium-3. For
example, a mining engineer would clearly need to know how common intact
rocks are, and what sizes they are likely to be, as one moves deeper
into the regolith, and if and how the properties of the deeper regolith
differ from those of the surface layers studied by the Apollo missions.
It is worth noting that in any scenario, mining helium-3 from the
Moon will be a massive, difficult operation. Even with our most
optimistic estimates of the abundances and distribution, we found that
at the most promising sites, helium-3 makes up only one part in 100
million of the regolith (by mass), so extracting one ton of helium-3
would require mining 100 million tons of regolith, even if the
extraction were perfect, which it will not be. This is comparable to
the annual work of some of the largest terrestrial mines. Adding in the
fact that only the top few meters of the regolith contain any helium-3
at all, to mine one ton per year would require digging up seven square
kilometers of the Moon's surface each year, at the most promising site
under the most optimistic set of assumptions, so it would not take many
years for the mine to become large enough to be visible from Earth with
even a small pair of binoculars. Although massive mining operations are
increasingly mechanized, humans are still the best way to make
decisions, diagnose equipment problems, and make repairs.
There are several other potential resources, most notably oxygen,
whose extraction would require far less ambitious mining projects.
However, they typically share the common property that we would need to
know more about the basic science of the lunar regolith to be able to
properly implement them, or even to properly evaluate their potential.
Once again, while it is certainly possible to imagine ways to
attack these basic science questions robotically, it would require a
level of sophistication far in advance of any mechanisms yet launched
into space, though well within the reach of human-conducted
exploration. Furthermore, in the case of helium-3, it is worth
stressing that at present, a full assessment of the feasibility is far
cheaper and simpler than an attempt at implementation.
In summary, the Moon holds valuable clues to the early history of
Earth, at the time when life was forming, and may hold valuable
resources for the future of Earth. But to evaluate either properly,
there is lunar science that would need to be done, and the way to do
that lunar science best is with human beings.
Biography for Timothy D. Swindle
Dr. Timothy D. Swindle is a Professor of Planetary Sciences and
Geosciences at the University of Arizona. He received a Ph.D. in
Physics from Washington University in St. Louis in 1986. Prof.
Swindle's main area of research has been using the noble gases, such as
helium, argon and xenon, to study meteorites and lunar samples. His
lunar work has included studies of the impact bombardment history of
the Moon and the incorporation of gases into the lunar regolith. His
current research emphases are on the chronology of the Moon and on
constructing instrumentation to be used on robotic spacecraft to
determine the ages of rocks on bodies where human exploration is not
yet possible.
Discussion
Chairman Rohrabacher. Well, thank you very much. We have
just been called to a vote, and so what I would suggest is if
we took the vote and then come right back and begin the--I
think it is one vote--come back and conduct the questions right
afterwards.
Mr. Feeney. Mr. Chairman, with your indulgence, I am going
to have go to the White House after this. I appreciated all the
testimony, and I would like to ask some questions now--well,
no, I just wanted to leave one simple statement because I am
not a scientist by background. But 100 years ago, most people
thought that about 98 percent of the surface of Florida was
practically unusable so we have got to learn, I think, is what
I learned from the witnesses.
Chairman Rohrabacher. Thank you very much.
Mr. Feeney. But that was before air conditioning, which is
just as vital in practical terms as water and oxygen to humans
in Florida, anyway.
Chairman Rohrabacher. All right. We have several major
issues to discuss, and so when we come back, we will get right
to them, and this committee is in recess for 15 minutes.
[Recess.]
Helium-3
Chairman Rohrabacher. All right. This hearing is called to
order. Thank you very much for waiting. We have had some very
fine testimony today. I would like to ask the panel a question.
For those who would like to, several panelists have mentioned
helium-3. Isn't it the case that helium-3 has no value now and
we are only talking about something that has value if it is--if
we can perfect fusion energy? Is there some other value that I
am missing there? So, please feel free to jump in.
Dr. Swindle. I would agree with that assessment. The fusion
reactors are coming, perhaps, but perhaps. They are not there
yet.
Chairman Rohrabacher. I would say a big perhaps. I will let
you know.
Dr. Swindle. And there is no other reason to mine helium-3
that I have heard suggested.
Chairman Rohrabacher. All right. Dr. Lewis, is that--does
anyone disagree with that assessment? Nobody disagrees with
that assessment.
Dr. Lewis. Mr. Chairman?
Chairman Rohrabacher. Yes?
Dr. Lewis. We shouldn't discount fusion reactors. It is a
perpetual truth that they are 30 years away.
Chairman Rohrabacher. And they always will be.
Dr. Lewis. It has been true since 1960.
Chairman Rohrabacher. Right.
Dr. Lewis. But there is an interesting application, which
is that when a new fusion reactor is first built, during the
test runs of it, they use helium-3-deuterium mixtures to test
the reactor because that fuel combination is very clean. It
doesn't induce radioactivity in the reactor, but that is not a
commercial-level activity. That is done in very tiny
quantities.
Solar Energy on the Moon
Chairman Rohrabacher. Yes. Several years ago, I made a
study of how successful we have been in developing fusion, and
I came to the conclusion that it is the least successful of all
of our scientific endeavors was trying to--but it promoted--but
it actually employed more people with less success than any
other of our scientific endeavors. Also, we are talking about
the concept of solar power on the Moon. I believe Mr. Lewis was
talking about that, and beaming energy--this is something that
I think has much more potential than fusion energy.
Dr. Lewis. That is correct if we are talking about economic
impact on Earth on a foreseeable time scale. Fusion energy
could be made to work at any time, and then might become a big
player, but the Sun does exist. We do know how to make
electricity from it. We do know how to convert that electricity
into microwave power. And, I would strongly recommend that at
the very least, your staff get in contact with Professor David
Criswell at----
Chairman Rohrabacher. Well----
Dr. Lewis.--the University of Houston and----
Chairman Rohrabacher. Oh, yes.
Dr. Lewis.--get his slant on this.
Chairman Rohrabacher. Why would it be better to have the
solar system on the Moon rather than orbiting?
Dr. Lewis. The advantages and disadvantages pile up pretty
much like this: if you install the--a system in, say,
geosynchronous orbit around the Earth, that system has to be
lifted in its entirety from the surface of the Earth. But, if
you install the system on the surface of the Moon, you can make
the structures and the solar cells themselves out of local
lunar materials, so you don't have to transport nearly as much
mass. You bring up a small factory.
Chairman Rohrabacher. And----
Dr. Lewis. However, there is a downside.
Chairman Rohrabacher. Okay.
Dr. Lewis. The downside is that to get that power back to
the surface of the Earth, you need a much larger transmitter on
the Moon than you do in geosynchronous orbit, so that would
have to be made out of lunar resources, and that means you
would need a fairly large-scale up-front industrial base on the
Moon to manufacture these items. If you see your way through
that up-front cost in installing such a system, then the
economy of the system seems hard to avoid. It is just that the
up-front investment is enormous.
Chairman Rohrabacher. Enormous as in billion?
Dr. Lewis. Oh.
Chairman Rohrabacher. Tens of billions?
Dr. Lewis. Tens of billions.
Chairman Rohrabacher. Hundreds of billions?
Dr. Lewis. Yeah.
Chairman Rohrabacher. No, not hundreds.
Dr. Swindle. Could I make a comment on that?
Chairman Rohrabacher. Yes, sir.
In Situ Resources
Dr. Spudis. It is certainly true that when Dave Criswell
talks about this concept, he is envisioning giga-watt
production for use, basically, to electrify and industrialize
the third world, and that is certainly the goal of this. But
you could start with doing proof-of-concept and demonstration
experiments with a very minimal return to the Moon. For
example, Professor Alex Ignatiev from the University of Houston
has developed a miniature rover that rolls around and actually
manufactures amorphous silica solar cells in situ from lunar
soil, and this has actually been built and is in test
demonstrations. So you could land a robot payload on the Moon,
develop--let us set it out. Let it make solar cells, connect
them together, and demonstrate that the concept is feasible
without investing billions of dollars in industrial
infrastructure. So you can start small and then ramp up as you
get more.
Chairman Rohrabacher. And you could do that with a robot--
totally robotically?
Dr. Swindle. That is what he is looking at right at the
moment, but that is just an initial test. It is not a
production phase.
Chairman Rohrabacher. All right. Any one else want to jump
back or back----
Dr. Lewis. Yes, just let me point out that there will be
substantial power demands for a lunar base.
Chairman Rohrabacher. Yes.
Dr. Lewis. And there is no reason why one couldn't start
with a facility of this sort to power the lunar base and then
later add the ability to transfer part of that power to Earth.
Chairman Rohrabacher. Okay. And we also had a suggestion
that we could land some type of equipment on the Moon that
would then be able to produce, I guess, a fuel from hydrogen so
that once people got there, they could refuel. They would have
a refueling operation that would be ready to go, or already
operating. Now, who is it that suggested that? Somebody
suggested that, or maybe I was just thinking that.
Dr. Lewis. I mentioned it. You know, oxygen extraction from
the Moon is the big attraction. The hydrogen----
Chairman Rohrabacher. What about hydrogen?
Dr. Lewis. The hydrogen concentration on most of the Moon
is very low, so that you run into sort of a pale version of the
helium-3 problem where you need to process huge quantities of
dirt to get the hydrogen out. However, if you are asking--if
you are considering a vehicle on the surface of the Moon about
to bring a crew of astronauts back to Earth, the propellant
that they need is 90 percent by mass oxygen and only 10 percent
hydrogen.
Chairman Rohrabacher. Oh, I see. Okay.
Dr. Lewis. So one can imagine ferrying hydrogen to the Moon
and then beefing that up with a huge quantity of lunar oxygen.
One can imagine, in fact, running the rocket engines way over
on the oxygen-rich side so that you are using lots of extra
oxygen because it is relatively cheap on the Moon.
Dr. Spudis. But it is not impossible to extract hydrogen
from any place on the Moon. It is just--he is right. It is very
low concentration. But, if you have time and you have energy,
you can set up a robotic system to roll across the surface and
extract what it can and store it and let it operate
autonomously, and when it is full, then you can go up and use
it as fuel. That is certainly feasible. We are fortunate in the
sense that the hydrogen on the lunar dust is put there by the
solar wind. The solar wind hits the Moon, it implants these
atoms on dust grains. Those atoms come off fairly easily. You
have to heat the soil to about 700 degrees Centigrade and that
gas comes off and it can be collected and then condensed and
liquefied. So it is possible to do this, as long as you are
willing to wait. It won't be something you can do immediately,
but it is something you can do over a long period of time.
Possible Return Dates to the Moon
Chairman Rohrabacher. Well, this all is very exciting about
then, and let me ask you this. Maybe you can just give me your
own concept there, do you--just down the panel. How long do you
think, and how much do you think, it will cost us to--before we
can get back to the Moon with a human being and have some sort
of manned operation on the Moon?
Dr. Spudis. Well, technically, there is no reason why we
couldn't be on the Moon within five to seven years of the
program start. Now the principle reason why the President's
proposed initiative takes a slower pace is that the trade there
is the difference between money and schedule, that if you fund
it at pretty much the current NASA level, slightly augmented
and growing with inflation----
Chairman Rohrabacher. Uh-huh.
Dr. Spudis.--then we could be back on the Moon, with robots
first in '08, and beyond and people starting as early as 2015,
but that is based on the assumption of essentially constant
funding, slightly augmented. If you wanted to accelerate that,
you could. There is no technical reason why we couldn't be on
the Moon within, let us say, 2010. It is possible.
Chairman Rohrabacher. Is there----
Mr. Spudis. It is a money issue.
Chairman Rohrabacher. Is there any disagreement with the
panel on that? Okay, good. Well, I am going to let Mr. Lampson
take over, and I may have a few more questions as we move on.
Timeframe for In Situ Resource Development
Mr. Lampson. How long, Dr. Spudis, would it take, if you
say you have time to wait, for the development of that fuel?
What were you talking about? Were you talking amount minutes,
days, years?
Dr. Spudis. Months. Basically, what you would want to do is
you would want to set up a rover that was solar powered,
basically, so you would only operate during the daytime. So in
that scenario, it would operate for 14 days and then basically
hibernate during the lunar night of 14 days, and it would
basically go back and forth across the soil, collecting solar
energy with a passive mirror--solar-thermal--concentrating it
like a heating element onto the soil, taking evolved gasses,
collecting evolved gasses that come off, and then processing
those.
Mr. Lampson. So that is the direction in which we want to
go, we want to do that pretty quickly----
Dr. Spudis. Well----
Mr. Lampson. Right?
Dr. Spudis.--I am not advocating this. I am saying that it
is technically possible. I think the first step to going back
to the Moon is to get a better understanding of where the ore
deposits are. The problem with the equatorial sites is that
those are fairly low-grade ores. The concentration levels are
very low, just like Dr. Lewis says. We need to find out what is
at the poles. What is going on there? How much is there? Where
is it? What is the physical state? And then decide whether that
is the answer to the problem or not.
Prioritization of Lunar Science
Mr. Lampson. How would all of you prioritize the research
that we want to do, or should be done on the Moon? I mean, what
has the highest priority? Any or all of you?
Dr. Spudis. In terms of science?
Mr. Lampson. Uh-huh.
Dr. Spudis. I think that one of the most intriguing things
is what I mentioned in my testimony and that--and also Tim
Swindle mentioned too--and that is the impact history of the
Earth-Moon system. Fundamentally, the biggest scientific
accomplishment of Apollo was an appreciation for the importance
of hypervelocity impact. That is something we didn't really
appreciate before we went to the Moon, and yet, we found that
it is fundamental to the evolution and history of life on
Earth. The dinosaurs, for example, went extinct 65 million
years ago because of a giant impact, and we now suspect that
these impacts may occur occasionally in the geologic record,
but we can't verify that because the Earth's record is
incomplete. The Moon's record is complete. You can go back and
recover and read that record, and it applies to the Earth
because Earth and Moon are in the same part of the solar
system. Tim, do you have any comments on that?
Mr. Lampson. Anybody else have a----
Dr. Swindle. No.
Mr. Lampson.--different priority or a different set of
priorities? That is the most important thing. Are you going to
list anything else?
Dr. Lewis. Yes, the fundamental science that needs to be
done to assess these various resource schemes. I would put that
in the same list. And, incidentally, the apparatus and the
personnel involved in doing those experiments overlap
substantially with those who would be doing the basic science
that Dr. Spudis is talking about. This is not a separate or
conflicting or competing agenda, but it is part of the
scientific assessment of the Moon. It is something that can be
done substantially with unmanned probes. As I mentioned in my
testimony, one can envision even producing tanks of liquid
oxygen that would be available, sitting there on the Moon when
the first----
Timeframe for a Human Return to the Moon
Mr. Lampson. Much of this can be done robotically. At some
point, you have to have humans involved----
Dr. Lewis. Right.
Mr. Lampson.--and do you have a feeling as to when that
might be?
Dr. Lewis. Well, let us just break it into phases. There is
a robotic phase where you are learning the basic principles and
demonstrating the processes. Then, there is an industrial phase
where you are actually doing it on a commercial scale. That
first phase could be initiated this year, and could be flying
missions within a couple of years. That is not a problem.
People have thought a great deal about how to do these things.
Many of the instruments involved already exist. The commercial
phase, if one has a large liquid oxygen plant on the Moon, let
us say just for purposes of concreteness, would almost
certainly benefit from being attended by human beings from time
to time for maintenance and repair and so on. So I suppose that
you could say that within a few short years, we could have the
ability to produce that first big commercial batch of oxygen,
but beyond that point, you need the people there, A, to
maintain the plant, and B, to use the product. And there is a
synergism there. I would hate to see the landing of people on
the Moon delayed because of inadequate attention to building
infrastructure on the Moon to support them.
Mr. Lampson. Let me go on one different direction for a
minute and we will come back on the--oh, I am sorry. Dr.
Swindle.
Dr. Swindle. One other thing on the same topic, Professor
Lewis was talking about the resource aspect. Let me address the
same question from the science aspect which is to say that some
robotic missions in terms of addressing the impact history
would be very nice, and, in fact, I believe that Dr. Spudis and
I are competitors on proposals for such a mission in for launch
in 2007? Something like that.
Dr. Spudis. Right.
Dr. Swindle. And we will learn a huge amount by having a
few samples from some places we haven't been. Beyond that, to
really make progress, we need to have the advantage of having
people who can look and pick up the one rock that you really
needed out of that landscape that you can't really with just--
even a good camera.
Mr. Lampson. Okay. Do you want to go ahead and then we will
come all the way back.
Chairman Rohrabacher. All right. Dr. Bartlett.
Other Potential Lunar Fuels
Mr. Bartlett. Thank you very much. Are there other
potential fuels on the Moon, other than hydrogen, that could be
exploited?
Dr. Lewis. Yes. Yes, there are a number, but they all
require--they are all at the bottom of deep chemical potential
energy wells. They need to be extracted at considerable cost,
and part of that cost is in the complexity of the equipment
needed to do it. An example would be extracting a metal from
the lunar surface, such as aluminum, that can be burned in the
oxygen. There are no completely satisfactory schemes for using
powdered aluminum in oxygen right now. I have seen some that
scare me to death and some that I don't think would work enough
to scare me. But, indeed, there is a possibility of extracting
metals to be burned with the oxygen. I would say that that
research is in a very primitive state. How you would make an
autonomous propulsion system on the Moon compared to the state
of knowledge of how to extract oxygen.
Dr. Spudis. There are two other possibilities. It was
looked at in the '80s of using lunar surface sulfur. There is
sulfur in the lunar regolith, and that can actually be burned
as a rocket fuel. You can actually make solid rockets on the
Moon. That was looked at quite extensively by the Los Alamos
group back in the early '80s, and that looked feasible. The
other thing that we don't yet know about is we--if there is ice
in the poles--the dark areas of the poles that was deposited by
cometary cores, cometary cones contain methane, and there may
be methane, there may be ammonia, in the floors of the polar
craters, and both of those can be used as rocket propellant as
well.
Mr. Bartlett. Thank you. In spite of enormous insulation,
the Moon is very cold because it is simultaneously radiating to
space. If you put a piece of glass over it, of course, the
incoming energy ends up, a lot of it, as infrared, which
doesn't get back through the glass. What happens to lunar
temperature if you put glass over it?
Dr. Lewis. You----
Mr. Bartlett. You would get a greenhouse effect, obviously.
Dr. Lewis. You would get a greenhouse effect, but the
numerical answer depends very sensitively on the exact on the
exact transmission of the glass, wavelength dependent on
transmission.
Mr. Bartlett. Okay.
Dr. Lewis. But you can easily bump the temperatures up by,
you know, 20, 30 percent, absolute temperatures.
Mr. Bartlett. It will get them up to habitable temperatures
just by the greenhouse effect?
Dr. Lewis. It will probably be easier to build a habitat
and step inside it. Building a glass structure on the Moon
invites a--becomes a very sensitive method of determining the
rate at which meteoroids are striking the Moon, the rate at
which your glass house crumbles. So, yes, you can indeed
enhance temperatures that way. One can imagine small devices on
the Moon that trap solar energy in that manner. One can also
imagine producing electricity by using a device to trap
sunlight, boil water, and drive a Ranking cycle generator and
so on, but if you are talking about terraforming, trying to
make Earth-like conditions on the Moon, the Moon is so utterly
un-Earth-like that you better try to do it one square yard at a
time, not think about it in terms of a global scale.
Mobile Solar Stores
Mr. Bartlett. When you are thinking about transportation on
the Moon, obviously the energy source that is continuously
available is solar, and it is easy to imagine a solar ATV that
goes wherever you can go with a solar ATV. What attention has
been given to developing solar kangaroos? Something that just
stores the energy and then hops over obstacles when enough has
been stored?
Dr. Lewis. On the Moon? I don't know, ultimately. I don't
think a lot of attention has been given to that. It is assumed,
in a lot of scenarios that when you go back there, you use
solar energy. After that, it gets real fuzzy. Sometimes, you
see big arrays that are laid out that are many football fields
across and providing megawatts to the lunar base, but
ultimately, you have got a problem, that on the Moon, you have
got 14 days of night. And, in addition, 14 days of daylight,
because it rotates once on its axis every 28 days. So you have
to have something to get you through the night anyway. If you
decide to go nuclear, then that provides the power that you
would need day and night. So you don't have to worry about
solar. If you don't go nuclear, you have to think of something
else, either sub-battery, which could be very massive, or
rechargeable fuel cells, which is the most likely possibility.
The other possibility is that if you have established your
outpost near the poles, there are areas near the poles that are
in near constant sunlight because the Moon spins perpendicular
on its axis and the Sun is always at grazing incidence. And in
those areas, you could collect solar energy constantly. The
problem you have got in all these things is that solar energy
is not something that lends itself to powering mobile things.
It is very massive. It has a very high kilogram per kilowatt
cost. So, if you want to have mobile things that go around to
different places to do jobs, you need to have a more
concentrated energy source.
Gravity Gradient Stabilization
Mr. Bartlett. Is there any gravity gradient stabilization
on the Moon?
Dr. Lewis. On the Moon? The gravity of the Moon----
Mr. Bartlett. Gravity gradient stabilization.
Dr. Lewis. Well, if you were--that would be relevant only
if you were in orbit around the Moon. If you were on the
surface of the Moon, then the gravity gradient is what holds
you on the Moon, so----
Mr. Bartlett. Relative to Earth, is there gravity gradient
stabilization?
Dr. Lewis. It is possible for an object in low lunar orbit
to be gravity gradient stabilized, but the----
Mr. Bartlett. But the Moon is not?
Dr. Lewis. Well, as a matter of fact, the fact that the
Moon always keeps one side toward Earth is an example of
gravity gradient stabilization.
Mr. Bartlett. Okay. Which means that it will be light and
dark because its gravity gradient stabilized to the Earth.
Okay.
Dr. Lewis. It means that one side will always face the
Earth.
Mr. Bartlett. Because its gravity gradient stabilized to
the Earth, yes.
Dr. Lewis. That is right. Mr. Bartlett?
Mr. Bartlett. Yes?
Mobile Solar Stores II
Dr. Lewis. Your question regarding the hoppers on the Moon,
if I may have put a frivolous noun on it, has actually been
studied in the case of Mars, where devices that use either
nuclear or solar power, extract carbon dioxide from the
atmosphere of Mars, separate it into oxygen and carbon monoxide
and liquefy them, and then use them as rocket propellants to
hop around the surface. So you can hop from one location to
another until your tanks are empty, and then sit there and
absorb sunlight and refill the tanks with oxygen and carbon
monoxide.
Mr. Bartlett. Well, couldn't one imagine a mechanical kind
of thing. Gravity on the Moon is so low that, you know, you
could hop quite a distance.
Dr. Lewis. You could indeed, but you would have no control
over your landing. You would have to know exactly where you are
going to come down. You do not get an opportunity to think
twice about landing on that sharp rock over there.
Chairman Rohrabacher. Might hop right into the briar patch.
As just a, you know, I am waiting for some learned
environmentalist to step forward and tell us that they would be
afraid to have all this mining going on on the Moon because it
might affect our tides, but I will--believe me. That will
happen. That will happen. It might happen 20 years from now,
but we will note--you will note----
Mr. Lampson. What would that do to surfing?
Moon as a Way Station
Chairman Rohrabacher. That is the point, right. Anyway, as
I was just actually--was at a discussion with some people along
the coast about desalinization, and one lady got up--a learned
person got up to talk about, well, how do we know, you know,
what effect desalinating the water so we can use it would have
on the ocean, and, anyway, we won't go back to that. Mr.
Lewis--or Dr. Lewis, you stated that it makes no sense
whatsoever to use the Moon as a way station, and that is sort
of the concept a lot of people have in mind. They have in mind
that we go to the Moon and then--so they are a little hesitant
about whether we are going to learn things there, or whether we
use that as a jumping off point, and we have heard those
phrases. But let me ask you this. We go the Moon, and we land
on the Moon, what about if we find a way to refuel the system
on the Moon?
Dr. Lewis. Let us assume that we have done that.
Chairman Rohrabacher. All right.
Dr. Lewis. That we can manufacture cheap liquid oxygen on
the surface of the Moon.
Chairman Rohrabacher. Or whatever. Some kind of fuel----
Dr. Lewis. Okay.
Chairman Rohrabacher.--that we are going to get in that
vessel that can----
Dr. Lewis. Okay.
Chairman Rohrabacher.--now go on to Mars.
Dr. Lewis. Here is an expedition sitting at the space
station in low orbit around the Earth and they take off. They
have a choice. They can either go to, for example, establish an
orbit around the Moon and then wait for oxygen to be brought up
to them from the lunar surface to refuel their tanks to prepare
them for travelling on to Mars, or they can depart directly to
Mars. The amazing truth is that it requires almost identical
amounts of fuel at the space station to do those two things. In
other words, if you go to the refueling base, it costs you
extra fuel that you could have used to go to Mars instead.
Chairman Rohrabacher. But, what I mean--well, if you could
manufacture the fuel on the Moon itself.
Dr. Lewis. That is right.
Chairman Rohrabacher. Then you don't have to haul it up in
order to refuel.
Dr. Lewis. You have to haul it up to where your expedition
is in orbit around the Moon.
Chairman Rohrabacher. Oh, in orbit around the Moon, I get
it.
Dr. Lewis. If you bring your expedition down to the surface
of the Moon, you are deep into the red ink in the ledger,
because the cost of landing and taking off completely erases
any advantage you might have hoped to get.
Chairman Rohrabacher. Dr. Spudis, do you have something to
jump in on that point?
Dr. Spudis. Well, I think it is--I think there is a little
confusion. The Moon's enabling role in Mars exploration is not
to build a Cape Canaveral on the Moon and to launch the mission
from there. It is to act as a logistics depot, and there have
been a variety of mission scenarios looked at by the
exploration people at Johnson Space Center where they stage all
missions from Earth Moon L1, that is the point that is halfway
between--well, it is not halfway, it is where the gravity
points balance, and it co-orbits with the Moon, so it always
hangs in space, it is always between Earth and Moon. And it
turns out that if you build a staging node at that L1 location,
a lot of things become very easy. You could have global access
to the Moon with no penalty for going to different latitudes.
You can stage returns to the Earth, so you can return exactly
when the orbital plane, for example, of the space station, if
you wanted to go to the space station, is in alignment, and it
is a good place to stage these missions. What they did was they
looked at the production of lunar rocket fuel, hydrogen and
oxygen, and worked that into a scenario for Mars missions, and
it turned out that if you did it for one Mars mission, it
wasn't worth it, but if you continually went to Mars--
basically, if you made a Mars launch at every opportunity to
send a mission there, that lunar produced fuel actually ended
up saving you a great deal of money because you were not
lifting that fuel up from the gravity well of the Earth.
Chairman Rohrabacher. That may well be too far out----
Dr. Spudis. It may be.
Chairman Rohrabacher.--for people to think about.
Dr. Spudis. But the real significance for producing fuel on
the Moon is not for the Mars trip, it is to have routine access
to cislunar space, because right now, that is where all of our
assets are. All of our communications satellites, all of our
GPS resource satellites, all of our national security
satellites, are in the volume of space between Earth and Moon,
and right now, we have no way to access those. We launch them
and they are gone. If one fails, we write it off and launch
another.
The Value of Telescopes on the Lunar Surface
Chairman Rohrabacher. Okay. One other point of contention
that we had here was--two other points, and then I have got one
question, but I will let colleagues go before my last question.
There was some disagreement over the value of a telescope on
the Moon, and I noticed that Dr. Lester and Spudis disagree.
Maybe you can--you have each heard each other's testimony. Dr.
Lester or Dr. Spudis, what is--who is right? Somebody is wrong.
Dr. Spudis. I am right. No, I think it is a matter--I don't
think we disagree as much as it would appear. The question is
not, all things considered, where are you going to build the
biggest telescope we can, because nobody is asking the
astronomers that question. The question is if you are on the
Moon and you have some capability, does it make any sense to do
any astronomy from there, and I think the answer to that
question is yes. It may not be the ideal location, but it is a
location where significant things can be done. In some cases,
unique things. I think the dust issue is a completely solvable
one. That was looked at 12 years ago when we did the SEI
studies, and we have a lot of ways to mitigate that problem.
Chairman Rohrabacher. So going to the Moon to do astronomy
is not a good excuse to do astronomy. Once you are there, might
as well do it. You think that is----
Dr. Lester. I think it is a question of bang for the buck.
If you want to spend a certain amount of money and you want to
get the most science out of it astronomically, putting a
telescope on the Moon is not necessarily the smartest thing to
do. Now, if somebody was going to give me a billion dollars and
say, Dan Lester, go put a telescope--would you want to go put a
telescope on the Moon, I would say, well, as long as that
billion dollars isn't being taken away----
Chairman Rohrabacher. I see.
Dr. Lester.--from doing astronomy somewhere else, I guess
so. You could give me a billion dollars to put a telescope in
Central Park and I would go put a telescope there and I could
get some astronomy done from Central Park, but I don't think it
is----
Amount of Water on the Lunar Surface
Chairman Rohrabacher. All right. I got your point. Now,
there was one other disagreement with Dr. Spudis, this time by
Dr. Campbell, over exactly how much water there is on the Moon,
and it seems we have a disagreement here. Again, who is right?
Who is wrong?
Dr. Campbell. Well, of course, as Paul would obviously say,
you know we would jointly say, you know, I am. But I am not
sure that--the issue is not how much water there is on the
Moon. The real issue--because all that hydrogen could be
combined with the oxygen and form water if you are willing to
mine 10,000 tons of lunar regolith to give you one ton of
hydrogen, you could then produce more. It is a very expensive
way to produce it. What you need is to have sources of water
that are in sufficient concentration that it is worthwhile and
adequately located--that it is worthwhile to actually make use
of them. So, you need reasonable concentrations of water. That
seems to occur potentially in the shadows craters--bottoms of
these shadows craters at the lunar poles, 1.5 percent, but if
that turns out to be a number or potentially higher area. If we
have better resolution and can look at smaller areas, we may
locate regions with high concentration. Possibly radar systems
may locate areas where we have thick deposits that are
currently not visible from the--not visible from the Earth or
the Clementine radar mission. And, so, what we need to find is,
say, is not, you know, how much water, but we need to find
water in real usable concentrations. And the other issue, of
course, is accessibility, as Dr. Lewis has pointed out, that
these are likely to be in the bottoms of large impact craters.
And I am talking about large--anything 10 kilometers or
larger--accessibility to the bottom of those craters where the
temperature is 100 degrees Kelvin or lower, that are
extremely--they are deep. We are talking about craters that are
6,000 feet deep or more, and so--and with very steep slopes,
and so this is--these are not easy locations to actually look
for water, and so we have to be realistic about the
accessibility issue.
Chairman Rohrabacher. Now, what----
Dr. Campbell. Now, hopefully, maybe, we might find it in
somewhat more accessible areas, but----
Chairman Rohrabacher. But over the years, I remember in the
beginning the only reason we discovered that there is water on
the Moon is the fact that you had a bunch of rebels who were
willing to basically not listen to the skeptics and force the
issue. I mean, this first--the first missions that we had there
were just--were not really the established--the space
establishment was actually against this, and then when there
was some indication that water existed, then everybody wanted
to get on board. Well, Mr. Spudis, do you want to say
something?
Dr. Spudis. Yeah. First, I would like to comment on the
previous question about the disagreement. It is actually what
he and I believe is irrelevant. The real issue is we don't know
the answer.
Chairman Rohrabacher. Yes.
Dr. Spudis. And what we really need to do is to fly a
spacecraft that will get us the answer.
Chairman Rohrabacher. All right.
Dr. Spudis. And in NASA's plan, that is what they are
doing.
Chairman Rohrabacher. But let us resist consensus. If I can
say there is a consensus that everybody seems to agree that the
most important factor to determine that we need to put very
high on our priority list in going back is determining how much
water and how accessible it is on the Moon.
Dr. Spudis. But also, what condition it is found in. Now,
it is in low concentration, but remember, we are looking at low
resolution, and in that case, you have a problem. You don't
know if a low resolution signal from a big--low signal from a
big target, does that mean it is all uniformly distributed
throughout that target? In which case, it is very hard to
recover it. Or, does it mean that it is lumpy like a chocolate
chip cookie where there is ice bits here and there that are in
concentrated form. If we have this mission, we can determine
that answer. As far as the terrain and accessibility issues go,
the Moon is actually--this doesn't seem--this is
counterintuitive, but the Moon is actually a very smooth
object. Craters that look very steep at low sun angle actually
have accessible slopes. The crater at the center right near the
south pole, Shackleton, is 23 kilometers across. It looks like
the rim is a knife edge, and it looks like it slopes down at a
big cliff. In actual fact, the rim--the slope up to the rim is
only about five percent and the slope from the rim crest down
to the floor is about 15 percent. Both of those are traversable
with rover-type equipment, so it is not as hazardous as it
looks. And secondly, in space, it is very easy to keep warm
when it is cool. It is very energy intensive to keep cool, so I
anticipate that operations in the dark will be challenging, but
I don't anticipate that they will be impossible. But again,
that is another thing that we have to go and actually learn.
Chairman Rohrabacher. Mr. Lampson.
Additional Data Needed Before a Human Return Mission
Mr. Lampson. Given the data acquired by the Apollo lunar
landing program and its robotic precursors, as well as the data
obtained by the subsequent Clementine and Lunar Prospector
spacecraft, what additional information, if any, will be needed
by NASA before NASA can send humans back?
Dr. Spudis. Well, the missions that I think several of us
have outlined in our testimony are the obvious first step, is a
reconnaissance from a polar orbit to map the deposits in the
environment of the poles. Then, you want to land at those
deposits and sample them and make some in situ measurements to
see what they are really made of and what their physical state
is. And, then, finally, you want to maybe land some
demonstration experiments where you might process that stuff to
see if it is possible, and those things should precede human
return. Now, they don't have to. I mean, you could send people
right now with what we know. It would be a bit risky, but we
could do that.
Canceled Apollo Missions as Future Expeditions
Mr. Lampson. Anybody else want to make a comment? If not,
the last few Apollo missions which were cancelled by President
Nixon in the '70s were intended to explore scientifically
interesting locations on the Moon. Would it be appropriate to
use the plans for those mission as the basis for the next human
expeditions to the Moon?
Dr. Swindle. Probably not, in my opinion, because----
Mr. Lampson. Why not?
Dr. Swindle.--what is important now is to learn about some
regions that we weren't able to go to at that time, and so the
Apollo missions were rather restricted, and I believe those
were also in the same general geographic area, so we would want
to go someplace different. And, so, I suspect that those would
not be the appropriate mission plans.
Dr. Spudis. You can still get valuable science from almost
any site you want to go to on the Moon, even returning to an
Apollo site, because there are questions we would ask now,
going to an Apollo site, that we weren't smart enough to ask 30
years ago. But, I agree with Tim that basically you want to try
to sample terrains we haven't been to, like the far side or the
limb region, the Orientale Basin, and areas near the poles
because we have never been there and we don't know what is
there.
International Cooperation
Mr. Lampson. Most of the discussion of the President's
program is focused on what NASA will do, but the President did
clearly invite participation by other nations. We know that
Europe, Japan, China and India have robotic lunar programs--
probes planned. To what extent is the lunar--is the robotic
exploration of the Moon is being coordinated internationally?
What is the mechanism for that coordination? Are we going to
share data? What are your thoughts about what we do with that?
Dr. Spudis. It is interesting you ask that because I
haven't observed any coordination. There is a group called
ILEWG, which is the International Lunar Exploration Working
Group, and they allegedly coordinate missions between different
countries, but if you look at the manifests for these missions
that are going to the Moon, a lot of them are carrying the same
instruments. So, if that is coordination, they are not doing a
very good job. It appears that when it comes to lunar missions,
a lot of these countries want to fly their own experiments, and
regardless of whether the data set exists or not, they tend to
go ahead and fly the same instruments again and again.
Mr. Lampson. Dr. Lewis.
Dr. Lewis. It is a rather interesting, but I might be able
to answer your questions two years from now. In the summer next
year, I am taking a leave of absence for one year to go to
Tsinghua University in Beijing where I will be a visiting
professor and teach space science there, the first planetary
science course ever taught in China. The reason for going to
that particular location is that Tsinghua is the home of most
of the engineers who are responsible for the Chinese space
program. It is the leading science and technology university in
China, and I hope to return, not just older, but considerably
wiser after that experience.
Mr. Lampson. Good luck with that. That sounds like it would
be a fascinating one. Any recommendations that you have to
try--any of you, to try and further any kind of coordination?
Well, what you are doing is wonderful. Hopefully that will lead
to a greater mutual participation. Dr. Campbell, were you going
to say something?
Dr. Campbell. I wasn't actually, but----
Mr. Lampson. Oh.
Dr. Campbell.--the answer to that is that--while these
personal efforts are great, but I think these need to be done
on government to government bases and it would be nice if they
were to coordinate and to put together other countries.
Mr. Lampson. If we develop a plan--should we plan for a
comprehensive sized program on the Moon, or maybe break it into
specialties somehow or other, specializing in certain
activities, and maybe let certain of our--certain cooperatives
do one thing and us do another?
Dr. Spudis. Do you mean sort of divide the responsibility--
--
Mr. Lampson. Yeah.
Dr. Spudis.--for things to do on the Moon among different
countries?
Mr. Lampson. Yes.
Dr. Spudis. That is one model. I don't know if you would
have any particular advantage to that. I think, in part, it
depends on what the national agenda is of the various countries
that go to the Moon. Some are going for differing reasons, and
I suspect that, if the past is any guide with our country, we
will try to cram as much as we can onto what we can do, and we
will try to cover as many disciplines as we can.
Mr. Lampson. For me, with the European Smart One probe----
Dr. Spudis. Yes?
Mr. Lampson. It is supposed to reach the Moon in 2005. It
is designed to look for water ice to--and prepare detailed
mineral maps. What role does the United States in that? Will we
have access to the data that is gleaned from it--from their
studies?
Dr. Spudis. My understanding is they plan to share the
data, but I am not aware of any Americans that are directly
involved in the mission. It is strictly a European mission,
and--but I--they certainly--I have been talking to scientists
involved with that, and they are very anxious to share the data
with us.
Mr. Lampson. If we learn something that would be helpful,
is it possible that we could eliminate some of our own probes
or particular missions, perhaps?
Dr. Spudis. I don't think so because the instruments they
are carrying--and Smart One is a technology mission. It is
being--it is electric propulsion. It is going to go in a very
elliptical orbit. It is not an ideal mapping orbit. Parts of
the Moon will be photographed at high resolution, other parts
will be not covered at all, and one of the goals of the
missions we have described in our testimony is that we want to
systematically map the Moon to assess things like the resource
capability and the science issues. And Smart will contribute to
that, but it is not a replacement for what we want to do.
Mr. Lampson. Okay. Mr. Chairman, by the clock, I am out of
time.
Chairman Rohrabacher. All right. We have Mr. Bartlett.
Mr. Bartlett. Thank you. I understand that both India and
China are planning to go the Moon before we go back. Are we
collaborating with them?
Dr. Spudis. Well, the Indians have made available a 10-
kilogram payload space on their lunar mission Chandrayaan-1.
Mr. Bartlett. For us?
Dr. Spudis. For anyone in the world.
Mr. Bartlett. Anybody, okay.
Dr. Spudis. And they have received a bunch of proposals. In
fact, I submitted one myself.
Mr. Bartlett. Okay. Do they share--plan to share the
information they gather with the world, or is it going to be
proprietary to their country? Have they told us?
Dr. Spudis. The Indians plan to share.
Mr. Bartlett. They plan to share?
Dr. Spudis. Yes.
Mr. Bartlett. We don't know about the Chinese?
Dr. Spudis. We don't know.
Mr. Bartlett. Okay. I am old enough to have been involved
in the space program since its inception. I remember at
Pensacola, Florida, I was involved in what I think was the
first sub-orbital primate flight, Monkey Able and Monkey Baker.
Monkey Able, an Army monkey that they gave a general anesthetic
to to take the electrodes out and he died. We didn't do that
with Monkey Baker, and she was a little squirrel monkey which
lived on for a long time at Pensacola, Florida. And then I
went----
Chairman Rohrabacher. Later elected to Congress, I might
add.
Mr. Bartlett. Yeah. Then I went to the Applied Physics Lab,
and that was before we landed on the Moon. And there was a big
question about what the lunar surface would be like, and one of
the suspicions was that it might be a dust ball and that you
stepped off the spacecraft, the spacecraft itself might just
sink down over its ears in the lunar dust. So we developed a
lunar spacesuit which is really a big sphere about eight feet
across that had, on one side of it, a little dome for your head
and spacesuit arms and legs so that you could use it like a
spacesuit, and the Moon is a very low gravity, so you could
easily carry that on your back. And if it was a dust ball, you
could simply walk inside of it, like a big ball--as a matter of
fact, we demonstrated that it really would do that by walking
on water for the first time in 2000 years. The little pond
there at APL, if you are familiar with that.
Dr. Lewis. Very well.
Our Knowledge of the Lunar Surface Regarding Vehicles on Mars
Mr. Bartlett. We walked down the slope and out on the water
in this lunar, I guess, it would have worked no matter what the
surface of the Moon was like. Fortunately, the powder was
packed and we didn't need that. My question is do we know
enough about the surface of the Moon and Mars to know if they
are sufficiently similar so that experience gained on the Moon
will help us in designing vehicles to get around on Mars?
Dr. Lewis. We know a considerable amount about both
surfaces, and they are in many ways quite different from each
other. There would be no difficulty at all in designing a rover
that can run around on Mars. You just--you know, we run them.
Mr. Bartlett. And we have--yeah--in one area limited, that
is correct.
Dr. Lewis. Yeah. There is some difficulty involved in
having a truly autonomous rover that has good enough sensors
and smart enough little brain to know how to avoid obstacles
and not kill itself. If you are aware of the recent attempt to
race fully automated and autonomous vehicles across the Mojave
Desert, you probably will understand that there is--the art is
yet imperfect. It would be very valuable to have a man in the
loop. If you are running rover around on the Moon, it would be
extremely useful to have a--what, a 12-year old with a joystick
sitting there in a nearby dome actually monitoring its
television transmissions and running it. Human intelligence has
many functions in exploration, and that is one of them. But it
is not an uncertainty in the nature of the bearing surface, but
simply an uncertainty about where the individual sharp rocks
are.
Mr. Bartlett. Both of them have a bearing surface that we
can get around on.
Dr. Lewis. Both of them definitely have a bearing surface.
Percent of the Moon That Has Constant Light
Mr. Bartlett. What percent of the Moon has constant
sunlight?
Dr. Spudis. An extremely small amount. It is just very tiny
little patches that are near the pole. And, in fact, we don't
actually know if they are constant sunlight because we have not
observed them through a seasonal cycle. But, Clementine
observed the North pole in the southern winter and we found
three spots that are in sunlight 100 percent of the time. It
observed the southern hemisphere through southern summer-or
southern winter, and we only found--we found three places that
are illuminated for greater than 75 percent of the lunar day.
There is no permanent sunlight at the South pole. We don't know
if that is true at the North pole.
Mr. Bartlett. Wouldn't there be big advantages in making
your first station there where there was perpetual sunlight?
Dr. Spudis. I believe so. In fact, I have advocated that.
Mr. Bartlett. Even though it is a very small area. Dr.
Lewis.
Dr. Lewis. If you were in such a location, you would be on
top of a crater rim on a point of high providence, and the
terrain around you would mostly be in darkness, some of it in
perpetual darkness. These are areas that are very difficult.
Not only are they essentially unmapped from Earth, but they are
very difficult to map from orbit because of the darkness
problem, so you would be limited in the--there would have to be
some other attraction to be there. The energy storage problem
on the Moon, as Dr. Spudis mentioned earlier, is a very serious
one. It is true that such a location at the poles solves the
energy storage problem, but it also introduces the problem that
you may not be where you want to be on the Moon for other
reasons, and that has to be looked at carefully and
synoptically.
Mr. Bartlett. But mapping the lunar surface would tell us
more about this?
Dr. Lewis. That depends on how you map it because you can't
map permanently shadowed crater bottoms optically.
Dr. Spudis. Well, you can with imaging radar.
Mr. Bartlett. Can we not with radar?
Dr. Spudis. Yes.
Mr. Bartlett. Yeah, we have to be able to. Yeah. Not with
optical, certainly, but with radar we have to be able to map
and know right precisely what is there. Yes. Thank you very
much.
Chairman Rohrabacher. One last question.
Dr. Campbell. I want to make--oh.
Chairman Rohrabacher. Go right ahead.
Dr. Campbell. Thank you. Can I make a comment that----
Chairman Rohrabacher. Oh, yes.
Dr. Campbell.--to your walking around inside your plastic
balloon, that Professor Thomas Gold at Cornell is a very great
and inventive scientist, but this was--he was responsible for
the suggestion that the Moon--you may just sink into the Moon
if you step on the surface, and over time has caused
considerable discussion of that issue at the time of the Apollo
landings. And, I guess he is probably happy he is--he is
probably sorry that he has put you to that trouble.
Mr. Bartlett. But this was OART that sponsored this, and
Dr. Walt Jones. They would come over--Captain Walter Jones come
over from the Navy after his retirement to chair the--or head
the OART. Does it still exist, OART?
Dr. Spudis. I don't know. It might have been subsumed into
another organization.
Mr. Bartlett. Okay. Thank you very much.
Role of Private Sector
Chairman Rohrabacher. One last question, and perhaps what I
will do is ask any of you who have a vision of the private
sector playing a role on the Moon after, or even during, the
initial phases of our return to the Moon, if you could write me
a one-pager on it and just give me your thoughts of what the
private sector could do, how you could see that, what you could
see them doing, and I will make sure that your thoughts and
your vision on this are put in as part of this record of this
hearing. And with that said, I would like to thank the
witnesses.
[The information referred to follows:]
Response by Paul D. Spudis
The role of the private sector in lunar development
Ultimately, I believe that lunar resources will be almost
exclusively developed by the private sector. At the present time,
however, there are significant barriers to involvement by the private
sector. These barriers fall into three principal categories: fiscal,
technological, and legal.
The private sector possesses neither the amounts of capital needed
nor the inclination to significantly invest in lunar resource
processing or development. This is largely because payoff on investment
is quite distant, at least on the order of a decade, and possibly
longer. The emplacement of significant capability on the lunar surface
requires not only investment in machines and equipment to conduct the
processing, but also a significant transportation cost. It takes
roughly 15 lbs. in low-Earth orbit to put one pound on the lunar
surface; at commercial launch costs exceeding several thousands of
dollars per pound, initial investment involves not millions, but
hundreds of millions of dollars.
The technical barriers are equally formidable. Although we know a
great deal about the polar deposits of the Moon in principle, the
specific details of deposit purity, thickness, physical properties, and
composition are all completely unknown. Acquiring this knowledge is an
important goal of NASA's robotic mission set, but prior to these
flights, much about the lunar ice remains conjectural. Even if the
properties of these deposits were known, we have no experience
extracting and processing such material. The acquisition of such
knowledge and experience should be a major programmatic goal of NASA's
lunar program.
Finally, legal problems will severely impact any significant
private sector involvement for the near future. Specifically, the
current legal regime of lunar resources is very unclear. I believe that
private property rights on the Moon do exist and are not precluded by
the U.N. Outer Space Treaty of 1967 (to which we are signatories), but
legal opinions differ. Congress should consider addressing this issue
at a very early stage in the initiative; a law guaranteeing private
property rights on the Moon (at least as recognized by the United
States government) would go a long way towards removing the current
ambiguity in the law.
I believe that the best way to encourage private sector investment
in lunar development is to phase it in gradually, as the NASA
exploration initiative gathers the necessary strategic scientific and
engineering information and develops the requisite technology. Early
involvement by the private sector could involve government incentive
schemes (e.g., tax breaks, prizes) or data purchase (e.g., NASA would
pay a set amount for a given piece or set of data and information). As
the initiative proceeds, activities that push back the envelope of
technology or engineering state-of-the-art can be privatized.
Government would likely be an early customer of lunar products, but
commercial activities would soon follow, particularly in the production
of propellant from lunar resources.
Space Exploration and National Security
Mr. Lampson. Well, before you go, could I just ask----
Chairman Rohrabacher. Mr. Lampson, go right ahead.
Mr. Lampson.--one thing that is sort of in passing of Dr.
Spudis. You had made some comments in your testimony about
protection of national strategic assets. Is this some of the
discussion that is going on with the Aldridge Commission? Is
there--can you enlighten us?
Dr. Spudis. I am not going to discuss any Commission
activity. All of my opinions that I presented today are my own.
Mr. Lampson. Is--has there been any discussion at any place
about that? I am a little interested in knowing if there is
going to be a greater involvement in our space exploration
effort more from the aspect of defense than from civil science.
I am curious about that.
Dr. Spudis. There is a lot of discussion going on. I don't
know if there are any official discussions going on. There was
a talk given here in D.C. a few months ago by James Oberg who
has written a book about space power theories, sort of the
Mahan of the 21st Century, and he is basically arguing--talking
about American space control, the idea of us being able to
protect and control our assets in space. I am for pushing it
from a slightly different point of view. I am not really
looking at the defense angle. I am saying that if you have the
capability to routinely travel throughout this volume of space,
that has to have implications on everything you do in that
volume of space, and that includes national security
activities, and it includes all of our commercial space
activities as well.
Mr. Lampson. Thank you.
Chairman Rohrabacher. Do you have something to say about
that, Dr. Lewis?
Dr. Lewis. Yes. There is some relevant ancient history
here, which is that back in the 1980s, there was a summer study
on Defense uses of space resources. It was instigated by,
actually, me knocking on Hans Marx's door when he was Secretary
of the Air Force, I think, and selling him the idea of the--the
study was done, I believe, in the summer of 1983 at the
California Space Institute, and the proceedings of that study
are still available, certainly not up-to-date, but it shows
that Defense Department has thought about these matters.
Chairman Rohrabacher. Now, let me leave you with one
admonishment, Dr. Lewis. You are on the way to China.
Dr. Lewis. In a year.
Chairman Rohrabacher. In a year.
Dr. Lewis. Yes.
Chairman Rohrabacher. I don't expect a major shift in
political structure in China in that year, and one of--I mean,
I would think that it would be a catastrophe for us to go to
the Moon, and then when we get there, find, you know,
chopsticks laying all over the place or something, evidence
that our Chinese friends have beat us to it. But I think what
is more important here is that I believe in cooperation--space
cooperation, but I believe in space cooperation between free
people, and I think that the worst thing that happened to us
was during the 1990s when our companies went over to China and
transferred know-how and technology that has permitted, now,
the Chinese to come to this point where they may well be doing
some things in space that we are not capable of doing right
now, and no matter how far along they are, I would just
admonish the scientific community that when we are dealing with
countries that are not free countries, it, sometimes, is not
beneficial for us to provide them the knowledge and the
technology they need to move ahead as fast as the Chinese, for
example, have moved ahead.
Dr. Lewis. I agree completely, and there will be no
technology transfer whatsoever. There will simply be an attempt
to inspire them in the vision of a cooperative exploration of
the solar system.
Chairman Rohrabacher. And let us hope that some day I don't
have to do that, because perhaps someday the Chinese people
will have a free country, and I am a great admirer of the
people themselves. And their government, of course, is a big
problem. But, for example, the Chinese--did you ever hear of
the South Pointing Chariot? They call it the South Pointing
Chariot. The Chinese developed----
Dr. Lewis. Are you talking about a magnetic compass or----
Chairman Rohrabacher. Well, everyone thought it was a
magnetic compass. But, I worked in the White House as a
speechwriter for President Reagan. President Reagan was going
to China, a very famous trip to China, I might add, and one of
the issues that I looked at was the South Pointing Chariot,
because I was writing some of his speeches, and I wanted him to
talk about some of the things the Chinese had accomplished over
the centuries. And, just for the record, what I found out is
what most historians believe was the development of a compass
by the Chinese, because they had a device which they put on top
of a wagon which would always point to the South. It was a
statue with its arm out like this, so they would not be lost in
the Gobi Desert and the far reaches of the desert. And what I
found is it was not a compass. And I did research on it, and
found out that it instead dealt with the development of a
differential gear in the wagon itself, which kept, no matter
which way the wagon turned, the statue stayed the same place.
There was not a differential gear developed in western
societies until about 150 years ago. And, so, while the compass
itself would have been quite a discovery, the idea that Chinese
engineers, back all those centuries ago, were able to conceive
of, and actually implement, a differential gear in a piece of
technology is quite astounding.
Dr. Lewis. There is no shortage of intelligence there.
Chairman Rohrabacher. That is for sure. Well, thank you all
very much. There is no shortage of intelligence in this panel,
and we really appreciate all of you witnesses testifying today,
and I will look forward to any input that you might have
suggestions of what the private sector could possibly do,
commercial as well as the foundations, education, business,
whatever types of things you would think they could do. Please
be advised that Subcommittee Members may request additional
information. For the record, I would ask other Members, of
course, who are going to submit written questions, to do so
within one week of the date of this hearing. And that concludes
this hearing, and I now say that we are----
[Whereupon, at 3:27 p.m., the Subcommittee was adjourned.]
Appendix:
----------
Answers to Post-Hearing Questions
Responses by Paul D. Spudis, Senior Staff Scientist, Johns Hopkins
University Applied Physics Laboratory; Visiting Scientist,
Lunar and Planetary Institute, Houston, Texas
Questions submitted by Chairman Dana Rohrabacher
Q1. NASA's Office of Space Science is responsible for the lunar
robotic portion of the Space Exploration Initiative. How would you
recommend the office reach out to the science community to carry out
this program? Is NASA using science advisory panels to select
instrument proposals for upcoming missions?
A1. There are two considerations here. First, is a mechanism in place
to assure that the correct measurements are being planned and made in
the correct priority? Second, how should instruments be selected for
the upcoming lunar robotic missions?
In answer to the first question, the measurement requirements are
being created through an ad hoc process, whereby a definition team,
selected by Code S, sets up a list of measurement requirements that the
LRO mission must obtain. This process created a requirements list that
more-or-less meets the critical priorities, with the exception that a
fairly heavy ( 20 kg) radiation experiment received a much higher
priority than is actually warranted (the radiation environment of the
Moon is already well characterized and such measurements do not
significantly impact the design of possible architectures for human
lunar missions). There should be a formal process to correct such
errors, but I believe in this case, the issue will be resolved
correctly.
The process that NASA currently uses to select mission instruments,
i.e., the competitive AO process, is as good as any, provided that
critical measurement needs are addressed in a timely manner. In this
process, NASA will assemble ad hoc panels of interested, but not
involved, scientists to judge the merits of proposed investigations. In
general, this process works well, except for certain unique or very
high-technology instruments or measurement capabilities that may only
be available through non-competitive channels. One important
consideration is the systems engineering/requirements process used in
these robotic missions, since the current Office of Space Science-
National Academy of Sciences driven strategy tends to produce ``one
off' solutions, not spiral development. This problem could be mitigated
by having Code T manage the robotic lunar program from the start.
Giving requirements to another legacy organization to implement can
produce less than optimum results.
Q2. The Space Exploration Initiative proposes establishing an extended
human lunar mission. Based on your knowledge of the Moon's environment
and resources, how difficult a task will it be to develop and sustain
humans for a two-month period? For a stay of that duration, would it be
practical to develop in situ resources to help sustain lunar
astronauts? How about a six-month stay?
A2. Lunar stays for periods of two months can be easily accommodated
without recourse to the use of local resources. However, since I
believe that one of our primary goals in a human return to the Moon is
to learn how to live off-planet, I would want to conduct some
experiments with resource extraction before and during such a human
mission. For example, one can imagine the landing of a small robotic
plant designed to process the local regolith and extract both hydrogen
and oxygen from the soil. This robot plant could operate continuously
for several months, producing and storing this material. The products
would then be available for use by the human crew upon their arrival on
the Moon.
For lunar stays of six months and more by people, I would want to
incorporate local resources into my habitation architecture. At a
minimum, I would want to use the local regolith as a radiation shield
(because of both continuous cosmic ray exposure and the likelihood of a
solar flare in that time period). Also, the production and use of lunar
oxygen would both provide the air supply in the habitat and also permit
fueling of the return vehicle and hydrogen and oxygen for fuel cell
energy storage. I think one of the primary goals of a human return to
the Moon is to learn the technical and operational difficulties of
living off-planet and use of local resources should be made a primary
mission goal. Energy storage will be a key issue. While nuclear energy
is feasible for some applications it will be very expensive. If there
are well lit areas at the poles, the use of locally produced water as
an energy storage medium could greatly expand the capabilities and
safety of the lunar operation. Also, nuclear energy is not well suited
for mobile applications.
Questions submitted by Representative Nick Lampson
Q1. Given the data acquired by the Apollo lunar landing program and
its robotic precursors, as well as data obtained by the subsequent
Clementine and Lunar Prospector spacecraft, what additional
information, if any, will be needed before NASA can send humans back to
the Moon by 2020?
A1. Primarily, we want to follow up on the Clementine and Lunar
Prospector discoveries that suggest the poles of the Moon are important
environments, with key deposits that will enable us to live and work on
the Moon for extended periods. Thus, we first need reconnaissance from
orbit to map the polar ice deposits, determine their thicknesses,
extent, and purity, measure the temperatures, lighting conditions, and
topography of the polar areas to determine the setting of the deposits,
and improve the geodetic control of the Moon so that we can land
precisely on it and navigate across its surface when we return. These
knowledge requirements should be met by the proposed Lunar
Reconnaissance Orbiter (LRO), currently planned for launch in 2008.
Cooperation with an international mission could enable some enhancing
measurements not possible with a single spacecraft.
After successful completion of an LRO mission, a lander should be
flown that will conduct detailed, surface measurements of the polar ice
deposits; a surface rover would likely be required for this mission. We
are specifically interested in knowing the composition and physical
state of the polar deposits and the nature of the environments of the
dark regions. Such a landed mission should be followed by a series of
robotic landers that would conduct demonstration experiments, testing
the processes and techniques of resource extraction. These small,
robotic missions should be completed before return of people to the
Moon so as to maximize the capability of the human outposts prior to
their establishment.
Q2. What will it take to definitively answer the question of how much
water ice might be on the Moon? How much time is it likely to take to
characterize the global availability of water on the lunar surface?
How many remote-sensing missions will be necessary to
obtain this complete characterization?
What will it take to map other lunar resources?
A2. The robotic mission series that I outline above should definitively
resolve whether there is ice on the Moon, where it occurs and its
physical state, the total quantities of ice, and its detailed chemical
and isotopic make-up. This information is critical to make informed
decisions about the kinds of processing to be undertaken to make the
commodities that we need from the lunar surface (mostly water, air, and
rocket fuel). Note that all this information is gathered by the first
two robotic missions: one orbiter and one lander. We could use
additional landers to go to different locations (for example, twin
larder/rovers to explore both the north and south polar regions), but
our fundamental questions should be answered after the successful
flights of these two missions.
Other lunar resources are either already well characterized (e.g.,
the mineralogical and chemical maps made by Clementine and Lunar
Prospector) or will be mapped at higher resolution and greater
precision by future lunar orbiters to be flown by other countries
(e.g., Japan's SELENE mission). Depending on the results of our polar
mission series, we may decide that it is important to explore
robotically new areas in equatorial regions that may contain
significant hydrogen and other volatile resources (e.g., regional
deposits of volcanic ash, such as near Rima Bode); none of these types
of deposits were studied during the Apollo program.
Q3. Would any of the scientific research you have discussed require
astronauts on the Moon as opposed to robotic orbiters, landers, rovers,
or research stations? If so, which research and why? Does any of the
scientific research or resource extraction you have discussed require a
permanent human presence on the Moon? If so, how soon should that
permanent human presence be established?
A3. Much scientific research on the Moon is possible with robotic
missions, but to truly solve the sophisticated questions we are now
asking, we need to have trained human explorers on the Moon and other
planetary surfaces. These human explorers should work in tandem with
robotic spacecraft to produce the best results. The specific example I
cited in my testimony--the impact flux in the Earth-Moon system--can be
addressed initially by robotic spacecraft taking grab samples from
carefully selected surfaces. But to fully understand the richness and
complexity of the lunar impact record, we need human experts in lunar
geology, mapping units, making careful observations in the field, and
selecting critical samples for laboratory analysis. In short, although
we can address scientific questions using only robotic spacecraft, the
full details of planetary history and evolution will yield themselves
only to a combined campaign using the best capabilities of both
machines and people.
Resource extraction from the Moon will likely be done mostly by
machines, but these machines will doubtless need constant human
supervision, maintenance, and repair. The Apollo program is replete
with examples where a swift kick from an astronaut was needed to get
some complicated machine to work properly. We will likely require such
kicks again and again in this new, difficult endeavor. I envision human
presence growing simultaneously with the robotic presence; send
machines first to do the initial processing, then send people within a
few months to monitor, maintain, and augment the robotic installations.
Humans could arrive for increasingly extended periods starting a few
months after the initial surface infrastructure is established.
Q4. Science by itself is not going to sustain the public's support for
the long-term program contemplated in the President's plan. After all,
the 1960s Apollo lunar landing program had developed some impressive
science capabilities, and Apollo 17 carried the first scientist-by-
training (geologist Harrison Schmidt) to work on the Moon.
Unfortunately, he was also the last. What is different enough about the
ideas you are advocating here that will avoid the fate suffered by the
Apollo program?
A4. The Apollo program was not about science, but about beating the
Soviets to the Moon. After that goal had been accomplished, the
political rationale for the program evaporated. Although excellent
science was done on Apollo, it was ``retro-fitted'' onto an operational
program and this fit was never completely comfortable. Apollo was a
non-optimum tool for lunar exploration, even though superb exploration
was done during the course of the missions (a tribute to the Apollo
astronauts and scientists for accomplishing as much as they did!).
Our return to the Moon is likewise not about science; it is about
creating a new and sustainable capability to journey beyond low-Earth
orbit. The key features of the new initiative to return to the Moon--
resource extraction, habitation, sustained presence--are all new; none
of these activities were part of the Apollo program. If we can create
new space-faring capability using lunar resources, we can access
routinely all of cislunar space (the volume of space between Earth and
Moon), where all of our current space-based assets reside. Such a
capability would have enormous implications for our national security
and economic health. In contrast to the Apollo program, which required
large amounts of funding in short time periods to meet its decadal
deadline imposed by the President, the new vision calls for a return to
the Moon under existing space funding. We merely need to direct our
research and spending toward a focused goal. Thus, the new space vision
is both affordable and sustainable, in contrast to the ``we're at war--
costs be damned!'' mentality of Apollo.
Answers to Post-Hearing Questions
Responses by Daniel F. Lester, Research Scientist, McDonald
Observatory, University of Texas, Austin
Questions submitted by Chairman Dana Rohrabacher
Q1. Please provide your views on what roles the private sector,
including businesses and educational institutions, can contribute to
the successful development and exploitation of lunar resources, and to
the provision of services in support of NASA's lunar exploration
program.
Based on current capabilities, do you believe the
private sector has unique expertise needed by NASA to return to
the Moon?
What are the biggest obstacles to private sector
participation in lunar exploration and resource exploitation
activities?
Once NASA has established a long-term presence on the
Moon, are there markets you believe could be exploited by
private industry, and if so, what might they be?
A1. The effort to develop and exploit lunar resources, should they be
found to be present in quantities that would make such exploitation
cost effective, will take a long time. Even in the new Vision for Space
Exploration, it may be several decades before such exploitation can be
achieved. With this understanding, concern about sustainability of the
Vision plan across many Congresses and many Presidential
administrations is an important one, and such concern should be applied
to the private sector as well. To the extent that our country is
dedicated to making lunar development happen, reliance on the private
sector to take a leadership role in doing it must be couched in a
certain level of long-range business planning that we are not used to
seeing. This mismatch of planning time scales is perhaps the biggest
obstacle to private sector participation, if not leadership, in space
exploration. If resources--in particular water for life support and
propulsion--are to be found on the Moon where the low gravity makes
supply of exploration missions energetically less costly, the private
sector could be called upon by the space agency to bid on such supply
efforts. Market forces could then decide whether such supply is better
done from the surface of the Earth, where resources are cheap but
transportation more costly, or from the Moon, where the reverse may be
true. Such a market-based approach is feasible, however, only if the
exploration plan is structured with regular short-term opportunities
for success and return on investment. Without such short-term
opportunities, we should not assume that the private sector will
significantly invest in opportunities that are several decades out.
The importance of educational institutions in the success of lunar
development can be understood from this same perspective of
sustainability. The students we train now are the science and
technology leaders of the future. They carry with them into their
careers the motivation and rationale for the exploration agenda. The
exploration initiative as a whole will be driven by those who can think
outside the box, accept risks, and be able to map the excitement about
space travel onto national priorities and long-range business success.
While students do not have the experience to carry out the detailed
efforts required, they are better able to look beyond yearly balance
sheets for corporate profits, and make these strategic leaps. Providing
schools with mechanisms for a general sense of ownership in space
travel is thus a wise national investment. Such mechanisms for
ownership could be training partnerships with the space agency and
space entrepreneurs, challenges and contests, and drawing clear lines
between technology needs of all kinds and space efforts. It is clear to
me, from a university environment, that space efforts are exciting to
everyone, but those who would enter the workforce developing
microprocessors, building bridges, and understanding the molecular
processes in cells do not feel as linked to space exploration as those
few who design rocket engines and space telescopes. That has to change.
For younger students, it is less important to cultivate understanding
of space technology and astrophysics than it is to cultivate an
appreciation for exploration. We teach social studies and history. Why
don't we teach exploration? Curriculum that highlights the achievements
of explorers (whether they be scientists, ship captains, or inventors)
and teaches exploration as a national priority builds in children the
kind of national self-image that the Vision initiative will need
several decades hence.
Whether or not the private sector is called upon in this way, it is
clear that development of the Moon must be clearly and conspicuously
coupled to a real national need, such that we are willing to spend
money to underwrite and bring enthusiasm to it. This national need
could be driven by resource development (supply of exploration missions
with, e.g., water, as above), return to Earth of lunar-unique resources
(e.g., 3He), or simply national pride and accomplishment.
Our lunar program of thirty years ago was clearly based on the latter,
and our success was astonishing. We now measure our ability as a nation
to do hard things against our national effort to go to the Moon--one of
the hardest things ever done by mankind. The can-do spirit that drives
our nation has some grounding in this success, I believe.
The importance of a long-term presence on the Moon within the new
Vision for Space Exploration has yet to be established. As the plan
states, the scope and types of human lunar missions and systems will be
determined by their support to furthering science, developing and
testing new approaches, and their applicability to supporting sustained
human space exploration to Mars and other destinations. Should long-
term presence on the Moon become part of the new Vision plan, it can be
assumed that it is because such presence brings value to the enterprise
and as such offers obvious opportunities for private industry in the
market-driven model proposed above. Private industry is much better
suited to supply-and-demand roles than the Federal Government. In the
same way that private industry is now used routinely by the Federal
Government in a cost-conscious manner through competitive procurement
to maintain and operate federal investments, whether for science
management, resource development, or facility operations, so it can be
on the Moon. To the extent that such efforts have to be consistent with
a broader operations plan, as it is at military bases and agency
centers on Earth, these efforts will likely have overall management by
the space agency. Should lunar resource development or manufacturing
eventually find markets that are external to federal investments (for
example, if 3He is mined on the Moon specifically for
marketable power production on Earth) this model will need
reevaluation.
Q2. NASA's Office of Space Science is responsible for the lunar
robotic portion of the Space Exploration Initiative. How would you
recommend the office reach out to the science community to carry out
this program? Is NASA using science advisory panels to select
instrument proposals for upcoming missions?
A2. It is my understanding that the Office of Space Science is using
advisory panels that include a strong scientific background to select
instrument proposals for upcoming missions, such as the upcoming Lunar
Reconnaissance Orbiter. The needs for the exploration initiative are
fairly specific with regard to lunar exploration. They are in part
scientific, and in part an assessment of resources available. Thus
these panels necessarily include scientific, technological and
engineering representation. The resources we find on the Moon may
dictate very strongly the way we use the Moon in the future, and the
role that it plays in the exploration agenda. As a result, it is of
great strategic importance to understand what these resources are, and
how easily they may be harvested and utilized. The Office of Space
Science has historically done an excellent job in reaching out to the
science community to develop missions, and I expect it to do the same
for lunar exploration that is part of the Vision initiative.
Q3. The Space Exploration Initiative proposes establishing an extended
human lunar mission. Based on your knowledge of the Moon's environment
and resources, how difficult a task will it be to develop and sustain
humans for a two-month period? For a stay of that duration, would it be
practical to develop in situ resources to help sustain lunar
astronauts? How about a six-month stay?
A3. An extended lunar mission, as distinct from the long-term presence
discussed above, will be a challenging effort that could bear strongly
on our ability to carry out a mission on Mars. It should be clearly
understood, however, what such an extended mission offers us beyond the
considerable knowledge provided by our long-term human space experience
on the International Space Station. Although I do not have background
on human life support in space, I will venture to say that efforts to
simply extrapolate our Apollo several-day experience to several months
will likely involve a lot more than increased masses of consumables.
Knowing what we know now about the lunar surface, while relying on in
situ resources offers a real challenge, it does not offer a clear path
to near-term success. Landing humans on the Moon requires technology
that could also land supplies nearby with a separate vehicle, and I
would predict that launch costs of a dedicated supply vehicle would be
lower than development of reliable low-risk systems to, say, extract
oxygen from lunar rocks or ice. Since the extended lunar mission is
specifically envisioned as paving the way for Martian efforts, near-
term success is a priority. Also, it is by no means clear how
exploitation of lunar resources can be used productively to teach us
how to survive on Mars, as those two surfaces are considerable
different. Efforts to develop lunar resources in this manner could thus
be considered a fiscal and managerial distraction from the Martian goal
if not approached wisely.
Question submitted by Representative Nick Lampson
Q1. Science by itself is not going to sustain the public's support for
the long-term program contemplated in the President's plan. After all,
the 1960s Apollo lunar landing program had developed some impressive
science capabilities, and Apollo 17 carried the first scientist-by-
training (geologist Harrison Schmitt) to work on the Moon.
Unfortunately, he was also the last. What is different enough about the
ideas you are advocating here that will avoid the fate suffered by the
Apollo program?
A1. While I believe that the Moon is an important science target, and
quite possibly a useful station for the exploration of the solar
system, we should not lose sight of the fact that many opportunities,
both science and otherwise, are to be found in free-space, whether in
low-Earth orbit or beyond. Our investment in the International Space
Station has given us expertise in this regard. Low-Earth orbit has been
an enabling destination, giving confidence in microgravity performance,
rendezvous skills, and deployment and construction strategies. From a
science standpoint, and quite likely from a capabilities standpoint,
exploration of the solar system will be more about free-space than
about dirt. If resources on the Moon present a low-cost opportunity to
develop free-space, then the Moon has great value. If we as a nation
decide that survivability as a species requires long-term presence on
the Moon, then it also has value. If those resources are not to be
found there, or if that survivability decision is not cogent, the Moon
is less important to the grand picture. Going to the Moon simply to be
on the Moon does not seem a defensible goal, and can only divert
attention and resources from a human voyage to Mars, which is the next
great challenge that space offers.
The fate of the Apollo program was that we succeeded. We set out a
goal that was an enormous challenge to the Nation, and we lived up to
it. We proved our stuff to ourselves and to others. After we achieved
that goal we were, quite simply, done. The termination of that program
was strategic acknowledgment of that fact. The fate of the space
program after Apollo was that we were reluctant to commit to new long-
range goals, and it is these long-range goals that the new Vision for
Exploration addresses. The Vision can succeed if it articulately
addresses key national needs, and represents value to the taxpayer.
Answers to Post-Hearing Questions
Responses by Donald B. Campbell, Professor of Astronomy, Associate
Director, National Astronomy and Ionosphere Center (NAIC),
Cornell University
Questions submitted by Chairman Dana Rohrabacher
Q1. Please provide your views on what roles the private sector,
including businesses and educational institutions, can contribute to
the successful development and exploitation of lunar resources, and to
the provision of services in support of NASA's lunar exploration
program.
Based on current capabilities, do you believe the
private sector has unique expertise needed by NASA to return to
the Moon?
What are the biggest obstacles to private sector
participation in lunar exploration and resource exploitation
activities?
Once NASA has established a long-term presence on the
Moon, are there markets you believe could be exploited by
private industry, and if so, what might they be?
A1. Based on the experience of the Apollo program and the International
Space Station, private industry expertise would clearly play a very
important role in a return to the Moon with industry participation
being contracted by NASA or some other government agency. I am
personally pessimistic that there are resources on the Moon that would
be commercially exploitable for use on the Earth or in near-Earth orbit
in the foreseeable future without substantial direct or indirect
government subsidies. Solar power generation has been mentioned. While
it may be possible to utilize local resources to fabricate the
collectors, beaming the power back to Earth requires relatively
sophisticated technology much of which would need to be transported to
the Moon. The cost of this, combined with difficulties related to the
lunar day/night cycle and the orbital motion of the Moon, would very
likely make a lunar based solar power system uncompetitive with one
placed in a synchronous orbit above a fixed location on Earth.
Q2. NASA's Office of Space Science is responsible for the lunar
robotic portion of the Space Exploration Initiative. How would you
recommend the office reach out to the science community to carry out
this program? Is NASA using science advisory panels to select
instrument proposals for upcoming missions?
A2. There seems little reason for NASA to change existing practices for
organizing and arranging for participation in space missions. An
``Objectives and Requirements Definition Team'' was established for the
Lunar Reconnaissance Orbiter (LRO) mission that laid out the primary
objectives of the mission and a possible instrument payload which would
enable the objectives to be met to the greatest extent possible. An
announcement of opportunity was then issued by NASA soliciting
proposals for instruments to be carried on LRO.
Q3. The Space Exploration Initiative proposes establishing an extended
human lunar mission. Based on your knowledge of the Moon's environment
and resources, how difficult a task will it be to develop and sustain
humans for a two-month period? For a stay of that duration, would it be
practical to develop in situ resources to help sustain lunar
astronauts? How about a six-month stay?
A3. The MIR and International Space Station have shown that it is
possible to support humans in space over extended periods. The
difficulties in maintaining a human presence on the Moon, however, for
even a few months should not be underestimated. Only a determined and
sustained preparatory effort would make such an enterprise feasible.
Issues such as the radiation environment and power requirements during
the long lunar night have been extensively discussed and various
solutions proposed including siting a base at the lunar poles where
there may be areas that are in near permanent sunlight and where
resources such as water ice may be present.
Developing the infrastructure to allow local resources to be
utilized will require an extended and sustained effort. An initial two-
month stay by astronauts must be preceded by pre-positioning of vital
supplies and shelters and, if it seems feasible during the planning
stages, the establishment of automated facilities for extraction of
lunar resources such as oxygen. There is no point to such a long stay
unless it is part of a sustained effort to establish a base that would
allow even longer stays (e.g., six months) and the use of local
resources to the maximum extent possible.
Questions submitted by Representative Nick Lampson
Q1. Given the data acquired by the Apollo lunar landing program and
its robotic precursors, as well as data obtained by the subsequent
Clementine and Lunar Prospector spacecraft, what additional
information, if any, will be needed before NASA can send humans back to
the Moon by 2020?
A1. The Clementine and Lunar Prospector orbiters provided maps of the
mineralogy and elemental composition of the lunar crust, and Lunar
Prospector data suggest the possible presence of water ice in
permanently shadowed regions near the lunar poles. What is needed, and
could be accomplished by the instrument suite recommended for the Lunar
Reconnaissance Orbiter (LRO), is a comprehensive survey of the Moon's
polar regions, focused on identifying possible deposits of ice that
could be viable resources for even temporary human habitation. The LRO
mission and possible follow on missions, will also need to carry out
detailed surveys for possible base sites. This involves issues such as
landing safety, lighting conditions over the course of a year, suitable
terrains for vehicles and proximity to resources.
Q2. What will it take to answer definitively the question of how much
water ice might be on the Moon? How much time is it likely to take to
characterize the global availability of water on the lunar surface?
How many remote-sensing missions will be necessary to
obtain this complete characterization?
What will it take to map other lunar resources?
A2. While there may be very small quantities of water ice in the
general lunar soil due to protons implanted by the solar wind, they are
not recoverable. The only likely locations with significant recoverable
concentrations of water ice are permanently shadowed terrains at the
lunar poles. Only two methods are currently known to remotely sense the
presence of water ice; radar and neutron spectrometers. A single
mission with these two instruments will provide the best information
that we can obtain from orbit. Radar can detect ice in the form of
relatively thick sheets, a meter or more in thickness depending on the
wavelength of the radar. These sheets can be buried under two meters or
more of lunar soil and would still be detectable by radar. Neutron
spectrometers detect the presence of hydrogen which may or may not be
associated with oxygen in the form of water molecules. Very high
concentrations of hydrogen can reasonably be interpreted as indicating
the presence of water ice. This ice could be in any form, small
crystals or larger sheets, in the upper meter or so of the surface. A
survey of the lunar polar regions with these instruments on an orbiter
such as the planned Lunar Reconnaissance Orbiter, would take a few
months. Verification could be accomplished by in situ measurements
carried out by landers or penetrators.
Other lunar resources include iron- and titanium-rich lava flows,
and possibly isolated deposits of volcanic glasses that may contain
useful materials. Most of these deposits have been well-mapped from
orbit, and would require little additional information to target
initial surface experiments in resource extraction.
Q3. Would any of the scientific research you have discussed require
astronauts on the Moon as opposed to robotic orbiters, landers, rovers,
or research stations? If so, which research, and why? Does any of the
scientific research or resource extraction you have discussed require a
permanent human presence on the Moon? If so, how soon should that
permanent human presence be established?
A3. It has long been suggested that the Moon would be a preferred site
for astronomical telescopes operating at wavelengths that are affected
by the Earth's atmosphere or, in the case of radio astronomy, to
isolate the telescope from the effects of radio frequency interference
on the Earth. While there is a debate as to whether, in the long-term,
it is preferable for such telescopes to be free-flying space
instruments or located on the lunar surface, if they are placed on the
Moon then a human presence will probably be needed for the initial
installation and, possibly, periodic maintenance. They should be able
to run robotically in normal operation.
Unless some commercially viable resource is discovered on the Moon
I would think that there is little justification for establishing a
permanent human presence on the Moon. However, this comment could have
also been made about the Earth's south pole but for geopolitical and,
more recently, scientific research considerations, the United States
maintains a permanent presence there.
Q4. Science by itself is not going to sustain the public's support for
the long-term program contemplated in the President's plan. After all,
the 1960s Apollo lunar landing program had developed some impressive
science capabilities, and Apollo 17 carried the first scientist-by-
training (geologist Harrison Schmitt) to work on the Moon.
Unfortunately, he was also the last. What is different enough about the
ideas you are advocating here that will avoid the fate suffered by the
Apollo program?
A4. The United States has been supporting a human presence in space for
over forty years. Withdrawing from space seems unthinkable. Explaining
to students that we once had the capability to regularly visit the Moon
but have not been back in over 30 years is difficult enough. For the
next generation of teachers to explain to students that sending humans
into space was once relatively routine but that we decided to withdraw
from space would be even more difficult. However, the practical issue
of ``why do we want to be in space'' is a difficult one. It is clear
that the International Space Station is not the science platform that
its backers long touted and that its major use is the study of the
long-term effects on humans of micro-gravity. That leaves the only
possible reason for a human presence in space, exploration, the
traditional reason that great risks in both lives and money have been
taken. Setting up a base on the Moon is little different from the Space
Station, just more expensive and accompanied by greater risk. Therefore
its only justification has to be in terms of preparations for an
expedition to Mars. Sustaining public interest in, and the willingness
to continue to expend large sums on this decades long endeavor will be
a significant challenge. The Apollo program enthralled the American
(and the world's) people despite much of that decade being one of great
social turmoil. We need to engender the same enthusiasm for a Mars
program.
Answers to Post-Hearing Questions
Responses by John S. Lewis, Professor of Planetary Sciences, Co-
director, Space Engineering Research Center, University of
Arizona
Questions submitted by Chairman Dana Rohrabacher
Q1. NASA's Office of Space Science is responsible for the lunar
robotic portion of the Space Exploration Initiative. How would you
recommend the office reach out to the science community to carry out
this program? Is NASA using science advisory panels to select
instrument proposals for upcoming missions?
A1. NASA's traditional method of issuing an announcement of
opportunity, receiving proposals, peer review, and selection is
appropriate for use in future science missions. However, experiments
directed toward resource extraction and processing enter new terrain,
and there are no acceptable precedents. The one flight experiment on
resource extraction selected to date was hand-picked by JSC without
peer review and without competition, a poor precedent for the future.
Further, the NASA organizational structures responsible for space
resource processing have been repeatedly decimated, dissolved, and
transplanted. A stable program office with competence in space resource
processing is essential for further progress. How NASA will choose to
handle this problem is completely unknown.
Changes in the administrative structures for resource-related
research over the past 20 years, even when well-intended, have been
poorly implemented. The unintentional cancellation of the NASA
Universities Space Engineering Research Centers (as described to me
privately by Dan Goldin) is a case in point. Another example was the
decision to place space resource research under the aegis of the
Microgravity Processing research program, which previously, over a
period of several years, had insisted that it had no interest in
processing extraterrestrial materials. The announcement of this new
proposal opportunity by the Microgravity office was sent to their list
of prior clients, none of whom had worked on space resource extraction,
and the opportunity remained essentially unknown in the space resource
community until after the money was awarded. These two fiascoes
resulted in the permanent loss of some 90 percent of the research
groups that had competence in this area.
The system for resource-related research is broken and must be
fixed.
Q2. The Space Exploration Initiative proposes establishing an extended
human lunar mission. Based on your knowledge of the Moon's environment
and resources, how difficult a task will it be to develop and sustain
humans for a two-month period? For a stay of that duration, would it be
practical to develop in situ resources to help sustain lunar
astronauts? How about a six-month stay?
A2. For sufficiently short mission durations, the advantages of
resource utilization vanish. Basically, for short missions the mass of
processing equipment may be greater than the mass of products needed,
so that it would make more sense to carry the required products from
Earth. Whether the break-even point lies at mission durations of one
month, or two, or some other number depends in a complex way on the
size and nature of the demand, the available power level, and the
specific resources available at the site.
Note, however, that the time duration of a manned mission may be
completely unrelated to the length of time the processing equipment can
function: it would be highly desirable to land an automated processing
unit well in advance of the arrival of a manned mission, so that an
abundant supply of consumables (air, water, propellant) can be at hand
from the moment of the crew's arrival on the Moon. With proper advance
planning, any manned mission of any duration could profit from the
prior emplacement of unmanned processing equipment.
Questions submitted by Representative Nick Lampson
Q1. Given the data acquired by the Apollo lunar landing program and
its robotic precursors, as well as data obtained by the subsequent
Clementine and Lunar Prospector spacecraft, what additional
information, if any, will be needed before NASA can send humans back to
the Moon by 2020?
A1. Strictly speaking, no new data are required before the resumption
of manned expeditions to the Moon. If, however, cost containment and
operational flexibility are priorities, then resource characterization
and small-scale demonstrations of processing schemes should both be
accomplished before resumption of manned missions.
Q2. What will it take to answer definitively the questions of how much
water ice might be on the Moon? How much time is it likely to take to
characterize the global availability of water on the lunar surface?
How many remote-sensing missions will be necessary to
obtain this complete characterization?
What will it take to map other lunar resources?
A2. It is actually more useful to know the concentration of ices, the
chemical nature of the ices, and the vertical distribution of ice in
the uppermost one or two meters of the regolith than it is to know the
total magnitude of the ice deposits. From a practical point of view, it
is not necessary to have a global understanding of the abundance and
distribution of ice from the outset, only to have assurance that there
is at least one locale where the resource constitutes a true ore body,
meaning that the location, abundance, purity, extractability,
suitability for processing, and proximity to a plausible site of demand
combine to make the use of that resource profitable.
A single mission could, with luck, provide such data. With poor
luck, dozens of lander missions in the polar regions may not find a
single suitable location; indeed, there may not be any suitable
locations.
Mapping of other attractive resources, such as ilmenite (a source
of oxygen, high-purity iron, and refractory oxides) has already been
accomplished to a remarkable degree from Earth and from spacecraft.
Rich, wide-spread deposits are well documented. It is not obvious that
better mapping would be of any practical significance.
Hydrogen mapping, aside from ice, can be done only very indirectly
by remote sensing. Our experience with the Apollo samples shows that
hydrogen and helium, both implanted by the solar wind in surface
mineral grains in the near-side Mare basins, are strongly enriched in
the mineral ilmenite. Therefore existing ilmenite maps are likely to be
very good guides to the distribution of hydrogen. However, the
concentration of hydrogen in even the most ilmenite-rich regions is
generally no higher than 50 to 100 parts per million (50 to 100 grams
per tonne).
Should helium-3 emerge as a desirable fusion fuel, the same
ilmenite maps would serve as excellent guides to helium-3 ``deposits''
(recalling that the ceiling on the helium-3 concentration is about 0.01
parts per million).
In general, I remain skeptical of the practical value of polar ice
and confident that other oxygen sources can be practically utilized.
Q3. Would any of the scientific research you have discussed require
astronauts on the Moon as opposed to robotic orbiters, landers, rovers,
or research stations? If so, which research, and why? Does any of the
scientific research or resource extraction you have discussed require a
permanent human presence on the Moon? If so, how soon should that
permanent human presence be established?
A3. I shall consider only research oriented toward resource
characterization and extraction, since these are the matters touched on
in my testimony. The answer is that all such research missions can, and
arguably should, be unmanned. The emphasis should be on lowering the
cost and enhancing the capabilities of humans, when they eventually
arrive, rather than using humans to search out and demonstrate
resources.
The only resource whose extraction would clearly require a massive
human presence is helium-3, but commercial-scale helium-3 extraction,
if it ever becomes possible, is far in the future. A similar
consideration applies to construction of lunar solar power stations.
My vision of the future of space travel is that permanent human
presence anywhere will follow only if that presence generates benefits
that justify the costs. Science exploration is a wonderful benefit, but
will not carry us very far by itself. I simply do not see purely
scientific endeavors as providing a justification for permanently
manned lunar facilities. I regard it as premature and indefensible to
arbitrarily set up a goal of having a permanent human presence on the
Moon, Mars, or elsewhere in space. However, I regard it as completely
plausible that some profitable activity may emerge as the result of
acquiring a better understanding of the lunar environment. Such a self-
supporting activity may, as others argue, involve utilization of lunar
polar ice or helium-3, but I personally think that lunar solar power
collection is a more probable economic foundation for permanent human
presence.
Q4. What would it take to be able to extract usable quantities of
oxygen and hydrogen from the Moon for use as a rocket fuel? How long
would it take to develop such a capability, and how much do you think
it would cost? What is the most significant challenge in developing
such a capability?
A4. Extraction of oxygen from the lunar surface could in principle be
carried out by any of over a dozen different processing schemes. A
thorough engineering and cost assessment of all competing schemes has
not yet been conducted. Nonetheless, for the sake of concreteness, I
will outline one very simple scheme that would be appropriate for use
in an early automated lander.
In this scheme, the lander carries a mechanical arm and scoop that
can be used to reach and load regolith material. It also carries a tank
of compressed hydrogen gas for use in the process. The scoop loads
regolith material into a reaction vessel, which is then sealed.
Hydrogen gas is admitted into the sealer reaction chamber and the
regolith/gas mixture is heated by a parabolic solar collector to a dull
red heat. At this temperature, the hydrogen gas reacts with iron oxides
in the regolith minerals, principally ilmenite, olivine, and pyroxene,
to extract oxygen from the iron oxides and make metallic iron and water
vapor. The gas is slowly circulated through a condenser, and water is
condensed and removed from the circulating stream of hydrogen gas. The
remaining hydrogen is returned to the reaction chamber. The liquid
water is tapped off and electrolyzed by a DC electric current, which
can be provided by solar cells or a nuclear power supply. The products
of electrolysis are hydrogen gas, which is returned to the reaction
vessel, and oxygen, which is compressed and cooled to make liquid
oxygen. This is our principal product.
Since the ilmenite in the regolith sample contains some hydrogen
from the solar wind, the heating process will cause that gas to be
released along with water vapor. Any hydrogen lost during the cycle
will automatically be replaced or enhanced by the hydrogen released in
this manner. The processing of 1000 pounds of regolith with a 20
percent ilmenite content uses up about two pounds of hydrogen and
releases 24 pounds of water. Upon electrolysis, this amount of water
makes about 22 pounds of oxygen and gives back the two pounds of
hydrogen for reuse. The amount of solar wind hydrogen released by
heating this amount of regolith is about another 0.1 pounds. With some
care, the total supply of hydrogen may be slowly increased over time;
however, it is clear that hydrogen extraction can never keep pace with
oxygen extraction. The supply of hydrogen in the regolith is simply too
small. In other terms, extracting 100 tons of hydrogen from the
regolith requires heating one million tons of the most hydrogen-rich
regolith and recovering its hydrogen content with perfect efficiency.
Extracting 100 tons of oxygen, by contrast, requires processing only
four thousand tons of regolith, equivalent to a cube of lunar dirt
about 12 meters on a side.
Separating the lunar regolith powder to extract most of the
ilmenite in rather pure form would make the chemical processing step
far easier, since we would need to heat only 200 pounds of pure
ilmenite to make the same 24 pounds of water. However, the separation
process, called ``beneficiation'' in the minerals industry, requires
crushing, sieving, and magnetic or electrostatic sorting of the mineral
grains, all of which adds considerable complexity to the process. Rock
crushing should not be undertaken lightly in the absence of a human
crew to diagnose and repair the inevitable equipment breakdowns.
Further, the loss of ``sticky'' ilmenite dust from the process and the
difficulty of liberating ilmenite grains from the other minerals in the
regolith rock fragments are both essentially unsolved problems. For
this reason, I consider such ``improvements'' as inappropriate for
early use on an automated lander.
Adopting the simpler process and processing bulk uncrushed,
unsorted regolith appears simple enough so that a 100-pound
demonstration experiment suitable for testing on the Moon could be
built and made ready for flight in about two years. Building the
equipment would be relatively quick and cheap compared to the cost of
transporting it to the lunar surface with current rocket hardware.
Costs could be reduced more dramatically by changing to competitive
launch services than by any plausible changes in the payload itself. To
my mind, the most severe technical challenge is making reliably air-
tight seals on the processing chamber in the dusty operational
environment.
Q5. Science by itself is not going to sustain the public's support for
the long-term program contemplated in the President's plan. After all,
the 1960s Apollo lunar landing program had developed some impressive
science capabilities, and Apollo 17 carried the first scientist-by-
training (geologist Harrison Schmitt) to work on the Moon.
Unfortunately, he was also the last. What is different enough about the
ideas you are advocating here that will avoid the fate suffered by the
Apollo program?
A5. There is one overwhelming difference between the approach of the
Apollo program and that which I advocate. The Apollo program was a very
dramatic race, little constrained by considerations of cost, to make a
political statement of American technical superiority vis a vis the
Soviet Union. Quite the opposite, I propose and endorse the use of
every plausible means to reduce costs, including use of private
competitive launch services, the use of non-terrestrial resources to
give space missions a high degree of self-sufficiency and autonomy, and
the complementary use of manned and unmanned missions. I propose a
diligent search, based on the intelligent use of unmanned small probes,
for economically self-sufficient future activities on the Moon. I have
discussed these issues with Jack Schmitt, and I am pleased to find that
he agrees with these principles. We differ on our assessments of the
likely profitability of different forms of lunar enterprise, but we
differ because the evidence is at present inadequate to assess these
competing forms of enterprise. We agree that small and early unmanned
missions are required to reduce these uncertainties, and that plans for
the longer term must await the results of these studies.
My vision of the future is not a governmental ``space program''
supported by massive federal infusions of funds. My vision assigns to
the Federal Government the responsibility for fundamental scientific
research and technology development, and leaves to industry and
commerce the task of making a profit in space and paying taxes on their
profits. My vision is a space enterprise dominated by organizations
that pay tax dollars, not those that spend them. It is a democratic and
capitalistic, not a socialist and government-monopolist, vision.
Answers to Post-Hearing Questions
Responses by Timothy D. Swindle, Professor of Geosciences and Planetary
Sciences, University of Arizona
Questions submitted by Chairman Dana Rohrabacher
Q1. Please provide your views on what roles the private sector,
including businesses and educational institutions, can contribute to
the successful development and exploitation of lunar resources, and to
the provision of services in support of NASA's lunar exploration
program.
Based on current capabilities, do you believe the
private sector has unique expertise needed by NASA to return to
the Moon?
What are the biggest obstacles to private sector
participation in lunar exploration and resource exploitation
activities?
Once NASA has established a long-term presence on the
Moon, are there markets you believe could be exploited by
private industry, and if so, what might they be?
A1. I won't comment about the obstacles to private sector
participation, since that is not something that I have considered in
any detail. Whether there are markets that can be exploited by private
industry will depend on the scale of the presence on the Moon. As Dr.
Lewis said in his testimony, while there are lunar resources that can
be very valuable, most of them are valuable only on or near the Moon.
The two exceptions that have been suggested most prominently are the
use of 3He as a fusion reactor fuel, and the use of lunar solar power
``farms'' to generate energy to be beamed back to Earth. As I said, I
believe that the first, which I have studied, will be a very large and
difficult project, though it should not be ruled out. Sending solar
power generated on the Moon back to Earth is a concept that certainly
deserves more study.
Q2. NASA's Office of Space Science is responsible for the lunar
robotic portion of the Space Exploration Initiative. How would you
recommend the office reach out to the science community to carry out
this program? Is NASA using science advisory panels to select
instrument proposals for upcoming missions?
A2. The Office of Space Science has been pursuing a program for
exploration that includes a mixture of missions that are arrived at by
some consensus method and missions that are proposed by individual
investigators and then chosen by peer review. For example, NASA
requested a ``decadal survey'' of the scientific community. This
document, produced under the auspices of the National Research Council
and released in 2002, received input from a large fraction of the
scientific community, and so far has been used by the Office of Space
Sciences. One of the first things the Aldridge Commission did was to
seek the input of scientists at the annual Lunar and Planetary Science
Conference, which is attended by the vast majority of lunar scientists.
Assuming the commission's recommendations reflect that input, and that
NASA follows those recommendations, that is an appropriate approach.
Q3. The Space Exploration Initiative proposes establishing an extended
human lunar mission. Based on your knowledge of the Moon's environment
and resources, how difficult a task will it be to develop and sustain
humans for a two-month period? For a stay of that duration, would it be
practical to develop in situ resources to help sustain lunar
astronauts? How about a six-month stay?
A3. I have not studied the problem of development of lunar bases, so I
will not reply.
Questions submitted by Representative Nick Lampson
Q1. Given the data acquired by the Apollo lunar landing program and
its robotic precursors, as well as data obtained by the subsequent
Clementine and Lunar Prospector spacecraft, what additional
information, if any, will be needed before NASA can send humans back to
the Moon by 2020?
A1. Given the success of the Apollo program, it is clear that for very
short stays at some places on the Moon, we do not need any additional
information. For stays at other locations that are not as well-mapped
from orbit as the Apollo sites, we would need imagery comparable to
that used in the Apollo program. For longer, or permanent, stays, we
need to have information on what resource utilization schemes can work.
Some of this is laboratory work, simply designing and testing potential
equipment, but I would think that we would need missions to at least
test those schemes that seem most promising in the lunar environment.
Q2. What will it take to answer definitively the question of how much
water ice might be on the Moon? How much time is it likely to take to
characterize the global availability of water on the lunar surface?
How many remote-sensing missions will be necessary to
obtain this complete characterization?
A2. I will defer to Drs. Campbell and Spudis, who have far more
expertise on this than I do.
Q3. What will it take to map other lunar resources?
A3. It depends on the resource. For 3He, it would require
one or two sample returns from specific places (far-side sites with
relatively high titanium) as well as one or two missions to the surface
to investigate the properties of the lunar ``regolith'' (soil) in more
detail. For most other resources, where the proposals have been simply
for extraction of relatively common materials from the lunar regolith,
the requirement is again to learn enough about the properties of the
regolith to be able to implement extraction schemes. In particular, for
many techniques, it is crucial to learn more about how the properties
of the regolith change with depth, but a lot of that could be learned
with one or two fairly simple missions.
Q4. Would any of the scientific research you have discussed require
astronauts on the Moon as opposed to robotic orbiters, landers, rovers,
or research stations? If so, which research, and why? Does any of the
scientific research or resource extraction you have discussed require a
permanent human presence on the Moon? If so, how soon should that
permanent human presence be established?
A4. Any research that requires the selection of samples will be far
more effective with astronauts than without, for the simple fact that a
human brain coupled with the human visual system can make selections
much more efficiently than any robotic system yet designed. In
Antarctic tests, a sophisticated robot designed to search for
meteorites was far inferior to non-geologists with a few days of
training. Much of the science on the Moon could be done without humans
by a brute force technique, simply acquiring many more samples than are
really needed, in hopes of finding the right ones. However, humans are
remarkably good at finding the ``right'' sample, as was amply
demonstrated by the well-trained Apollo astronauts. Using humans to
operate things by telepresence would be an intermediate option, but
even that would work far better with the remote presence on the Moon,
with virtual no delay between command and response, than on Earth, with
the delay caused by the finite speed of light. On the other hand,
science that involves measuring global or average properties is far
less likely to need human presence. As an extreme case, information
that can be determined best from lunar orbit is unlikely to gain much,
if any, benefit from the presence of humans.
A large portion of most resource utilization schemes could probably
be done robotically. However, the more complex the task and the
equipment, the more likely it is that there will be equipment failures
of one sort or another. In these cases, a human with a tool kit is far
more valuable than any robotic service mission.
Whether any of this requires permanent human presence probably
depends on the scale of activities. If only low-level activity is
planned, occasional human presence, to go collect a particular set of
samples or to service a particular piece of equipment, would be
sufficient. The more ambitious the plans, the more valuable continuous
human presence would be.
Q5. Science by itself is not going to sustain the public's support for
the long-term program contemplated in the President's plan. After all,
the 1960s Apollo lunar landing program had developed some impressive
science capabilities, and Apollo 17 carried the first scientist-by-
training (geologist Harrison Schmitt) to work on the Moon.
Unfortunately, he was also the last. What is different enough about the
ideas you are advocating here that will avoid the fate suffered by the
Apollo program?
A5. Science was never the primary purpose of the Apollo program, simply
getting to the Moon was. Although the astronauts did a wonderful job as
scientists, that was only their secondary purpose. Furthermore, the
science that they did was not that compelling to the non-scientist,
since it was really exploratory, just trying to figure out as much
about the Moon as possible.
We now know enough about the Moon to understand that the Moon
provides a record of early events, particularly impacts, whose record
is lost on Earth. Furthermore, this is intimately tied not only to the
impact history of the Earth, but to the origin of life on Earth. Hence,
by studying this portion of the Moon's history, we now recognize that
we are studying the question of the origin of life itself, one of the
most compelling questions in science at the start of this century.
While this science will never be enough to justify the entire Moon-
Mars initiative, it is enough to be easily understood as a crucial and
worthwhile component.