[House Hearing, 115 Congress]
[From the U.S. Government Publishing Office]





                          IN-SPACE PROPULSION:
                     STRATEGIC CHOICES AND OPTIONS

=======================================================================

                                HEARING

                               BEFORE THE

                         SUBCOMMITTEE ON SPACE

              COMMITTEE ON SCIENCE, SPACE, AND TECHNOLOGY
                        HOUSE OF REPRESENTATIVES

                     ONE HUNDRED FIFTEENTH CONGRESS

                             FIRST SESSION

                               __________

                             JUNE 29, 2017

                               __________

                           Serial No. 115-20

                               __________

 Printed for the use of the Committee on Science, Space, and Technology


[GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT]





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              COMMITTEE ON SCIENCE, SPACE, AND TECHNOLOGY

                   HON. LAMAR S. SMITH, Texas, Chair
FRANK D. LUCAS, Oklahoma             EDDIE BERNICE JOHNSON, Texas
DANA ROHRABACHER, California         ZOE LOFGREN, California
MO BROOKS, Alabama                   DANIEL LIPINSKI, Illinois
RANDY HULTGREN, Illinois             SUZANNE BONAMICI, Oregon
BILL POSEY, Florida                  AMI BERA, California
THOMAS MASSIE, Kentucky              ELIZABETH H. ESTY, Connecticut
JIM BRIDENSTINE, Oklahoma            MARC A. VEASEY, Texas
RANDY K. WEBER, Texas                DONALD S. BEYER, JR., Virginia
STEPHEN KNIGHT, California           JACKY ROSEN, Nevada
BRIAN BABIN, Texas                   JERRY MCNERNEY, California
BARBARA COMSTOCK, Virginia           ED PERLMUTTER, Colorado
BARRY LOUDERMILK, Georgia            PAUL TONKO, New York
RALPH LEE ABRAHAM, Louisiana         BILL FOSTER, Illinois
DRAIN LaHOOD, Illinois               MARK TAKANO, California
DANIEL WEBSTER, Florida              COLLEEN HANABUSA, Hawaii
JIM BANKS, Indiana                   CHARLIE CRIST, Florida
ANDY BIGGS, Arizona
ROGER W. MARSHALL, Kansas
NEAL P. DUNN, Florida
CLAY HIGGINS, Louisiana
RALPH NORMAN, South Carolina
                                 ------                                

                         Subcommittee on Space

                     HON. BRIAN BABIN, Texas, Chair
DANA ROHRABACHER, California         AMI BERA, California, Ranking 
FRANK D. LUCAS, Oklahoma                 Member
MO BROOKS, Alabama                   ZOE LOFGREN, California
BILL POSEY, Florida                  DONALD S. BEYER, JR., Virginia
JIM BRIDENSTINE, Oklahoma            MARC A. VEASEY, Texas
STEPHEN KNIGHT, California           DANIEL LIPINSKI, Illinois
BARBARA COMSTOCK, Virginia           ED PERLMUTTER, Colorado
RALPH LEE ABRAHAM, Louisiana         CHARLIE CRIST, Florida
DANIEL WEBSTER, Florida              BILL FOSTER, Illinois
JIM BANKS, Indiana                   EDDIE BERNICE JOHNSON, Texas
ANDY BIGGS, Arizona
NEAL P. DUNN, Florida
CLAY HIGGINS, Louisiana
LAMAR S. SMITH, Texas






















                            C O N T E N T S

                             June 29, 2017

                                                                   Page
Witness List.....................................................     2

Hearing Charter..................................................     3

                           Opening Statements

Statement by Representative Brian Babin, Chairman, Subcommittee 
  on Space, Committee on Science, Space, and Technology, U.S. 
  House of Representatives.......................................     4
    Written Statement............................................     6

Statement by Representative Ami Bera, Ranking Member, 
  Subcommittee on Space, Committee on Science, Space, and 
  Technology, U.S. House of Representatives......................     8
    Written Statement............................................    10

Statement by Representative Eddie Bernice Johnson, Ranking 
  Member, Committee on Science, Space, and Technology, U.S. House 
  of Representatives.............................................    12
    Written Statement............................................    13

                               Witnesses:

Mr. William Gerstenmaier, Associate Administrator, Human 
  Exploration and Operations Directorate, NASA
    Oral Statement...............................................    15
    Written Statement (shared written statement with Mr. Stephen 
      Jurczyk)...................................................    17

Mr. Stephen Jurczyk, Associate Administrator, Space Technology 
  Mission Directorate, NASA
    Oral Statement...............................................    25
    Written Statement (shared written statement with Mr. William 
      Gerstenmaier)..............................................    17

Dr. Mitchell Walker, Chair, Electric Propulsion Technical 
  Committee, AIAA
    Oral Statement...............................................    26
    Written Statement............................................    29

Dr. Franklin Chang-Diaz, Founder and CEO, Ad Astra Rocket Company
    Oral Statement...............................................    36
    Written Statement............................................    38

Mr. Joe Cassady, Executive Director for Space, Washington 
  Operations, AerojetRocketdyne
    Oral Statement...............................................    44
    Written Statement............................................    46

Dr. Anthony Pancotti, Director of Propulsion Research, MSNW
    Oral Statement...............................................    55
    Written Statement............................................    57

Discussion.......................................................    64

             Appendix I: Answers to Post-Hearing Questions

Mr. William Gerstenmaier, Associate Administrator, Human 
  Exploration and Operations Directorate, NASA...................    82

Mr. Stephen Jurczyk, Associate Administrator, Space Technology 
  Mission Directorate, NASA......................................    87

Dr. Mitchell Walker, Chair, Electric Propulsion Technical 
  Committee, AIAA................................................    94

Dr. Franklin Chang-Diaz, Founder and CEO, Ad Astra Rocket Company    99

Mr. Joe Cassady, Executive Director for Space, Washington 
  Operations, Aerojet Rocketdyne.................................   104

Dr. Anthony Pancotti, Director of Propulsion Research, MSNW......   107
 
                AN OVERVIEW OF THE NATIONAL AERONAUTICS
          AND SPACE ADMINISTRATION BUDGET FOR FISCAL YEAR 2018

                              ----------                              


                        THURSDAY, JUNE 29, 2017

                  House of Representatives,
                             Subcommittee on Space,
               Committee on Science, Space, and Technology,
                                                   Washington, D.C.

    The Subcommittee met, pursuant to call, at 10:05 a.m., in 
Room 2318 of the Rayburn House Office Building, Hon. Brian 
Babin [Chairman of the Subcommittee] presiding.

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    Chairman Babin. The Subcommittee on Space will now come to 
order. Without objection, the Chair is authorized to declare 
recesses of the Subcommittee at any time.
    Welcome to today's hearing titled ``In-Space Propulsion: 
Strategic Choices and Options.'' I would now like to recognize 
myself for five minutes for an opening statement.
    We are on the cusp of a giant leap in space transportation 
technology. Advances in in-space propulsion systems hold the 
promise of radically altering space exploration. Breakthroughs 
will allow for faster travel, larger payloads, and greater 
efficiency. All of this will allow humanity to access the very 
farthest reaches of the solar system. This is clearly a subject 
that excites the imagination.
    NASA has led the way in developing in-space propulsion 
since its inception. The Space Electric Rocket Test, or SERT-1, 
as well as the Deep Space 1 (DS1) and Dawn missions laid the 
foundation of electric propulsion. The Nuclear Engine for 
Rocket Vehicle Applications program, or NERVA, demonstrated the 
viability of nuclear thermal propulsion. These investments have 
ensured U.S. leadership in in-space propulsion, which is 
important for not only civil space missions, but also national 
security missions and commercial applications. Commercial in-
space propulsion systems, operating at kilowatts of power, are 
a relatively mature technology today: In 2015 Boeing began 
offering the first all-electric commercial satellites.
    Because of these successes, we stand on the threshold of a 
new era, one in which in-space propulsion and power systems 
could grow to a scale and sophistication that would support 
human spaceflight and exploration. NASA is currently developing 
in-space power and propulsion systems that are an order of 
magnitude more powerful than modern commercial systems. 
Originally developed for the cancelled asteroid retrieval 
mission, this system will now be appropriately incorporated 
into NASA's exploration architecture and may be used on NASA's 
Deep Space Gateway.
    Similarly, developing this technology has taught us 
valuable lessons that will inform the next generation of in-
space propulsion, which will send humans on to Mars. NASA's 
Human Exploration Mission Directorate is supporting research on 
three new in-space propulsion technologies. These systems 
operate at hundreds of kilowatts of power which is another ten 
times more powerful than the systems under development for use 
around the Moon, and could be used on a Deep Space Transport 
system for missions to Mars and even beyond.
    The next-generation in-space propulsion technologies under 
development by three of today's witnesses will be critical to 
ensuring that the exploration of Mars is possible, sustainable, 
and affordable. I hope that their testimony can help the 
Committee better understand the unique mission options that 
each technology will offer.
    As important as these developments are for the journey to 
Mars, the most exciting payoffs may come from the ability to 
develop these new engines even further. As discussed in NASA's 
Technology Roadmaps, scaling up the power levels another order 
of magnitude and building systems that will operate with 
thousands of kilowatts of power will significantly transform 
how humanity explores the solar system. These systems could 
even put the outer planets within reach of human explorers.
    To be clear, these developments are not simply about human 
spaceflight; rather it is an across-the-board change in 
technology on par with the jump from sailing vessels and steam-
powered ships. That long-term vision is still quite a ways off 
and will require further work, but the promise is utterly 
exciting.
    Smart investments, focused exploration goals, and constancy 
of purpose will maintain U.S. leadership in not only in-space 
propulsion, but also space exploration more broadly.
    Our witnesses today can help us better understand how all 
of these efforts fit together. I look forward to hearing about 
how in-space propulsion can expand our reach. Advancements in 
these technologies will literally open up a universe of 
possibilities.
    [The prepared statement of Chairman Babin follows:]
    
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    Chairman Babin. And I would now like to recognize the 
Ranking Member, the gentleman from California, for an opening 
statement.
    Mr. Bera. Thank you, Mr. Chairman.
    Chairman Babin. I'm sorry. Can I----
    Mr. Bera. Yes, please.
    Chairman Babin. I'm about to forget our Ranking Member of 
the full Committee. Sorry about that. Go ahead, Mr. Bera.
    Mr. Bera. Although before I read my opening statement, I'm 
told that there's a group from the Society of Physics students 
here today, and I just want to recognize those students that 
are here in the audience because they're interning in a variety 
of places including our own House Science, Space, and 
Technology Committee, and you guys represent the future, and 
that's why we do what we do, so if you could stand up for a 
quick second so we can recognize all of you. Thank you for 
being here.
    You know, Mr. Chairman, I think this is a very timely 
topic, and I'm looking across at this distinguished panel. It 
may take us a while to get through all of your statements but I 
think we're going to be well-educated.
    You know, chemical propulsion remains a critical part of 
today's human exploration program. The two rocket boosters on 
NASA's Space Launch System use a solid chemical propellant and 
SLS's RS-25 core stage rockets utilize liquid chemical 
propellant. However, relying solely on chemical propulsion for 
deep space travel would result in spacecraft having to carry 
large amounts of propellant, possibly requiring multiple 
launches even before a mission can be initiated. That is why 
many experts believe that NASA will need advanced propulsion 
systems to power the agency's future robotic and manned 
spacecraft.
    NASA is currently using non-chemical in-space propulsion in 
the form of electric propulsion. Electric propulsion is a 
continuous, low-thrust process and has been used by a few NASA 
robotic spacecraft, such as the Dawn probe, which has 
investigated the asteroid Vesta and is now orbiting Ceres.
    The Department of Defense space vehicles and commercial 
satellites also make use of solar electric power, but primarily 
for orbit raising and repositioning. For example, each Advanced 
Extremely High Frequency Space Vehicle, which provides critical 
global communications to our warfighters, uses solar electric 
propulsion subsystems.
    Another type of in-space propulsion enabled through the use 
of nuclear reactors was studied to a limited extent in the 
1960s. However, engineers found that the amount of shielding 
needed to protect crew from the dangerous effects of prolonged 
exposure to radiation generated by the nuclear reactor as well 
as other technical difficulties were challenges that were hard 
to overcome at that time.
    Now that we're planning on extended human travel into 
space, research into all forms of advanced propulsion 
technologies, including nuclear fission, is likely to intensify 
in the years ahead. It's critical that we find ways to reduce 
the time crew is exposed to galactic cosmic rays and other 
dangerous deep-space radiation. Significantly reducing mission 
duration times can only be achieved through advanced in-space 
propulsion.
    As NASA continues to develop our plans on how to send 
humans to Mars and returning them safely to Earth, now is a 
good time to examine the present and future options for in-
space propulsion.
    Mr. Chairman, I look forward to hearing from our witnesses 
about different propulsion technologies and the unique 
characteristics that make them best suited to particular 
missions in space.
    Thank you, and I yield back.
    [The prepared statement of Mr. Bera follows:]
    
    
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    Chairman Babin. Absolutely. Sorry about the confusion. Now 
the Ranking Member.
    Ms. Johnson. Thank you very much. Let me say good morning 
to everyone and welcome our witnesses, and thank you, Mr. 
Chairman. I appreciate the opportunity to discuss in-space 
propulsion with a wide range of government, academic, and 
industry experts.
    In-space propulsion will be a critical enabler of our 
future missions, especially those involving human exploration 
beyond Earth orbit, and I'm delighted that all of the young 
people of the future are here, and I hope that I see the 
enthusiasm as we have experienced in the past.
    It is important that the Subcommittee assess the state of 
research and development related to in-space propulsion 
technologies, which NASA, the National Academies, and the NASA 
Advisory Council all consider a priority. Not only is this 
technology important for NASA and our space program, but it 
would also have benefits for the commercial sector, which 
already uses electric propulsion for maintaining commercial 
satellite positioning.
    Mr. Chairman, I look forward to this hearing from our 
witnesses about the range and types of in-space propulsion 
technologies being studied and the progress of the research and 
development into each. When we consider progress, we also need 
to understand whether sufficient resources are being invested 
to make sure the technologies will be ready when NASA needs 
them. It is important to note that the budget for NASA's Space 
Technology Mission Directorate, which includes work on in-space 
propulsion, has been relatively flat. Can we achieve the 
milestones for the needed technology development on a flat 
budget?
    Mr. Chairman, our investments in research and development 
of enabling technologies such as in-space propulsion are our 
seed corn for achieving our goals for space exploration. It is 
our job to ensure that we make the needed investments will 
yield us the kind of results we seek.
    I thank you, and yield back.
    [The prepared statement of Ms. Johnson follows:]
    
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    Chairman Babin. Thank you.
    Let me introduce our very distinguished panel of witnesses 
today. The first one I'd like to introduce is Mr. Bill 
Gerstenmaier, Associate Administrator of the Human Exploration 
and Operations Directorate at NASA. Mr. Gerstenmaier provides 
strategic direction for all aspects of NASA's human exploration 
of space and cross-agency space support functions including 
programmatic direction for the operation and utilization of the 
International Space Station. He holds a bachelor of science in 
aeronautical engineering from Purdue University, and a master 
of science in mechanical engineering from the University of 
Toledo. Welcome.
    Next I'd like to introduce Mr. Stephen Jurczyk, our second 
witness today, Associate Administrator of the Space Technology 
Mission Directorate at NASA. As Associate Administrator, he 
manages and executes the space technology programs focusing on 
infusion into the agency's exploration and science mission 
needs, proving the capabilities needed of the greater aerospace 
community and developing the Nation's innovation economy. Mr. 
Jurczyk is a graduate of the University of Virginia, where he 
received a bachelor of science and a master of science in 
electrical engineering. We welcome you.
    Our third witness today is Dr. Mitchell Walker. He is 
Chairman of the Electric Propulsion Technology Committee of the 
American Institute of Aeronautics and Astronautics. Dr. Walker 
is also a Professor of Aerospace Engineering at the Georgia 
Institute of Technology, where he directs the High Power 
Electric Propulsion Laboratory. From 2011 to 2012, Dr. Walker 
served on the National Research Council Aeronautics and Space 
Engineering Board for the Air Force reusable booster system 
study. His research interests include both experimental and 
theoretical studies of advanced plasma propulsion concepts for 
spacecraft and fundamental plasma physics. He also conducts 
research on Hall-effect thrusters, gridded ion engines, 
diagnostics for plasma interrogation and thruster 
characterization, and several other aspects of electric 
propulsion. He received his Ph.D. in aerospace engineering from 
the University of Michigan, where he specialized in 
experimental plasma physics and advanced space propulsion. We 
welcome you, Dr. Walker.
    Fourthly is Dr. Franklin Chang-Diaz, Founder and CEO of Ad 
Astra Rocket Company. Dr. Chang-Diaz has flown a record seven 
space missions, logging over 1,600 hours in space including 19 
hours on three separate spacewalks. In 1994, he founded and 
directed the Advanced Space Propulsion Laboratory at the 
Johnson Space Center where he continued developing propulsion 
technology. Prior to founding Ad Astra, Dr. Chang-Diaz joined 
the technical staff of the Charles Stark Draper Laboratory in 
Cambridge, Massachusetts, where he conducted research in 
fusion. He earned a bachelor of science in mechanical 
engineering from the University of Connecticut and his Ph.D. 
from MIT. We welcome you, Dr. Franklin Chang-Diaz.
    Fifth is Mr. Joe Cassady, Executive Director for Space of 
Washington Operations for Aerojet Rocketdyne. Mr. Cassady has 
33 years of experience in propulsion as well as mission and 
systems analysis. This includes flight projects for both the 
Air Force and NASA. He is also the Vice President of the 
Electric Rocket Propulsion Society. Mr. Cassady earned a 
bachelor's of science and a master's of science in aeronautics 
and astronautics from Purdue University. He also received a 
graduate certificate of systems engineering from George 
Washington University. We welcome you.
    Our sixth witness today is Dr. Anthony Pancotti, Director 
of Propulsion Research at MSNW. Dr. Pancotti previously worked 
at the Air Force Research Laboratory at Edwards Air Force Base 
where he reviewed and investigated a range of advanced 
propulsion concepts. In 2011, he joined MSNW to work on a 
variety of fusion and propulsion and plasma concepts and is now 
the Principal Investigator for their Next Step Propulsion 
program. He earned his Ph.D. in aerospace engineering from the 
University of Southern California, where he designed, built and 
tested an experimental high-efficiency electrothermal ablative 
pulsed plasma thruster--that's a mouthful--called a capillary 
discharge.
    I now recognize Mr. Gerstenmaier for five minutes to 
present his testimony.

             TESTIMONY OF MR. WILLIAM GERSTENMAIER,

                    ASSOCIATE ADMINISTRATOR,

       HUMAN EXPLORATION AND OPERATIONS DIRECTORATE, NASA

    Mr. Gerstenmaier. Thank you very much, Members of the 
Committee for the opportunity to be here to discuss in-space 
propulsion.
    Propulsion is a critical element of any human exploration 
plan or architecture. We need to further develop the ability to 
move humans and cargo in space to expand human presence into 
the solar system. Electric propulsion can be a key enabler to 
successful missions and activities beyond the Earth-Moon 
system. It offers significant advantages over other forms of 
propulsion, most notably, efficiency. Electric propulsion can 
offer the ability to move large masses through space with 
minimum fuel usage. The other advantages are, the fuel is 
storable, does not boil off, and can be easily resupplied. 
However, the thrust level of current electric propulsion 
systems is typically low and it requires a significant amount 
of time to move the spacecraft in space. Even for habitats in 
the vicinity of the Moon, we are planning to use 12-1/2-
kilowatt electric thrusters, which is about 5 kilowatts, or 40 
percent, higher thrust than typical thrusters used today.
    This disadvantage of long times is substantial when you're 
considering transporting crew. We prefer to transport crew as 
fast as possible to avoid prolonged exposure to microgravity 
and high radiation conditions. We anticipate the early systems 
for sending crew beyond the Earth-Moon system will use a 
combination of chemical and much higher thrust level electric 
propulsion systems, possibly 50 to 100 kilowatts or greater.
    The future systems we are investigating would increase 
thrust level and shorten transit time while still maintaining 
the high efficiency. We are looking at increasing thrust levels 
by factors of 10. These systems are at lower technology 
readiness levels but offer the promise for new technologies in 
the future. We have partnered with American industry through 
our next step broad agency announcement including some of the 
panelists here today to investigate and advance the 
capabilities of these emerging systems. Looking at a variety of 
systems in the early stage of development is important. 
Maturing technologies and demonstrating system performance 
through ground testing prior to committing to utilizing them 
and operational systems and beginning a major systems 
development activity helps constrain program costs and schedule 
risk. NASA and other R&D organizations have learned that 
starting systems development activities prematurely can lead to 
significant technical challenges and unacceptable cost and 
schedule growth. The broad agency analysis process allows us to 
investigate the specifics of systems design before committing 
to technologies into an actual spacecraft or system.
    As we prepare for missions in the vicinity of the Moon and 
ultimately Mars, electric propulsion will be a key enabling 
technology. We will build off of the work done in support of 
the Asteroid Redirect Mission. Our ARM concept worked the 
tremendous benefits of electric propulsion for moving large 
masses in space, which transformed our approach for human 
exploration in deep space. The Asteroid Redirect Mission also 
helped us to understand the advantages of departing the Earth-
Moon system for Mars from the vicinity of the Moon rather than 
from Earth orbit, and we believe using electric propulsion to 
preposition key large elements will be necessary for human 
Mars-class missions.
    Electric propulsion will play a key role in emerging 
concepts such as crew-tended habitation modules in the vicinity 
of the Moon. With advanced electric propulsion, we will have 
the ability to move habitat systems to various orbits around 
the Moon. We can support crewed science operations from the 
module and various lunar orbits--equatorial, halo orbits, or 
even an orbit around Lagrangian point two on the far side of 
the Moon. This far-side lunar orbit location would allow 
telerobotic operations from crews onboard the habitat module on 
the far side of the Moon, something we--a region of the Moon we 
have never explored. The module is not stuck in one place 
around the Moon. It can be moved to various locations, thanks 
to electric propulsion.
    As we look to electric propulsion for crew-tended 
habitation systems around the Moon, we will look for synergies 
with the commercial communications satellite industry and take 
advantage of electric spacecraft development in that market. 
Combining these capabilities with higher-power electric 
propulsion systems being developed by NASA's Space Technology 
Mission Directorate will enable both the advance of U.S. 
industrial capabilities and the creation of the in-space 
infrastructure we need in the lunar vicinity to further 
Nation's space exploration goals.
    Electric propulsion and advanced propulsion systems will be 
a key enabler for human exploration systems of the future.
    Thank you for the opportunity to discuss this topic with 
the Committee, and I look forward to your questions.
    [The prepared statement of Mr. Gerstenmaier follows:]
    
    
    [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT]

        
    Chairman Babin. Thank you, Mr. Gerstenmaier.
    Now I recognize Mr. Jurczyk for five minutes to present his 
testimony.

               TESTIMONY OF MR. STEPHEN JURCZYK,

                    ASSOCIATE ADMINISTRATOR,

           SPACE TECHNOLOGY MISSION DIRECTORATE,NASA

    Mr. Jurczyk. Chairman Babin, Ranking Member Bera, and 
Members of the Subcommittee, thank you for the opportunity to 
appear today to discuss NASA's in-space propulsion research and 
development activities with a focus on the agency's efforts in 
space technology.
    NASA's Space Technology Mission Directorate--STMD--programs 
are aimed at key research and technology challenges that will 
enable more ambitious missions in the future and create a new 
space economy. STMD is developing new capabilities for in-space 
propulsion including higher-performing chemical propulsion, 
high-power electrical propulsion, and nuclear thermal 
propulsion. The goal is to demonstrate these new capabilities 
in the near term to transition them into robotic and human 
missions in the next decade.
    Solar electric propulsion technology has long been a 
priority technology investment by STMD and such capabilities 
have been of great interest to NASA, other government 
organizations, and industry for many years. The focus of the 
current STMD technology project has been on increasing the 
solar power generation capability of spacecraft and development 
of advanced thrusters that are about two and a half times the 
power level of existing thrusters with significant increases in 
operational lifetime. Recently, NASA has demonstrated full 
performance of a high-power electric propulsion thruster system 
with more than 2,500 total hours of testing with no degradation 
in system performance. The agency subsequently awarded a 
contrast to Aerojet Rocketdyne for development and delivery of 
engineering units of a 12-1/2-kilowatt thruster system by the 
end of 2018.
    The activities to advance solar power generation capability 
culminated in the successful development of advanced solar 
arrays by our industry partners, Deployable Space Systems and 
Orbital ATK, that are two times lighter and use four times less 
stowed volume for the same amount of electricity produced as 
compared to today's commercially available solar arrays.
    NASA recently completed an Air Force Research Lab-sponsored 
test of the Deployable Space Systems Solar Array Technology on 
the ISS. The current STP system being developed for 
demonstration-class mission will provide between 300 and 500 
kilowatts of power. The initial deep-space transport capability 
for crewed missions beyond the Earth-Moon system requires an 
approximately 300-kilowatt system. STMD intends to continue 
advancing thruster technology, increasing the power level up to 
10 times current thruster systems to enable this capability.
    The Solar Electric Propulsion Project illustrates the 
strength of a multi-application approach to technology 
development. Other government agencies and the commercial space 
sector have shown interest in utilizing the component 
technologies, especially the deployable solar arrays at 5 
kilowatts to 30-kilowatt power levels. Commercial satellite 
firms will soon use these arrays with their lower weight and 
improved packaging efficiency to lower the cost of future 
communications satellites.
    STMD is also currently in the second year of a three-year 
effort to develop a safe and affordable nuclear thermal 
propulsion system. This effort is focused on addressing the 
most significant challenges in developing an NTP system 
including reducing the risk and cost of the reactor system, 
enabling long-term storage of liquid hydrogen, the working 
fluid for NTP, and developing approach for safe ground testing 
of the system. The agency will use the results of these 
activities to determine the feasibility and cost of advancing 
NTP by development and testing of a ground demonstration 
system. Although NASA does not expect to require advanced 
propulsion technologies such as NTP in the initial crewed 
missions to the Mars system, NTP can reduce trip times to Mars 
significantly.
    Finally, STMD will continue to advance power systems 
technologies to enable high-performing electric propulsion 
systems including both solar- and nuclear-based power 
generation.
    Mr. Chairman, thank you for your support and that of this 
Committee. I would be pleased to respond to any of the 
questions that you or the other Members have.
    Chairman Babin. Thank you, Mr. Jurczyk.
    I'd now like to recognize Dr. Walker for five minutes. 
Thank you.

            TESTIMONY OF DR. MITCHELL WALKER, CHAIR,

         ELECTRIC PROPULSION TECHNICAL COMMITTEE, AIAA

    Dr. Walker. Mr. Chairman, Ranking Member Bera, and Members 
of the Subcommittee, thank you for the invitation to share my 
views on strategic investments in America's in-space propulsion 
technology program. I've been fortunate to serve on the faculty 
of the Daniel Guggenheim School of Aerospace Engineering at the 
Georgia Institute of Technology since 2005. It gives me great 
pride to work closely with undergraduate and graduate students 
as they develop into the space propulsion engineers and 
scientists of our Nation's future.
    I presently service as the Vice Chair of the American 
Institute of Aeronautics and Astronautics Technology Committee, 
an Associate Editor of the journal Spacecraft and Rockets, and 
the General Chair of the 2017 International Electric Propulsion 
Conference. I'm here today as an individual, and the views I 
express are mine alone.
    Electric propulsion is the acceleration of propellant with 
electric energy to generate thrust for spacecraft. Hall-effect 
thrusters and gridded ion engines are successful examples of 
electric propulsion used in commercial, defense, and civil 
applications. Electric propulsion offers a significant 
advantage over chemical propulsion because the exhaust velocity 
is not limited by the amount of energy released from the 
chemical bonds of the propellant. Compared to chemical 
propulsion, the electrical approach enhances the efficiency of 
the propulsion system by more than an order of magnitude and 
leads to significant reductions in propellant mass. Typically, 
electric propulsion devices do not have large thrust because of 
the limited spacecraft power available.
    NASA has been a leader in the development and flight of 
electric propulsion technology. NASA flew its first electric 
propulsion device in 1964. In 1998, the NSTAR ion propulsion 
system on NASA's Deep Space 1 spacecraft flew. The NSTAR ion 
engine enabled a trip that included fly-bys of an asteroid and 
a comet. In 2007, NASA launched the Dawn spacecraft that also 
uses NSTAR ion engine as primary propulsion. To date, Dawn has 
orbited both Ceres and Vesta. Scientists will continue to 
embrace the unique capabilities of electric propulsion to 
explore our solar system.
    Our world has gradually shifted to a space-based 
infrastructure. That includes GPS, satellite radio, satellite 
TV, DOD communications, weather monitoring systems, and we 
stand in the midst of a paradigm shift in the requirements for 
these spacecraft from traditional chemical propulsion to 
electric propulsion. This shift is a result of a dramatic 
increase in available satellite electrical power. During the 
last 20 years, investments in solar array technology have 
increased geosynchronous satellite power from 1 kilowatt to 
over 25 kilowatts. In 2015, this trend culminated in the launch 
of Boeing's first all-electric spacecraft. All-electric 
satellites use electric propulsion as a primary propulsion and 
to provide 15 years of station keeping on orbit. The enormous 
propulsion mass savings achieved with electric propulsion 
allows two electric-satellites to launch on one smaller, less 
expensive launch vehicle. Current projections show that 50 to 
75 percent of all future geostationary spacecraft will use 
electric propulsion.
    All-electric spacecraft coupled with low-cost launch 
vehicles enabled our Nation to recapture the global launch 
vehicle market for commercial satellites. To remain 
economically competitive with this success, all launch vehicle 
providers are forced to upgrade their systems. In addition, 
Europe and Russia continue significant investments in electric 
propulsion. India and China each launched their first 
electrically propelled geostationary satellite this year. Japan 
is scheduled to launch its first all-electric commercial 
satellite in 2021. Electric propulsion is recognized as a 
competitive factor in the technology portfolios of these 
countries.
    There are three activities that I strongly believe will 
bolster our Nation's leading position in electric propulsion 
technology. First, investments are required in electric 
propulsion technology across a spectrum of expected time to 
return on investment. Second, the Nation must invest in ground-
based test facilities to develop and then fly the next 
generation of electric propulsion devices. Third, NASA must 
maintain a steady steering of investment in university research 
programs to ensure that the unique intellectual talent required 
to fly these systems is available when we are ready to execute 
on these ambitious missions.
    The role of electric propulsion in the exploration of our 
solar system, economy and security will increase in the coming 
decades. Thus, investment in NASA's electric propulsion program 
helps maintain our leading position in space technology, aids 
economic competitiveness of our Nation, enhances our 
understanding of the physical world, and inspires current and 
future generations to pursue STEM careers.
    Thank you for the opportunity to be here today. I look 
forward to your questions.
    [The prepared statement of Dr. Walker follows:]
    
    
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    Chairman Babin. Thank you, Dr. Walker.
    I'd now like to recognize Dr. Chang-Diaz for five minutes.

             TESTIMONY OF DR. FRANKLIN CHANG-DIAZ,

                        FOUNDER AND CEO,

                    AD ASTRA ROCKET COMPANY

    Dr. Chang-Diaz. Thank you, Mr. Chairman and distinguished 
Members of the Subcommittee. I am honored to be called to 
testify before you on this important topic for our Nation and 
for our civilization.
    In securing our ability to travel in deep space safely and 
sustainably, we are also ensuring, or helping to ensure the 
survival of our species. I believe that space travel actually 
beckons humanity a lot more today than it did 50 years ago. But 
we need to secure a safe and robust and fast means of 
transportation. Going to the Moon is one thing; going to Mars 
is a completely different thing.
    So on the screen I wanted to put up that graphic 
representation of the in-space propulsion challenge before us. 
Despite decades of progress in many areas of space technology, 
the challenges of deep-space transportation remain as clear and 
present as they were in the 1960s. Our transportation 
workhorse, the chemical rocket, has reached an exquisite level 
of refinement but it has also reached its performance limit. 
That technology will not provide us with a sustainable path to 
deep space. It does not mean that we need to discard it. On the 
contrary, chemical rockets will continue to provide 
foundational launch and landing capabilities for the 
foreseeable future and reducing their cost is a worthy goal.
    But once you're in space, the path to sustainable 
transportation lies in high-power electric propulsion, and by 
high power, I mean power levels of 100 kilowatts and up. A 
hundred kilowatts is roughly the power of a small car. Three 
hundred kilowatts is the power of an SUV, just to give you a 
sense for what these things means.
    Each one of us in the NextSTEP Program is due to 
demonstrate the efficient operation of our respective 
technologies at a power level of no less than 100 kilowatts for 
100 continuous hours. These rockets will first be solar 
electric and later, as we move outwards from the sun, they must 
transition to nuclear electric power.
    Ad Astra Rocket Company is an American corporation, 
developing a uniquely American technology. We are based in 
Texas. Our flagship project is the VASIMR engine. It is an 
electric rocket that fits squarely within the high-power niche 
as previously defined and can scale naturally to multi 
megawatts. The VASIMR originated at MIT in the 1980s. The 
technology was transferred to NASA in the 1990s and privatized 
in 2005 by Ad Astra Rocket Company in 2005. The most advanced 
VASIMR engine is the VX-200, which is a 200-kilowatt engine 
which has executed more than 10,000 reliable and efficient 
firings at power levels of 200 kilowatts and higher. Its 
performance data has been well vetted by the science community 
and published in the top peer-reviewed journals of our 
industry. The technology readiness level of the VASIMR is now 
between four and five. The lion's share of this development has 
been achieved at Ad Astra Rocket Company with more than $30M of 
private investment from U.S. and international investors.
    In 2015, NASA became a partner and awarded us a three-year, 
$3-million-per-year NextSTEP contract to help bring the 
technology to TRL-5. We are halfway through this program and 
moving smartly to its successful completion in mid-2018.
    Mr. Chairman and Members of the Subcommittee, our Nation as 
we move to explore deep space with humans, we must be able to 
travel fast to reduce the debilitating effects of space on the 
human body, to reduce the burden of consumables, life support, 
to be less constrained by planetary alignments and tight launch 
windows and to expand our capability to recover from unforeseen 
contingencies en route. In short, this is the problem punch 
list we still need to solve to give our astronauts a fighting 
chance in deep space. The development of high-power electric 
propulsion is critical to checking these boxes and to meeting 
our Nation's goals in space, and I look forward to your 
questions. Thank you very much.
    [The prepared statement of Dr. Chang-Diaz follows:]
    
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    Chairman Babin. Thank you, Dr. Chang-Diaz.
    I now recognize Mr. Cassaday for five minutes for your 
testimony.

                 TESTIMONY OF MR. JOE CASSADY,

                 EXECUTIVE DIRECTOR FOR SPACE,

                     WASHINGTON OPERATIONS,

                       AEROJET ROCKETDYNE

    Mr. Cassady. Good morning. Chairman Babin, Ranking Member 
Bera, Members of the Committee and your staff, I appreciate the 
opportunity to be here this morning to discuss how in-space 
propulsion will enable and enhance the Nation's space 
exploration efforts together with the Space Launch System and 
the Orion.
    I'm going to summarize my remarks here but I'd like to 
request that the written testimony be included in its entirety 
in the record. Thank you, sir.
    On behalf of all Aerojet Rocketdyne employees across the 
country, I'd like to thank you and your Committee here for the 
relentless work the Members and staff have put forth to ensure 
that the Nation's space program is a success. Your commitment 
to exploration and discovery should be lauded.
    This is a time of excitement and inspiration within the 
space community and, for that matter, across the country and 
around the world. We are building today the systems necessary 
to get humankind back to deep space and onto Mars starting in 
the early 2020s with the Deep Space Gateway in lunar orbit.
    Just for a moment I'd like to tell you a little bit about 
who we are. Aerojet Rocketdyne is a world leader in power and 
propulsion. We've supported the Nation's defense, civil and 
commercial space efforts for over 70 years. Among the 
accomplishments we take pride in are having launched every 
astronaut from U.S. soil, landing seven spacecraft successfully 
on the surface of Mars, and sending spacecraft to visit every 
planet in the solar system, and I include Pluto in that because 
it was a planet at the time we launched that mission.
    Of particular relevance to this hearing, we've been 
pioneers in the application of electric propulsion since the 
1980s. In fact, right now there are some 160 spacecraft 
orbiting the Earth flying our electric propulsion products of 
one type or another.
    As NASA looks to expand human presence in the solar system, 
development of efficient in-space transportation systems is 
critical. Solar electric propulsion, or SEP, is key to the 
sustainable architecture shown in the projected graphic by 
enabling efficient transfer of cargo, habitats and payloads to 
deep-space destinations in advance of astronaut arrival. Here's 
why that's important. Today we can land one metric ton on the 
surface of Mars. In order to do these human missions, we need 
to land 80 metric tons of supply and equipment. Mars missions 
will also send humans much farther than ever before. This 
combination of heavier payloads and the need to travel over 
greater distances drives us to seek a solution that takes 
advantage of strategic logistics planning.
    An analogy to explain this approach is the way that 
military deployments are conducted today. First, the heavy 
equipment, supplies and other logistical items are pre-deployed 
by large cargo ships and planes to the region. Then once the 
equipment is in place, the troops follow by fast air transport. 
SEP systems are the equivalent to the cargo ship for deep-space 
missions. These systems are now under development by NASA and 
Aerojet Rocketdyne to reduce the amount of propellant needed 
for these space missions by a factor of 10. This is important 
because it costs just as much to launch propellant as it does 
to launch scientific instruments or other mission-critical 
equipment. With SEP, we can reduce the number of launches 
needed and thereby taxpayers cost to achieve the mission. We're 
well on our way to having efficient in-space transportation 
with SEP. We must continue to adequately fund these development 
and demonstration efforts.
    The primary challenge facing high-power SEP development is 
the risk of losing focus as we go through the critical 
transition period from development to flight demonstration and 
subsequently operational use. This requires a stable budget and 
a constancy of purpose. Everything we do should be with the 
goal of landing human on Mars in the 2030s.
    Currently, we're on a development path that will result in 
an SEP system capability in the 100-kilowatt to 200-kilowatt 
total power range. This is more than adequate for early outpost 
missions to Mars.
    As SEP is scaled up to several hundred kilowatts, another 
challenge we face is managing the power transfer from the solar 
arrays to the thrusters. To reduce transit times, it's 
important that power is transferred as efficiently as possible. 
Since commercial spacecraft power systems are designed to power 
payloads and those are sized at 10 to 20 kilowatts, a power 
system from a traditional spacecraft cannot be adapted for a 
high-power SEP cargo vehicle. We're currently working on three 
separate SEP system developments with NASA, and details are 
provided in my written testimony.
    So finally, let me just thank you, and I look forward to 
answering your questions about our in-space propulsion 
activities.
    [The prepared statement of Mr. Cassady follows:]
    
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    Chairman Babin. Thank you, Mr. Cassady.
    I'd like to recognize Dr. Pancotti for five minutes.

               TESTIMONY OF DR. ANTHONY PANCOTTI,

             DIRECTOR OF PROPULSION RESEARCH, MSNW

    Dr. Pancotti. Chairman Babin, Ranking Member Bera, and 
Members of the Subcommittee, thank you for the opportunity to 
testify on in-space propulsion in the United States. I thank 
the Committee for its longstanding support of space exploration 
and plasma physics research in this country. I am pleased that 
the Committee is considering such important topics.
    I would also like to thank the Air Force Research 
Laboratory including the Office of Scientific Research as well 
as the SBIR program, which initiated and developed FRC 
propulsion over the past decade.
    High-power electric propulsion is a key technology for 
humanity's sustained presence in deep space. In order to build 
a permanent existence beyond the bounds of Earth, advanced in-
space transport will need to break today's impulse and coast 
approach and advance to continuous direct burns to destinations 
in our solar system. For this approach to be effective, high 
specific impulse devices are needed. This metric ensures that a 
large fraction of the expensive masses we launch into orbit are 
payload and not just more propellant to get the job done.
    Considering that even the most conservative manned missions 
to Mars are predicted to require almost 100 metric tons to 
reach the planet's surface, the cost of this endeavor becomes 
unsustainable.
    The above argument for high specific impulse provides good 
testimony for all electric propulsion systems. While low-power 
systems could effectively transport spacecraft almost anywhere 
in our solar system, it would take years or even decades. A 
trip from Earth to Mars with today's electric propulsion and 
the world's largest solar array on board the International 
Space Station would take over ten years. These time scales do 
not lend themselves to a sustainable deep-space astronauts. To 
be truly a sustainable endeavor, high power is needed to 
deliver any significant amount of mass in a reasonable period 
of time.
    While all the technologies being presented here today 
address this fundamental issue of high specific impulse and to 
a varying degree high power, MSNW's 100-kilowatt FRC thruster 
supported by the NASA program has some key advantages. In 
addition to the aforementioned, FRC propulsion is very light 
weight, and as we all know, lighter is faster, and for 
spacecraft, allow more payload on board. If humanity's intent 
is to explore, build and ultimately inhabit far-reaching 
destinations, it will require propulsion systems that are very 
light weigh.
    Variable power is another area where FRC propulsion has 
strong advantages. Interplanetary missions that use solar 
energy have a large decrease in power as you travel further 
away from the sun. Because FRC thrusters are pulsed fixed 
energy devices, not fixed power devices, they can accommodate a 
large range of power inputs in a single design. This means that 
FRC thrusters can be validated in cislunar space and the exact 
same hardware can be applied to a Mars transfer mission.
    Another important benefit with regards to power is FRC's 
ability to scale up. The physics of this technology were born 
out of the fusion community that currently operate FRC devices 
at energy levels that would correspond to a 70-megawatt 
thruster. Considering these origins, FRCs would be able to 
service the propulsion demands for several generations and 
expand deep space astronauts to Mars and the ocean worlds 
beyond.
    The most unique characteristic of FRC propulsion is their 
ability to operate in a wide variety of propellants including 
oxygen, which typically degrades vital components in other 
propellant systems. FRC thrusters have been demonstrated on 
pure oxygen as well as carbon dioxide, a major component in 
Martian atmosphere. FRCs have also been formed on vaporized 
water, which is easily stored and available--maybe available 
throughout our solar system. As part of MSNW's NextSTEP 
program, the FRC thruster will be operated on Martian 
atmosphere and methane.
    While this fact may have some benefit to traveling to Mars 
and beyond, the real advantages are when we return home, 
whether that trip is to bring back explorers or sample 
materials, the ability to refuel at almost any planetary body 
within the solar system has huge advantages. The cost savings 
of this approach are significant, and NASA is already focused 
on this topic called institute resource utilization.
    We cannot have the future we want tomorrow without 
investing in its technology today. This is no easy task when 
there are many expensive and pressing matters that require our 
attention at home. While many of those matters cannot be 
ignored, we must keep our eyes lifted to the horizons and 
invest in our future. While this task may be daunting and 
overwhelming, it happens one step at a time.
    By making strategic choices, the next step we take will put 
us on a path to the future that we all want. I applaud NASA and 
the U.S. government for their commitment to space technology 
and exploration, and with your continued support, my colleagues 
and I can make the right next step for a better future for all 
of humanity.
    Thank you.
    [The prepared statement of Dr. Pancotti follows:]
    
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    Chairman Babin. Thank you, Dr. Pancotti. Fascinating 
testimony. I notice we had even some more young folks come into 
the room. It's great to see so many people here this morning to 
hear this testimony.
    I'd also like to introduce two interns I've got that are 
sitting over there, both of them real small fellows. You all 
stand for us, Bo Swanson and Jonathan Ladd. We need a bigger 
office, I can tell you that.
    Anyway, we appreciate all of you being here this morning, 
and thank you for this testimony.
    I want to thank the witnesses for your testimony, and I'd 
like to recognize myself for five minutes of questions.
    I'd like to direct this to Dr. Chang-Diaz and Mr. Cassady 
and Dr. Pancotti because I'd like for you to kind of delve into 
it a little bit more for the benefit of all of us here. What 
capabilities--and let me just say this--I've had the privilege 
of touring and visiting two of you guys' facilities, very, very 
interesting. What capabilities does your specific technology 
have that makes it unique? We'll start with you, Dr. Chang-
Diaz.
    Dr. Chang-Diaz. For the VASIMR, there are certain features 
that are unique. One is that it can vary the thrust and the 
specific impulse of the rocket, keeping the power the same. 
It's essentially the same thing that you do when you shift 
gears in the car, and if you drive a car like a racecar driver 
you step on the gas and you never let go and all you do is 
shift gears, and so when you're climbing a steep hill, you 
would want more torque in your wheels so you shift to higher 
thrust, and when you are speeding in flat terrain such as 
interplanetary space, you would want to upshift to fifth and 
sixth gear, and then you will have a higher specific impulse, 
still the same power, maximum, because you paid dearly for the 
power. And so it's important to have that feature. That's one.
    The other one of course is that when you're dealing with 
plasma, you're talking about very hot substances, and you want 
to keep them off of the surrounding rocket casing, so you want 
to have magnetic nozzles, magnetic pipes that guide the plasma. 
The way you heat the plasma also is unique. We use 
electromagnetic waves, pretty much the same way you heat your 
coffee in a microwave oven: you don't touch it. You just launch 
these waves and these waves wiggle the plasma and get it really 
hot, and we're talking about temperatures of the order of two 
to three million degrees. So these are some of the features, 
and that gives you a great deal of capability to open up in the 
technology, so that's a summary.
    Chairman Babin. Mr. Cassady?
    Mr. Cassady. I think the unique feature of our approach on 
the NextSTEP program is that we're building upon what we've 
already flown. Our device that runs at 100 kilowatts is what we 
call a nested Hall thruster, and there's some description of it 
in the written testimony, but just for the group here today, we 
fly a 5-kilowatt Hall thruster on the advanced DHF spacecraft 
now as was mentioned earlier. It has a single annular region 
where the plasma is generated. The nested Hall thruster takes 
that, adds a second ring outside and then even a third ring, 
and each of those rings you're running essentially the Hall 
discharge. So we're able to take what we've known today that we 
fly today and scale it up simply without making it that much 
physically larger, we can scale it up to the much higher power.
    The other part of it is, I'd really like to delve into the 
system aspects. Because we're doing that approach, we're able 
to also deal with the power processing issues that we've 
learned a lot of lessons on in our flight experience--I'm not 
sure what's going on there.
    Chairman Babin. Ignore that.
    Mr. Cassady. Ignore it? Okay. Thank you.
    So the other half of the system--the thrusters are 
obviously very important part and they're the visible part that 
we all see but the other half of the system is the power, and 
Franklin referred to that. We have to shepherd that power 
through very carefully because wasted power is time to us. We 
need all the power we can get to keep that time down. So we're 
building blocks that we've learned from our flight experience 
into modular designs that we can scale up incrementally to 
these higher powers, and as Steve Jurczyk mentioned earlier 
that we are also working now on the 12-1/2-kilowatt Hall 
thruster. It's another incremental step. So incrementalism is 
my, I guess, word that I would use.
    Chairman Babin. Thank you very much.
    Dr. Pancotti?
    Dr. Pancotti. Thank you, Mr. Chairman. I think in my 
testimony I highlighted quite a bit about what we call ISRU, 
in-stage research utilization, and for me, when we're looking 
long term towards sustainable infrastructures in space, to 
become a space-faring race or a multi-world species, advanced 
capabilities that will allow us to use the resources of our 
solar system will become vital. Just like today, if you wanted 
to drive across our country, you wouldn't fill up an 18-wheeler 
worth of gasoline to make it. You would stop along the way and 
refuel, and I feel this is a very important aspect of building 
a sustainable infrastructure to be able to go to Mars, scoop up 
atmosphere, and use that to propel your spacecraft to the next 
destination or to return home. ISRU has a large payoff for 
return missions and also return missions from icy moons. So if 
we did want to go to far-off destinations, asteroids or icy 
moon planets, we could take water, use that as propellant and 
return very large samples to Earth.
    The other aspect I think that is fairly unique about FRC 
propulsion is the power. Not only is it scalable for a very, 
very large range of powers, like I indicated for many 
generations of propulsion systems to come, we can use the same 
technology but also the ability to vary that power over a 
mission. Because it's fixed energy, we can optimize an impulse 
for an exact energy condition, and then by changing how often 
we fire it, we optimize it or we can use it over a very, very 
large of power within a single design.
    Chairman Babin. Thank you very, very much.
    Now I'd like to recognize the Ranking Member of our 
Subcommittee, Mr. Bera.
    Mr. Bera. Thank you, Chairman Babin.
    I'm a simple person. I'm a doctor, not a rocket scientist, 
but if I'm thinking about this correctly, let's think about it 
in the context of travel to Mars just for sake of being 
concrete. We know the distance that we have to travel. We know 
the safe amount of cosmic radiation that a human being can get 
exposed to in terms of the time potentially. I think just 
listening to the testimony, we can think about this in two 
different ways. If we're sending supplies that are nonorganic, 
non-human beings, you know, you can send that at one speed, 
perhaps using one type of propulsion system, but then if we are 
sending human beings, we've got to send them at a different 
speed, perhaps faster, but at less weight. Am I thinking about 
this correctly? You know, just as a doctor, you could also then 
think about as we're thinking about how to send them faster, 
you know, what kind of additional shielding potentially we 
could do to prolong the time that they could be exposed to 
cosmic radiation. That's correct as well?
    So it's not an either/or, it's, you know, perhaps all of 
these propulsion technologies that we ought to be thinking 
about here as well as, you know, working with our scientists 
and the folks that are looking at that.
    Dr. Pancotti, you also talked about taking water, if we 
find planets with ice and, you know, there's some thought that, 
you know, part of our travel back to the Moon is potentially 
looking for ice in some of these deep craters that could--that 
we could then turn into fuel and use the Moon as a launch site. 
Is that correct or----
    Dr. Pancotti. Yeah, that's correct. Earth has a very deep 
gravity well, which means it's very expensive. That's why it 
costs so much to launch mass out of our gravity well. If we can 
find resources outside our gravity well or in smaller gravity 
wells that we can use, it will ultimately save us money.
    Mr. Bera. Okay. So for us as we're thinking about it and 
explaining to our constituents and the public, when they say 
well, we've already been to the Moon, why would we want to go 
back to the Moon. One reason we would want to go back to the 
Moon is that that is a potential secondary launch site. Is 
that--or not?
    Dr. Pancotti. Yes.
    Mr. Gerstenmaier. Yes.
    Mr. Bera. Well, again, I'm using your expertise to make 
sure I'm educated so that when I'm out talking to constituents 
and they ask these questions or talking to the broader public, 
it's like well, here's why this matters, or if they say well, 
why are you looking at solar propulsion or different 
technologies, well, here's why this matters.
    So, you know, kind of looking at the human element, maybe, 
you know, Mr. Gerstenmaier, what is that--you know, just to 
kind of put it in context, what is that safe time for a human 
to be exposed, you know, using current technology, again 
thinking about travel to Mars?
    Mr. Gerstenmaier. When we look at Mars today, basically 
with chemical propulsion, the transit time to Mars is roughly 
about a year or so and a year return. That's right at the limit 
of the radiation levels that a human can tolerate. So we might 
have to take a small waiver to some of our radiation 
constraints but we can basically make it with chemical 
propulsion. The big advantage here with the higher-power 
electric propulsion is you can cut that time down and get more 
margin and so the radiation exposure for our crews is 
dramatically less. So I think that's interesting about this 
technology is, it really opens up our way to do mission design, 
the way you described. We've talked about the gravity well 
being tough to leave the Earth. it's much nicer from the 
vicinity of the Moon or a high elliptical orbit around the 
Moon. Now we can station keep there with electric propulsion, 
then use these high-energy power systems to transit the Earth-
Moon system to these distant locations with much higher speed 
with a higher thrust level. So this technology really opens up 
the ability--we can do mission design to essentially optimize 
the overall systems design since we've minimized the exposure 
of the human to radiation in a microgravity environment.
    Mr. Bera. So we really should be thinking about multiple 
modes of propulsion.
    You know, one theory that someone was also suggesting were 
these Lagrangian points where, you know, things can sit 
stationary potentially for lack of a better way of describing 
it, having a gas station up there where, you know, having 
propellant up there, you break through the gravity well, you're 
able to able to go up there, refuel, and then go on. Is that 
just theoretical or is that something that folks think about?
    Mr. Cassady. I think as Bill was just saying, some of the 
groups getting together now to study how we go, what this 
architecture ought to look like, and you saw a little bit of 
that in the graphic I put up, one of the thoughts is, you could 
aggregate things out there in the lunar vicinity and then 
depart from there, and part of that aggregation--when I say 
aggregate, I mean bring different pieces of the eventual Mars 
spaceship to that point and that could include fuel. So--and 
then as Anthony alluded to in his testimony, you know, as we 
get better at making fuel on other places where we're going, we 
don't have to, you know, use the gas station or bring 
everything from Earth. We'd like to use the things that we find 
when we get out there into the solar system and perhaps we have 
a couple more nodes in the overall subway system, if you want 
to consider it like that, going between Earth and Mars where we 
can refuel the systems.
    Mr. Bera. Great. Thank you. I'll yield back.
    Chairman Babin. Yes, sir. Thank you.
    I'd like to recognize the gentleman from Oklahoma, Mr. 
Lucas.
    Mr. Lucas. Thank you, Mr. Chairman.
    Mr. Gerstenmaier, what we seem to be talking about here, I 
think can best be described as the concept of extensibility, 
that technologies developed in the near future will be useful 
for future exploration as well, and extensibility prevents the 
development of incapacities. Discuss with us for a moment how 
NASA ensures that its investments in in-space propulsion 
technologies have that ability.
    Mr. Gerstenmaier. Again, I think as you've kind of heard 
from this discussion, we're kind of investing in a variety of 
technologies so we don't pick one technology to focus on 
solely. We do the broad agency announcements to go look at a 
variety of technologies. We test those on the ground. We make 
sure they show promise. We have this requirement for this 100-
kilowatt system to run for 100 hours. That's a good proof of 
concept that can be done on the ground. Then when that's kind 
of behind us, we know the system is mature enough, then it can 
start being fielded into an operational system, and for 
example, the concept of the habitat around the Moon that uses a 
12-1/2-kilowatt system that Steve and the Space Technology 
Mission Directorates have been investing in, that's a step up 
from where we are with electric propulsion today and Hall 
thruster regime but that's an incremental step moving forward. 
So I think by taking these steps but also investing in these 
far-reaching technologies that are not yet--we're not sure what 
promise they have, that's also advantageous too so we need to 
have that mixed investment philosophy of where we're looking at 
each one of these but then we also look at the application 
moving forward.
    So we know today commercial communication satellites have 
electric propulsion on them. If we go to this 12-1/2-kilowatt 
size, that can remove the liquid apogee motors that are used 
from some launch vehicles that even helps the commercial 
satellite industry more. So these things have application not 
only for NASA use but also for use of the next generation of 
satellite technology. So I think we invest in a variety of 
activities not knowing exactly where the outcome is and we do 
it in a measured way that we can then get the best technology 
for future applications.
    Mr. Lucas. Along that very point, Dr. Chang-Diaz, Mr. 
Cassady, Dr. Pancotti, would you expand for a moment? Besides 
the government interest, and we just talked about this to a 
degree, how would you quantify commercial interest in high-
powered in-space propulsion systems, gentlemen?
    Dr. Chang-Diaz. For our company, we started out actually as 
a purely private venture, and it was all funded by private 
investors, and our interest was not really to go to Mars 
because going to Mars is really not a good business right now. 
So--but it is important to build the scaffolding that 
eventually will make it into a good business, and right now the 
business of space is closer to Earth, and so our vision is more 
of the vision of the trucking business of space, you know, 
building essentially a logistics capability, an electric high-
power electric truck, and we think of ourselves as sort of the 
diesel engine of space that enables all these trucks to be 
traveling back and forth between the vicinity of the Earth and 
the Moon to make some revenue for the company and then as needs 
expand why we go further, so that's the vision.
    Mr. Lucas. Mr. Cassady?
    Mr. Cassady. I would just say very similarly, we've been in 
the commercial side. We're supplying hardware now to most of 
the commercial satellite providers who fly electric propulsion. 
What we do see, as Bill said, as we're working with NASA on 
these higher-power devices, there are other functions on those 
spacecraft that can be accomplished like taking them from the 
drop-off orbit where the launcher leaves them to their final 
destination. Then there's a whole world of expanding 
possibilities that we're seeing open up. People are talking 
about these large 6,000 satellite low-Earth orbit 
constellations. Those satellites have to go to individual 
points around the globe and be positioned. You can do that very 
effectively with a space tug, and I like Franklin's term, the 
space truck. We think of it very similarly. It's pretty, you 
know, multipurpose. It really serves a lot of different 
functions. We see interest in the DOD world because they're 
looking at reducing the cost to get their assets where they 
need to be, and as well as improving the resiliency of the 
assets, and that all involves more maneuverability in space, 
which is, again, something that solar electric can provide to 
them.
    And then finally, I would say, you know, there's going to 
be probably an expanding sphere of influence of the economy as 
we move out and do these exploration missions around the Moon. 
We're going to start supporting people who want to go mine the 
Moon and do things like that. They're going to need 
transportation systems as well, and so as we're moving out to 
Mars, they're going to be coming along behind us and doing 
things that are economically viable and they'll need these 
transportation systems to support that.
    Mr. Lucas. Thank you.
    Mr. Chairman, I see my time's expired.
    Chairman Babin. Yes, sir.
    Now the gentleman from Virginia, Mr. Beyer.
    Mr. Beyer. Thank you, Mr. Chairman, very much, and thank 
you for holding this hearing. It was just fascinating.
    Dr. Chang-Diaz, you've been in space, and I was impressed 
with your opening paragraph where you said ``In securing our 
ability to travel in deep space safely and sustainably, we're 
also ensuring the survival of our species.'' Can you expand on 
that? Are you worried about the survival of our species, and 
how will going into deep space help that?
    Dr. Chang-Diaz. Well, this has been voiced by many of my 
colleague astronauts, and we all believe that, you know, we are 
all astronauts in this one planet that we have, and it's the 
only one we have, and we have no redundancy, and astronauts 
like redundancy. You know that. You know that. And so if you 
look at the way humanity is all housed in this, you know, this 
one ball, it is our life support that matters right now. We 
have no way to survive if something were to happen to us, 
something that could be brought by some external beyond our 
control event, we would be history that no one could tell, and 
it doesn't matter that much to the universe whether we are here 
or not but it does matter to us. And so I think the important 
thing here is for us to enable ourselves to be beyond and to 
work beyond and live beyond our Earth is fundamental to our 
survival.
    Mr. Beyer. Thank you very much.
    Dr. Pancotti, much of this testimony in this hearing is 
with the understanding that the Asteroid Redirect Mission was 
canceled and that all the work that was done basically--I mean, 
some of it moves forward. I want to ask this of our NASA 
gentlemen but was it a mistake to cancel it and to defund it?
    Dr. Pancotti. From my personal view, I don't think it is. I 
like to use the term, keep our eye on the prize, and that prize 
is Mars. I think the next step forward for humanity I think is 
a huge calling like Dr. Chang-Diaz mentioned, to get to Mars 
and put people on another planet, and in doing so, I think the 
most direct approach to that is the best path forward.
    As far as technology goes, propulsion devices, all three of 
us that are here talking today, those propulsion devices were 
initiated under the ARM mission and they are one of the most 
direct technologies that is going to move forward. No matter 
what we do in deep space, we are going to need advanced 
propulsion.
    Mr. Beyer. Great. Thank you very much.
    Dr. Walker, in your both written and oral testimony, you 
wrote--you said ``Investments are required in electric 
propulsion technology across the spectrum of expected time to 
return on investment.'' Is that just a really polite way of 
saying that they show no return on investment?
    Dr. Walker. No, it's not.
    Mr. Beyer. Or not in our lifetimes. And is it reasonable to 
expect a reasonable return on investment when we're talking 
about the exploration of deep space?
    Dr. Walker. Sure. Let me explain. I think the spectrum is 
very important. There are commercial things right now that 
impact our economy from how we deliver commercial satellites. 
That's a significant business. That business is up for grabs 
now as electric propulsion has become more mainstream, and the 
country or group that creates the next best electric propulsion 
device will own that business. So we need to make some very 
short-term investments so that we can make sure we have that. 
In the long term as the power available on orbit continues to 
rise, then we can begin to feed in these higher-power devices. 
So yes, it's a spectrum, some things that will be very 
impactful in the next five years and other things won't see for 
15 to 20 years. Does that answer your question?
    Mr. Beyer. Yes, it does. Thank you very much.
    Mr. Cassady, you talked about how you're on the development 
path that results in SEP system capability in the 100-kilowatt 
to 200-kilowatt power range, and yet we heard I guess Dr. 
Chang-Diaz's company, they're already doing a consistent 200 
kilowatt. Are you lagging behind or is it just because there's 
different technologies with different uses, or--you know, you 
seem uncompetitive relatively.
    Mr. Cassady. So I guess what I was trying to focus on there 
was the total system power that we need to get to Mars in the 
2030s, and my point was, we don't need to go to a megawatt to 
be ready to go to Mars; we can do it with 100 to 200 kilowatts. 
We've done a lot of internal studies on the architecture as was 
shown in the diagram that I presented there, and I know our 
colleagues at NASA are doing the same thing. What we're trying 
to do, and I used the word ``incrementalism'' earlier--we're 
trying to come up with a ``walk before you run approach,'' 
approach, I guess. We know the budgets are tight. We know that 
we're going to have to work under a constrained budget 
environment for the foreseeable future, and within that 
environment, we're trying to be responsible and say what's the 
minimum amount that we need to have to ensure we can do this 
mission and make the mission close, and for the cargo part of 
that mission, we can live with about 200 kilowatts, something 
in that range.
    Mr. Beyer. Great.
    Mr. Cassady. That's for the total system, and then the idea 
is that we plug in these 12-1/2-kilowatt thrusters that we're 
developing right now for STMD onto that vehicle and that would 
be the cargo vehicle. That's why most of that payload that we 
talked about to Mars before the astronauts get there and pre-
deploy it.
    Mr. Beyer. Great. Thank you.
    Mr. Chair, I yield back.
    Chairman Babin. Yes, sir. Thank you.
    Now the gentleman from California, Mr. Rohrabacher.
    Mr. Rohrabacher. Thank you very much, Mr. Chairman, and 
thank you, Mr. Chairman, for having this hearing today and 
organized as it is so that we can have a better understanding 
of the goals and the technology needed to achieve those goals, 
and I appreciate the witnesses and I appreciate your leadership 
on this.
    We had a hearing on materials and the development of new 
materials and how that relates to human progress yesterday or 
the day before, and when we are talking about the electric 
propulsion systems now which is being presented to us as some 
new type of options that we have, how much of this is 
dependent, was dependent on new materials? Is this something 
that's part of this formula? Whoever wants to, go right ahead.
    Dr. Chang-Diaz. It was quite dependent on materials, 
advanced materials, particularly when you deal with very hot 
plasmas, and you have to encase these plasmas in materials that 
will not erode away or melt away, so there are some special 
ceramics that have been developed that enable us to shine these 
electromagnetic waves and make the plasma hot yet they go right 
through the walls of the rocket. So the material development 
has been critical.
    For us, some of the means of delivering this energy to the 
plasma requires materials and special antennas and special 
coatings that we use, very new materials, of course, that are 
proprietary right now but definitely materials is very 
important.
    Mr. Rohrabacher. Do any of these materials--I have not been 
a friend of necessarily spending more money on fusion energy. I 
felt that was something that doesn't seem like we've made much 
progress. However, I've been told that fusion energy, or actual 
or attempt to develop it has helped produce new materials. Is 
this part of that?
    Dr. Chang-Diaz. In our case, it is, and I think in the case 
of Anthony's as well. I think we both have the same pedigree 
from the fusion energy program way back in the--well, he's a 
lot younger but I go back to the 1970s when we were trying to 
develop fusion and they told us it was 20 years away.
    Mr. Rohrabacher. In light of that expression where the 
young kid says ``I don't know where I'm going but I'm on my 
way,'' and I think with fusion energy, as I say, I've been 
skeptical. I'm working to the point where we can use it for the 
production of electricity here but we can see that there's 
benefits that we don't know were going to happen, and so I'm 
very pleased to hear that all that money that we spent on 
fusion energy didn't go to waste. So thank you very much.
    I'd like to ask Mr. Jurczyk about the choices here that we 
do have, and maybe it's like a choice between fission and 
fusion. I don't know. But the idea of having a refueling 
station, cryogenic propellant storage station there, is that 
with this type of new technology that we're taking about 
developing and putting into place, is it still important for us 
to do cryogenic storage facilities and refueling, basically 
refueling stations if we have this capability?
    Mr. Jurczyk. As Mr. Gerstenmaier mentioned, one of the real 
advantages of electric propulsion is the storability of the 
propellant. So for the 12-1/2-kilowatt thruster system, xenon 
is the propellant and xenon is storable, and so we don't have 
to come up with credibility to either passively or actively 
cool the system to keep that propellant available to the 
thruster system. However, if we look at more advanced chemical 
propulsion systems like locks hydrogen propulsion systems for 
space, and that would require advances in technology for both 
long-term storage of locks and particular hydrogen, long-term 
storage of hydrogen is very challenging and you'll need active 
cooling to be able to do that in transfer technologies. So that 
would be more geared towards if we went to higher-performing 
in-space chemical propulsion stages. The real advantage of 
electric propulsion is the storability of the propellant and 
not needing to go to cryogenic propellants.
    Mr. Rohrabacher. I'm not sure if that was a yes or no, 
but--do we see that if we're going to be having a successful--
there's talk that maybe--you know, keep your eyes on the prize, 
like you say. I'm not necessarily involved with trying to 
eliminate all these other options we need to do in space in 
order to just get to Mars, but in order to do some of our 
Moon--if we readjust so it's Moon first, then Mars, will we 
need a cryogenic storage facility as compared to a deep space 
propellant like was being described today?
    Mr. Jurczyk. Yeah. If we continue to go down the route of 
chemical propulsion, we talk about--we talked about being able 
to produce a fuel with water resources on the Moon and then 
being able to handle that propellant, store it and transfer it 
would be a capability we'd want to need if we wanted to use 
that ISRU capability on the Moon as was mentioned previously, 
yes.
    Mr. Rohrabacher. Well, thank you, gentlemen, very much. 
It's been a very educational experience. God bless.
    Chairman Babin. Thank you.
    Now I'd like to recognize the gentleman from Florida, Mr. 
Posey.
    Mr. Posey. Thank you very much, Mr. Chairman, and I thank 
all of you on the panel for this very informative session, all 
of you.
    Dr. Chang-Diaz, I was particularly pleased that you 
mentioned survival of our species as an important aspect of our 
space missions. I don't think that's emphasized enough. For a 
number of years, I know anytime any of us mentioned it, critics 
said you're trying to scare people into supporting space, and a 
lot of those critics dropped off a year or so ago when that 
relatively small, undetectable asteroid detonated over an 
uninhabited area of Russia a thousand miles from the closest 
living person and still injured over a thousand people, and 
made them reflect a little bit more about the cause of the last 
Ice Age, the cataclysmic asteroid that hit the Yucatan 
peninsula.
    But anyway, thank you for mentioning that. I wish we would 
all be more informed about it and mention it more often. I 
think the public would have an interest in that. Since there's 
no more shuttles for Bruce Willis to change the course of these 
things on, we'd be in a bit of a bind. The longest silence I 
ever heard in this place was when I asked three of our top-
ranking space officials what would happen if we found a 
relatively small one, the size of the one that exploded over 
Russia, headed for the Big Apple and we had three days, and we 
never would have three days to do something about it. It's the 
longest silence I've ever heard in this Committee.
    But anyway, having always been informed that there's no 
such thing as perpetual motion or a perpetual energy machine, I 
wonder if any of you would care to comment on the closest thing 
to it that you have ever seen.
    Dr. Chang-Diaz. I mean, in our case, we deal with it every 
day, it's superconductivity. The magnet that produces the 
strong magnetic field that houses the plasma in the rocket is a 
superconducting magnet, and this magnet runs electricity 
through its windings with almost zero, absolute zero 
resistance. So in a sense it's like this current can keep going 
forever. It's almost like a perpetual motion machine. It is 
not. There is a tiny little bit of resistance that you have to 
deal with, and that comes out in the electric bill that you do 
have to pay to keep the magnet running. It's just about 100 
watts but you do have to pay for that. And this is technology 
that's already in the field and we see it in hospitals. MRI 
machines are basically superconductors, and we want to improve 
that technology to the high-temperature superconductors, which 
are much cheaper, much more capable so that we can have MRI 
machines in ambulances and perhaps in field hospitals or 
clinics and something that really can be done that way. So this 
is the way space feeds back to our society.
    Mr. Posey. There's been some theories that some other folks 
may have harnessed isolated and focused magnetism in a way that 
would propel without sparks. What do you think about that?
    Dr. Chang-Diaz. Well, I've seen a lot of fringe projects 
that promise to deliver tremendous results, but we're all 
scientists and we all believe in the scientific process that's 
in place where scientists vet these things and you have to do 
an experiment and measure and be able to prove to your peers 
that you are measuring the right thing, and after you've done 
that, then people believe you. But until you do that, it's all 
just smoke and mirrors.
    Mr. Posey. Do any of you foresee any advances or 
breakthroughs in battery storage capacity in the relatively 
near future?
    Mr. Cassady. Yeah, I think that's something we're working 
pretty actively right now. We just replaced the batteries on 
the Space Station with lithium ion, an upgrade from the nickel 
hydrogen batteries that were the primary technology available 
at the time we started putting the Space Station together, and 
so we have a group in our company that's always looking at the 
next battery wave that's coming ahead of where we are now. A 
lot of that's being driven by what you see across multiple 
industries including the automotive industry, laptop computers 
and things like that, but we're looking always for what's the 
next energy-efficient without the problems of some of the 
reactivity that you have in something like a lithium ion 
battery, and there's a lot of applications for that that are 
driving that including long-term undersea as well as space, so 
yes, sir.
    Mr. Posey. I was going to ask you about a form of hydrogen 
but I'm about out of time and----
    Chairman Babin. No, sir. I'm going to take the liberty of 
the Chair and say we're going to ask some more questions. Go 
ahead. Finish.
    Mr. Posey. You know, when we talk about hydrogen that 
there's all kinds of hydrogen. During World War II we were 
having some disasters with some of our Navy frogmen, I 
understand. They'd be down there welding up a hole in a ship 
and their mask would explode, and it's my understanding that it 
was finally determined that the bubbles from the welding that 
they're doing contained a hydrogen and very explosive, and that 
was causing the problems with their masks. I don't know if 
that's a fact. I've been informed that from several sources.
    So I saw a person one time have a fish tank filled with 
water, a stream of carbon at the bottom of the tank, put a 
welding rod in there, ignited the carbon, and it continued to 
burn by itself, and it made bubbles, and he had like a bell jar 
on top, and the bubbles burst and he captured the hydrogen in 
the bell jar, and pumped it into a compressor. He just used 
like a diver's air tank, sealed it up, hooked it up to a little 
engine, started the engine. The engine ran off it for about ten 
minutes that I witnessed, could put my hand on the engine, 
could put my face on the exhaust pipe. It ran that cool, and 
I'd just like your thoughts on that. I mean, I perceived all 
kinds of things just from looking at that and all kinds of uses 
for it, and I'm just----
    Dr. Chang-Diaz. Yeah, your--I think your description, it 
seems to me that it was electrolysis----
    Mr. Posey. Yes, yes.
    Dr. Chang-Diaz. --was what was happening here, and it was 
producing just--it happens that the electricity and that spark 
that you were seeing was breaking the water molecules into 
oxygen and hydrogen, and so there must have been two streams of 
gas, one that he captured in the bell jar, which was hydrogen, 
but there was also oxygen coming out, and yes, in fact, in our 
company, we're very deep in the hydrogen economy. In my home 
country of Costa Rica, we're trying to deliver and produce 
hydrogen from water and solar and wind energy electrically to 
power transportation, to power cars and mostly urban buses and 
trains and so on. So it is very much here and now.
    Mr. Posey. The typical hydrogen that you might put in a 
balloon and the balloon would be flat the next day. So we put 
some of this in a balloon and it was still just about fully 
blown up for over a month, and I just thought maybe the bucky 
balls were different in there, they were thicker, bigger, and 
that would not have let them escape, but I imagine by now--and 
this was 20 years ago--I thought now we'd be seeing something 
like this in progress and making energy for it and running 
people's homes and over-the-road trucks, and I'm just 
surprised.
    Anyway, I know my time's up now, Mr. Chairman. Thank you so 
much, Mr. Chairman.
    Chairman Babin. No, sir, I think he's into racing cars and 
I think he's trying to figure out some way to get an edge with 
hydrogen.
    Mr. Posey. You know, I did spend a day with Smokay Yunick 
before he passed away, the greatest automotive mind I think in 
American history, and Smokay's the one that said--I mean, we 
talked about it a long time. He scratched his head and he 
said--I mean, it's just hydrogen but it's different than any 
other hydrogen I've ever dealt with here.
    Thank you, Mr. Chairman.
    Chairman Babin. Yes, sir. Thank you, Mr. Posey.
    There was just a couple more questions that I wanted to ask 
as well of a couple of you, and Dr. Walker, what are the 
largest technological challenges associated with the 
development of advanced in-space propulsion generally? What are 
we dealing with her? What are we having to overcome?
    Dr. Walker. So the largest technological challenge is time. 
So whatever everyone alluded to here is I need a lot of 
electricity so I can get my trip time down. What they're not 
saying is that that means those engines that we use have to 
last thousands of hours, so the engine has to be able to run 
for years, and so if there is some small, little process that's 
slowly eating away at that engine, I have to have a great 
experiment to catch that process so I don't build it into my 
final product. So for us, we have to have really great 
facilities so we can catch the little, slow, progressing 
physics that will eventually kill the engine.
    Chairman Babin. And you're still talking about electric 
propulsion and solar electric propulsion, right?
    Dr. Walker. That's correct.
    Chairman Babin. The slightest little flaw over a period of 
years and you have a destroyed engine and you're dead. You're 
dead in the water.
    Dr. Walker. Correct.
    Chairman Babin. Yeah. Okay. And then I wanted to also ask 
Mr. Gerstenmaier, extensibility is the concept that 
technologies developed in the near term be useful for future 
exploration as well. Extensibility prevents the development of 
dead-end capabilities. How is NASA ensuring that its 
investments in in-space propulsion technologies are extensible?
    Mr. Gerstenmaier. Again, kind of what we're doing is, we 
look at systems that we put together, so when we talked about 
the cislunar habitat or the Deep Space Gateway, that uses 12-1/
2-kilowatt thruster technology. We think a lot of the things we 
saw for that 12-1/2-kilowatt thruster level can be then 
advanced and moved forward through things similar to the nested 
technology that Joe talked about a little bit and then you can 
advance that to the higher-level thrust, maybe 50-kilowatt 
thrusters, for the deep-space transport. So that technology we 
do around the Moon to allow us to maneuver the habitat to 
various locations, that same technology then can be advanced 
and pieces of it moved forward.
    We're also not only doing that but then we're also 
investing in this brand-new technology, the things that two of 
the panel members here are looking at that's a different 
technology but it has tremendous potential for us, so we want 
to invest in those on the ground to look at things like running 
them for 100 hours, and that was part of our test plan, and 
that was to look at this life issue that was described by the 
panel. So we think we can do that, then if that comes online, 
then we can interject that technology into that next generation 
of spacecraft. So the idea is to look at what we're doing with 
each piece, look at the individual technology underneath it, 
the power systems that have to convert from solar arrays and 
bring that power level to the thrusters. That same power 
conversion technology is common no matter what the thruster 
itself does. So that technology is common. So we look for those 
areas, those common threads across multiple technologies that 
can be expanded or extended into other areas, and we don't end 
up with a technology that only supports one type of spacecraft 
and has no applicability to other spacecraft.
    Chairman Babin. I appreciate that. We're talking about 
faster velocities. How much faster? I mean, if we're talking 
about this type of propulsion, and put it in terms of those of 
us who are laypersons can understand. How much faster are we 
talking about here? Any of you if you'd like to chime in.
    Mr. Cassady. So I mentioned the architecture studies that 
we're looking at. We typically want to try to work on about a 
two-year cycle for Mars missions as you know. About every other 
year there's a favorable opportunity to leave. So what we do--
when I mentioned that 100- to 200-kilowatt system power level, 
we are trying to time the launches of the cargo vehicles so 
that they will be there, have enough time to have that 
equipment in position before we launch the crew on the next 
opportunity so there's sort of a natural cycle there of about 
two years. If we don't have enough power, and for whatever 
reason the thruster technology isn't adequate or the power 
system technology doesn't give us the efficiency of the power 
transfer from the arrays to the thrusters, then we'd end up 
probably extending that by six months or a year. So then we're 
out of sync and we're not able to support the mission. So 
that's really the trade the way we look at it. It's fitting the 
longer transit time that the solar electric's going to take to 
the other mission constraints like when we're going to want to 
launch the crew and get them there so that everything lines up.
    Chairman Babin. Okay. Thank you.
    And then one last question, Mr. Jurczyk. Future in-space 
propulsion may require enormous amounts of power beyond what 
solar power can feasibly provide. What kinds of other power 
technologies is NASA pursuing to meet increasing power demands 
in coming decades?
    Mr. Jurczyk. Yeah, so right now we're focused on compact 
nuclear fission-based reactors targeted for surface power 
currently but we can evolve it to spacecraft power systems. So 
early next year in collaboration with DOE we're going to 
demonstrate a 1-kilowatt fission-based reactor at the Nevada 
Test Site that scales to 10 kilowatts. And then the other key 
technology that's part of that is the conversion technology. So 
that's going to use sterling cycle engine technology to convert 
the heat from the reactor to electrical power. There are other 
cycles that we need to look at too but that's going to be key 
to get the efficiency up to convert the heat from the reactor 
to electrical power and continue to advance that conversion 
technology. So we are working--your current efforts are focused 
on surface power but we're looking at how those technologies 
and systems are extensible for nuclear power for spacecraft.
    Chairman Babin. All right.
    Mr. Bera?
    Mr. Bera. I'll take advantage. I feel like a student in 
office hours with the professors here.
    So thinking about this with regards to solar electric 
propulsion, Mr. Cassady, the further you get away from the sun, 
does the amount you can generate diminish?
    Mr. Cassady. Yes.
    Mr. Bera. Okay.
    Mr. Cassady. Yes, and Anthony referred to that in his 
remarks. So we're falling off, it's roughly a factor of two out 
at Mars. If you look at the history of deeper space exploration 
with the exception recently of Juno, everything we've sent out 
further in the solar system has used some sort of either 
radioisotope or other type of nuclear power, and solar arrays 
are only going to be good probably for going between here and 
Mars. At that point, some point in the future as we start to go 
further out, especially with human-scale missions, we're going 
to need to have nuclear power developed.
    Mr. Bera. And again, it's appropriate. You know, part of 
the reason why we can use nuclear when we're going further out 
is, we don't have human beings and obviously the exposure 
factor is different.
    It's also accurate to think then, you know, so for us in 
the public, we see big launches and you see the big thrusts and 
so forth. That really is to break the gravity well. Once you're 
beyond the gravity well of Earth and you're in the vacuum of 
space--and I don't know, you know--I think of space as a vacuum 
but I don't know if it's a true vacuum. As you're accelerating, 
though, you're going to continue to accelerate. Is that not--
are we thinking about that correctly?
    Dr. Pancotti. Yes, that's correct. So part of what I was 
talking about, we're dominated by orbital mechanics, right? So 
if the chemical system is what I call in my initial argument 
was kind of the impulse and coast, and that's what we do with 
chemical systems. We apply a force and then we coast for a very 
long time so all of the orbits line up and we can get to our 
destination as efficiently as possible because with chemicals 
systems with low ISP, they're not efficient and we have to do 
that in order to rendezvous and make that approach.
    When I was talking about going to very high power and very 
high ISPs, we can talk about doing direct burns where we turn 
the thruster on and we leave it on and we just pick our target, 
we aim directly towards it, and we go straight for it. In order 
to do that in a short time, you need a large power, megawatts' 
worth of power, a nuclear reactor-type power.
    Mr. Bera. So you can--if you're continuously thrusting and 
burning, you can cut the time down?
    Dr. Pancotti. Yeah. In fact, sometimes you can even 
eliminate the need to do a fly-by, which is sort of another lap 
around the sun, and for some missions, there's a lot of 
missions right now in the new frontiers proposals that are out 
there that are looking at solar electric for that reason just 
because the science return, the time frame that they can get it 
back is reduced dramatically for these principal investigators.
    Dawn is another good example that was brought up earlier. 
The ability to directly fly orbit one body in the asteroid body 
and then depart and go to another body, that's unprecedented. 
We've never been able to do that. And Dawn actually, I believe 
I read this right, my friend John Brophy at JPL was telling me 
the total amount of impulse that Dawn provided to the 
spacecraft, the ion engines provided to the spacecraft, was 
greater than the Delta-2 rocket that launched it out of the 
gravity well, so that's just to give you some idea, and it was 
done with just a couple hundred kilograms of xenon that was 
onboard the spacecraft.
    Mr. Bera. So we spent a lot of time talking about 
acceleration and so forth but we also then have to think about 
deceleration, right? Do you have to use propellant to 
decelerate or do you through science use the natural gravity 
and atmosphere?
    Mr. Jurczyk. Missions now use propellant to decelerate to 
say, achieve Martian orbit. There are other approaches that 
we've studied like aerocapture so you can dip down into the 
Martian atmosphere and use atmospheric drag to decelerate and 
then come back out and achieve Martian orbit. So there are 
other approaches that do not need propellant. But we haven't 
tried any of those yet, and I'd be really looking forward to a 
mission that would be willing to sign up for aerocapture. We do 
aerobraking right now where we go into Mars orbit in a high 
elliptical orbit and then dip down in the atmosphere to slow 
down and circularize the orbit but we haven't done aerocapture 
yet.
    Mr. Bera. And then I guess my last question, one that I 
hadn't necessarily thought about, we've talked about what 
powers the engine, the propellant, the gasoline in that engine, 
and just again listening to the conversation, different 
propellants require different size gas tanks in essence, and 
right now are we also doing research on smaller propellants as 
well?
    Mr. Cassady. So there's a number of sort of lower 
technology readiness level things out there that people are 
looking at, especially now. I mentioned the constellations of 
satellites earlier. A lot of those constellations want to fly 
electric propulsion onboard a very small spacecraft, you know, 
maybe something that would sit on this table in front of me 
here, and for them, xenon, while it's good, it has some of the 
problems that you brought up--it needs a big tank of some 
sort--and they're looking at things that might be able to fly 
with a solid propellant, for instance, something like iodine 
and then let that propellant just sublime off into a gas and be 
run through the engine. So there are some programs like that I 
know that are out there and people are looking at.
    Mr. Jurczyk. Just to add, we have several public-private 
partnerships within STMD, not only with our programs but also 
SBIR to advance these very highly efficient, very compact 
electric propulsion systems for cube sats and small spacecraft, 
and that's come along pretty well. Iodine--solid iodine is 
definitely one of the propellants that you can get the energy 
you need in a very small package.
    Mr. Bera. Great. Thank you.
    Chairman Babin. Thank you, Mr. Bera.
    And Mr. Posey has some additional questions.
    Mr. Posey. Just since we have the extra time, Mr. Chairman, 
if nobody minds.
    As you know, we're still waiting on a map to Mars, a 
roadmap to kind of put everything in perspective, and so 
there's questions. We had the pleasure of asking today and 
learning the answers to today that maybe are a little bit ahead 
of the edge but we talk about the craft and the engines to take 
us to Mars, and we talk about the durability of them that's 
required, which is a serious issue, and I assume that we would 
use the craft and the engines continuously as much as possible. 
Once we would get them in orbit, we'd just have cyclers. We'd 
eventually have a supply train up there. Maybe we'd go back and 
forth to the Moon. I think Buzz Aldrin talked about it in his 
cyclers. You know, we ought to be able to get fuel on the Moon 
to go back and forth and refuel the cyclers and have stuff 
going all the time where if you were on Mars, you wouldn't have 
to wait two years to come home again, we'd have something going 
through there all the time. Thoughts about that?
    Dr. Pancotti. Yeah, I can comment. I think what you're 
talking about is a truly sustained architecture. Those are the 
words we use a lot, a sustainable deep-space architecture. What 
we're talking about today is building the foundations to make 
that possible. With advanced power, in particular high ISP, 
which electric propulsion devices can do, you can start talking 
about building those infrastructures in space where you do have 
a continuous supply of materials.
    Mr. Posey. I think the NASA guys thank you for answering 
that.
    Thank you, Mr. Chairman.
    Chairman Babin. Is that it? Okay.
    This has been a very fascinating hearing, one of the best 
ones that I believe I've had since I've been in Congress, so 
I'd like to thank the witnesses for being here and answering 
these questions, and I really, really appreciate your expertise 
in your fields, and without any further ado--let's see. Well, 
anyway we're going to have this thing opened up for a while to 
take any further questions or if any of the other Members who 
were not able to be here, if they want to ask further 
questions, they certainly can. It will remain open for two 
weeks for additional comments from our Members.
    So without any further ado, I adjourn this hearing. Thank 
you.
    [Whereupon, at 11:46 a.m., the Subcommittee was adjourned.]

                               Appendix I

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                   Answers to Post-Hearing Questions

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