Minimize FSP (Fission Surface Power)

FSP (Fission Surface Power) systems project of NASA for Moon and Mars Exploration

Introduction    Development status     References

Some background: Under the Vision for Exploration, NASA is evaluating options for human missions to the Moon and Mars. New and more capable power systems will be required to supply energy for sustained surface outposts. Lunar missions are expected to begin in the early 2020s. Mars missions may occur later, possibly in the 2030s. Some potential surface power electrical loads include landers, habitats, in-situ resource utilization plants, mobility and construction equipment, and science experiments. Total power requirements could range from 10 kWe to more than 100 kWe. The unique environments of the Moon and Mars pose many challenges for power systems. The 29.5-day lunar rotational period requires that extended surface missions include the capability for at least 354 hr of nighttime energy storage. Other lunar mission challenges include tenacious dust adhesion and extreme surface temperatures ranging from 375 K at lunar noon to 100 K during lunar night. 1)

The typical Mars equatorial day is 24.6 hr long with about 12 hr of night, so energy storage requirements are significantly less than the Moon. However, because of the greater distance from the Sun and the attenuation through the atmosphere, insulation at the Martian surface is reduced to about 20 percent of that on the Moon, and that value decreases significantly with dust storms. The potentially corrosive, carbon-dioxide atmosphere at Mars may also present problems for the power system. For either the Moon or Mars, power systems must be highly reliable to assure steady and continuous power for crew safety. The combination of high power, difficult environmental conditions, and assured reliability make fission-based power systems an advantageous option among the various power system choices.

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Figure 1: Simplified FSP system block diagram (image credit: NASA)

The FSP system block diagram, shown in figure 1, is defined by four major subsystems: (1) Reactor, (2) Power Conversion, (3) Heat Rejection, and (4) Power Conditioning and Distribution (PCAD). Heat is transferred from the Reactor to the Power Conversion and from the Power Conversion to the Heat Rejection. Electrical power generated by the Power Conversion is processed through the PCAD to the User Loads. The PCAD provides power for Power Conversion startup and for auxiliary loads associated with the Reactor and Heat Rejection. The PCAD also provides the primary communications link for command, telemetry, and health monitoring of the FSP system.

The FSP Systems Project Team is led by NASA Glenn Research Center (GRC) in partnership with Marshall Space Flight Center (MSFC), Department of Energy (DOE) labs (Oak Ridge National Lab, Idaho National Lab, Los Alamos National Lab, Sandia National Lab), and industrial partners.


Introduction

• August 20, 2020: As astronauts look to explore the Moon and Mars, they’ll need a reliable energy source to power their equipment and outposts on distant planets. The U.S. Department of Energy (DOE) is working with NASA to develop a fission surface power system that could be ready to launch within the decade. 2)

The successful deployment and operation of this nuclear power system on the lunar surface could ultimately lead to extended missions on the Moon, Mars, and beyond.

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Figure 2: DOE and NASA are looking to partner with U.S. companies to develop a fission surface power system for demonstration on the Moon by the late 2020s (image credit: DOE/NASA)

Here are 5 things you need to know about NASA and DOE’s latest venture in space exploration.

1) Fission surface power systems are powered by ...well ... fission

A fission surface power system works by splitting uranium atoms inside a reactor to generate heat that is then converted to electricity. This is the same physical process used by terrestrial reactors to generate power for use in homes, businesses, and industrial applications.

DOE and NASA are looking to partner with U.S. companies to develop a fission surface power system for demonstration on the Moon by the late 2020s. The system will leverage the latest innovations in advanced reactor development and must meet certain mission requirements such as the ability to operate autonomously to match energy demand.

2) Fission surface power units can provide kilowatts of electricity

The fission surface power demonstration is expected to generate at least 10 kW of electricity—enough to power one-hundred 100-watt light bulbs or roughly 1/100,000 of the power produced by a typical 1,000 MW commercial reactor. That may not seem like a lot of juice, but it will be enough to power a portion of the infrastructure and equipment needed by astronauts on the lunar surface.

As power needs for future missions grow, fission surface power systems could be scaled up to produce higher power levels to support permanent habitats, in-situ resource utilization, and more complex experimental programs.

3) Fission power systems will operate where the sun doesn’t shine

Fission power systems will provide consistent base load power regardless of the resources available on a planet or the environment.

NASA plans to land the first woman and next man at the Moon’s South Pole where solar energy is unable to provide sufficient, sustained power for extended missions. Lunar nights are equivalent to 14 days on Earth and reliable electricity provided by fission power systems will be needed to survive extreme temperatures.

The initial demonstration is expected to last for a minimum of one year but the system will be designed for longer operation to gather additional information. It may also be used as part of the lunar power infrastructure.

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Figure 3: Fission surface power systems can be scaled up to help meet future mission energy needs (image credit: NASA)

4) Fission surface power systems will be robust

Unlike terrestrial reactors, a surface power system for space must withstand the harsh vibration forces that occur during a launch or landing on a planet’s surface. To accomplish this, the units will have structural robustness to protect the coolant, reactor core, and electronic control systems, along with the support system that holds it all together.

5) This type of system isn’t new

Nuclear space reactors were first developed in the United States in the 1950s by NASA and the Atomic Energy Commission (now known as DOE) through its SNAP program. SNAP-10A, a sodium-potassium cooled fast reactor, was launched into space in April 1965 as part of a research project for the U.S. Department of Defense to power a satellite.

The reactor produced 500 watts of power and operated for 43 days during its flight test. It was prematurely shut down by a faulty command receiver.

Since that time, advances in nuclear fuels and materials research supported by DOE have led to smaller, compact advanced reactor systems that are currently being designed today. DOE and NASA are looking to leverage this innovation and expertise to apply these concepts for space flight.

Learn more about NASA’s Moon to Mars exploration and DOE’s role in space to support NASA space missions.

• July 8, 2021: NASA’s Space Technology Mission Directorate (STMD) intends to demonstrate a 10 kWe fission surface power (FSP) system on the surface of the Moon as part of a Capability Demonstration Mission. STMD tasked a joint NASA-DOE team to ‘outline an FSP reactor concept that can be readied for 2027 launch,’ and serves ‘as a pathfinder for future power modules for Mars.’ 3)




Development status

• June 21, 2022: NASA and the U.S. Department of Energy (DOE) are working together to advance space nuclear technologies. The agencies have selected three design concept proposals for a fission surface power system design that could be ready to launch by the end of the decade for a demonstration on the Moon. This technology would benefit future exploration under the Artemis umbrella. 4)

- The contracts, to be awarded through the DOE’s Idaho National Laboratory, are each valued at approximately $5 million. The contracts fund the development of initial design concepts for a 40 kW class fission power system planned to last at least 10 years in the lunar environment.

- Relatively small and lightweight compared to other power systems, fission systems are reliable and could enable continuous power regardless of location, available sunlight, and other natural environmental conditions. A demonstration of such systems on the Moon would pave the way for long-duration missions on the Moon and Mars.

- "New technology drives our exploration of the Moon, Mars, and beyond," said Jim Reuter, associate administrator for NASA's Space Technology Mission Directorate. "Developing these early designs will help us lay the groundwork for powering our long-term human presence on other worlds."

- Battelle Energy Alliance, the managing and operating contractor for Idaho National Laboratory, led the Request for Proposal development, evaluation, and procurement sponsored by NASA. Idaho National Laboratory will award 12-month contracts to the following companies to each develop preliminary designs:

a) Lockheed Martin of Bethesda, Maryland – The company will partner with BWX Technologies and Creare.

b) Westinghouse of Cranberry Township, Pennsylvania – The company will partner with Aerojet Rocketdyne.

c) IX of Houston, Texas, a joint venture of Intuitive Machines and X-Energy – The company will partner with Maxar and Boeing.

- “The Fission Surface Power project is a very achievable first step toward the United States establishing nuclear power on the Moon,” said Idaho National Laboratory Director John Wagner. “I look forward to seeing what each of these teams will accomplish.”

- The Phase 1 awards will provide NASA critical information from industry that can lead to a joint development of a full flight-certified fission power system. Fission surface power technologies also will help NASA mature nuclear propulsion systems that rely on reactors to generate power. These systems could be used for deep space exploration missions.

- NASA’s fission surface power project is managed by the agency’s Glenn Research Center in Cleveland. The power system development is funded by the Space Technology Mission Directorate’s Technology Demonstration Missions program, which is located at Marshall Space Flight Center in Huntsville, Alabama.

• November 22, 2021: NASA is seeking proposals from nuclear and space industry leaders to develop innovative technologies for a fission surface power (FSP) system for lunar power applications. It hopes to deploy such a system by 2030. 5)

- The FSP project is sponsored by NASA in collaboration with the Department of Energy (DOE) and Idaho National Laboratory (INL) to establish a durable, high-power, sun-independent power source for NASA missions on the moon by the end of the decade, as well as potential subsequent missions. The proposal request targets the initial system design.

- The RFP (Request for Proposals) - published on 19 November - calls for ideas for a flight-ready small fission reactor powered by low-enriched uranium. The FSP should be able to provide 40 kWe of continuous power for at least 10 years in the lunar environment. It must fit within a 4-meter-diameter cylinder, 6 meters in length in the stowed launch configuration, and weigh less than 6000 kg. It should also be able to switch itself on and off without human assistance. The FSP should be able to operate from the deck of a lunar lander or to be removed from the lander, placed on a mobile system and transported to another lunar site for operation.

- Proposals are due by 19 February 2022. The total maximum price for individual contract awards supporting the base scope effort resulting from this RFP is USD 5 million.

- Battelle Energy Alliance, which manages INL on behalf of the DOE's Office of Nuclear Energy, said a draft of the RFP released in December 2020 has received significant interest from industry.

- "The feedback and enthusiasm we continue to see for space nuclear power systems has been very exciting, and understandably so," said Sebastian Corbisiero, the Fission Surface Power Project lead at INL. "Providing a reliable, high-power system on the moon is a vital next step in human space exploration, and achieving it is within our grasp."

- "Plentiful energy will be key to future space exploration," added Jim Reuter, associate administrator for NASA's Space Technology Mission Directorate in Washington, DC, which funds NASA's fission surface power project. "I expect fission surface power systems to greatly benefit our plans for power architectures for the moon and Mars and even drive innovation for uses here on Earth."

- NASA's fission surface power project expands on the efforts of the agency's Kilopower project, which ended in 2018. It said a future lunar demonstration will pave the way for sustainable operations and even base camps on the Moon and Mars.

- Kilopower is a small, lightweight fission power system developed at the DOE's National Nuclear Security Administration (NNSA) laboratory in partnership with NASA. The system was successfully demonstrated in the Kilopower Reactor Using Stirling Technology (KRUSTY) experiment, which was conducted at the NNSA's Nevada National Security Site from November 2017 to March 2018. KRUSTY used high-enriched uranium powering a heatpipe system and Stirling engine to generate electricity.

• November 19, 2021: Exploration of the Moon and Mars requires the power of human imagination and vision. It also takes the power of electricity to bring science and technology to life when astronauts land and stay on the surface. 6)

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Figure 4: Artist's concept of a fission power system on the lunar surface (image credit: NASA)

- NASA has plans for a robust presence on the Moon under Artemis and eventually Mars, including the development of a fission surface power system for safe, efficient, and reliable electrical power. Fission surface power – in conjunction with solar cells, batteries, and fuel cells – can provide the power to operate rovers, conduct experiments, and use the Moon’s resources to produce water, propellant, and other supplies for life support.

- “Plentiful energy will be key to future space exploration,” said Jim Reuter, associate administrator for NASA’s Space Technology Mission Directorate (STMD) in Washington, which funds NASA’s fission surface power project. “I expect fission surface power systems to greatly benefit our plans for power architectures for the Moon and Mars and even drive innovation for uses here on Earth.”

- NASA, in coordination with the Department of Energy (DOE), is asking American companies for design concepts for a fission surface power system that could be ready to launch within a decade for a demonstration on the Moon. The system should be capable of autonomous operation from the deck of a lunar lander or a lunar surface rover.

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Figure 5: Artist's concept of a fission surface power system on Mars (image credit: NASA)

Why fission?

a) It’s reliable. Fission systems can operate continuously around the clock in shadowy craters and during the weeks-long lunar nights, when power generation from sunlight is difficult.

b) It’s powerful. The systems NASA is asking companies to design would provide at least 40 kilowatts of power, enough to continuously power 30 households for ten years.

c) It can be compact and lightweight. Systems like these could someday provide enough power to establish an outpost on Mars.

What's Next?

- “NASA and the DOE are collaborating on this important and challenging development that, once completed, will be an incredible step towards long-term human exploration of the Moon and Mars,” said Fission Surface Power Project Manager Todd Tofil at NASA’s Glenn Research Center in Cleveland. “We’ll take advantage of the unique capabilities of the government and private industry to provide reliable, continuous power that is independent of the lunar location.”

- Fission surface power technologies will also help NASA mature nuclear propulsion systems that rely on reactors to generate power.

- NASA and the DOE (through the Idaho National Laboratory operated by Battelle Energy Alliance) will select competing U.S. companies to develop initial designs over a 12-month period. The resulting designs will inform an industry solicitation for the final design and build of a flight-qualified fission power system to send to the Moon on a demonstration mission.

- NASA’s fission surface power project is managed by NASA’s Glenn Research Center in Cleveland. The technology development and demonstration are funded by the Space Technology Mission Directorate’s Technology Demonstration Missions program, which is hosted at Marshall Space Flight Center in Huntsville, Alabama.

• May 7, 2021: Unless disrupted by storms or grid problems, electrical power for most people is no further than an outlet away. However, the solar system does not provide easy access to electricity as we know it on Earth. Astronauts could take advantage of a reliable power supply to explore both the Moon and Mars. The system will need to be lightweight and capable of running regardless of its location, the weather, or available sunlight and other natural resources. 7)

- A small, lightweight fission surface power system could provide up to 10 kilowatts of electrical power – enough to run several average households – continuously for at least 10 years. Four 10-kilowatt units could provide enough juice to power robust operations on the Moon and Mars.

- NASA’s fission surface power project expands on the efforts of the agency’s Kilopower project, which ended in 2018. Currently, NASA is working with the Department of Energy (DOE) and industry to design a 10-kilowatt fission power system for the Moon. A future lunar demonstration will pave the way for sustainable operations and even base camps on the Moon and Mars.

Milestones:

a) NASA and DOE conducted an experiment to demonstrate heat transfer technologies using highly enriched uranium fuel in May 2018. The Kilopower Reactor Using Stirling Technology (KRUSTY) experiment showed that the system performed as expected under both normal and off-normal conditions.

b) A DOE reactor study completed in March 2020 identified low-enriched uranium reactor solutions roughly the same weight as the high-enriched system.

c) In partnership with NASA, DOE issued a draft request for proposals for fission surface power in December 2020. A forthcoming request for proposals will ask industry to begin designing a flight-ready fission surface power system.

d) A 2016 memorandum of understanding between NASA and DOE serves as the basis of this inter-agency work. An October 2020 NASA-DOE memorandum of understanding expands on it, establishing working groups that focus on space nuclear power and propulsion.

Fast Facts:

- Fission surface power can provide abundant and continuous power regardless of environmental conditions on the Moon and Mars.

- NASA plans to demonstrate and use a fission surface power system on the Moon first, then Mars.

- NASA is collaborating with DOE and industry to design, fabricate, and test a 10-kilowatt class fission power system to operate on the Moon by the late 2020s.

- NASA’s fission surface power project builds on heritage projects spanning 50 years, including SNAP-10A, NASA’s Kilopower project, and recent developments in commercial nuclear power and fuel technology.

- Fission surface power reactor designs will focus on using low enriched uranium fuels.

Partners:

- NASA’s fission surface power project is managed by NASA’s Glenn Research Center in Cleveland. The technology development and demonstration are funded by the Space Technology Mission Directorate’s Technology Demonstration Missions program, which is located at Marshall Space Flight Center in Huntsville, Alabama.

- NASA is partnered with DOE and its national laboratories on the fission surface power project. The space agency will define the mission and system requirements.


FSP (Fission Surface Power) / Kilopower of NASA

• November 10, 2020: Reliable, long-life power systems are among the basic requirements of any space exploration mission. NASA has relied upon plutonium-based radioisotope power systems (RPSs) for decades for deep space missions like Pioneer, Voyager, Galileo, and Cassini, where solar power was not a feasible option. RPSs provide reliable and lightweight power for missions in the 100 W(electric) to 1 kW(electric) range. 8)

Small [1-10 kW (electric)–class] fission power systems (FPSs) are being developed to address a major gap in NASA’s power portfolio which could enable future flagship science missions and exploration precursor missions that may not otherwise be possible.

Under the Kilopower Project, the development of a FPS was centered on designing, building, and testing a working nuclear prototype. This technology could enable high power science missions or could be used to provide surface power for manned missions to the moon or Mars. The centerpiece of the Kilopower Project is the development and testing of a ground technology demonstration of a small FPS based on a 1 kW (electric) space science power requirement.

This test was named the KRUSTY (Kilowatt Reactor Using Stirling TechnologY) test. NASA’s Glenn Research Center (GRC) led the effort to design the test. GRC also built and demonstrated the balance of plant heat transfer, power conversion, and heat rejection portions of the KRUSTY system.

NASA’s Marshall Space Flight Center (MSFC) developed the electrical reactor simulation heat source for the nonnuclear testing at GRC and the shielding for nuclear testing.

The U.S. Department of Energy’s (DOE’s) Los Alamos National Laboratory (LANL) led the design of the reactor and performed nuclear testing, the DOE’s Y-12 National Security Complex fabricated the highly enriched uranium (HEU) reactor core, and the Nevada Nuclear Security Site Mission Support and Test Services supported nuclear testing. KRUSTY was the first US space nuclear reactor power system test in over 50 years.

System Level Testing of KRUSTY

Kilopower was designed for both planetary surface power and deep space missions. In addition to surface power missions to the moon and Mars, Kilopower is also well suited for deep space missions like the Neptune/Triton, Chiron, Titan/Enceladus, Pluto, and Kuiper Belt Object Orbiters. Kilopower is also an option for the Titan Saturn System Mission as well.

The Kilopower Project has stepped through a build-and-test sequence of phases that completed the demonstration of a flight-like system operated at prototypic conditions in a relevant environment (Technology Readiness Level 5). This accomplishment establishes the readiness of nuclear-tested FPS technology for affordable, lightweight application to human and robotic exploration wherever it is needed.

The success of the Kilopower / KRUSTY test in 2018 has resulted in growing interest in the development of fission power systems for lunar and Mars surface power. The Fission Surface Power (FSP) Project is developing plans for a lunar fission powered Technology Demonstration Mission.

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Figure 6: KRUSTY fully assembled and ready for testing at the National Criticality Experiments Research Center (NCERC), image credit: NASA/GRC



1) Lee Mason, David Poston, Louis Qualls, ”System Concepts for Affordable Fission Surface Power,” NASA/TM—2008-215166, January 2008, URL: https://ntrs.nasa.gov/api/citations/20080013229/downloads/20080013229.pdf

2) ”5 Things You Need to Know about Fission Surface Power Systems,” Office of Nuclear Energy, 20 August 2020, URL: https://www.energy.gov/ne/articles/5-things-you-need-know-about-fission-surface-power-systems

3) Dasari Venkateswara Rao, Mikaela E. Blood, ”Analysis of alternative core designs for Fission Surface Power capability demonstration mission,” Report LA-UR-21-26460, LANL, July 8, 2021, URL: https://permalink.lanl.gov/object/tr?what=info:lanl-repo/lareport/LA-UR-21-26460

4) ”NASA Announces Artemis Concept Awards for Nuclear Power on Moon,” NASA Press Release, 22-062, June 21, 2022, URL: https://www.nasa.gov/press-release/nasa-announces-artemis-concept-awards-for-nuclear-power-on-moon

5) ”NASA seeks proposals for lunar reactor,” World Nuclear News, 22 November 2021, URL: https://www.world-nuclear-news.org/Articles/NASA-seeks-proposals-for-lunar-reactor

6) ”Fission System to Power Exploration on the Moon’s Surface and Beyond,” NASA/GRC Feature, 19 November 2021, URL: https://www.nasa.gov/feature/glenn/2021/fission-system-to-power-exploration-on-the-moon-s-surface-and-beyond

7) ”Fission Surface Power,” NASA STMD, 7 May 2021, URL: https://www.nasa.gov/mission_pages/tdm/fission-surface-power/index.html

8) ”Fission Surface Power (FSP) / Kilopower,” NASA/Glenn Research Center, 10 November 2020, URL: https://www1.grc.nasa.gov/research-and-engineering/thermal-energy-conversion/kilopower/


The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: ”Observation of the Earth and Its Environment: Survey of Missions and Sensors” (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates (herb.kramer@gmx.net).

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