Countdown to fission on the moon: Candidate designs wanted
NASA and Idaho National Laboratory have just opened a competitive solicitation for U.S. nuclear and space industry leaders to develop innovative technologies for a fission surface power system that could be deployed on the surface of the moon by the end of the decade. Battelle Energy Alliance, the managing and operating contractor for INL, issued a request for proposals and announced the news on November 19. Proposals are due February 17.
Why fission? That’s a question that a November 19 news release from NASA’s Glenn Research Center answered succinctly: It’s reliable, . . . It’s powerful. . . . It can be compact and lightweight.” The facility in Cleveland, Ohio, is managing NASA’s fission surface power project.
Companies are being asked to design a reactor that can provide at least 40 kWe—enough to continuously power 30 typical earthling households for 10 years. “Systems like these could someday provide enough power to establish an outpost on Mars,” according to the news release.
The specs: Space Policy Directive 6, issued by the Trump administration in December 2020, directed NASA to “by the mid-to-late 2020s, demonstrate a fission power system on the surface of the moon that is scalable to a power range of 40 kWe and higher to support sustained lunar presence and exploration of Mars.”
While the target is now “by the end of the decade,” the RFP is based on that directive and states that the design package shall include estimates for the technical, schedule, and cost requirements to design, build, and test a qualification unit and subsequent flight system. The specifications include a minimum end-of-life 40 kWe continuous power output for at least 10 years (higher power ratings are “desirable”); a system that fits within a stowed cylinder measuring 4 meters in diameter and 6 meters in length; a total system mass that does not exceed 6 metric tons; and autonomous operation from the deck of a lunar lander or from a separate mobile system that permits the reactor to be moved to another lunar site.
NASA and the DOE will select competitive proposals to develop initial designs over a 12-month period, with a total maximum price for individual contract awards of $5 million. “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,” according to NASA. The technology development and demonstration are funded by the Space Technology Mission Directorate’s Technology Demonstration Missions program, which is housed at the Marshall Space Flight Center in Huntsville, Ala.
HALEU or HEU? The RFP does not specify an enrichment level for the reactor fuel. Opting for HALEU (enriched up to 20 percent U-235) over the high-enriched uranium that NASA used for its Kilopower reactor project, which ended in 2018, would mean that the fuel wouldn’t be classified as special nuclear material and could potentially open the project to more industry and university collaborators.
Space Policy Directive 6 made it clear that although the use of HEU in space is not prohibited, it should be limited to applications for which the mission would not be viable with other nuclear fuels or nonnuclear power sources. “Before selecting HEU or, for fission reactor systems, any nuclear fuel other than low‑enriched uranium, for any given SNPP design or mission, the sponsoring agency shall conduct a thorough technical review to assess the viability of alternative nuclear fuels,” it stated. Separate DOE/NASA industry solicitations for nuclear propulsion technologies have stipulated that those devices use HALEU TRISO fuel.
Background: In partnership with NASA, DOE issued a draft request for proposals for fission surface power in December 2020. The draft RFP was preceded by a request for information released in July 2020.
“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,” said Jim Reuter, associate administrator for NASA’s Space Technology Mission Directorate, 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.”