NASA and the US Department of Energy have developed a new nuclear fission reactor design for space applications, the Kilopower. NASA successfully conducted testing and demonstration of the Kilopower system during November 2017 to March 2018 testing at the DOE National Nuclear Security Administration (NNSA) Nevada National Security Site. This moves the reactor one step closer to providing power in space. But what are the challenges of developing nuclear for space and will we see nuclear power on the moon or Mars?
For 50 years there has been a drought of new nuclear technology at NASA. A singular flight was made with a nuclear reactor as part of the Systems Nuclear Auxiliary POWER (SNAP) programme in the 1960s, when the SNAP 10-A reactor was launched from the Californian coast on 3 April 1965. SNAP 10-A had enough uranium to provide 600W of power over a year, but just 43 days into orbit an electrical failure led to the system shutting down.
Since SNAP there have been several costly projects, but all were cut before they even reached the testing stage. Instead, NASA turned to solar as the preferred power source, but as missions move further from the sun, solar potential falls. Mars receives 40% of the sunlight that Earth does, dramatically reducing its efficacy, and lunar nights are equivalent to 14 Earth days.
But after a long hiatus, NASA has now completed the first successful test of a new nuclear design called Kilopower. Kilopower is a small, lightweight fission reactor that can generate up to 10KW for ten years. It has been in development since 2013 and became an official NASA project in 2015 as part of the Game Changing Development programme within NASA’s Space Technology Mission Directorate.
After a successful test run earlier this year and plans for a potential test mission in the early 2020s, will Kilopower be the first nuclear reactor to operate on another planet?
A Unique Nuclear Reactor: Designing a nuclear reactor for space requires a unique approach. A proof of concept test was completed in 2013 – the Demonstration Using Flattop Fission (DUFF) experiment, at the Nevada National Security Site. Following DUFF, the team worked to further ensure the reactor was the best fit for outer space. “The design is unique, using heat pipes to passively move the heat from the reactor up to the power conversion,” says NASA Glenn Research Center lead Kilopower engineer Marc Gibson. “We got the fuel from the Y-12 National Security Complex, we designed the core, sent them all the drawings and the manufacturing specs, and they supplied the highly enriched core. Then we mate it up with our power-conversion system, which we designed, built and tested electrically here at NASA. We combine the fuel and power conversion at the test site in Nevada and that became the Kilopower Reactor Using Stirling Technology (KRUSTY) experiment.”
Safe and Economical Fission: On top of the technical challenges, Gibson also had to contend with the nuclear legacy within NASA. “A lot of people didn’t believe that we could test nuclear reactors at a low cost and in a timely manner,” says Gibson. “It’s hard to overcome that scepticism. It proved a lot of people wrong, especially those that thought this was going to take hundreds of millions of dollars.”
The KRUSTY Test: We combine the fuel and power conversion at the test site in Nevada and that became the Kilopower Reactor Using Stirling Technology (KRUSTY) experiment.” Kilopower has already proved to be NASA’s most successful nuclear project in half a century, not only reaching the testing phase, but also proving itself in the KRUSTY test in March this year. “I think [KRUSTY] was very significant in that past projects spent hundreds of millions of dollars and didn’t get very far,” says Gibson. “We spent less than $20m over the three-year time period and were able to do a full nuclear ground test for roughly 28 hours.”
To Infinity and Beyond? Unlike the SNAP reactor that came before, the team hopes that Kilopower will one day provide long-term sustained power for manned mission to other planets. “The ultimate goal could be the Moon, it could be Mars, and it could be in space somewhere,” says Gibson. “We’re trying to come up with a fission reactor that we could use for multiple missions, so the same design would hold true whether it’s a power system on the Moon, Mars, or whether it’s used in space.” Gibson and his team are now working on formulating missions on which the technology can be tested. They are using NASA’s Technology Demonstration Missions Directorate to identify the best mission for Kilopower in the early 2020s. As missions bring mankind further from Earth, reliable, sustainable power will be needed to ensure vital life support and communications systems never go out. Nuclear power could provide this.
NASA Kilopower Links
NASA Space Technology Mission Directorate - Kilopower
Demonstration Proves Nuclear Fission System Can Provide Space Exploration Power, 2 May 2018
NASA Brief: Kilopower Press Conference, Kilopower Reactor Development and Testing, 2 May 2018
NASA Brief: Kilopower Overview and Mission Applications, 16 Jan 2018
Kilopower: What's Next?, 1 Jan 2018
Powering Up NASA's Reach for the Red Planet, 13 Nov 2017
NASA Paper: NASA's Kilopower Reactor Development and the Path to Higher Power Missions, 2017