The Kilopower Project To Put a Nuclear Reactor On Mars

Nuclear energy has been used in space for a while for operation and propulsion, the best examples being NASA’s Curiosity rover, the Voyager 1 and 2 probes, the New Horizons craft. Kilopower has come up with a new use for it with its prototype of a mobile system continuously producing energy - let’s say, on the same Red Planet. It’s quite compact, fits easily inside a rocket, and its output is about 40 kilowatt, which is enough for about eight Earthly homes to have light. Installed on Mars, it could help crews better orient themselves when approaching the Red Planet on manned missions in the near future

Robotic space explorers today work on radioisotope thermoelectric generators (RTGs) transforming the heat resulting from plutonium-238 radioactive decay into electrical power. However, their output isn’t very high: the generators in NASA’s Curiosity rover and the upcoming Mars 2020 rover, for example, produce about 110 watts of electricity when new, and with time, the output gradually declines.

Kilopower’s solution is a fission reactor similar to those in power plants on Earth. It uses Stirling engines to convert heat into energy. KRUSTY (Kilopower Reactor Using Stirling Technology) ground-tests that were performed until March 2018 had the reactor convert 30% of fission heat into electricity, while RTG reactors only convert about 7%. The next step for Kilopower would be to try an experimental fission reactor in space.

Kilopower technology envisions reactors that will last 15 years. They will certainly be needed to help facilitate long-duration manned missions to Mars, as well as other deep-space expeditions. 

One such reactor is estimated to be able to put out 1 Kilowatt of power that can be used as required. A manned mission to Mars - and, namely, NASA’s research station planned to be set up there before the next twenty years are out, will require about 40 kilowatts (40 kWe) of electricity available without interruption for operations like oxygen generation, charging their rovers, heating their accommodation and work facilities, and purifying water - among other things.

The Kilopower project leader Patrick McClure said during a presentation in July, “I think we could do this in three years and be ready for flight,” meaning a first reactor to be used could make its way to Mars around 2022.

This, however, was an estimate, not an official announcement. 

The Kilopower project launched in 2015, with its creators conducting the Demonstration Using Flattop Fissions (DUFF) experiment in 2012 to test and prove the concept. 

Helen Borodina