US space agency NASA is planning to build a nuclear power plant (NPP) on the moon by 2026 and has invited proposals from companies for the manufacture for an NPP. According to a US Department of Energy (DoE) statement, the proposal involves the construction of a 10 kilowatt (kW) fission surface power system to be used for demonstrative purposes.
The head of NASA’s nuclear technology section at the Space Technology Mission Directorate, Anthony Calomino, told reporters last week that the demonstration will continue for one year, and if successful, it could pave the way for other missions to both the moon and Mars. The plant is to be manufactured and assembled on earth, following which it would be shipped to the moon on a launch vehicle. This vehicle will take the plant to the moon’s orbit, from where a lander will place it on the lunar surface.
“Once the technology is proven through the demonstration, future systems could be scaled up or multiple units could be used together for long-duration missions to the moon and eventually Mars. Four units, providing 10 kW of electrical power each, would provide enough power to establish an outpost on the moon or Mars”, Calomino said. “The ability to produce large amounts of electrical power on planetary surfaces using a fission surface power system would enable large-scale exploration, establishment of human outposts, and utilization of in situ resources, while allowing for the possibility of commercialization”, he added.
A fission reactor works by splitting atoms and releasing energy in the form of heat, which is converted to electricity. As per NASA’s proposed plan, this nuclear power plant demonstrator will have the capacity to run for 10 years with a generation capacity enough to power the equivalent of 3-4 large households.
The idea for using nuclear power in space dates back to the late 1950s, when they were considered for providing propulsion. In the 1960s, a series experimental space nuclear reactors were developed by NASA under the Systems Nuclear Auxiliary Power program. According to the space agency, however, public safety concerns and an international treaty banning nuclear power in space stopped development of the project.
Researchers at NASA and the DoE have already tested relevant technologies for developing a nuclear fission reactor that could power a human outpost on the moon or Mars, proving that it would be possible to build such a safe, reliable, and efficient system. The new nuclear power system is part of a NASA project started in 2006, called Fission Surface Power, that is looking at small reactors designed for use on other planets. According to the researchers, such reactors would be designed to be completely safe, based on the premise that these were not being built for large systems like those that supply hundreds of gigawatts (GW) of power to cities.
Nuclear power is being considered for moon and Mars missions because, unlike renewable alternatives like solar, it can provide constant power for human life support systems, recharging rovers, and mining for resources. Solar power use in space would also require energy storage systems like batteries or fuel cells, adding unwanted mass to the system. Solar power is further limited because the moon is dark for up to 14 days at a time. On Mars less solar power can be harvested since it is further away from the sun.
The most common example of nuclear power use in outer space is a radioisotope thermoelectric generator, which has been used on many space probes and on crewed lunar missions. In the 1960s, many scientists thought fission reactors for space would follow on the heels of radioisotope generators. In 1965, the US launched a small nuclear fission–powered satellite named SNAP-10A, but electrical issues caused it to fail in just over a month after launch. The Soviet Union launched 31 nuclear fission–powered satellites over the next two decades.
Thereafter, early in the last decade, researchers at NASA and America’s DoE began work on a joint project called the Nuclear Fission Power Project, whose goal was to develop a new nuclear fission power system for space that would be capable of producing 10 kW of electrical energy. In September 2020, NASA and the DoE issued a formal request for proposals for a lunar nuclear power system designed to select preliminary designs completed by the end of 2021, while in a second phase by early 2022, they would select one company to develop a 10 kW fission power system to be placed on the moon in 2027.