If you’ve ever wanted to design a key piece of space infrastructure, now is your opportunity, as NASA is asking for ideas on how to put a nuclear power reactor on the Moon. You have three months to come up with a proposal for a lunar nuclear reactor that could operate on the Moon, although since astronauts' lives will depend on this, back-of-the-envelope sketches are probably not what is being sought.

"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," Sebastian Corbisiero of the Idaho National Laboratory, which is collaborating with NASA on the project, said in a statement. 

With NASA's Artemis mission, humans are returning to the Moon in 2025. Future research bases on our satellite (and possibly even Mars) will need a sustainable source of power, and most of what we rely on from Earth isn’t really viable up there. There’s no wind or falling water to drive turbines. The greenhouse effect might not be a problem for the Moon, but there are also no fossil fuels to burn, and we have other priorities for the oxygen they would need to be burned in. Transporting them there would be absurdly expensive, too.  

As for most space missions, that leaves two options: solar and nuclear. A lunar night, which lasts 14 Earth days, presents solar-powered Moon bases with storage challenges far beyond anything on Earth.

However, there are many ways to build a nuclear reactor, and it’s not like we have off-the-shelf solutions. The power requirements, at least initially, will be a tiny fraction of what commercial-scale reactors produce, but weight and size are at a premium. 

NASA is under no illusions that fusion power will be available in time for the initial Moon mission, so it specifies they are looking for fission that will operate on the surface of the Moon. A fission reactor works by splitting atoms and releasing energy in the form of heat, which is converted into electricity. Rather than being dependent on a single reactor, they are planning four reactors, each producing at least 10 kilowatts of power and able to do so continuously for at least 10 years.

Other requirements are each reactor fits inside a cylinder 6 meters (20 feet) long and 4 feet (23 feet) wide and does not weigh more than 6,000 kilograms (13,200 pounds). From bitter experience, NASA would like its contractors to work in metric units. There are also limits on the radiation exposure for anyone a kilometer away, and requirements for fault tolerance.

Those with ideas, or simply keen to learn the full details, can check out the draft contract. Proposals must be submitted before February 19, 2022. 

“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,” Jim Reuter, NASA associate administrator, said.