GoKawiilNASA’s announcement Tuesday that it will “pause” work on a lunar space station and focus on building a surface base on the Moon was no big surprise to anyone paying attention to the Trump administration’s space policy.
But what should NASA do with hardware already built for the Gateway outpost? NASA spent close to $4.5 billion on developing a human-tended complex in orbit around the Moon since the Gateway program’s official start in 2019. There are pieces of the station undergoing construction and testing in factories scattered around the world.
The centerpiece of Gateway, called the Power and Propulsion Element, is closest to being ready for launch. NASA’s rejigged exploration roadmap, revealed Tuesday in an all-day event at NASA headquarters in Washington, calls for repurposing the core module for a nuclear-electric propulsion demonstration in deep space.
This is not the first time NASA has announced a nuclear propulsion demo. More than 20 years ago, NASA was working on a nuclear-electric propulsion initiative called Project Prometheus. It was canceled. In 2021, NASA and DARPA, the Pentagon’s research and development agency, started work on a nuclear rocket engine known as DRACO. NASA and the Pentagon canceled the DRACO program last year.
Like on Gateway, NASA and other agencies have spent billions of dollars on nuclear power and propulsion in space, with little to show for it. There are good reasons for using this technology. Nuclear power enables more ambitious robotic missions deeper into the Solar System, where the Sun’s energy is not sufficient to generate electricity. Closer to Earth, nuclear reactors on the Moon can be used to power habitats, robots, and lunar bases during the two-week-long lunar night.
Nuclear-powered rocket engines are more efficient than chemical rockets. They come in two forms: nuclear-thermal and nuclear-electric engines. Nuclear-thermal rockets produce higher thrust, using heat from a reactor to heat up a chemical rocket fuel. Nuclear-electric engines have lower thrust but greater efficiency. The now-canceled DRACO mission would have used the former approach. NASA’s new nuclear mission will use the latter.