NASA, DOE fund three nuclear thermal space propulsion concepts

Nuclear-powered spaceships for fast trips to Mars may now be one step closer to reality.

NASA and the U.S. Department of Energy (DOE) have teamed up to fund three design concepts for reactors that could become part of a nuclear thermal propulsion system, a next-generation technology that could make the exploration of deep space faster and more efficient.

For example, a spacecraft powered by a nuclear thermal rocket could potentially get to Mars in just three to four months, experts say — about half the time required using traditional chemical rockets.

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"By working together, across government and with industry, the United States is advancing space nuclear propulsion," Jim Reuter, associate administrator for NASA's Space Technology Mission Directorate, said in a statement. "These design contracts are an important step towards tangible reactor hardware that could one day propel new missions and exciting discoveries."

The newly announced contracts will be awarded through the Idaho National Laboratory (INL), the DOE's chief site for nuclear energy research. Each contract is worth up to $5 million. The money will fund 12 months of development work, which will culminate in the production of a reactor design concept. INL experts will evaluate those concepts, then provide recommendations to NASA about how to proceed, agency officials said.

The three companies that received contracts are Virginia-based BWX Technologies, Inc., which will work with Lockheed Martin on the project; General Atomics Electromagnetic Systems of San Diego, which will partner with X-energy LLC and Aerojet Rocketdyne; and Seattle-based Ultra Safe Nuclear Technologies, whose partners are Ultra Safe Nuclear Corporation, Blue Origin, General Electric Hitachi Nuclear Energy, General Electric Research, Framatome and Materion.

Nuclear energy has powered spacecraft almost from the dawn of the space age, helping robots such as NASA's Curiosity and Perseverance rovers on Mars, Cassini Saturn probe and twin Voyager craft do their pioneering work. 

That type of nuclear tech harnesses the heat generated by the radioactive decay of plutonium-238, converting it to electricity that powers scientific instruments and other gear. Nuclear thermal propulsion systems are something different entirely. They would transfer the heat generated by a nuclear reactor to a liquid propellant such as hydrogen, which would then transition to the gas phase, expand and be funneled through a nozzle, creating thrust.

Nuclear thermal propulsion systems would feature higher thrust and twice the propellant efficiency of traditional chemical rockets, NASA officials have said. Those advantages are quite appealing to the space agency, which is working to send astronauts to Mars in the 2030s and wants to minimize travel time to and from the Red Planet.

Nuclear reactors could also help humanity set up shop on other worlds after they get there. For example, NASA is working on a fission power system for use on the moon and Mars.

"NASA intends to partner with the DOE and INL to release a request for proposals that asks industry for preliminary designs of a 10-kilowatt class system that NASA could demonstrate on the lunar surface," agency officials wrote in the statement. "Maturing fission surface power can also help inform nuclear electric propulsion systems, another candidate propulsion technology for distant destinations."

Mike Wall is the author of "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.