The United States has revised policy to allow the launch of spacecraft that utilise nuclear-powered systems.

Coinciding with the latest public meeting of the National Space Council, President Trump formally issued the revisions on August 20. The new policy outlines guidelines on the use of nuclear systems for both commercial and government spacecraft.

The review process outlined within the policy requires payloads carrying nuclear power systems to be assigned with one of three designations. These designations are based on the amount of radioactive material a payload is carrying and the likelihood of radiation exposure should an accident occur.

Any payload that falls within the first two designations will need to be approved by the agency sponsoring it. Payloads falling into the highest risk third designation will be required to seek presidential authorisation.







Speaking at the National Space Council on August 20, Kelvin Droegemeier, director of the Office of Science and Technology Policy explained the importance of the new policy. “Our primary objective here is to ensure that rigorous and effective nuclear safety analysis and reviews are conducted prior to the launch of any space nuclear system,” said Droegemeier. “To that end, we must provide clear guidelines to help mission planners and launch approval authorities ensure that launch safety is maintained.”

Despite the new policy, there is currently little interest from commercial operators to develop nuclear power systems. Although NASA is using a radioisotope thermoelectric generator (RTG) for its Mars 2020 rover and plans to use an RTG for Dragonfly, the agency does not seem to be pursuing widescale use of nuclear power systems.

There is however one program that could act as a catalyst for the widespread adoption of nuclear power systems. Kilopower is a joint program between NASA and the US Department of Energy that hopes to develop a small nuclear fission reactor.

After successfully completing the Kilopower Reactor Using Stirling Technology (KRUSTY) experiment in March 2018, the team behind the program began to look for mission concepts to utilise the technology. Currently, NASA has proposed using it to power human outposts on the Moon and Mars where large scale solar arrays would be difficult to construct. It is, however unclear when a Kilopower reactor is likely to utilised for an actual mission.