Overview of the U. S. flight safety process for space nuclear power

The two current types of nuclear power sources used in U. S. spacecraft are described along with the flight safety philosophies governing their use. In the case of radioisotope thermoelectric generators, the design philosophy consists of containment, immobilization, and recovery of the nuclear materials. For reactors, the emphasis is on maintaining a subcritical configuration in all credible accident environments. To document the safety activities, a safety analysis report is prepared for each mission. These reports, which are based on the probabilistic risk assessment methodology pioneered by the space nuclear safety community, are subjected to an interagency safety review before a recommendation is made to approve the launch of a nuclear-powered spacecraft