Considerations for Implementing Presidential Memorandum-20 Guidelines for Nuclear Safety Launch Authorization for Future Civil Space Missions

Abstract

National Security Presidential Memorandum-20 (NSPM-20) (Launch of Spacecraft Containing Space Nuclear Systems) provides updated guidelines for launch authorization for three categories of proposed launches of spacecraft with space nuclear systems: Federal government civil space including the National Aeronautics and Space Administration (NASA), Federal government defense and intelligence, and commercial. These space nuclear systems provide power, heat, and/or propulsion to the spacecraft. NSPM-20 requires a rigorous, risk-informed safety analysis and launch authorization process. The launch approval process of previous NASA missions each took several years and cost multimillion dollars. NSPM-20 provides guidelines to potentially streamline the process and improve cost and schedule. This technical note examines three NSPM-20 guidelines on a future example interplanetary mission (EIM) as to their potential implementation feasibility for three accident categories: Earth gravity assist reentry, solid propellant fires, and flight termination system design. It is found that the safety technology for these accidents were constantly improved over the last several missions, but in some cases may not be adequate for direct use in the EIM’s launch authorization process.

Keywords:

• Accident categories
• cost improvements
• NSPM-20
• nuclear safety