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.

摘要

国家安全总统备忘录 20 (NSPM-20)（包含空间核系统的航天器的发射）为三类拟发射具有空间核系统的航天器提供了发射授权的更新指南： 联邦政府民用空间，包括美国国家航空航天局(NASA)、联邦政府国防和情报以及商业。这些太空核系统为航天器提供动力、热量和/或推进力。NSPM-20 需要严格的、风险知情的安全分析和发射授权流程。之前 NASA 任务的发射批准过程均耗时数年，耗资数百万美元。NSPM-20 提供了可能简化流程并改进成本和进度的指南。本技术说明审查了有关未来行星际任务 (EIM) 示例的三项 NSPM-20 指南，以了解它们对三种事故类别的潜在实施可行性：地球重力辅助再入、固体推进剂火灾和飞行终止系统设计。发现这些事故的安全技术在过去几次任务中不断改进，但在某些情况下可能不足以直接用于 EIM 的发射授权过程。