Abstract The future of human exploration missions to Mars is dependent on solutions to the technology challenges being worked on by the National Aeronautics and Space Administration (NASA) and industry. One of the key architecture technologies involves propulsion that can transport the human crew from Earth orbit to other planets and back to Earth with the lowest risk to crew and the mission. Nuclear thermal propulsion (NTP) is a proven technology that provides the performance required to enable benefits in greater payload mass, shorter transit time, wider launch windows, and rapid mission aborts due to its high specific impulse and high thrust. Aerojet Rocketdyne (AR) has stayed engaged for several decades in working NTP engine systems and has worked with NASA recently to perform an extensive study on using low-enriched uranium NTP engine systems for a Mars campaign involving crewed missions from the 2030s through the 2050s. Aerojet Rocketdyne has used a consistent set of NASA ground rules and they are constantly updated as NASA adjusts its sights on obtaining a path to Mars, now via the Lunar Operations Platform-Gateway. Building on NASA’s work, AR has assessed NTP as the high-thrust propulsion option to transport the crew by looking at how it can provide more mission capability than chemical or other propulsion systems. The impacts of the NTP engine system on the Mars transfer vehicle configuration have been assessed via several trade studies since 2016, including thrust size, number of engine systems, liquid hydrogen stage size, reaction control system sizing, propellant losses, NASA Space Launch System (SLS) payload fairing size impact, and aggregation orbit. An AR study activity in 2018 included examining NTP stages derived from Mars crew mission elements to deliver extremely large cargo via multiple launches or directly off the NASA SLS. This paper provides an update on the results of the ongoing engine system and mission trade studies.

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LEU NTP 引擎系统交易和任务选项

摘要 人类火星探索任务的未来取决于美国国家航空航天局 (NASA) 和工业界正在研究的技术挑战的解决方案。一项关键的架构技术涉及推进，可以将人类机组人员从地球轨道运送到其他行星并返回地球，同时对机组人员和任务的风险最低。核热推进 (NTP) 是一项经过验证的技术，由于其高比冲和高推力，可提供所需的性能，以实现更大的有效载荷质量、更短的传输时间、更宽的发射窗口以及快速的任务中止。Aerojet Rocketdyne (AR) 几十年来一直从事 NTP 发动机系统的工作，最近与 NASA 合作，对使用低浓缩铀 NTP 发动机系统进行了一项广泛的研究，该研究涉及从 2030 年代到 2050 年代的载人飞行任务。Aerojet Rocketdyne 使用了一套一致的 NASA 基本规则，并且随着 NASA 调整其对获得通往火星的路径的关注，这些规则会不断更新，现在通过月球操作平台网关。在 NASA 的工作基础上，AR 通过研究 NTP 如何提供比化学或其他推进系统更多的任务能力，将 NTP 评估为运送机组人员的高推力推进选择。自 2016 年以来，已通过多项贸易研究评估了 NTP 发动机系统对火星转运车辆配置的影响，包括推力大小、发动机系统数量、液氢级尺寸、反应控制系统尺寸、推进剂损失、NASA 太空发射系统 (SLS) 有效载荷整流罩尺寸影响和聚集轨道。2018 年的一项 AR 研究活动包括检查源自火星乘员任务元素的 NTP 阶段，以通过多次发射或直接从 NASA SLS 发射超大货物。本文提供了正在进行的发动机系统和任务交易研究结果的更新。