Human Mars Mission In-Space Transportation Sensitivity for Nuclear Electric / Chemical Hybrid Propulsion

NASA’s Human Exploration and Operation Mission Directorate is continuing to study different concepts and options to field human Mars missions as part of NASA’s Moon2Mars directive. In this study, an update to the Hybrid propulsion system was established with the introduction of nuclear electric propulsion system to replace the solar electric propulsion system in an effort to understand the potential impact of a shorter mission to Mars. For crewed missions to Mars, the transportation system sizing is highly dependent on the type of mission and the mission duration. An integrated trajectory analysis capability has been developed and updated to enable this investigation. Longer duration missions may utilize higher efficiency low thrust propulsion system more, but would require higher payload mass due to increased crew logistics loading and habitation volume. Conversely, shorter duration missions may have lower payload mass, but will require significant increase to propulsion system performance and/or overall system mass. An integrated trajectory optimization framework that was previously developed was recently updated to address deficiencies and to enable additional capabilities to perform large design space exploration. Using the updated framework, an overall integrated design trade space is defined in this paper to investigate the tradeoff between these scenarios to illuminate the optimality of the transportation system option from a mass perspective. The sensitivity analysis developed in this study will be crucial to understanding the Mars mission design trade space for crewed Mars missions, and will help inform design decisions and investment strategies.