DOE OSTI2016
For more than five decades, Radioisotope Power Systems (RPS) have played a critical role in the exploration of space, enabling missions of scientific discovery to destinations across the solar system by providing electrical power to explore remote, challenging and extreme environments. In particular, RPS enable deep space missions where increased heliocentric distances reduce the ability of solar power to adequately meet spacecraft and instruments power requirements. Some previous notable missions that were enabled by RPS include Nimbus III, the Apollo Surface Experiments, the Pioneers 10 and 11, the Viking Mars Landers, Galileo, Ulysses, Cassini, New Horizons and Curiosity. The current operating set of missions that are enabled by RPS are Voyagers 1 and 2, Cassini, New Horizons, and Curiosity. The Multi-Mission Radioisotope Thermal Generator (MMRTG) is the current RPS used for missions. An enhanced version of this generator outfitted with higher efficiency thermoelectrics is under development for potential use in the future. Other previously deployed power systems include the Multi-hundred Watt Radisotope Thermo-electric Generator (MHW RTG) and the General Purpose Heat Source Radisotope Thermo-electric Generator (GPHS RTG). The common thread for all of these power systems is that they are fueled with Pu-238. The use of this unique isotope involves additional planning activities and requires specific actions when the devices are delivered to Kennedy Space Center (KSC), launch site, and incorporated into the assembly, test and launch operations (ATLO) process to ensure mission success, met safety and security challenges. It has been forecasted that the use of a nuclear reactor system is on the horizon. This system could be used for either specifically powering S/C propulsion system or for surface power use once the mission arrived at its destina-tion. Since a nuclear-fission-based system has never been handled or integrated into a spacecraft at KSC, this nuclear reactor system would potentially require further challenges that must be accounted for in the ATLO process. This paper will explain ATLO considerations for the recent RTG-enabled launches that have occurred and planned in the near future (Mars 2020 NASA mission). It will also describe where further challenges that need to be met for the placement of a nuclear reactor (either for propulsion or transportation for surface power use) onto a space mission. Specifically, the following topics will be addressed: • Approach for nuclear safety planning for nuclear material use and its transportation to launch site • Planning for security posture for nuclear materials at launch site • Preparation for transportation of the nuclear power system from the fueling/testing location to the launch site • Preparation of documentation and procedures for nuclear material use at launch site • Planning for coordination between power system and space mission groups • Planning for appropriate staffing and scheduling of operations
07 ISOTOPE AND RADIATION SOURCES↗