Updating the Cassini-Era GPHS-RTG Life Performance Prediction Model in Preparation for the Next-Gen Mod-1 RTG Assessment

The Next Generation Radioisotope Thermoelectric Generator (Next Gen RTG) Project is a spaceflight system project within NASA’s Radioisotope Power Systems (RPS) Program. The project, in partnership with the Idaho National Laboratory (INL) / Battelle Energy Alliance (BEA), will build and deliver an unfueled, flight qualified Radioisotope Thermoelectric Generator (RTG) system per RPS Program needs. The design is to be based on the heritage Cassini-era General Purpose Heat Source RTG (GPHS-RTG). Changes to the GPHS sizing from the Step-1 to the more recent Step-2 configuration necessitates that the exact GPHS-RTG design cannot be perfectly duplicated. A physics-based life performance prediction model (LPPM) is being developed by NASA’s Jet Propulsion Laboratory (JPL) to help the Project assess the impact on the Mod-1 life-performance from this change. The developed modeling tools provide additional utility in assessing the uncertainties inherent in predicting performance of the Next Gen Mod-0 RTG, the leftover F5 unit from the GPHS-RTG program that is currently at INL. A status update on this progress in given.