The Next Generation Radioisotope Thermoelectric Generator – Power for Future Deep Space Missions

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 unfueled, flight qualified Radioisotope Thermoelectric Generator (RTG) systems based on NASA Mission and RPS Program needs. The Next Gen RTG Project aims to assure the availability of high-power, vacuum-rated RTGs to enable future deep space missions. The Project team is developing that capability through a multi-phase effort that effectively leverages the heritage General Purpose Heat Source - RTG (GPHS-RTG) design and available legacy hardware. The Project's primary aim is to re-establish the capability to manufacture a silicon germanium (SiGe) unicouple based thermoelectric converter and associated hardware with minimal changes to the heritage GPHS-RTG design. This includes utilizing heritage designs and processes for the SiGe unicouples and the converter assembly hardware. The goal is to build as closely to the heritage design as possible with changes confined to obsolescence of parts and to account for the use of Step-2 GPHS modules. The project also aims to refurbish the GPHS-RTG Flight Unit #5 (F-5) located at INL and verify its compliance with heritage GPHS-RTG requirements. The refurbishment plan includes preliminary health investigations, heritage hardware collection, and progressive performance testing of the F5 unit using legacy procedures and processes. The refurbishment of F5 will culminate with an electrically heated test in vacuum to determine Electrical Thermoelectric Generator performance and dynamic testing to heritage specifications. This paper will detail the project's plans for the development of these systems. Management approaches, technical challenges, and risks will also be discussed.