FIGURE S.1 Potential 238Pu demand and net balance, 2008 through 2028.

FIGURE S.1 Potential 238Pu demand and net balance, 2008 through 2028.

demand for 238Pu. NASA should continue to move the ASRG project forward, even though this has come at the expense of other RPS technologies.

Demonstrating the reliability of ASRGs for a long-life mission is critical, but it has yet to be achieved. The next major milestones in the advancement of ASRGs are to freeze the design of the ASRG, conduct system testing that verifies that all credible life-limiting mechanisms have been identified and assessed, and demonstrate that ASRGs are ready for flight. In lieu of any formal guidance or requirements concerning what constitutes flight readiness, ongoing efforts to advance ASRG technology and demonstrate that it is flight ready are being guided by experience gained from past programs and researchers’ best estimates about the needs and expectations of project managers for future missions. While this approach has enabled progress, the establishment of formal guidance for flight certification of RPSs in general and ASRGs in particular would facilitate the acceptance of ASRGs as a viable option for deep-space missions and reduce the impact that the limited supply of 238Pu will have on NASA’s ability to complete important space missions.


RECOMMENDATION. Flight Readiness. The RPS program and mission planners should jointly develop a set of flight-readiness requirements for RPSs in general and Advanced Stirling Radioisotope Generators in particular, as well as a plan and a timetable for meeting the requirements.


RECOMMENDATION. Technology Plan. NASA should develop and implement a comprehensive RPS technology plan that meets NASA’s mission requirements for RPSs while minimizing NASA’s demand for 238Pu. This plan should include, for example:



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