STATEMENT OF WORK BACKGROUND AS A RESULT OF THE FINDINGS FROM A 1999 GOVERNMENT/INDUSTRY TECHNOLOGY READINESS TEAM, THE FREE-PISTON STIRLING POWER CONVERTOR IS BEING CONSIDERED AS AN ADVANCED POWER CONVERSION TECHNOLOGY TO BE USED FOR FUTURE DEEP SPACE MISSIONS REQUIRING LONG LIFE RADIOISOTOPE POWER SYSTEMS. THIS ADVANCED TECHNOLOGY SHOULD REDUCE THE INVENTORY OF PLUTONIUM FUEL USED BY A FACTOR OF 4 OR GREATER; THE BENEFITS ARE MEASURED IN COST SAVINGS FOR THE FUEL, REDUCED USAGE OF THE LIMITED PLUTONIUM RESOURCE, AND IN DECREASED ENVIRONMENTAL IMPACT IN THE UNLIKELY EVENT OF RELEASE OF THE PLUTONIUM. GLENN RESEARCH CENTER (GRC) PLAYS A CRITICAL ROLE IN THE DEVELOPMENT OF THE STIRLING TECHNOLOGY. GRC HAS LONG BEEN RECOGNIZED AS THE LEAD CENTER IN STIRLING TECHNOLOGY EXPERTISE WITHIN THE GOVERNMENT AND NOW IS RESPONSIBLE FOR MANY ASPECTS OF TECHNOLOGY DEVELOPMENT FOR THE UPCOMING FLIGHT SYSTEM DEVELOPMENT. THIS ROLE INCLUDES DEMONSTRATING THE LONG-TERM DURABILITY AND RELIABILITY OF THE STIRLING CONVERTOR. SCOPE OF WORK THE ADVANCED RADIOISOTOPE POWER SYSTEM THAT IS BEING DEVELOPED IS DRIVEN BY REQUIREMENTS FROM A RANGE OF FUTURE POTENTIAL MISSIONS. KEY TECHNICAL AREAS MUST BE THOROUGHLY EVALUATED AS PART OF THIS IMPLEMENTATION. ONE AREA REQUIRING THIS EFFORT IS THE ADVANCED STIRLING CONVERTOR (ASC) HEATER HEAD. THIS NEW DESIGN USES GEOMETRY, OPERATING CONDITIONS, AND MATERIALS IN UNIQUE WAYS THAT REQUIRE COMPLEX THERMAL AND TIME-DEPENDENT STRUCTURAL ANALYSES AND STRUCTURAL BENCHMARK TESTING TO EVALUATE THE COMPONENT S DURABILITY AND RELIABILITY. ANOTHER COMPONENT REQUIRING ADVANCED EVALUATION IS THE ASC PLANAR SPRING. THIS SURFACE-TREATED PART MUST SURVIVE TENS OF BILLIONS OF STRESS CYCLES WITHOUT DEGRADATION DUE TO HIGH CYCLE FATIGUE. THE SCOPE OF WORK TO BE PERFORMED IN THIS TASK INCLUDES DETERMINISTIC AND PROBABILISTIC ANALYSES AND RELATED WORK FOR STRUCTURAL ASSESSMENT OF THE HEATER HEAD AND THE PLANAR SPRING FOR LONG-TERM DURABILITY.