National Aeronautics and Space Administration

Glenn Research Center


Advanced Stirling Convertor (ASC) In-House Testing

Extended operation testing of the Advanced Stirling Convertor (ASC) is underway in the Stirling Research Lab (SRL) at NASA Glenn Research Center (GRC). Currently, seven ASCs are under extended operation test and have reached a total run time (as of 2013) of over 150,000 hours. An additional 13 have been tested in SRL, but have since been moved to contractor facilities for controller and performance testing, and inspection of internal components. One pair completed over 10,000 hours of thermal vacuum testing.

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The Advanced Stirling Radioisotope Generator – Engineering Unit (ASRG-EU) is comprised of two convertors (ASC-E #2 & #3) assembled into a beryllium housing. The ASRG has operated for over 15,000 hours under ASC Control Unit (ACU) control and has a total run time of over 30, 000 hours. Total run time for all ASCs is nearly 250,000 hours (as of 2013). In addition to testing in SRL, the convertors also undergo Workmanship Vibration testing and EMI testing at GRC. The test data generated is in support of the Advanced Stirling Radioisotope Generator (ASRG) project for the Radioisotope Power System (RPS) program under NASA’s Science Mission Directorate.

The ASC is manufactured by Sunpower, Inc of Athens, Ohio. Eight ASCs are capable of 650 °C hot-end temperature operation (In718 heater head) and 12 are capable of 850 °C operation (LC 247 heater head). All use gas bearings to achieve non-contacting operation. The first ASCs were delivered to GRC in 2007. The first generation of engineering units (ASC-E) was delivered in 2008; the second generation (ASC-E2) followed in 2010 and 2011. The ASC-E3s were delivered in late 2012. Thermal loss, performance mapping and extended operation testing are being conducted. System performance testing and thermal vacuum testing are also planned. The E2 and E3 convertor pairs generate 160 We from two GPHS modules.