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Title: Cassini RTG acceptance test results and RTG performance on Galileo and Ulysses

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OSTI ID:347692
;  [1]
  1. Lockheed Martin Corp., Philadelphia, PA (United States)

Flight acceptance testing has been completed for the RTGs to be used on the Cassini spacecraft which is scheduled for an October 6, 1997 launch to Saturn. The acceptance test program includes vibration tests, magnetic field measurements, mass properties (weight and c.g.) and thermal vacuum test. This paper presents the thermal vacuum test results. Three RTGs are to be used, F-2, F-6, and F-7. F-5 is the backup RTG, as it was for the Galileo and Ulysses missions launched in 1989 and 1990, respectively. RTG performance measured during the thermal vacuum tests carried out at the Mound Laboratory facility met all specification requirements. Beginning of mission (BOM) and end of mission (EOM) power predictions have been made based on these tests results. BOM power is predicted to be 888 watts compared to the minimum requirement of 826 watts. Degradation models predict the EOM power after 16 years is to be 640 watts compared to a minimum requirement of 596 watts. Results of small scale module tests are also shown. The modules contain couples from the qualification and flight production runs. The tests have exceeded 28,000 hours (3.2 years) and are continuing to provide increased confidence in the predicted long term performance of the Cassini RTGs. All test results indicate that the power requirements of the Cassini spacecraft will be met. BOM and EOM power margins of over 5% are predicted. Power output from telemetry for the two Galileo RTGs are shown from the 1989 launch to the recent Jupiter encounter. Comparisons of predicted, measured and required performance are shown. Telemetry data are also shown for the RTG on the Ulysses spacecraft which completed its planned mission in 1995 and is now in the extended mission.

OSTI ID:
347692
Report Number(s):
CONF-970701-; TRN: 99:006215
Resource Relation:
Conference: 32. intersociety energy conversion engineering conference, Honolulu, HI (United States), 27 Jul - 2 Aug 1997; Other Information: PBD: [1997]; Related Information: Is Part Of Proceedings of the thirty-second intersociety energy conversion engineering conference. Volume 4: Post deadline papers and author index; PB: 153 p.
Country of Publication:
United States
Language:
English