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Thermal balance testing of MSAT 2 spacecraftThe present work reports on the recently completed infrared thermal balance/thermal vacuum testing of a MSAT satellite, the first satellite to provide mobile communications service for all of continental North America. MSAT is a two spacecraft program, using a three-axis stabilized Hughes HS-601 series Bus as the vehicle for the Canadian designed Payload. The thermal tests which were performed at the Canadian Space Agency's David Florida Laboratory in Ottawa, Canada, lasted approximately 35 days. The infrared (IR) heating rig was designed to provide radiant heat inputs into seven spacecraft zones during Thermal Vacuum (TV) testing. The TV test was divided into multiple phases. It began with a thermal balance cold phase, followed by a thermal cold cycle and a hot balance phase, complemented by a thermal hot cycle to finish with a thermal cycle with continuous monitoring of the Bus and Payload. The spacecraft's external heat fluxes were provided by IR lamp sources. To ensure flux uniformity, highly reflective baffles and IR East and West faces; the Earth facing (Nadir); and the inside of the thrust cylinder. The aft-end panel heat fluxes were provided by a heated LN2 shroud. The radiation flux intensity on the spacecraft zones from the various rig elements was measured using Monitored Background Radiometers (MBR's) and compared with direct calculations and with pretest predictions. The temperature measurement system was based on Uniform Temperature References (UTR's) located inside the chamber such that all feedthroughs were copper-copper. This system was devised to achieve a temperature measurement accuracy of plus/minus 0.5 C for over 850 thermocouples used in the test. A PC-(QNX-based) based real-time data acquisition system was utilized to provide continuous monitoring of all channels based on a 30-second time scan. In addition, the data acquisition system was able to retrieve telemetry stream from the Satellite Test Equipments (STE) station for real-time data manipulation. Preliminary results showed the test to be successful from both the thermal balance side and the electrical testing side.
Document ID
19950007667
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Samson, Serge
(Spar Aerospace Ltd. Sainte-Anne-de-Bellevue Quebec, Canada)
Choueiry, Elie
(Spar Aerospace Ltd. Sainte-Anne-de-Bellevue Quebec, Canada)
Date Acquired
September 6, 2013
Publication Date
November 1, 1994
Publication Information
Publication: NASA. Goddard Space Flight Center, Eighteenth Space Simulation Conference: Space Mission Success Through Testing
Subject Category
Spacecraft Design, Testing And Performance
Accession Number
95N14080
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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