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Thermal Assessment of Landsat-7 ETM+ Radiative Cooler in Instrument and Spacecraft Thermal Vacuum Tests and in FlightDuring the radiative cooler cool-down phase of the Landsat-7 Enhanced Thematic Mapper Plus (ETM+) instrument thermal vacuum test #3, the coldest temperature that the Cold Focal Plane Array (CFPA) achieved was 89.5 K. The cold stage/CFPA temperature decreased from 315 K to 89.5 K in 80 hours. In the spacecraft and instrument integrated thermal vacuum test, the cold stage/CFPA temperature decreased from 315 K to 86.9 K in 80 hours, and was still decreasing at a rate of 0.08 K/hr when the cool-down was terminated. The cool-down was faster, and a colder CFPA temperature was obtained. In flight, the cooler cool- down was even faster, and colder. The cold stage/CFPA temperature decreased from 315 K to 89.7 K in 33 hours, and was still decreasing at a rate of 1 K/hr when cool- down was terminated at 89.7 K. The factors that affected the ETM+ cooler cool-down are the radiation heat sink temperature for the cold stage and intermediate stage, parasitic radiation heat load to the cooler, parasitic conduction heat load to the cooler, and cooler outgas time preceding cooler cool-down.
Document ID
19990069905
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Choi, Michael K.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1999
Subject Category
Spacecraft Instrumentation
Report/Patent Number
SAE-1999-01-2628
Meeting Information
Meeting: Intersociety Energy Conversion Engineering
Location: Vancouver, British Columbia
Country: Canada
Start Date: August 1, 1999
End Date: August 5, 1999
Sponsors: Society of Automotive Engineers, Inc.
Distribution Limits
Public
Copyright
Other

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