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Validation of Landsat-7 ETM+ MEM Thermal Improvement in Thermal Vacuum Tests and in Flight Due to Lower Louver Set PointsThe Enhanced Thematic Mapper Plus (ETM+) Main Electronics Module (MEM) power supply heat sink temperature is critical to the Landsat-7 mission. It is strongly dependent on the thermal louver design. A lower power supply heat sink temperature increases the reliability of the MEM, and reduces the risk of over heating and thermal shut-down. After the power supply failures in ETM+ instrument thermal vacuum tests #1 and #2, the author performed detailed thermal analyses of the MEM, and proposed to reduce the louver set-points by 7C. At the 1998 Intersociety Energy Conversion Engineering Conference (IECEC), the author presented a paper that included results of thermal analysis of the MEM. It showed that a 70C reduction of the louver set points could reduce the maximum power supply heat sink temperature in thermal vacuum test and in flight to below 20"C in the cooler outgas mode and in the nominal imaging mode, and has no significant impact on the standby heater duty cycle. It also showed that the effect of Earth infrared and albedo on the power supply heat sink temperature is small. The louver set point reduction was implemented in June 1998, just prior to ETM+ thermal vacuum test #3. Results of the thermal vacuum tests, and temperature data in flight validate the MEM thermal performance improvement due to the 70C reduction of the louver set points.
Document ID
19990088761
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
Earth Resources And Remote Sensing
Report/Patent Number
SAE-1999-01-2629
Meeting Information
Meeting: Intersociety Energy Convesion Engineering
Location: Vancouver, BC
Country: Canada
Start Date: August 1, 1999
End Date: August 5, 1999
Distribution Limits
Public
Copyright
Other

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