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Development of an Infrared Lamp Array for the Smap Spacecraft Thermal Balance TestNASA launched the SMAP observatory in January 2015 aboard a Delta II into a sun-synchronous orbit around Earth. The science payload of a radar and a radiometer utilizes a shared rotating six-meter antenna to provide a global map of the Earth's soil moisture content and its freeze/thaw state on a global, high-resolution scale in this three-year mission. An observatory-level thermal balance test conducted in May/June 2014 validated the thermal design and demonstrated launch readiness as part of the planned environmental test campaign. An infrared lamp array was designed and used in the thermal balance test to replicate solar heating on the solar array and sunlit side of the spacecraft that would normally be seen in orbit. The design, implementation, and operation of an infrared lamp array used for this nineteen-day system thermal test are described in this paper. Instrumental to the smooth operation of this lamp array was a characterization test performed in the same chamber two months prior to the observatory test to provide insight into its array operation and flux uniformity. This knowledge was used to identify the lamp array power settings that would provide the worst case predicted on-orbit fluxes during eclipse, cold, and hot cases. It also showed the lamp array variation when adjustments in flux were needed. Calorimeters calibrated prior to testing determined a relationship between calorimeter temperature and lamp array flux. This allowed the team to adjust the lamp output for the desired absorbed flux on the solar array. Flux levels were within 10% of the desired value at the center of the solar array with an ability to maintain these levels within 5% during steady state cases. All tests demonstrated the infrared lamp array functionality and furthered lamp array understanding for modeling purposes. This method contributed to a high-fidelity environmental simulation, which was required to replicate the extreme on-orbit thermal environments.
Document ID
20170007020
Document Type
Conference Paper
External Source(s)
Authors
Miller, Jennifer R. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Emis, Nickolas (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Forgette, Daniel (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
August 1, 2017
Publication Date
July 12, 2015
Subject Category
Spacecraft Design, Testing and Performance
Quality Assurance and Reliability
Meeting Information
International Conference on Environmental Systems (ICES) 2015(Belleview, WA)
Distribution Limits
Public
Copyright
Other