Spacecraft often rely heavily on passive thermal control to maintain operating temperature. An important parameter in the spacecraft heat balance equation is the emittance of thermal control coatings as a function of coating temperature. One method for determining the emittance of spacecraft thermal control from elevated temperature to cryogenic temperatures relies on a calorimetric technique. The fundamental equation governing this test method can be found in numerous places in the literature and although it generally provides reasonable results, its formulation is based on a conceptual flaw that only becomes apparent when the sample temperature approaches the wall temperature during testing. This paper investigates the cause for this error and develops the correct formulation for calorimetric emittance testing. Experimental data will also be presented that illustrates the difference between the two formulations and the resulting difference in the calculated emittance.
An Improved Formulation for Calorimetric Emittance Testing of Spacecraft Thermal Control Coatings
PROTECTION OF MATERIALS AND STRUCTURES FROM SPACE ENVIRONMENT: Proceedings of the 9th International Conference: Protection of Materials and Structures From Space Environment ; 2008 ; Toronto (Canada)
AIP Conference Proceedings ; 1087 , 1 ; 117-123
2009-01-05
7 pages
Conference paper
Electronic Resource
English
An Improved Formulation for Calorimetric Emittance Testing of Spacecraft Thermal Control Coatings
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