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A Physics-Based Temperature Stabilization Criterion for Thermal TestingSpacecraft testing specifications differ greatly in the criteria they specify for stability in thermal balance tests. Some specify a required temperature stabilization rate (the change in temperature per unit time, dT/dt), some specify that the final steady-state temperature be approached to within a specified difference, delta T , and some specify a combination of the two. The particular values for temperature stabilization rate and final temperature difference also vary greatly between specification documents. A one-size-fits-all temperature stabilization rate requirement does not yield consistent results for all test configurations because of differences in thermal mass and heat transfer to the environment. Applying a steady-state temperature difference requirement is problematic because the final test temperature is not accurately known a priori, especially for powered configurations. In the present work, a simplified, lumped-mass analysis has been used to explore the applicability of these criteria. A new, user-friendly, physics-based approach is developed that allows the thermal engineer to determine when an acceptable level of temperature stabilization has been achieved. The stabilization criterion can be predicted pre-test but must be refined during test to allow verification that the defined level of temperature stabilization has been achieved.
Document ID
20090037689
Document Type
Conference Paper
Authors
Rickman, Steven L. (NASA Johnson Space Center Houston, TX, United States)
Ungar, Eugene K. (NASA Johnson Space Center Houston, TX, United States)
Date Acquired
August 24, 2013
Publication Date
October 13, 2009
Subject Category
Spacecraft Design, Testing and Performance
Report/Patent Number
LF99-8634
Meeting Information
25th Aerospace Testing Seminar(Manhattan Beach, CA)
Funding Number(s)
WBS: WBS 869021
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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