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Experiment Title: LDEF Thermal Measurements System

Original Principal Investigator(s): Greene, Jr., Robert - Invest. Role: Original, Berrios, Dr. William - Invest. Role: Present,

Many of the passive experiments flying on LDEF would be significantly enhanced if data were available postflight to indicate the temperature-time histories of test materials and other specimens exposed in the experiments. The baseline LDEF approach was to provide postflight calculated temperature histories of experiment boundaries and solar flux data for the mission, which can in turn be used by each investigator to calculate the temperature-time histories for critical experiment components. Without in-flight temperature measurements, a substantial uncertainty (40 degrees F) exists in the predicted boundary temperatures calculated with the pre-flight LDEF thermal mathematical model (TMM). The high uncertainties of the model arise from the large number of complex flight hardware elements being represented by a reduced node TMM and the large number of bolted and clamped joints with uncertain thermal conductance. Due to the LDEF's large size and the logistical problems associated with experiment tray integration, it was impractical to perform a pre-flight thermal test to verify the TMM. A verified LDEF TMM with reduced calculated temperature uncertainties is needed to provide a set of boundary temperatures for the calculation of detailed temperatures of experiments located on the external surfaces of the LDEF. The THERM experiment provided an economical way for performing a post-flight verification of the TMM by recording a limited number of flight temperatures on selected locations of the LDEF structure.The data measured by the thermal measurement system (THERM) significantly improved postflight knowledge of temperatures experienced by LDEF experiments. The THERM data is also valuable in validating the LDEF thermal design concept and in providing better design data for experimenters on future LDEF missions.

Photograph Classification: None

Associated Photograph(s):
LaRC - None
KSC - None
JSC - None

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