Date of Award


Document Type


Degree Name

Master of Science


Department of Aeronautics and Astronautics

First Advisor

W. Jerry Bowman, PhD


Future spacecraft technologies require advanced high-temperature thermal control systems. Liquid metal heat pipes are considered ideally suited for such applications. However, their behavior during microgravity operation is not yet understood. This study investigated liquid metal heat pipe performance in such an environment. Three stainless steel/potassium heat pipes were flown on space shuttle mission STS-77 in May 1996. The objectives of the experiment were characterization of the frozen startup and restart transients, comparison of flight and ground test data to establish a performance baseline for analytical model validation, and assessment of three different heat pipe designs. Heat pipe performance was characterized prior to the flight experiment. Predicted performance envelopes for each heat pipe were determined from theoretical calculations. Performance baselines were established from ground thermal vacuum test results. These pre-flight results were compared with those from the flight experiment. Thermal resistances were calculated for comparison of each heat pipe design.

AFIT Designator


DTIC Accession Number