A European heat-pipe experiment on the second flight of Space-Shuttle 'Challenger'

Design and functional features of the SPAS-01 heat pipe experiment carried into orbit as part of the STS-7 flight are summarized. The apparatus tested heat pipe behavior in microgravity conditions for a 24 hr duration. The package contained different lengths of stainless steel constant conductance artery heat pipes, four gas-controlled VCHP radiator configurations, two liquid trap diodes, and one gas diode. A liquid evaporated in the sun-exposed, heat source end, travelled along a wick, then recondensed within the shadowed, heat-sink end. Step changes of 10, 15, and 20 Wt were examined, up to a 150 Wt limit. The experiments were fully self-regulating and self-monitoring once activated, and were equipped for data storage.