Thermal Vacuum Test Performance of the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) Variable Conductance Heat Pipe Assembly

The Variable Conductance Heat Pipe (VCHP) Assembly of the HST Wide Field Camera 3 was subjected to thermal vacuum (T/V) environmental testing. The test program included both maximum and minimum environments as well as simulated on-orbit cycling. Elements of the VCHP assembly included a VCHP, an optical bench cold plate with an imbedded constant conductance heat pipe, and a VCHP reservoir radiator with a proportionally controlled heater.

The purpose of the test was to characterize and demonstrate the assembly's ability to control the temperature of the cold plate, which provides a stable thermal environment for the instrument's optical bench.

This paper discusses the VCHP Assembly control performance and control authority during the dynamic hot and cold 90-minute orbit cycling test phases.