LDEF (Prelaunch), S1001 : Low-Temperature Heat Pipe Experiment Package (HEPP) for LDEF, Tray F12 EL-1994-00319 The prelaunch photograph was taken during experiment functional checkout in SAEF II at the KSC prior to installation of the Low Temperature Heat Pipe Package (HEPP) experiment on the LDEF. The electrical cables in the lower part of the photograph are cables that connect the HEPP experiment with the ground support test equipment and are non-flight cables. The Low Temperature Heat Pipe Package (HEPP) experiment occupies two 12 inch deep LDEF experiment trays connected with an inter-tray wiring harness. The HEPP Experiment tray, a peripheral tray modified to accommodate radiator location and field of view requirements, is located in the LDEF tray location F12. The HEPP Power tray, an end corner tray, is located on the space end of the LDEF in tray location H01. The experiment tray (F12) contains a Constant ConductanceHeat Pipe, a Thermal Diode Low Temperature Heat Pipe, a radiator coupled with a phase change material canister, the data acquisition and control systems and the LDEF experiment power and data system (EPDS) for processing, recording and storing experiment data. The HEPP EPDS is also used to record and store thermal data from the CVCHPE (AO076) and the THERM (P0003) experiments. Fiberglass standoffs and internal multilayer insulation (MLI) blankets ther- mally isolated the experiment from the experiment tray and the LDEF interior. The radiator and radiator shield panels located in the left half of the tray were covered with silvered TEFLON_ tape to provide the desired optical properties. The outside of the HEPP, except the radiator shield panels and the radiator, was covered with an aluminized Kapton multilayer insulation (MLI) blanket with the outer Kapton layer coated with vapor deposited aluminum on one side only. The two patches of thin film materials, part of an experiment by NASA GSFC that consist of five patches of thirteen samples each and located at three different places on the LDEF (F09, F12 and H01), were attached to the cover of the external thermal blanket with Kapton tape. The experiment was assembled and mounted in the experiment tray with non-magnetic stainless steel fasteners.
