LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray B05 EL-1994-00088 LDEF (Flight), AO178 : A High-Resolution Study of Ultra-heavy Cosmic-Ray Nuclei, Tray B05 The flight photograph of the Ultra Heavy Cosmic Ray Experiment (UHCRE) was taken while the LDEF was attached to the Orbiter's RMS arm prior to berthing in the Orbiter's cargo bay. The white paint dots on the center clamp block of the experiment trays lower flange appears to be discolored by a dark brown stain. The tray flanges also appear to be discolored but with a lighter stain. The UHCRE detectors were contained in 16 peripheral LDEF trays with at least one UHCRE tray located on each row of the LDEF except row 3, row 9 and row 12. Each tray contains three cylindrical aluminum pressure vessels with an integral aluminum support structure. Each cylinder is filled with an Eccofoam insert that houses 4 UHCRE detector stacks. Each stack consist of layers of Lexan polycarbonate sheets (approximately 70) interleaved with several thin sheets of lead. Forty-seven of the 48 pressure vessels were pressurized to 1.0 bar of a dry gas mixture (oxygen, nitrogen and helium) and sealed. One of the units was left unsealed in order to investigate the effects of the vacuum environment on the detector materials. Thermal control was accomplished by attaching an aluminized Kapton thermal cover on the tray bottom (the Kapton facing the LDEF interior), placing the aluminum cylinder support structure on thermal isolators and covering the experiment with a thin (5 mil) silvered TEFLONﾮ thermal cover. The silvered TEFLONﾮ cover was supported by an aluminum frame, an integral part of the experiment structure, and held in place by Velcro pads selectively located on the frame and on the back of the cover. The copper colored strip extending over the trays upper flange is a copper coated pressure sensitive tape used to provide an electrical ground between the experiments thermal cover and the LDEF structure. The UHCRE thermal cover appears to be intact with no apparent damage but is stretched more taut than in the prelaunch photograph. The glossy black appearance of the thermal cover is apparently due to lighting conditions and not a change in the material optical properties. The bright spots on the dark thermal cover background are areas where Velcro pads are bonded to the back- side of the cover. The scalloped edge effect across the top, bottom and left side of the cover occurs between attach points. The ground strap appears to be in place with no visible damage.
