Filter experiment construction

In order to obtain a representative assessment of the effects of exposure to the space environment of the infrared filters and materials flown on the LDEF, a total of 46 components were distributed between two tray locations, as illustrated in Figure 12. One location was positioned to be continuously facing Earth (G12) at an angle of 90.8° off the RAM incidence angle (Figure 14), whilst the other location tray was positioned to continuously view space on the leading edge of the vehicle (B08) at 38.1° off the RAM incidence angle (Figure 15). Each tray was designed to maximise the exposure of the full aperture to the complete range of space radiation environments and temperature excursions.

Figure 12, Location of exposed filter experiment trays

The filters were each housed in chromic anodised BS.L93 aluminium alloy circular holders and mounted in 6061-T6 chromic anodised aluminium alloy base plates. Thermal contact was ensured by Pb washers located either side of the substrate. Induced pressure differentials across the substrates were relieved by a hole in each backing piece to prevent substrate flexing or deformation. Figure 13 shows the substrate holder construction.

Figure 13, Filter holder assembly

Figure 14, Earth facing tray G12

Figure 15, Leading edge tray B08

Effects of the space environment on infrared filters and materials

• Introduction
• LDEF experiment background
• Thermal cycling effects
• Solar flux
• Ionizing radiation
• Atomic oxygen
• Filter experiment construction
• Pre-launch / post-recovery filter analysis
• LDEF orbital meteoroid and debris impacts
• Micrometeorite impact characteristics
• Experiment conclusions