Experiment conclusions

The effects of space exposure on the infrared filters and materials flown on LDEF were minor. No significant changes were found either in transmission or spectral position of any hard coated II VI / PbTe based multilayers on Germanium substrates, or in uncoated crystal substrates. The softer materials however were adversely affected in their physical and optical properties by the long exposure in space, from exhibiting a reduced transmission to complete opacity. Although impacts by micrometeorites damaged some samples, these did not detract from their function and performance as an optical component. Likewise, atomic oxygen and space radiation caused no spectral effects which could be detected, other than in soft material samples which were exposed beyond that intended for these types of components.

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