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Experiment Title: Exposure to Space Radiation of High-Performance Infrared Multilayer Filters and Materials Technology Experiments

Original Principal Investigator(s): Lipscombe, Derek - Invest. Role: Original, Whatley, A. - Invest. Role: Original, Hawkins, Dr. Gary J. - Invest. Role: Present, Hunneman, Dr. Roger - Invest. Role: Original, Hunneman, Dr. Roger - Invest. Role: Present, Seeley, Dr. John - Invest. Role: Original, Seeley, Dr. John - Invest. Role: Present,

Infrared multilayer interface filters have been used extensively in satellite radiometers for several decades. Filters manufactured by the University of Reading have been used in Nimbus 5, 6, and 7, TIROS N, and the Pioneer Venus orbiter. Filters for those types of spaceflight radiometer instruments measure IR emissions from the major atmospheric gases, pollutants, and aerosols, and from the sea to land surface. Progress in the general science of radiometry from space has been rapid, having evolved to the extent that global change is considered observable; currently, radiometers are being planned to fly in the EOS/ERS/POEM satellites capable of monitoring parameters such as structure, atmosphere dynamics and composition in situ. Further, EOS accuracy is intended to be sufficiently good for valid deduction of temperature gradient, mixing/transport of the gases, surface flux, etc. As with the earlier radiometers, spectral bands are defined by optical filters for the selection of the particular molecular species of interest. The spectral width and resolution of filters, together with the stability and durability of their materials and processes, therefore remains especially significant. The ability of the filters to withstand the space environment in these applications is critical; if degradation takes place, the effects would range from worsening of signal-to-noise performance to complete system failure.

This LDEF experiment enabled the filters, for the first time, to be subjected to authoritative spectral measurements following space exposure to ascertain their suitability for spacecraft use and to permit an understanding of degradation mechanisms. The University of Reading experiment was intended to expose infrared multilayer interference filters of novel design, high performance, construction and manufacture to space radiation. The spectral behavior of these filters when in space was unconfirmed previously, but crucial to filter performance. High-performance, in this context, relates to the precision and discrimination with which the emission spectra of important atmo- spheric gases can be resolved.

Additionally, the understanding of the effects of prolonged space exposure on spacecraft materials, surface finishes, and adhesive systems is of great interest to the spacecraft designer. Thus, a series of materials technology experiments were included with the experiment on infrared multilayer filters.

Photograph Classification: Prelaunch

Associated Photograph(s):
LaRC - L84-07116
KSC - KSC-384C-294.07
JSC - None
LaRC - L90-13421
KSC - KSC-390C-1031.11
JSC - None
LaRC - L90-10380
KSC - None
JSC - S32-76-026
LaRC - L90-10388
KSC - None
JSC - S32-76-054
LaRC - L84-07165
KSC - KSC-384C-317.08
JSC - None
LaRC - L91-11718
KSC - KSC-390C-1997.02
JSC - None

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