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Experiment Title: Solar-Array-Materials Passive LDEF Experiment

Original Principal Investigator(s): Stella, Dr. Paul - Invest. Role: Original, Whitaker, Dr. Ann F. - Invest. Role: Present, Stella, Dr. Paul - Invest. Role: Present, Young, Mr. Leighton - Invest. Role: Original, Young, Mr. Leighton - Invest. Role: Present, Whitaker, Dr. Ann F. - Invest. Role: Original, Whitaker, Dr. Ann F. - Invest. Role: Present, Whitaker, Dr. Ann F. - Invest. Role: Original, Brandhorst, Henry - Invest. Role: Original, Forestieri, A.F. - Invest. Role: Original, Bass, James - Invest. Role: Original, Brandhorst, Henry - Invest. Role: Original, Gaddy, Edward - Invest. Role: Original, Forestieri, A.F. - Invest. Role: Original, Smith, Charles - Invest. Role: Original,

The long-duration functional lifetime requirements on lightweight high-performance solar arrays demand careful selection of array materials. The space environment, however, is a hostile environment to many materials, and some of the problems are well documented. A thermal-vacuum environment can affect materials by accelerating the outgassing of volatile species. The condensation of these outgassed products on array cover slips leads to reduced solar-cell electrical output, a situation that is especially critical at high astronomical units (AUs). Outgassing can reduce mechanical strength in materials, which will affect the integrity of the array substrate, hinges, and deployment mechanisms and create electrical problems through insulation breakdown. A further effect of outgassing is the degradation of thermal control and reflector surfaces. Some extended performance arrays that have been studied but never flown utilize deployable concentrators whose reflectance is especially important at large AUs. Protons, electrons, atomic oxygen, and UV irradiation contribute to surface damage in these array materials. Thin-film materials can be embrittled and thermal control surfaces can become discolored by this irradiation. Severe mission environments, coupled with the lack of knowledge of space environment materials degradation rates, require the generation of irradiation and outgassing engineering data for use in the design phase of flight solar arrays.

Photograph Classification: Flight

Associated Photograph(s):
LaRC - L90-10381
KSC - None
JSC - S32-76-027
LaRC - L90-13422
KSC - KSC-390C-1031.12
JSC - None
LaRC - L89-04422
KSC - KSC-384C-538.10
JSC - None
LaRC - L90-10403
KSC - None
JSC - S32-77-017

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