Abstract

The development of advanced composite structural materials for two subassemblies of the Optical Telescope Assembly (OTA) are discussed. The metering truss structure (MTS) uses high strength T300 and high modulus T50 (Thornel fibers). The flight focal plane structure (FFPS) uses ultra-high modulus pitch P75-S, a union carbide (UC) fiber and GY-70, a Celanese fiber. The optical bench structure (OBS) uses GY-70 and the fine guidance system (FGS) optical bench uses P75-S. The MTS and FFPS are the subject of this paper. All these fibers are prepregged by Fiberite using 934 epoxy resin and cured by Boeing Aerospace Company (BAC). Techniques and verification data for zero coefficient of thermal expansion (CTE) layups are presented for the 275°F cure selected. Typical strengths of selected lamina ranged from 100 KSI for P75-S or GY-70 to 240 KSI for T300 and epoxy, while the modulus (Engineering constant or Youngs modulus) ranged from 20 MSI (millions of pounds per square inch) for T300 to 46 MSI for P75-S. The FFPS and MTS were designed, built, tested and delivered by BAC under Perkin Elmer contract number 63731-SA.

© 1982 AIAA