1692. Comparison of Satellite Support Structure – Aluminum Versus Graphite Epoxy

Paper

Abstract

An engineering tradeoff and manufacturing development program for replacing aluminum support structure with graphite/epoxy resin laminates was performed for the GOES spacecraft. The primary objective was to arrive at minimum weight hardware for load carrying capability while providing for adequate stiffness within the constraints of meting or surpassing all existing structural and thermal requirements and introducing no redesign of remaining spacecraft elements. The maximum cost allowed to design, build, test, and integrate two spacecraft ship-sets of hardware could not exceed $50,000 per pound of weight ($22,700 per kilogram of mass) saved. The inherent strength and stiffness of graphite was exploited to meet the objective of the weight reduction program. Manufacturing techniques were developed in-house to lay up a hybrid composite laminate of high modulus GY-70 and high strength Celion 3000 and to debulk the layups to eliminate air pockets in a light vacuum bag at room temperature, usually overnight. Proof load tests demonstrated that strength and stiffness requirements were met or improved upon, and a 60 percent weight saving was realized at a cost of $27,500 per pound ($12,500 per kilogram) saved.