SEATTLE, October 2, 1996 -- The Boeing Company has developed a unique design for satellite structures that will enable the aerospace industry to make satellites lighter and less expensive.

The creative approach by Boeing features a graphite composite honeycomb sandwich structure, a one-piece, one-step fabrication process, and a minimal number of parts.

"A satellite's structure, which is like the frame of an automobile, must be strong to withstand large loads during launch," said Boeing program manager Tom Martin. "Reduction in the structure weight would allow additional payload to be launched, thus reducing the cost of launching satellites -- every extra satellite pound costs about $10,000 to get into orbit."

Traditional satellite structures are made of aluminum and usually weigh about one-fifth the weight of the entire satellite, Martin said. "Modern satellites have begun using composites, which reduce the structure weight to about one-seventh of the total spacecraft weight."

The Boeing design, which is being patented, lowers the weight even further, to only about one-eighth of the total spacecraft weight.

The new graphite fiber and poly-cyanate ester plastic composite material used in the design is four times stiffer and 40 percent stronger than aluminum. It conducts heat as well as aluminum, which is an advantage over other composites that have low conductivity and require additional equipment to cool the satellite electronics.

The structure has only three parts: a central uni-body and two decks. By drastically reducing the number of parts, Martin says the cost of manufacturing and assembling the structure is greatly reduced. A unique, one-step manufacturing and assembly process for the uni-body, using an inexpensive fabrication tool, further reduces cost.

"The composite design requires one-half the labor hours to fabricate and assemble, compared to a traditional aluminum design," he said. "This offsets by far the higher cost of the composite materials used in the design."

Boeing believes the advanced structure is ideal for future military satellites. Because of its light weight and low cost, the structure also is being considered for commercial communications and earth-imaging satellites.

Boeing Defense & Space Group developed the structure under the sponsorship of the Ballistic Missile Defense Organization in Washington, D.C., and the management of the U.S. Air Force Phillips Laboratory in Albuquerque, N.M., for the Space Technology Research Vehicle (STRV-2) experiment module to be launched in 1998. The structure has just been successfully tested prior to delivery to the Jet Propulsion Laboratory in Pasadena, Calif., for system test and integration.