For Release: July 31, 2000
Media Relations Office
Company Delivers Rockets and a Small-Business Research Success
Space rockets made of rhenium promise to last longer and, perhaps, fly, farther. Rhenium, though, is one of Earth's rarest metals. It is hard to obtain, hard to work, and hard to form.
But Rhenium Alloys, Inc., a small Elyria, OH, company, has delivered two small chemical rocket thrusters made of rhenium to the NASA Glenn Research Center, Cleveland, OH. The delivery completes the second and final phase of the company' s small business innovation research (SBIR) contract with Glenn and sets the stage for further improvements in the life and capabilities of rockets for both commercial satellites and NASA space exploration missions.
The thrusters are the product of new manufacturing processes that reduce both the manufacturing time and cost while improving the product quality. Room-temperature isostatic pressing, that is, applying pressure evenly to all sides of the item, was used to compact rhenium powder into the near final shape and dimensions of the thruster. Containerless hot isostatic pressing was used to consolidate the powder compact until its molecules align into the strongly bonded crystalline structure of conventionally cast metals.
"We would never have been able to develop these processes without the financial and technical support of the SBIR contracts," said Todd Leonhardt, chief metallurgist at Rhenium Alloys, Inc. "The advice and encouragement we received from Glenn researchers was also invaluable."
During the late 1980's Glenn researchers began looking for ways to reduce the costs of deep space missions by making rockets last longer and use less fuel. Rhenium, with its very high melting point (5756 oF or 3180 oC) and durability after repeated temperature swings, seemed to fit the bill. A rocket made of rhenium could be cooled simply by radiating its heat into space instead of being cooled by a fuel film layer against the thruster walls, a major source of combustion inefficiency.
The problem was not just with rhenium's scarcity and high cost, but also with the high cost and difficulty of making it into useable parts. Glenn researchers found several less costly forming methods, but believed the manufacturing community was best to perfect those methods and put them into practice.
That's where Glenn's SBIR program stepped in. "Meeting NASA's future mission needs by putting together NASA researchers and small businesses interested in conducting research is our primary task," said Walter Kim, SBIR program manager. "In this case we also contacted the two rocket manufacturers for help in evaluating both the manufacturing process and the thrusters," he said.
The rocket manufacturers, TRW, Cleveland, OH, and Primex Space Systems (formerly Kaiser Marquardt), Van Nuys, CA, provided their designs for making the thrusters. After the finished thrusters are coated with an oxidation resistant coating of iridium, TRW and Primex will test their respective thruster in their own facilities.
NASA is one of 11 federal agencies participating in the SBIR program, which was established by congress to promote small business participation in the research process. NASA SBIR contracts are let to encourage the development of new ideas in the areas of aerospace research and technology and the commercialization of products and processes that result.
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