Official Nasa Communication 96-13

Jim Cast Headquarters, Washington, DC (Phone: 202/358-1779)

January 25, 1996

Dom Amatore Marshall Space Flight Center, Huntsville, AL (Phone: 205/544-0031) RELEASE: 96-13 COMPOSITE HYDROGEN TANK TEST COMPLETED FOR DC-XA A new lightweight composite hydrogen tank for the Delta Clipper-Experimental Advanced (DC-XA) vehicle, an unpiloted, single-stage rocket being developed by NASA and McDonnell Douglas Aerospace, has successfully completed testing at the Marshall Space Flight Center, Huntsville, AL. "This is really quite a breakthrough," said NASA's DC-XA project manager Dan Dumbacher. "This is the largest composite hydrogen tank ever to successfully survive flight operating conditions. It demonstrates that composite tanks can be used for other reusable launch vehicles in the future." Permeability of composite materials has been a concern for engineers, but this tank withstood pressure testing at cryogenic temperatures that simulated the DC-XA flight environment without leaking hydrogen. Composite materials are formed by blending epoxies and various filaments to form strong structures with a variety of aerospace uses. NASA has been conducting intensive research and development on composites since the 1970s. The DC-XA is a flying experimental testbed that is demonstrating technologies for NASA's Reusable Launch Vehicle Program. Knowledge gained in developing and test flying the DC-XA will be used in development of the X-33 advanced technology demonstrator and ultimately in a full-scale reusable launch vehicle. The ability to use composites is important to the development of a single-stage-to-orbit reusable launch vehicle because of the weight reduction they provide. Getting the weight down is a key factor in launching a payload to orbit in a single stage rocket. DC-XA's 16-foot-tall hydrogen tank,

eight feet in diameter, is made of graphite composites and weighs 2,020 pounds -- 1,200 pounds lighter than the tank used in its predecessor, the DC-X. Yet the composite tank provides the same strength that an aluminum tank would. The successful on-time completion of this test is a big step forward for the DC-XA, Dumbacher said. "It's a major milestone in the DC-XA program," Dumbacher said . "It keeps us on track to flight test the vehicle in May. We've shipped the tank to McDonnell Douglas Aerospace in Huntington Beach, CA, where they will build the flight vehicle around it." "This will be the first graphite epoxy cryogenic fuel tank to undergo flight testing," said Dave Schweikle, McDonnell Douglas DC-XA program manager. "The tank was designed and fabricated by McDonnell Douglas to hold liquid hydrogen at minus 423 degrees Fahrenheit and to serve as an integral part of the DC-XA's structure." -endNASA press releases and other information are available automatically by sending an Internet electronic mail message to [email protected]. In the body of the message (not the subject line) users should type the words "subscribe pressrelease" (no quotes). The system will reply with a confirmation via E-mail of each subscription. A second automatic message will include additional information on the service. NASA releases also are available via CompuServe using the command GO NASA.