From NASANews@luna.osf.hq.nasa.govSun Jan 28 12:37:44 1996
Date: Thu, 25 Jan 1996 13:00:17 -0500
From: NASA HQ Public Affairs Office <NASANews@luna.osf.hq.nasa.gov>
To: press-release-com@mercury.hq.nasa.gov
Subject: Composite Hydrogen Tank Test Completed for DC-XA

Jim Cast
Headquarters, Washington, DC                 January 25, 1996
(Phone:  202/358-1779)

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." 

                         -end-

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