flight-testing a prototype spacecraft that could
become the first new human spacecraft to travel to
and from orbit in the past two decades, a spacecraft
developed at a fraction of the cost of past human
space vehicles.
The most immediate application of the
innovative project, designated the X-38, is to
develop the technology for a prototype emergency
crew return vehicle (CRV), or lifeboat, for the
International Space Station. But the project also is
aimed at developing a crew return vehicle design
that could be modified for other uses, such as a
possible joint U.S. and international human
spacecraft that could be launched on the French
Ariane 5 booster And the goal is to develop the
vehicle with an unprecedented eye toward
efficiency, taking advantage of available equipment
and already developed technology for as much as 80
percent of the spacecraft's design.
"Using available technology and off-the-shelf
equipment can significantly reduce costs," said
X-38 Project Manager John Muratore. "Some
estimates to build a capsule-type CRV several
years ago amounted to more than $2 billion in
total development cost. The X-38 concept could
develop and build four operational CRVS, vehicles
that are more capable and versatile than earlier
designs, for less than a quarter of that."
In the early years of the International Space
Station, a Russian Soyuz spacecraft will be
attached to the station as a CRV. But, as the size of
the crew aboard the station increases, a return
vehicle like the X-38 that can accommodate up to
six passengers will be needed.
The X-38 design uses a lifting body concept
originally developed by the Air Force's X-24A
project in the mid-1970s. Following the Jettison of
a deorbit engine module, the X-38 would glide
from orbit unpowered like the Space Shuttle and
then use a steerable, parafoil parachute, a
technology recently developed by the Army, for its
final descent to landing. Its landing gear would
consist of skids rather than wheels.
"Just because it is off-the-shelf technology
doesn't mean it is old technology. Many of the
technologies we are using have never before been
applied to a human spacecraft," Muratore said. "We
are out to prove that we can produce a highly
versatile human spacecraft for significantly less cost
than has ever been done before."
The X-38 flight computer is commercial
equipment that is already in use in aircraft, and the
flight software operatin system is a commercial
system already in use in many aerospace
applications. The video equipment being used on
the atmospheric test vehicles is existing equipment,
some of which has already flown on the space
shuttle for other NASA experiments. The
electromechanical actuators that are used on the
X-38 come from a previous joint NASA, Air Force
and Navy research and development project. A
special coatin. that had already been developed by
NASA is planned to be used on the X-38 thermal
tiles to make them much more durable than the
tiles used on the space shuttle. The X-38's primary
navigational equipment, the Inertial Navigation
System/Global Positioning System, is a unit
already in use on Navy fighters.
Although the design could one day be
modified for other uses such as a crew transport
vehicle, the X-38 would strictly be used as a CRV
in its current design. It is baselined with only
enou-h life support supplies to last about nine
hours flyinc, free of the space station in orbit. The
spacceraft's landing will be totally automated,
although the crew will have the capability to
switch to backup systems, control the orientation in
orbit, pick a deorbit site, and steer the parafoil, if
necessary. The X-38 CRV has a nitrogen gas-fueled
attitude control system and uses a bank of batteries
for power. The spacecraft will be 28.5 feet long,
14.5feet wide and weigh about 16,000 pounds.
A small, in-house development study of the
X-38 concept first began at JSC in early 1995, and,
in the summer of 1995, early flight tests were
conducted of the parafoil concept, dropping
platforms with a parafoil from an aircraft at the
Army's Yuma Proving Ground, Yuma, Arizona.
Early this year, a contract was awarded to Scaled
Composites, Inc., of Mojave, California, for the
construction of three full-scale atmospheric test
airframes. The first vehicle airframe was delivered
to JSC in September, where it is now being
outfitted with avionics, computer systems and
other hardware in preparation for drop tests next
year at the Dryden Flight Research Center,
Edwards, California. A second vehicle is scheduled
to be delivered to JSC in December.
Full-scale, unpiloted flight tests are planned to
begin in July and early August 1997, at DFRC with
4 4 captive carry" flights in which the vehicle will
remain attached to the NASA B-52 aircraft. Freeflight
drop tests, also unpiloted, from the B-52 are
planned to begin in September 1997.
Further testing could include an unpiloted
space flight test in early 2000, and the new CRV
could be attached to the International Space Station
by 2002. It is estimated that the total projected cost
of the X-38's development through the completion
of two space test vehicles could be less than
$90 million.
About 100 people are currently working on
the project at JSC, at DFRC and at the Langley
Research Center in Hampton, VA. This is the first
time a prototype vehicle has been built-up in-house
at JSC, rather than by a contractor, an approach
that has many advantages.
"BY buildinc, this ourselves, we are going to
have a better understanding of the problems
contractors experience when they build vehicles for
us, and we will have a detailed set of requirements
for the contractor. Using civil servants is among
the most efficient ways to perform a small project
like this, as well," Muratore said. "This gets NASA
back to its research and development roots, the
type of hands-on work that was done when it was
NACA, the National Advisory Committee on
Aeronautics, before the space age began."
TURN OF THE CENTURY SPACECRAFT:
The X-38,a new human spacecraft being designed at the
Johnson Space Center for use as a crew return
vehicle, or lifeboat, for the International Space Station, is
shown in the artist's concept above left as it reenters
the atmosphere. Below, the atmospheric flight test
vehicles for the X-38 are outfitted at JSC for unpiloted
drop tests from a NASA B-52 aircraft at the Dryden
Flight Research Center in 1997 and 1998. An unpiloted
space test vehicle also is being built at JSC for a shuttle
flight at the turn of the century.
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