Reusable Launch Vehicle
NASA's Reusable Launch Vehicle (RLV) program has dual objectives:
to demonstrate technologies leading to a new generation of space
boosters capable of delivering payloads at significantly lower
cost, and to provide a technology base for development of advanced
commercial launch systems that will make U.S. aerospace manufacturers
more competitive in the global market.
Launched in 1994, the RLV program moved ahead on two fronts
in 1996 with a restructuring of the X-34 air-launched small booster
project and selection of a contractor for development of the
larger X-33 technology demonstrator.
Under development by Orbital Sciences Corporation is the X-34,
an experimental vehicle for testing technologies for a single-stage-to-orbit
launch vehicle. First flight is targeted for 1998.
On June 10, 1996, NASA announced a program for the X-34 that
will be a technology demonstrator rather than an operational
system. Orbital Sciences Corporation (OSC), Dulles, Virginia
was selected as prime contractor from among nine bidders.
The X-34 will weigh about 45,000 pounds and will be air-launched
from a Lockheed L-1011 jetliner. The craft will be about 58 feet
long and span about 28 feet.
The aim of the revised program is to create a reusable, suborbital
test vehicle for demonstrating single-stage-to-orbit (SSTO) technologies,
most of which have applicability in the X-33 program.
The X-34 plan calls for development of a vehicle capable of
attaining a velocity of Mach 8 (roughly 5200 miles per hour),
flying to an altitude of about 50 miles, and returning to an
Earth base for a wheeled landing. The initial test flight must
be made by October 1, 1998.
Among the technology areas the X-34 will explore is a very
high flight rate: the vehicle must demonstrate potential for
25 flights a year. Other areas to be investigated are advanced
thermal protection systems, a composite airframe, reusable propellant
tanks, autonomous landing systems and advanced avionics.
OSC's development effort will be backed by a strong NASA/industry
team. The X-34's propulsion system will be provided by Marshall
Space Flight Center, which has been working since 1994 on an
advanced liquid oxygen/kerosene rocket engine with a low-cost,
partially reusable thrust chamber. The X-34 engine will have
60,000 pounds of thrust; since there is no requirement for attaining
orbit in the test program, no second stage is needed.
In development for first flight in 1999 is the NASA/Lockheed
Martin X-33 Advanced Technology Demonstrator, intended as the
prototype of a 21st century low-cost-to-orbit reusable launch
vehicle.
Ames Research Center will contribute thermal protection technology
and Langley Research Center will handle computational fluid dynamics
and aerodynamic testing.
Industry firms participating include AlliedSignal Aerospace,
Torrance, California, which is developing advanced avionics and
hydraulic power systems; Oceaneering Space Systems, Houston,
Texas (re-entry thermal control); and Charles Stark Draper Laboratory,
Cambridge, Massachusetts (navigation and guidance technology).
On July 2, 1996, Vice President Albert Gore announced the
selection of Lockheed Martin Corporation for Phase II development
of an experimental space booster that could become the prototype
of a 21st century operational reusable launch vehicle (RLV).
The vehicle is the X-33 Advanced Technology Demonstrator,
a half-scale version of the proposed operational system which,
Lockheed Martin says, will be able to deliver 40,000 pounds of
payload to low Earth orbit at a small fraction of the current
cost of launching payloads to orbit. Under a cooperative agreement,
the X-33 will be developed jointly by NASA and Lockheed Martin's
famed "Skunk Works," noted for its success in creating
such radical aerospace craft as the U-2 reconnaissance plane,
the SR-71 Mach 3 research plane, and the F-117 Air Force stealth
fighter.
The aim of the RLV program, NASA Administrator Daniel S. Goldin
said at the announcement ceremony, is "to build a vehicle
that takes days, not months, to turn around; dozens, not thousands,
of people to operate; with launch costs that are a tenth of what
they are now. Our goal is a reusable launch vehicle that will
cut the cost of getting a pound of payload to orbit from $10,000
to $1,000."
Goldin underlined the fact that the RLV project represents
a "radical departure" from the way NASA has done business
in the past. In line with its mission of financing high risk
developments in the interests of U.S. competitiveness and the
national economy, NASA is funding the major share of the X-33
development, but the 21st century operational RLV will be developed
on a commercial basis and NASA will become a user, rather than
an operator, of the system.
NASA is providing $941 million through 1999 for the X-33;
Lockheed Martin and industry partners will invest some $220 million
in startup costs and initial R&D. The development will be
carried out under a cooperative agreement-a true government/industry
partnership-that is different from conventional contracts; it
is a performance-based agreement under which NASA will make progress
payments only when the industry team completes predetermined
milestones.
The Phase II award-for design, construction and flight testing
of the X-33-follows a 15-month Phase I concept definition effort
during which each of three contractors developed its own design,
operations plan and business investment strategy. After a lengthy
evaluation of all the bids, Lockheed Martin was selected as NASA's
industry partner over competitors McDonnell Douglas Corporation
and Rockwell International.
Known as Venture-Star, the Lockheed Martin design is a wedge-shaped
lifting body type of vehicle in which the entire airframe, not
just the stubby winglets, generates lift. It is designed to be
launched vertically and land horizontally like the Space Shuttle,
but where the Shuttle uses conventional engines, a large throwaway
fuel tank and drop-off boosters for launch, the X-33 will be
totally reusable and employ what are known as "aerospike"
engines. Built by Rockwell Rocketdyne, the engines offer utmost
efficiency through a system that does not use conventional bell-shaped
engine nozzles but automatically compensates for decreasing atmospheric
pressure and regulates thrust as the vehicle ascends.
Lockheed Martin's industry partners include AlliedSignal,
Teterboro, New Jersey (subsystems, avionics and operations support);
Rockwell Rocketdyne Division, Canoga Park, California (aerospike
propulsion); Rohr, Inc., Chula Vista, California (thermal protection
system); Sverdrup Corporation, St. Louis, Missouri (launch site
architecture and engineering); and Alliant Techsystems, Magna,
Utah (fuel tanks).
The X-33 is being developed in a "fast track" program
that envisions first flight in March 1999. An incentive clause
provides a bonus if the Venture-Star can make 15 flights by the
end of the century, at least one of them to a velocity of Mach
15. A successful X-33 program could lead to commercial development
of a full-scale RLV and first operational use around 2005.
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