Reusable Launch Vehicle Program
Document: FS-SSC-012 (9612)
Modified: September 1997
The Reusable Launch Vehicle (RLV) Technology Program is a partnership between
NASA and industry to design a new generation of launch vehicles expected to dramatically
lower the costs of putting payloads in space. Today's launch systems are complex
and costly to operate. The RLV program stresses a simple, fully reusable vehicle
that will operate much like an airliner. NASA hopes to cut payload costs from $10,000
a pound, as it is today, to about $1,000 a pound. To accomplish this goal, NASA sought
proposals from U. S. aerospace industries for the RLV Technology Program.
Lockheed Martin chosen for X-33 program.
On July 2, 1996, NASA selected Lockheed Martin Skunk Works of Palmdale, Calif.,
to design, build, and test the X-33 experimental vehicle for the RLV program. The
reusable, wedge-shaped X-33 will be about half the size of a full-scale RLV. The
X-33 will not take payloads into space; it will be used only to demonstrate the vehicle's
design and simulate flight characteristics of the full-scale RLV. Lockheed Martin
originally planned to conduct the first flight test in June 1999 and achieve at least
15 flights by December 1999. The actual number of flights is not known, and the test
flights (as well as construction of the vehicle) have been postponed indefinitely.
NASA budgeted $941 million for the project through 1999 (excluding some work done
by NASA civil servants). Lockheed Martin initially invested about $220 million in
its X-33 design. That amount has grown since the beginning of Phase II. Upon the
conclusion of the flight test program, government and industry would decide whether
or not to continue with a full-scale RLV.
RLV not a Space Shuttle replacement.
The RLV will fly much like the Space Shuttle. It will take off vertically and
land on a runway. However, there are differences between the two vehicles. The RLV
will be a means of transport only. It will not be used as a science platform like
the current Space Shuttle.
Also, the RLV will be a single-stage-to-orbit spacecraft. It will not drop off
components on its way to orbit. It will rely totally on its own built-in engines
to reach orbit, omitting the need for additional boosters. Unlike the Shuttle, the
RLV will use a new linear aerospike engine, which looks and runs much differently
than the bell-shaped Space Shuttle Main Engine.
The linear aerospike engine.
NASA considered the aerospike engine for the Space Shuttle 25 years ago, but
opted to use the Space Shuttle Main Engine, also built by Rocketdyne. The aerospike
has been revived and enhanced to power the RLV. The aerospike nozzle is shaped like
an inverted bell nozzle. Where a bell nozzle begins small and widens toward the opening
of the nozzle like a cone, the aerospike decreases in width toward the opening of
the nozzle. The aerospike is 75 percent shorter than an equivalent bell nozzle engine.
It is also lighter, and its form blends well with the RLV's lifting body airframe
for lower drag during flight. The shape spreads thrust loads evenly at the base of
the vehicle, causing less structural weight. The half-scale X-33 test vehicle will
use two smaller test versions of the aerospike. The full-scale RLV in its current
configuration will use seven aerospike engines.