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The original goal of the X-33 program was to reduce the business and technical risks by the end of the decade (that is, by the year 2000) so that private industry could build and operate the next generation reusable launch vehicle. The flagship vehicle in NASA's Reusable Launch Vehicle (RLV) program, the X-33 initially was intended to pave the way for a full-scale, commercially-developed RLV to be built by Lockheed Martin after the turn of the century. The full-scale RLV would reduce dramatically the cost of putting payloads into space.

The Lockheed Martin Skunk Works design for the X-33 was selected from
three proposed designs submitted to NASA at the end of Phase I of the program.

The Lockheed Martin Skunk Works X-33 concept used a lifting body shape coupled with an aerospike rocket engine to propel the vehicle.

The X-33 was designed to simulate the ascent and re-entry environments of the full-scale RLV. It was scheduled to make as many as fifteen flights beginning in June 1999 [subsequently postponed indefinitely]. Launched vertically from Haystack Butte, near Edwards Air Force Base, California, the X-33 was intended to fly over 13 times the speed of sound (Mach 13) at altitudes approaching 50 miles. The actual speed and altitude of the X-33 vehicle probably would not have been reduced by the heavier aluminum-lithium tanks that will replace the failed composite liquid hydrogen fuel tanks. Announced landing sites are located in Utah and Montana.

Reusable Launch Vehicle Program Fact Sheet

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