English: This artist's rendering depicts the NASA/Lockheed Martin X-33 technology demonstrator alongside the Venturestar, a Single-Stage-To-Orbit (SSTO) Reusable Launch Vehicle (RLV). The X-33, a half-scale prototype for the Venturestar, is scheduled to be flight tested in 1999. NASA's Dryden Flight Research Center, Edwards, California, plays a key role in the development and flight testing of the X-33. The RLV technology program is a cooperative agreement between NASA and industry. The goal of the RLV technology program is to enable signifigant reductions in the cost of access to space, and to promote the creation and delivery of new space services and other activities that will improve U.S. economic competitiveness. NASA Headquarter's Office of Space Access and Technology is overseeing the RLV program, which is being managed by the RLV Office at NASA's Marshall Space Flight Center, located in Huntsville, Alabama. The X-33 was a wedged-shaped subscale technology demonstrator prototype of a potential future Reusable Launch Vehicle (RLV) that Lockheed Martin had dubbed VentureStar. The company had hoped to develop VentureStar early this century. Through demonstration flight and ground research, NASA's X-33 program was to provide the information needed for industry representatives such as Lockheed Martin to decide whether to proceed with the development of a full-scale, commercial RLV program. A full-scale, single-stage-to-orbit RLV was to dramatically increase reliability and lower costs of putting a pound of payload into space, from the current figure of $10,000 to $1,000. Reducing the cost associated with transporting payloads in Low Earth Orbit (LEO) by using a commercial RLV was to create new opportunities for space access and significantly improve U.S. economic competitiveness in the world-wide launch marketplace. NASA expected to be a customer, not the operator, of the commercial RLV. The X-33 design was based on a lifting body shape with two revolutionary "linear aerospike" rocket engines and a rugged metallic thermal protection system. The vehicle also had lightweight components and fuel tanks built to conform to the vehicle's outer shape. Time between X-33 flights was normally to have been seven days, but the program had hoped to demonstrate a two-day turnaround between flights during the flight-test phase of the program. The X-33 was to have been an unpiloted vehicle that took off vertically like a rocket and landed horizontally like an airplane. It was to have reached altitudes of up to 50 miles and high hypersonic speeds. The X-33 program was managed by the Marshall Space Flight Center and was to have been launched at a special launch site on Edwards Air Force Base. Due to technical problems with the liquid hydrogen tank, and the resulting cost increase and time delay, the X-33 program was cancelled in February 2001. NASA Identifier: NIX-ED97-43929