Reusable Launch Vehicles

The development of RLVs is driven by the desire to reduce launch costs. Potential reduction in RLV long-term production costs is attributed to vehicle refurbishment and reuse after each flight, rather than replacement. RLVs are designed for quick-turnaround operations that will allow for a higher volume and launch rate, resulting in economies of scale. Many studies suggest that reductions in launch costs will enable the emergence and development of new space missions and businesses.

In the 1990s, NASA and the Department of Defense weren committed to progress in RLV development. The DC-X (later the DC-XA and Clipper Graham) was funded by the military in the early 1990s and later by NASA. This vehicle demonstrated RLV materials and operations and paved the way for the current NASA X-vehicle prototype development programs. The US military is continuing its RLV study involving military spaceplane concepts.

Recognizing the commercial value in the development of RLV technologies, NASA successfully negotiated two government-industry partnerships in 1994 to finance and administer current X-vehicle projects. The X-33 is a vehicle being developed by a Lockheed Martin-NASA partnership, and the X-34 is being developed by Orbital Sciences and NASA. Five years later, in 1999, NASA negotiated a third major government-industry partnership with Boeing to develop the X-37.

In 1998, NASA devised a budgetary platform referred to as Future-X to award further contracts to industry for RLV technology development. The Future X initiative defined two development programs: trailblazer and pathfinder. In general, a trailblazer program is devoted to a single demonstrator vehicle that tests integrated vehicle systems. A trailblazer class vehicle is funded in excess of $300 million. A pathfinder program includes development of several specific RLV technologies and smaller X-vehicle projects to demonstrate pathfinder technologies.

In keeping with the spirit of this initiative, NASA created the Pathfinder program office in May 1999 to manage the X-34 and the newly awarded X-37 projects. These two vehicles are small testbed demonstrators designed to validate RLV technologies. The only trailblazer-class vehicle under development, the X-33, is managed by a separate NASA program office.

In addition to the trailblazer and pathfinder vehicles, NASA is also leading the development of a crew return/transfer vehicle called the X-38. The European Space Agency was NASA's partner for the X-38 program. The fifth vehicle, the X-40A, is being loaned to NASA for its X-37 project by the Air Force. In return, the Air Force became a partner in the project and will be testing military RLV technologies.