WELCOME! The X-33 was a technology demonstrator for NASA's "next-generation" of space launch vehicles.

On March 1, 2001, NASA announced that the X-33 Program would not receive Space Launch Initiative funds. The X-33 Program consequently will conclude upon completion of the cooperative agreement between NASA and Lockheed Martin on March 31, 2001. Lockheed Martin may choose to underwrite development of the X-33 with its own funds, or it may pursue funding from the Defense Department.

The X-33 history project documented the development of the complex X-33 program from its beginnings to its completion.

Additional information also appears on other RLV technology programs, such as NASA's X-34, the defunct DC-X program (also known as the Delta Clipper and the Clipper Graham), and a few others still in the planning stage.