Orbital Sciences Corp. manufactured three airframes. They flew a total of three flights between 1999-2001. In the summer of 1996, NASA contracted with Orbital Sciences Corp. to design, build, and test-fly the X-34, a small, reusable technology demonstrator for a launch vehicle. The X-34 was a single-engine rocket that was to be carried aloft and launched from an Orbital Sciences L-1011 aircraft. On June 29, 1999, the prototype test version of the X-34 made its first captive-carry flight attached to the belly of its newly modified L-1011 carrier aircraft. A second captive-carry flight occurred successfully on Sept. 3, and a third and final flight occurred on Sept. 14. The X-34 was intended to fly at Mach 8 and to reach an altitude of 250,000 feet, but in 2001 NASA ceased funding the program.