"[4] The uncrewed X-40A was a 80%-90% subscale version of the Boeing X-37 reusable spaceplane, but lacking in propulsion or thermal protection systems.

Boeing built the X-40A originally for the Air Force as part of that service’s Space Maneuver Vehicle program.

[4][2] The aircraft was built at Boeing Phantom Works at Seal Beach, California, in partnership with the Air Force Research Laboratory.

[2][3] In 2001 it successfully demonstrated the glide capabilities of the X-37's fat-bodied, short-winged design and validated the proposed guidance system.

[4] One test flight the craft was towed by an Army CH-47D Chinook helicopter to an altitude of 15,000 feet, and then released to fly an autonomously controlled 75-second descent to a landing on the main runway at Edwards Air Force Base, where it then glided and guided itself.