The Boeing X-37 is an unpiloted demonstration spaceplane that is intended to test future spaceflight technologies while in orbit and during atmospheric reentry. It is a reusable robotic spacecraft based on the smaller X-40. The X-37 began as a NASA project in 1999, then was transferred to the US Department of Defense in 2004. The X-37 had its first flight as a drop test in April 2006 at Edwards AFB. The spacecraft was launched in April 2010 to begin a United States Air Force mission.