English: Artist concept of the X-37 advanced technology flight demonstrator re-entering Earth's atmosphere. The X-37 will be a testbed for dozens of advanced structural, propulsion and operational technologies that could dramatically lower the cost of future reusable launch vehicles. The X-37 will operate in both the orbital and reenty phases of flight. The X-37 measures approximately 27.5 feet (8.3 meters) long and 15 feet (4.5 meters) in wingspan. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the X-37 project. The X-37 industry team is led by The Boeing Co. of Seal Beach, Calif.