Ground crewmen help guide the alignment of the X-40 technology demonstrator as the experimental craft is gently lowered to the ground by a U.S. Army CH-47 Chinook cargo helicopter following a captive-carry test flight at NASA's Dryden Flight Research Center, Edwards, California. The X-40 is an unpowered 82 percent scale version of the X-37, a Boeing-developed spaceplane designed to demonstrate various advanced technologies for development of future lower-cost access to space vehicles. The X-37 will be carried into space aboard a space shuttle and then released to perform various maneuvers and a controlled re-entry through the Earth's atmosphere to an airplane-style landing on a runway, controlled entirely by pre-programmed computer software. Following a series of captive-carry flights, the X-40 made several free flights from a launch altitude of about 15,000 feet above ground, gliding to a fully autonomous landing. The captive carry flights helped verify the X-40's navigation and control systems, rigging angles for its sling, and stability and control of the helicopter while carrying the X-40 on a tether.