The Orbiter 101 Enterprise separates from the NASA 747 carrier aircraft to begin its first "tail-cone off" unpowered flight over desert and mountains of Southern California. A T-38 chase plane follows in right background. Astronauts Joe Engle, and Richard Truly controlled the Orbiter on its two-minute, 34-second unpowered mission on this the fourth of five Approach and Landing Tests (ALT) with free flight phases, from Dryden Flight Research Center (DFRC).