(07/21/1999) --- The STS-93 crew wave to onlookers as they walk out of the Operations and Checkout Building for the second time enroute to Launch Pad 39-B and liftoff of Space Shuttle Columbia. After Space Shuttle Columbia's July 20 launch attempt was scrubbed at the T-7 second mark in the countdown, the launch was rescheduled for Thursday, July 22, at 12:28 a.m. EDT. The target landing date is July 26, 1999, at 11:24 p.m. EDT. In their orange launch and entry suits, they are (starting at rear, left to right) Mission Specialists Michel Tognini of France, who represents the Centre National d'Etudes Spatiales (CNES), and Catherine G. Coleman (Ph.D.); Pilot Jeffrey S. Ashby; Mission Specialist Steven A. Hawley (Ph.D.); and Commander Eileen M. Collins. STS-93 is a five-day mission primarily to release the Chandra X-ray Observatory, which will allow scientists from around the world to study some of the most distant, powerful and dynamic objects in the universe. The new telescope is 20 to 50 times more sensitive than any previous X-ray telescope and is expected unlock the secrets of supernovae, quasars and black holes. Collins is the first woman to serve as commander of a Shuttle mission