NASA Set to Launch

(CNN) -- More than two years after losing the space shuttle Columbia and its seven crew, NASA said Friday it has set May 15 as its target date for once again launching shuttles into space. NASA said Discovery's launch is to be followed by a July 12 Atlantis launch. Discovery's crew of seven is to be led by Commander Eileen Collins. The shuttle fleet has been grounded since Columbia broke apart over Texas while on landing approach to Florida's Kennedy Space Center on February 1, 2003. In August 2003, the Columbia Accident Investigation Board officially concluded that insulating foam flew off the shuttle's external fuel tank during liftoff, striking and cracking a panel on the orbiter's wing. When the shuttle re-entered the atmosphere, searing hot gases seeped into the wing and incinerated the spacecraft. Because of these restrictions there are only a limited number of opportunities to launch the space shuttle. The first starts May 15 and runs through June 3, when NASA hopes to launch Discovery. The second window opens July 12, when NASA hopes to launch Atlantis. Discovery and Atlantis will be so-called rescue shuttles for each other should something go wrong. NASA has been readying both shuttles side by side. The daylight launch restriction may be lifted if both Discovery and Atlantis go up without any critical debris falling off the external tank during liftoff. NASA has been testing a new radar which it claims day or night has a better eye than optical cameras for debris shedding from the external tank. "I'd be very surprised if we had any damage as a result of debris shedding. ... We will be flying much more safely than we've ever flown before," Bill Readdy, NASA associate administrator, told reporters Friday. Both the Discovery and Atlantis missions will be test flights to the international space station to demonstrate the shuttle is once again safe to fly.