Discovery Set For Launch

Passes First Of Several Tests Before Today's 10:39 A.M. Blast-Off

(CBS/AP)  While in orbit, Discovery's crew will inspect the most vulnerable areas of the spacecraft, using a new 50-foot, laser-tipped boom. They will also practice repairing samples of deliberately damaged thermal tile and panels.

Discovery's fuel sensors are designed to prevent the main engines from running too long or not long enough, in case the fuel tank is leaking or some other major breakdown occurs. An engine shutdown at the wrong time could be catastrophic.

Over the past few days, NASA has rewired two of the sensors to try to diagnose the trouble and repaired faulty electrical grounding aboard Discovery in hopes that would solve it.

A retired agent in NASA's inspector general office, Joseph Gutheinz, says the space agency does not appear to have learned its lesson with Columbia. Accident investigators criticized NASA's tendency to downplay risks and discourage engineers from speaking up.

"It is clear to me that NASA continues to put mission over safety," Gutheinz said. "I fear that if NASA is wrong this time, as they were for Apollo 1, Challenger and Columbia, manned space missions may be halted for a very long time in the United States."

The launch promised not only to be an appraisal of changes in NASA's safety culture, but also a test of a redesigned fuel tank that was altered after the Columbia disaster to minimize debris falling off it.

Columbia's fuel tank lost a large chunk of foam insulation at liftoff. The debris slammed into the left wing, smashing a hole that proved catastrophic during re-entry Feb. 1, 2003. All seven astronauts were killed.

Discovery has until the beginning of August to fly to the space station on a 12-day supply and repair mission; the next launch opportunity would be Sept. 9.