Despite more than $1 billion in fixes, the space shuttle is still far from safe.
CAPE CANAVERAL, Fla. (AP) -- In the 21/2 years since Columbia plummeted from the sky in a cascade of flames and halted U.S. space travel, NASA has stripped its fuel tanks of excess foam insulation and added launch-surveillance cameras.
It's toughened up the spacecraft and cracked down on know-it-all managers. It's created a laser-tipped boom to scour the shuttles' thermal skin for cracks and developed bandages for these ominous sores.
It's done everything it can to make the shuttles safer.
Yet even after all this -- an overhaul exceeding $1 billion -- the space shuttle is still vulnerable, unpredictable, dangerous, unforgiving.
That's not the claim of critics.
With the expected return to space Wednesday, NASA leaders stress this will be a test flight in the true sense, almost like the original Mercury space shots.
Managers believe they have licked the overriding problem of foam shrapnel, but warn that no one will know for sure until Discovery goes up. Ice from the fuel tank could also prove to be a deadly spoiler.
As for those little shuttle bandages, the astronauts don't trust them enough to ride home with them covering any holes, even those considerably smaller than the one that doomed Columbia.
An oversight group found the remedies to be so deficient that it ruled NASA noncompliant with Columbia accident investigators' 2003 insistence on practical space repairs. The task force also found NASA lacking on two other crucial requirements, shuttle hardening and elimination of fuel-tank launch debris.
"Eileen Collins and Vegas Kelly and their associates will be lifting off in the face of unknown risk," NASA Administrator Michael Griffin cautioned employees in June.
Commander Collins and her co-pilot, James "Vegas" Kelly, will be at Discovery's controls during the eight-minute climb to orbit and the hourlong descent at mission's end.
It used to be only the launches that were nerve-racking, but no more. Columbia's destructive re-entry Feb. 1, 2003, and the deaths of seven astronauts made landings equally feared.
NASA expects to see more launch debris than on any other mission in the program's 24 years..
"This is a very symbolic mission," said Stephen Robinson, one of Discovery's seven astronauts. "We're getting back on a horse and we're doing it in a much better and wiser and safer way."