Washington, July 12: Even though they have flown for 22 years, US space shuttles should be treated as test vehicles, not as craft approved for routine use, investigators probing the 'Columbia' disaster said on yesterday.
However, NASA often treats the shuttles as if they are proven operational vehicles whose performance is predictable from one mission to the next, letting some on-board monitoring equipment fall into disuse, said Harold Gehman, head of the independent Columbia Accident Investigation Board.

"The fact that we've allowed cameras and range instrumentation and on-board instrumentation ... to kind of gracefully atrophy over the years leads me to bring this issue up, that there are some signs that it's been considered an operational vehicle rather than an investigative vehicle," Gehman said at a briefing.

This is a "pervasive" and "significant" problem that has a direct impact on how the shuttles are treated, he said.

Shuttle Columbia, the first of the shuttle fleet to fly in April 1981, disintegrated over Texas on Feb. 1 as it re-entered the atmosphere, killing all seven astronauts.

Investigators generally agree that what doomed Columbia was a chunk of foam insulation that fell off the shuttle's massive external fuel tank some 81 seconds after launch, damaging the craft's left wing and allowing superheated gas to penetrate the shuttle on re-entry, tearing the ship apart. Bureau Report