CAPE CANAVERAL, Fla., April 7 (UPI) -- The piece of foam insulation that fell off shuttle Columbia's fuel tank and struck its wing during launch raised safety flags at NASA, which had planned to halt future flights for further analysis, an agency program manager said Monday.
The debris strike is a primary suspect in what caused the shuttle to break apart over east Texas as it attempted to re-enter Earth's atmosphere for landing on Feb. 1. Seven astronauts died in the accident.
Although the shuttle's fuel tanks had shed debris during launch on several previous missions, the insulation that came off Columbia's tank hit the orbiter itself -- a scenario that had been determined highly unlikely by engineering analysis. However, in October 2002, a piece of foam fell off from the same area of the tank and hit one of shuttle Atlantis's booster rockets.
"Following STS-112 (the October 2002 mission) and STS-107 (the January 2003 Columbia flight), we now had a major issue that had to be dealt with before we rolled out the next orbiter, much less fly," Jim Halsell, an astronaut who is heading a NASA task force on return-to-flight issues, told the Columbia Accident Investigation Board during a public hearing.
Although NASA considered the shuttle's thermal protection system a top critical item -- meaning it must work or the shuttle and crew would be lost because there is no backup system -- falling chunks of foam insulation failed to raise flags of caution.
"There was no elevated level of concern that anything liberated from the foam in (the bipod area) would strike the orbiter," Halsell said.
The agency was aware of launch debris dating back to 1981, the shuttle's inaugural year of flight. It caught the attention of top shuttle managers in October 2002 when Atlantis lifted off for a space station mission. However, based on engineering analysis, NASA officials thought the foam strikes were an acceptable and understandable risk.
They might have been horribly wrong. A 2-pound chunk of foam broke off Columbia's tank 81 seconds after liftoff and hit the underside of the shuttle's left wing. Sixteen days later a breach in the wing allowed superheated gas to get inside the structure, melting the aluminum frame and triggering NASA's worst accident since the 1986 Challenger disaster.
Bob Castle, a longtime flight director, said if NASA had realized Columbia's wing was damaged, the agency would have made every effort to try to come up with a solution to save the crew. The agency was told it could order spy satellite photos of the shuttle during its mission to try to image the wing and look for damage. But, believing the wing would not have been seriously damaged, managers declined the offer. In addition, NASA has no known options to rescue a shuttle crew in orbit or return a damaged vehicle to Earth.
Nevertheless, said Castle, "If we'd known about it, we'd pull out all the stops and do everything we could to try to find an answer, I'm sure."
The public hearing continues on Tuesday in Houston.