Engineers may have found the cause of gas leaks in the reusable booster rockets of two space shuttles, but they are not much closer to a solution, the U.S. space agency said on Friday.
Space agency officials revealed that extra work on the boosters could have had disastrous results for the two shuttles during their June and July launches.A procedural change - to inject more caulklike insulation into the boosters than necessary for good measure - "has had a detrimental effect instead," said Brewster Shaw, who heads the shuttle program for the National Aeronautics and Space Administration.
The extra insulation compressed air bubbles into "paths" for searing propellant that scorched critical O-ring seals in the nozzles of the white, jointed rockets that the Discovery and Atlantis shuttles used for a skyward boost, according to Shaw.
NASA's revelation of the tiny leaks in late July prompted a public recollection of the 1986 Challenger disaster, which was blamed in part on a similar O-ring that failed to seal properly in cold weather.
The astronauts were not harmed during the recent flights, but NASA decided it was too risky to send up Endeavour with its five-man crew until experts can contain the dangerous seepage.
Endeavour remained grounded indefinitely Friday, the eve of what was to have been its launch day.
Shaw had been scheduled to report on the progress of repairs to the shuttle but instead told reporters, "We're not there yet."