CAPE CANAVERAL, Fla. - The space shuttle Columbia finally landed Saturday, but two lingering mysteries from 1996's last shuttle flight - if they aren't solved soon - could delay missions early next year. Why did a hatch stick and prevent astronauts from spacewalking? And why did dozens of unusual burns reappear in booster rocket insulation? Both questions must be answered before Atlantis flies next month, officials said.
Columbia landed smoothly through mottled clouds after a twice-extended record 7,043,950-mile mission, which lasted 17 days, 15 hours and 54 minutes. It was a flight that Commander Ken Cockrell said will be remembered unfairly for what went wrong instead of what went right. Astronauts did grow pure chips for electronics semiconductors and released a special telescope that looked at 300 stars. "We had a fine machine that had one little sticky doorknob on it," Cockrell said at a post-landing newsconference.
That "doorknob" was a hatch handle that couldn't turn enough to open the airlock and allow astronauts Tom Jones and Tammy Jernigan outside for two spacewalks. Both walks were canceled, and the astronauts said they were tempted to bang the hatch door in frustration - but didn't.
A working hatch is crucial for the next two flights, NASA shuttle program manager Tommy Holloway said. The hatch has to open for astronauts on Atlantis to go into a docking tunnel to enter the Russian space station Mir. Servicing the Hubble SpaceTelescope in February will require three spacewalks.
Late Monday, technicians will look at both sides of the hatch to see why it didn'twork. Holloway said he suspects some trash or unwanted leftover equipment could be jammed in the motor that opens the door. Mike McCulley, vice president for United Space Alliance, which handles shuttle operations and preparations, said he hopes that is not the cause.
"We work really hard to keep that vehicle clean," he said. "We vacuum it at the beginning of every shift and we vacuum at the end of the shift."
But if it was debris or the fault of the space alliance, NASA will penalize the private company some yet-to-be-determined amount of money.
The other problem of booster insulation burns delayed Columbia's launch more than a week. When Atlantis flew in August, NASA discovered one of the booster rocket's nozzles had 60 unusual groove-style burns in its insulation. Two special teams looked at the boosters and didn't find a single cause for the problem. But they decided that a few factors occurring simultaneously triggered the burns and probably wouldn't cause a fatal shuttle accident.
When Columbia's boosters were examined there were 30 burns in one booster and 22 in the other, which is more than NASA had ever seen until Atlantis' last flight, Holloway said.
The burns weren't as deep, but a third team will re-examine what caused the problem, he said.
"Boosters scare me all the time," Cockrell said, adding that he wouldn't change the shuttle boosters because there's nothing better. Columbia's landing also ended the flying part of the 30-year career of record-setting astronaut Story Musgravecq, who at 61 was the oldest person in space. He flew in a record six space shuttle trips.
"This one was pure ecstasy," Musgrave said. "If this was the last spaceflight, this was the one to finish on."