NASA told Columbia's astronauts Thursday that they may have to perform an emergency spacewalk to fix or remove a loose seal that could prevent proper closure of the space shuttle's cargo bay doors.
"We're trying to determine by analysis if we'll be able to close the door safely with the environmental seal where it is currently," Mission Control's Jan Davis told the crew. "We have a lot of good folks working on that, and we're hopeful we can clear it by analysis.""If we can't, there's a possibility that we'll do" a spacewalk, Davis said. She said a spacewalk would not occur before the fourth flight day, Saturday. The flight is scheduled to last nine days.
The cargo bay doors must be closed tightly for the shuttle to safely make the fiery re-entry through the atmosphere. Two of the astronauts - Tamara Jernigan and James Bagian - are trained in spacewalking in case the doors must be closed manually.
Television pictures beamed to the ground Wednesday showed that several white blankets of insulation had come loose in the payload bay. And some weatherstripping, a long sealing belt, also came loose along the edge of one of the doors that covers the bay during launch and landing.
Engineers still were assessing the situation to see if the doors can be shut tightly by themselves at the end of the mission.
Columbia's astronauts began their second day of experiments inside Spacelab this morning, drawing more blood from one another as part of NASA's most in-depth biomedical research mission.
Four of the seven astronauts didn't have far to go when they woke up. They slept inside the pressurized laboratory module in the shuttle's cargo bay.
"They all thought it was a great place to sleep," shuttle commander Bryan O'Connor said.
Television images beamed down from space showed cell biologist Millie Hughes-Fulford calmly taking blood from F. Drew Gaffney, a cardiologist. He offered his left arm casually.
Less than an hour later, Bagian, a physician, took more blood from Gaffney. Again, he did not flinch.
M. Rhea Seddon, another physician, told Mission Control it was taking a little longer than anticipated to collect the blood.