Endeavour crew members inspected their space shuttle's heat shield on Thursday, to ensure the external damage suffered during liftoff does not pose a threat to their safe return to Earth.
Cameras captured pieces of foam insulation falling away from the external fuel tank during Wednesday night's liftoff, though NASA officials initially cautioned that the damaged appeared to be less severe than what was seen on the last shuttle flight.
"The bottom line is we saw some stuff," said Mike Moses, chairman of the mission management team. "Some of it doesn't concern us. Some of it you just can't really speculate on right now. But we have the tools in front of us and the processes in front of us to go clear this vehicle for entry."
The shuttle was hit at least two or three times, said Bill Gerstenmaier, NASA's space operations chief.
According to the NASA website, the Endeavour's seven-person crew used the shuttle's robotic arm and its related sensor system for the inspection.
"They are using the Canadarm and the camera on the end of it to see if there is anything serious enough not to let the shuttle come back," said Marc Garneau, the first Canadian in space, who spoke with Â鶹´«Ã½ Channel on Thursday.
He added that there will also be cameras at the International Space Station -- where the astronauts will be on Friday -- "to look very carefully at all of the thermal tiles on the shuttle and make sure no critical tile has been damaged."
Kevin Shortt, president of the Canadian Space Society, said until that inspection is complete, it is too soon to tell if the damage Endeavour suffered during liftoff is significant.
"The cameras that caught the debris falling off of the external fuel tank were a little too far away to really calculate the size of the debris that fell off," he told Â鶹´«Ã½ Channel during an interview on Thursday.
Because of the Columbia accident six years ago, NASA has become highly vigilant about monitoring the condition of the foam on the exterior of the external fuel tank during liftoff, Shortt said.
NASA now uses a variety of monitoring and inspection technologies to keep track of the foam on the fuel tank, which comes under intense pressures and forces during liftoff.
"They scan using all sorts of different technologies, different camera angles and really quantify what the problems are," said Shortt.
The space shuttle Columbia had a piece of foam break away from its fuel tank and strike its left wing, creating a small hole on its leading edge. Tragically, upon re-entry, the shuttle disintegrated, killing all of its seven crew members on Feb. 1, 2003.
"The primary cause that led to the disastrous re-entry of Columbia was the fact that this piece of foam debris had struck the wing of Columbia, creating a big gaping hole, so when it came back into the atmosphere, hot gases got in and melted the wing," Shortt said.
NASA will do everything in its power to ensure that the shuttle is repaired and ready to return to Earth safely.
If the space agency decides that Endeavour could not be repaired, it would send up another shuttle to retrieve the astronauts from the International Space Station, Shortt said.
"That is the absolute last case," Shortt said. "The astronauts will first try to go out on a spacewalk -- on an extra-vehicular activity -- and go under the belly of the shuttle, to the leading edges of the wings, and see if they can use some of the repair techniques that NASA developed shortly after the Columbia accident."
Aside from the safety concerns regarding the launch, more joyful news is expected Friday.
Canadian history will be made when Julie Payette meets up with Bob Thirsk at the International Space Station, making them the first two Canadians to meet in space.
"I'm sure the two of them will have a big visible hug," said Garneau. "This is quite an accomplishment for Canada, and I'm certainly very proud."
Endeavour blasted off from Kennedy Space Center just after 6:00 p.m. on Wednesday, after five consecutive launch delays.
Prior problems with hydrogen gas leaks held the launch up last month, while bad weather delayed the mission earlier in July.
With files from The Associated Press
