Astronauts checked Endeavour for damage Wednesday, and officials back on Earth said the shuttle appeared to have been struck by three pieces of foam insulation.
But NASA did not think any of the damage was critical, John Shannon, chairman of the mission management team, told The Associated Press.
The seven astronauts, led by veteran flyer Scott Kelly, checked the shuttle's wing edges and nose cap as well as the orbiter's vital heat shield Thursday, during the first full day in orbit.
Barbara Morgan, a teacher-turned-astronaut, used a 30-metre robot arm and extension boom to scan the outside of the shuttle. Morgan is expected to conduct several educational programs during the mission.
Wednesday's launch was an emotionally charged event for family and friends of Canadian astronaut David Williams, who was expected to break a record for the number of spacewalks by a Canadian.
The Saskatoon-born Williams has been assigned up to three of the four scheduled spacewalks as the crew carries out significant upgrades to the International Space Station. He will be only the third Canadian to walk in space.
Dr. Joe MacInnis, a friend of Williams, not only got to watch the launch live but was also the only guest to have a few minutes with his good friend where he was quarantined before take-off.
"We're very proud of him," said MacInnis. "Of course they carry us all with them when they go up, especially Dave who carries the Canadian Flag for us."
MacInnis said just before the launch, Williams talked about the past, the future, the training and the effort involved.
"We had lunch, I met the team," MacInnis told Canada AM Thursday from Orlando, Fla. "They're wonderful people, they're shy, modest and so devoted to what they do.
"(They have) real love for each other, they rely on each other," he continued.
Though Williams was literally in another world, that didn't stop him from being with family and friends in spirit. His tight-knit circle of loved ones held a big party Wednesday night in his honour, complete with a cardboard cut-out of him.
"It was an idea I had so he could be with us at the party," said his wife Cathy Fraser, also speaking to Canada AM.
Fraser said she spoke to her husband just before he suited up and that he was doing very well and was in great spirits.
"He's very focused on doing a good job for Canada and for the space station," she said. "Incredibly proud is exactly what I am."
Endeavour is scheduled to dock on Friday.
Mission STS-118 is the first voyage into space for Endeavour since 2002. This will be the 22nd shuttle trip to the International Space Station.
The shuttle carried 2,600 kilograms of cargo, supplies and a space station segment aloft.
During its 11 days at the space station, the Endeavour will attach a new truss to part of the station and replace a gyroscope that helps control the orientation of the station.
Williams said he expects the second of the three spacewalks, when he will be attached to the robotic Canadarm 2, to be the highlight of the flight.
"I'm just hanging there out in space looking at this incredible view of the world underneath me, and you can imagine what that's going to be like, the spectacular beauty of it."
It will be Williams' second spaceflight following a mission in 1998.
The mission is the second of four that NASA plans to carry out this year. The U.S. space agency is pushing to complete the US$100 billion space station prior to the retirement of the three remaining U.S. shuttles in 2010. Since no Canadians are scheduled to fly on the remaining missions, Williams will be the last Canadian astronaut to fly on a shuttle.
Endeavour last flew in November 2002. On Feb. 1, 2003, seven astronauts were killed when the shuttle Columbia disintegrated upon re-entry to the atmosphere.
A piece of falling insulation had knocked a hole in Columbia's protective heat shield during the launch, unbeknownst to the astronauts and NASA. That put a temporary halt to the shuttle program.
Since then, Endeavour has undergone a major overhaul and has been equipped to tap into the space station's power grid. That could allow it to extend its 11-day mission to 14 days.
With files from The Associated Press
