CAPE CANAVERAL, Fla. (AP) Astronauts used the international space station's robotic arm to examine a spot on the shuttle Discovery's left wing Monday where sensors detected a "very low" impact, NASA officials said.
"It looks like something happened," said John Shannon, chairman of the mission management team, noting that the wing looked fine during the focused inspection earlier that day.
The sensor recorded a level of impact not considered worrisome, Shannon said, but managers decided to take a closer look to be safe. NASA officials have not determined the significance of the blip, though they don't expect it to affect the mission.
The inspection came after the shuttle reached the space station following a two-day journey for a weeklong stay to continue construction on the orbiting lab and rotate out a crew member.
Discovery commander Mark Polansky closed in on the station at a tenth of a foot per second before latches automatically linked the spacecraft shortly before a sunrise.
"Space shuttle Discovery arriving," space station resident Michael Lopez-Alegria told Mission Control in Houston at 6:54 p.m. EST as the hatch between the two spacecraft opened to the traditional ringing of a bell.
Televised images from the orbiting space lab showed Bob Curbeam, due to perform three spacewalks, bouncing over two hugging astronauts to shake the hand of space station resident Thomas Reiter, who will return to Earth with the shuttle crew. Christer Fuglesang, now the first Swede in space, spoke into a video camera, then let it float away.
Eventually the two crews gathered for a group shot, all smiles and with some ponytails floating, as they flew 220 miles above Australia.
"You guys all look great," Mission Control radioed up. "We're waving back."
Six of Discovery's seven astronauts planned to spend a week at the space station. The seventh astronaut, Sunita "Suni" Williams, will live there for six months, replacing German astronaut Reiter of the European Space Agency.
The two will swap places before the end of the day, making Williams only the third woman in history to reside long-term at the space station.
About an hour before docking, Discovery did a slow back flip so the space station crew could photograph its belly for any signs of liftoff damage.
Polansky executed the maneuver as the shuttle flew about 600 feet beneath the station.
The space agency has been especially alert to damage to the shuttle's heat shield since the Columbia tragedy in 2003. A piece of foam broke off Columbia's external fuel tank during liftoff and gashed a wing, allowing hot gases to penetrate the spacecraft during its return to Earth. All seven astronauts died.
NASA on said Sunday that the shuttle's heat shield appeared to be in good shape, but that it will be a few days before engineers can rule out any damage from Saturday's liftoff, the first nighttime shuttle launch in four years.
Discovery was carrying a 2-ton addition to the space station.
The $11 million component will be put into place on Tuesday during the first of the mission's three spacewalks. Astronauts also plan to rewire the space lab, switching it from a temporary source to a permanent one, during the two other spacewalks.