The space shuttle Discovery has linked up with the International Space Station two days after launching from Florida.
During the operation, astronauts on board the ISS managed to take photos of the outside of the shuttle.
They will be used to see if it was damaged by foam which fell off its fuel tank during launch.
Nasa is so worried about the incident they've stopped all shuttle flights. A similar incident caused the loss of the shuttle Columbia in 2003.
SHUTTLE RETURN TO FLIGHT
Mission known as STS-114
Discovery's 31st flight
17th orbiter flight to ISS
Location: Kennedy Space Center, Launch Pad 39B
Discovery crew: Collins, Kelly, Noguchi, Robinson, Thomas, Lawrence and Camarda
But Nasa spokesman Dr Mike Griffin doesn't think we should worry too much.
"Everything that we see at this point says that the orbiter is in fact a clean bird," he told the ABC's Good Morning America programme.
If the shuttle is damaged, its crew could wait in the International Space Station until a rescue craft arrives.
But whether another shuttle, the Atlantis, would be allowed to go and get them, hasn't been decided.