An astronaut on the US space shuttle Discovery has successfully removed two ceramic strips sticking-out from between the shuttle's tiles.
Stephen Robinson used a robotic arm to get under the space craft, where he pulled the strips off with his fingers.
Nasa engineers were worried the strips could cause the craft to overheat during re-entry to Earth's atmosphere.
It's the first time an astronaut has carried out a repair like this, or seen the underneath of the shuttle in orbit.
Mission known as STS-114
Discovery's 31st flight
17th orbiter flight to ISS
Launched from: Kennedy Space Center, Launch Pad 39B
Discovery crew: Collins, Kelly, Noguchi, Robinson, Thomas, Lawrence and Camarda
Nasa had been concerned Robinson would not be able to remove the ceramic-coated cloth with just his fingers, so he was armed with tweezers and a home-made hacksaw just in case.
But in the end he didn't have to use them as the strips came away when he pulled them.
Earlier in the mission, Discovery hit problems when a piece of foam fell off a panel during take-off.
But Nasa says the damage to its protective tiles was minor, and laser scans and pictures have not shown any serious problems.
This is the first shuttle mission since 2003, when the shuttle Columbia's heat shields were damaged when it launched, causing it to break up during its return.