Space shuttle experts are reportedly examining a small hole that was discovered on Atlantis after it landed.
The small crater, labelled "Ding 18," is about a tenth of an inch (2.7 mm) in diameter. It is located on the aluminium surface of one of the shuttle’s two thermal radiators, panels that unfold from the spacecraft’s open payload bay doors in flight to dump excess heat from the cabin. They are folded back inside the shuttle for the return to Earth.
The Shuttle orbiter Atlantis was hit by a micrometeorite or orbiting debris during the STS-115 mission. NASA describes the impact as the "first or second largest hit" of the entire Shuttle program. The debris luckily hit the radiator panel on the cargo bay doors; if the micrometeorite had impacted Atlantis' heatshield then it would have created a hole that would have severely compromised the mission.