At a news conference five hours after the much-delayed lift-off, NASA officials footage of the launch had shown several piece of debris, possibly foam and ice, breaking off but no damage could be seen. But they emphasised this was a preliminary assessment and said more checks would be needed.
Atlantis is carrying a six-member crew on an 11-day mission to resume construction of the international space station. NASA is planning another 15 shuttle trips to complete the orbiting laboratory by 2010, when the three shuttle fleet is due to retired.
Foam shed during the launch caused the space shuttle Columbia to disintegrate on re-entry in 2003. The two flights since then have been focussed on correcting the problem and improving flight safety.