Nasa scientists are continuing to search for evidence of damage to the space shuttle Discovery after it was hit by debris shortly after take-off on Tuesday. Prior to docking with the international space station the craft performed manoevres to allow its entire surface to be photographed.Following the 2003 Columbia disaster in which another space shuttle disintegrated on re-entry the experts are leaving nothing to chance Nasa chiefs say there are eleven signs of potential impacts but nothing that would endanger the ship on its return journey which is due to end on August the 7th. Concerns were first raised when a small piece of insulating foam was seen peeling off and striking one of the wings. Discovery’s seven astronauts boarded the International Space Station on Thursday in a mission that was supposed to mark a triumphant return to manned US space flight. All shuttle missions were suspended after the Columbia disaster. Nasa has said grounded its shuttle fleet until the current problem is resolved. The incident has had disturbing echoes of the 2003 tragedy . Loose foam from Columbia’s fuel tank knocked a hole in the heat shield of its wing during take-off. Some 16 days later, the shuttle broke up over Texas as it glided toward Florida for landing, killing all seven astronauts onboard.