Space junk 'may have hit Shuttle'

A small meteorite or piece of man-made space junk may have struck the Columbia shuttle while it was still in orbit causing it to crash on its return to earth, Nasa said today.

Even a tiny scrap of debris grazing the shuttle could have damaged thermal tiles just enough to start a chain reaction once it started re-entering the atmosphere, said Milt Heflin, the space agency’s flight director.