NASA has suspended all future space shuttle flights after debris fell from Discovery during lift-off on Tuesday.Worryingly for the US space agency, it is an echo of the problem that doomed sister ship Columbia and its crew, two and a half years ago. Two shielding tiles were damaged as Discovery set off on its 12-day mission to the International Space Station, and two large pieces of insulating foam fell during blast-off. It was damage from a piece of foam falling off during launch that caused Columbia to break apart on re-entry to the Earth’s atmosphere in 2003. All seven people on board perished. The Discovery crew has been using a special robotic arm to inspect the craft. NASA does not want to take any chances with the lives of its astronauts at stake. They are due to return to earth on August 7 but could be obliged to wait at the ISS for a rescue craft if Discovery is deemed unsafe.