<i>Discovery:</i> 'Back a little, OK, keep going... that's it, stop!'

All had been euphoria at Nasa when Discovery blasted off from the Kennedy Space Centre in Florida on Tuesday morning, in the first launch since the Columbia disaster in February 2003. The mood quickly changed, however, when it was discovered that a large chunk of insulating foam flew off the external fuel tank shortly after lift off - a repeat of the incident that doomed Columbia. On that occasion, the flying debris hit the spacecraft, knocking away a panel of its heat-resistant silicon tiles, causing Columbia to catch fire and disintegrate as it re-entered the atmosphere with the loss of the seven astronauts aboard.

This time the piece of foam, 33in long and 9in wide, missed the shuttle - although it lost two small pieces of tile for unspecified reasons, one of them close to the craft's landing gear. Nasa officials are confident that the shuttle has not been harmed and will be able to return to Earth on 7 August.

"Everything that we see at this point says that the orbiter is in fact a clean bird," Michael Griffin, Nasa administrator, said after Discovery performed a gentle backflip just before the docking so that space-station crew members could take photos of the damaged area on the shuttle's belly. Further inspections are due today.

But the dispiriting reality is that all future shuttle missions have been put on hold until the insulating foam problem is resolved. The shuttle Atlantis was scheduled to take off in September, in what Nasa had hoped would be a smooth reprise of the entire programme until the shuttle's retirement in five years' time.

Officially that remains the goal: "Right now, we are planning on flying the shuttle until 2010, using it to assemble the international space station, and then helping return US astronauts to the moon," Mr Griffin said yesterday. But all those plans depend on the agency's technicians finding out why the foam is splintering off the fuel tank.

The conundrum could also have a major impact on the still-unfinished $95bn (£54bn) space station, parts for which are delivered by the shuttle. Discovery is scheduled to spend a week with the station, transferring 15 tons of supplies, including a replacement steering gyroscope.

Yesterday, the shuttle docked just after noon GMT, for what was the first link-up between the station and the shuttle in almost three years. About two hours later, following routine leak and pressure checks, the seven Discovery astronauts entered the orbiting lab. There they received the traditional Russian greeting of bread and salt, when a visitor crosses the threshold of another person's home.

Unlike the US, Russia seems firmly committed to the international space station project. Last month Alexander Medvedchikov, deputy head of the Russian Space Agency, said that if the US withdrew, the Russians would take over, using a new manned spacecraft called Kliper that is still on the drawing board.

Under proposals unveiled in 2004, President George Bush has suggested that once Nasa develops a successor to the shuttle, and prepares to return to the moon, the US should hand over the station programme to its partners.