Troublesome to the end

摘要

A Graceful retirement is eluding NASA's Discovery space shuttle. It was supposed to be in space by now, its final mission almost complete. Instead it will be grounded until 30 November while the agency probes a crack that has formed in the foam insulation on its fuel tank. The fissure, now 50 centimetres long, appeared on 5 November as the tank was being drained of liquid hydrogen after an earlier fuel leak prevented the shuttle from launching. "It's not something we like to see," says Mike Moses, the shuttle's launch integration manager.