The space shuttle Endeavour and its crew of six left the International Space Station and headed home to end Nasa's next-to-last shuttle flight on Sunday, pausing just long enough to perform a victory lap and test equipment for a future interplanetary ship. Nasa's youngest shuttle – with just 25 space voyages – is due back in Florida tomorrow. Its next stop after that will be a museum in Los Angeles for what some consider to be a too-early retirement.