EDWARDS AIR FORCE BASE (California) - SPACE shuttle Endeavour slipped out of a brilliant desert sky and touched down safely in California after a nearly 16-day mission to repair and upgrade the international space station.

Stormy weather at the shuttle's main Florida landing site forced controllers to divert Endeavour and its crew of seven astronauts across the country to Edwards Air Force Base, where it glided to Earth on Sunday afternoon.

'It's great to be back on the ground, and it's great to be in California,' shuttle commander Christopher Ferguson said, standing with three of his crew members on the tarmac near the shuttle.

The shuttle program's 124th mission remodeled the space station, doubled its crew capacity to six and repaired a rotating joint on a solar wing.

Endeavour delivered a new bathroom, kitchenette, exercise machine, two sleeping quarters, and a recycling system that converts astronauts' urine and sweat into drinking water.

The mission wasn't without setbacks, however. The urine converter required extra tinkering to get it to work, and astronaut Heidemarie Stefanyshyn-Piper lost a US$100,000 (S$152,465) tool bag during a spacewalk to repair the solar-wing joint.

Nonetheless, Mr Ferguson called it ambitious and extremely successful.

'We improved the space station inside and out, of course, with the new water recycling system and then the solar rotary joint, which Heide and her team so adeptly managed to repair,' he said.

'From what I've heard it's performing very well.' Endeavour's also delivered astronaut Sandra Magnus to the space station and brought home astronaut Gregory Chamitoff, who had spent six months aboard the station.

Mr Chamitoff, Ms Stefanyshyn-Piper and astronaut Donald Pettit did not accompany Mr Ferguson when he spoke at day's end, but Mr Ferguson said they were 'just fine.' 'Greg Chamitoff of course is a six-month space flier, and it takes just a little bit longer for them to reacclimate to the gravity and re-adapt to being on Earth again,' he said, adding that the other two were 'keeping a good eye on Greg.'

Endeavour had to use a temporary runway at Edwards because the permanent runway is being revamped. The commander said using the temporary runway was 'kind of a unique opportunity ... but I think it all worked out in the end very well.'

The astronauts also inspected the thermal-tile-coated underside of Endeavour after landing, and Ferguson said the orbiter 'seems to have fared entry pretty well.' The shuttle's California landing delayed reunions between astronauts and their families, who were waiting in Florida. They were expected to reunite on Monday afternoon in Houston.

The diversion also means a delay in returning Endeavour to its home base. It takes about a week and costs US$1.8 million to transport the shuttle from California to Florida atop a modified jumbo jet. -- AP