Astronauts aboard space shuttle Endeavour closed their ship's cargo bay doors today and prepared to land in California after bad weather prompted Nasa to bypass the prime Florida landing site.

Touchdown was set for 22.25 p.m. at the backup landing site at Edwards Air Force Base in California's Mojave desert.

Nasa had hoped to land the seven astronauts at the Kennedy Space Center in Florida but thunderstorms and high winds prompted flight directors to opt for a California landing.

"Based on the forecast... we're going to elect to press ahead with the Edwards opportunity," astronaut Alan Poindexter radioed to the crew from Mission Control in Houston.

Endeavour commander Chris Ferguson replied, "We'll see you on the ground in California."

Nasa prefers to land in Florida to save about a week and almost $2 million to ferry the shuttle cross-country.

Endeavour, which launched 16 days ago, is returning from a home-improvement mission at the International Space Station.

The crew installed a water recycling system that will enable Nasa to add three more astronauts to the space station's permanent live-aboard crew.

They also conducted four spacewalks to repair the station's power system and delivered two new bedrooms, a second toilet, exercise gear, a small galley and other gear.

A Russian cargo ship at the space station arrived early Sunday with fuel, water and more supplies. Flight engineer Yury Lonchakov remotely guided the Progress vessel to a docking port after its automated system failed.

Nasa's next station visit is slated for February when the outpost's last solar wing panel will be installed. The agency plans eight more shuttle flights to the station, as well as a final servicing call to the Hubble Space Telescope, before retiring the ships in 2010.