Faced with bad weather in Cape Canaveral, Florida, NASA ordered the space shuttle Atlantis to land at Edwards Air Force Base in California at 1540 GMT on Sunday.
Mission control in Houston ordered the seven astronauts to start their descent around 1424 GMT, for a landing a bit more than an hour later. The landing had originally been scheduled for Friday.
Atlantis blasted off on May 11 with a crew of seven astronauts on what was scheduled to be an 11-day mission to repair the Hubble space telescope and extend its range and life for another five years.
NASA earlier had scrubbed a planned first attempt to land Atlantis at its home base in Florida on Sunday.
With storms not too far from the Florida space center, the Houston, Texas, control center asked the seven astronauts to take another whirl around Earth hoping weather conditions improve in Florida ahead of another try.
But as things failed to look clear enough for a Florida green-light, the California landing was set.
NASA prefers to bring it down in Florida to save the two million dollars it costs to move the shuttle back to base in Florida. The crew has enough fuel to fly until Monday at the latest.
Saturday, heavy cloud cover and crosswinds forced the US space agency to put off the space shuttle Atlantis' return to Earth for at least another day, extending an otherwise successful mission to repair the Hubble telescope.
NASA routinely readies Edwards Air Force Base in California as a back-up landing point in case conditions are problematic in Florida.
Under NASA rules, a decision on whether to attempt a landing has to be made one hour and a half hours before the planned touchdown. Once the crew begins its descent toward Earth, the decision cannot be reversed because the shuttle lacks engine power that would allow it to regain altitude.
Atlantis blasted off on May 11 with a crew of seven astronauts on what was scheduled to be an 11-day mission to repair the Hubble space telescope and extend its range and life for another five years.
NASA has set several conditions for a landing: the cloud cover in the skies must not be more than 50 percent, visibility must be at least eight kilometers (five miles) and lateral winds must not be blowing at more than 28 kilometers an hour (17 miles an hour).
As early as Thursday, the astronauts were told by NASA to shut down some of the computers on board the shuttle to conserve electricity in the event that their landing was delayed.
The Hubble observatory was released on Tuesday after five obstacle-filled spacewalks.
The enhancements have equipped Hubble to search for the earliest galaxies, probe the mysteries of dark matter and dark energy as well as study planet-making processes.
But the trouble was well worthwhile.
John Grunsfeld, an astronomer turned astronaut who led three of the mission's five spacewalks, told lawmakers Thursday that Hubble "is probably the most significant science instrument of all times."
As NASA struggled with the Atlantis landing, the White House announced Saturday that President Barack Obama had nominated former astronaut Charles Bolden to be the agency's new administrator.
If confirmed, Bolden would be the first African American to lead NASA and only the second astronaut.
A retired Marine Corps major general, Bolden made four shuttle voyages during his years as an astronaut and piloted the shuttle Discovery when it deployed Hubble into orbit in 1990.
Source: AFP American Edition
