For the second day in a row, NASA has been forced to delay the scheduled landing of the space shuttle Atlantic. Thunderstorms have prevented the shuttle from returning to its home base on Saturday, keeping the astronauts circling Earth after a successful repair job at the Hubble Space Telescope.

Offshore storms were what prompted the space agency to skip both morning landing attempts at the Kennedy Space Center. Sunday's forecast isn't looking too good either, but NASA is still opting to wait out the bad weather instead of taking a detour to California.

The Atlantis crew are hoping to soon wrap up their Hubble repair mission, which started on May 11. It was NASA's last visit to the now 19-year-old space observatory, and the $1 billion overhaul and repairs are expected to keep the telescope working for a good five to ten years.

The shuttle's backup landing site, Edwards Air Force Base in California, is expected to have good weather all weekend. However, NASA is holding off on using the backup landing site as it takes quite a bit of time and money - about $2 million - to have a shuttle ferried across the country.

Atlantis has just enough supplies to remain in orbit until Monday. If the weather does not clear up Sunday, the likelihood of having to land in California increases significantly.

The astronauts' visit to Hubble was the fifth and final visit by NASA. The agency's three remaining space shuttles are slated for retirement next year, and there will be no way to arrange another repair mission at the space telescope. A docking ring was installed by Atlantis' astronauts so that it can be steered into the Pacific sometime in the early 2020's.