NASA gave up on plans to land the space shuttle Atlantis here on Saturday with thick cloud cover at Cape Canaveral, and said it would try to bring the craft down to Earth on Sunday.
It was the second consecutive day that NASA, faced with heavy clouding and crosswinds, decided to push back the Atlantis' landing. The crew has enough fuel to keep flying until Monday at the lastest.
The US space agency has prepared Edwards Air Force Base in California as a back-up landing point in case conditions do not clear up in Florida.
But NASA would prefer to land the shuttle in Florida as it would cost the agency some two million dollars (1.4 million euros) extra to get the craft back home from California.
Atlantis is returning to Earth after conducting crucial repairs on the Hubble Space Telescope.