(AP) -- Thunderstorms prevented space shuttle Atlantis from returning to its home base Saturday for the second day in a row, and kept the astronauts circling Earth after a successful repair job at the Hubble Space Telescope.
The offshore storms, which later moved in, prompted NASA to skip both morning landing attempts at Kennedy Space Center. Despite an equally dismal forecast for Sunday, Mission Control opted to wait out the bad weather rather than take a detour to California.
As Atlantis soared overhead, right around what would have been landing time, commander Scott Altman called down that he saw "a pretty solid mass of clouds."
"It looks to us like maybe it is starting to break up and move out, so we're hopeful to get home tomorrow," he said.
"We're sharing your optimism," Mission Control replied.
Atlantis' seven astronauts made it further into their landing preparations than they did Friday, when storms directly over the Florida landing site resulted in much earlier cancellations.
A cooling-system problem cropped up aboard Atlantis soon after the astronauts got word of the latest delay, and they were advised to hold off on opening the payload bay doors just in case an emergency return was required. Within minutes, however, Altman was assured everything was fine, and the doors were opened to radiate the heat generated by all the equipment.
Altman and his crew are trying to wind up their Hubble repair mission, which began May 11. It was NASA's last visit to the 19-year-old observatory. The $1 billion overhaul should keep the telescope working for another five to 10 years.
The weather at the backup landing site, Edwards Air Force Base, is expected to be good all weekend, but it takes time and money - close to $2 million - to ferry a shuttle cross-country.
As for Florida, forecasters expected more bad weather from the same low-pressure system that has been drenching Florida for days. But there was a slight chance that conditions would improve, and that was enough for NASA to ride it out another day.
Atlantis has enough supplies to remain in orbit until Monday.
"We'll be fine going around another day," Altman said.
As the astronauts settled in for another day in space, President Barack Obama announced his choice for NASA's next administrator, Charles Bolden, a former shuttle commander. Obama told the Atlantis crew earlier in the week, in a phone call, that an announcement was imminent. If confirmed by the Senate, Bolden would become only the second astronaut ever to lead the space agency.
Mission Control relayed the news to the astronauts two hours later. "I guess it wasn't any of us in the flight after all," Altman joked.
Atlantis' mission culminated earlier this week with the release of Hubble, freshly restored and considered at its scientific peak thanks to the astronauts' effort. In five back-to-back spacewalks, they gave the observatory new science instruments and fixed two others, and replaced batteries, gyroscopes and other aging parts.
This was the fifth and final visit to Hubble by astronauts. With NASA's three remaining space shuttles slated for retirement next year, there will be no way to stage another repair mission at the space telescope. It will be steered into the Pacific sometime in the early 2020s; a docking ring was installed by Atlantis' astronauts just for that purpose.
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