CAPE CANAVERAL, Florida (Reuters) - Shuttle Atlantis crew members prepared on Tuesday for their planned touchdown at the Kennedy Space Center in central Florida after delivering Europe's first permanent orbital laboratory to the International Space Station.
The weather at the Cape Canaveral seaside spaceport was expected to be nearly perfect for Atlantis to descend through the skies and land at 9:07 a.m. EST on Wednesday, completing a 13-day flight.
"I'm really optimistic, looking at the weather briefs, that things are going to play out really well for Kennedy," flight director Bryan Lunney said in a briefing at Johnson Space Center in Houston.
Just in case the weather changes, NASA is staffing its backup landing site in California, spurred by the military's desire to get the ship home as quickly as possible so it can proceed with a plan to shoot down a failed spy satellite that is loaded with toxic rocket fuel.
Lunney said, however, there was "no pressure" from the military to hurry the shuttle back to Earth. "I'm not going to land the vehicle until it's safe to do so," he said.
The shuttle and space station orbit at a much higher altitude than the ailing satellite. But NASA wants Atlantis to re-enter the atmosphere and land before the shootdown to avoid having the ship fly through a cloud of debris.
"In the very small possibility that we don't land tomorrow, they'll hold off (the shootdown) another day," Atlantis commander Stephen Frick said during an interview from space.
Frick and pilot Alan Poindexter tested the shuttle's landing systems on Tuesday while crew mates tidied up the cabin and set up a reclining seat for astronaut Dan Tani, who is returning after four months on the space station.
The re-adaptation to gravity is harder for people who have been in weightlessness longer and the reclined chair will ease his transition back to gravity.
Tani said he missed gravity's grasp at times during his stay in space and that he was looking forward to "having food on your plate that you don't have to go chase around the room."
During the equipment checkout, Frick and Poindexter shifted Atlantis' position so that the sun would warm a broken heater that wiped out four of the shuttle's small steering jets. NASA said the equipment is not needed to drive the shuttle from orbit or glide through the atmosphere but would need to be repaired before Atlantis blasts off again later this year.
Atlantis' next mission is to ferry a servicing crew to the orbiting Hubble Space Telescope in late August or September.
Atlantis left the space station on Monday after installing Europe's $1.9 billion Columbus science module. The flight was extended one day after spacewalker Hans Schlegel fell ill with an undisclosed medical condition and had to be replaced by backup Stanley Love.
Schlegel recovered to complete the second spacewalk of the flight to work on the station's cooling system.
During a third spacewalk, Love and Rex Walheim installed two science experiments to the outside of Columbus.
Another day at the station was added to give more time for Schlegel to set up equipment in the laboratory. That work now falls to Tani's replacement on the station, French astronaut Leopold Eyharts, who launched aboard Atlantis.
The extra time in orbit allowed the astronauts to take a bit of a break and enjoy the view from 200 miles planet.
"Compared to the size of the Earth, we're just skimming above the top," Frick said.
"You can see this small little blanket of atmosphere that is protecting the whole Earth. It really does drive home the fact that it's the whole world's concern about how we treat the planet."
Editing by Philip Barbara