NASA aims to land space shuttle Atlantis

CAPE CANAVERAL, Fla., June 22 (Reuters) The astronauts on the US space shuttle Atlantis closed their ship's cargo bay doors today, hoping for good weather that would allow them to return to Earth after two weeks in orbit.

The first opportunity to land at the shuttle's home port at the Kennedy Space Center in Florida will be at 2:18 pm EDT 2348 hrs IST but thick clouds and nearby rain could prompt flight directors to divert the spaceship to a backup landing site in California.

The first opportunity to land at Edwards Air Force Base in California would occur at 3:49 pm EDT (0119 hrs IST).

NASA had planned to end its first shuttle mission of the year on Thursday but the spacecraft and its seven astronauts were told to stay in orbit an extra day due to summer thunderstorms at the Florida space port.

Although the shuttle has enough fuel and supplies to remain in orbit until Sunday, NASA intends to bring it back to Earth today.

''The mindset is we're going to land you safely some place today,'' astronaut Tony Antonelli from Mission Control in Houston radioed to Atlantis commander Frederick Sturckow.

Atlantis was returning from a nine-day stay at the International Space Station, a 100 billion dollars project of 16 nations that is a little more than half finished.

The shuttle carted a third pair of power-producing solar wing panels to the outpost and its crew conducted four spacewalks to install them, fold up another older wing that will be moved to a new location and install equipment needed to prepare for the arrival of additional laboratories.

The astronauts also were called upon to repair a hole in the heat shield on Atlantis, which arrived in orbit with a corner of an insulating blanket torn loose.

The US space agency has been meticulous about scouring the shuttles for damage once they reach orbit since a heat shield failure triggered the destruction of the shuttle Columbia in 2003 and the deaths of seven astronauts.

The crew also delivered a new astronaut to the station. Clayton Anderson replaced station flight engineer Sunita Williams, who is returning home aboard Atlantis after a record-breaking six months in space. She surpassed Shannon Lucid's 188-day mission for the longest duration spaceflight by a woman.

NASA needs to fly 12 more construction missions to finish building the station before the end of 2010, when the shuttle fleet is due to be retired. The US space agency also would like to squeeze in two resupply missions and a final servicing call to the Hubble Space Telescope.

Atlantis' construction mission at the space station was overshadowed by a major computer breakdown in the Russian modules that could have led to the station being temporarily abandoned. Work was continuing on the station computers.

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