NASA delays US space shuttle's landing

CAPE CANAVERAL, Fla, June 21 (Reuters) NASA will try again tomorrow to bring the US space shuttle Atlantis and seven astronauts home after clouds and rain at its Florida landing site prevented a touchdown today.

The shuttle has been in orbit for 13 days to install a pair of solar power wings on the International Space Station and prepare the outpost for new laboratories built by Europe and Japan.

Flight directors had two opportunities to land the shuttle on Thursday, but the Kennedy Space Center was socked in by thick clouds and threatened by thunderstorms -- typical summer weather for the sultry subtropical Florida peninsula.

''We looked at it as hard and long as we think is reasonable,'' astronaut Tony Antonelli radioed from mission control to Atlantis commander Frederick Sturckow, explaining the decision to skip today's landing opportunities.

The shuttle has enough fuel and supplies to stay in space until Sunday, but it cannot land in rain because it could damage the thousands of ceramic tiles that protect the spaceships's belly from the fiery heat of re-entry.

Flight directors told Sturckow to lower the shuttle's orbit to add an extra landing opportunity tomorrow at the backup runway at Edwards Air Force Base in California, should poor weather continue to dog Florida.

The first possible touchdown at Kennedy Space Center tomorrow will be at 2:18 p m EDT (2348 hrs IST) and a second at 3:54 p m (0124 hrs IST on Saturday), though flight directors could decide to use that flyover to divert Atlantis to California, with a possible landing occurring there at 3:49 p m EDT (0119 hrs IST on Saturday).

Additional California landing opportunities are at 5:24 p m EDT (0254 hrs IST on Saturday) and 6:59 p m EDT (0429 hrs IST on Saturday).

WEATHER QUESTIONABLE Weather conditions at both sites are questionable, with more rain and clouds in store for Kennedy Space Center and high winds forecast for the shuttle's Mojave Desert site.

''We're going to be fighting the same challenges at KSC. At Edwards, the winds are going to pick up,'' Antonelli said. ''We are going to try to land tomorrow,'' he added.

While NASA battled weather on the ground, its Russian partners in the 100 billion dollar space station program wrestled with the outpost's balky computers.

The primary system shut down last week while astronauts were hooking up the station's new solar panels.

Station commander Fyodor Yurchikhin and flight engineer Oleg Kotov were able to bypass suspect circuitry and eventually revive the computers, which are needed to keep the station properly positioned in orbit.

The station crew disconnected two of the three computer systems on Thursday from the jumper cables used to bypass the circuits but failed to restart the network.

A third computer system remained operational.

The cause of the computer crash, which raised the prospect that the station might have to be temporarily abandoned, remains a mystery.

The Atlantis mission, which was delayed from March after the shuttle's external fuel tank was damaged in a hail storm in late February, is the first of four shuttle flights scheduled this year.

REUTERS PDS BST0228