Atlantis mission back on track

Atlantis astronauts are gearing up to check the tail section of their spacecraft for a minor tear in the heat shield while they prepare for a spacewalk that was postponed by 24 hours because of a German crew member's illness.

Seven astronauts on board space shuttle Atlantis arrived at the International Space Station on Saturday, delivering a massive European science lab and a fresh crew member to the growing orbital outpost.

NASA said the sick crew member, Hans Schlegel, had recovered but will not take part in Monday's space walk, scheduled at 20:05 IST. He will be replaced by Mission Specialist Stanley Love, who will be accompanied by Rex Walheim in installing the European Space Agency's 'Columbus' laboratory to the ISS.

The European Space Agency had on Sunday confirmed that German Astronaut Schlegel was suffering from a temporary medical condition that was 'neither life threatening nor contagious'.

Though he will not leave the station on Monday, Schlegel will help choreograph the spacewalk from inside the orbital base. He is expected to participate in a second spacewalk on Wednesday.

"At the moment, the medical community is confident that Hans will be able to perform his second (spacewalk)," said the European agency's chief astronaut medical officer, Dr Volker Damann.

In Monday's spacewalk, the astronauts will also install the Power Data Grapple Fixture on Columbus. This will allow the station's robotic arm to grab the laboratory module and move it from the shuttle's payload bay to the space station's Harmony module.

The spacewalkers also will detach nitrogen lines from the ISS and begin work to remove the Nitrogen Tank Assembly, a part of the station's thermal control system. The assembly needs to be replaced because the nitrogen is running low.

Meanwhile, the shuttle damage survey, which was earlier scheduled for later in the mission, will also be undertaken on Monday. The crew will use the shuttle's camera-tipped robot arm for a close-up examination of heat shielding on the right side of the tail section.

A corner of a thermal blanket wrapped across the region had lifted up slightly, probably pulled away by aerodynamic forces at liftoff, NASA's Mike Sarafin, the mission's lead flight director, said.

Similar damage was spotted during a June mission. Spacewalkers made repairs with a surgical stapler.