Shuttle Atlantis crew prepares for return to Earth

HOUSTON, Sep 19 (Reuters) Astronauts on the shuttle Atlantis packed up gear and checked out their spacecraft today as they prepared to come home from their 11-day mission to the International Space Station.

In the midst of preparations, they took part in a three-way conference call with their counterparts on the station and a Russian Soyuz spacecraft.

NASA said tests of the shuttle's flight controls and steering jets turned up no problems, which followed the good news that Atlantis' heat shield appears fit for the fiery return through Earth's atmosphere.

Atlantis was due to land at Kennedy Space Center at 1529 hrs ist tomorrow, but forecasters said weather conditions looked iffy and could force a delay.

In the conference call, which NASA said may have been the first time three orbiting spaceships had spoken on a shared radio link, the space travelers joked and chatted in a sometimes awkward 10-minute conversation.

''It's a little crowded in the sky this morning,'' said station astronaut Jeff Williams.

''We were wondering if we had to hire some more air traffic controllers for the increased traffic up here,'' US astronaut Michael Lopez-Alegria replied from the Soyuz.

Atlantis is headed home after a week-long stay at the space station, while Soyuz is en route to the outpost after launching from Kazakhstan yesterday.

Space tourist Anousheh Ansari, an Iranian-American businesswoman, is on board the cramped Soyuz with Lopez-Alegria and Russian cosmonaut Mikhail Tyurin. But she did not sound too chipper when station crewmember Thomas Reiter tried to pull her into the conversation.

''Hello everyone, I look forward to see you on the station,'' she said.

''A few more hours and you will be here,'' Reiter said.

''Yes,'' she replied flatly.

Russian ground controllers broke off the call so a flight surgeon could consult with Ansari, who is believed to have paid 20 million dollars for the flight.

Whether Ansari had problems was not yet known, but it is not unusual for first-time space travelers to become ill in the weightless environment.

Counting the crewmembers on all three of the spacecraft, there are 12 people in orbit for the first time in several years, including six on Atlantis, three on the Soyuz and three on the station.

NASA said the record for simultaneous orbiters is 13, which occurred at least once before in 2001, when a shuttle and the Soyuz were flying at the same time as the station.

On that flight, the shuttle had seven astronauts on board, versus six on the current mission.

Atlantis launched September. 9 from Florida carrying a 372 million dollars solar power unit and truss structure that its crew installed on the space station.

It is on the first of at least 15 flights planned by NASA to complete the half-finished station, construction of which had been on hold since 2003 when shuttle Columbia disintegrated while returning to Earth.

The seven astronauts on board were killed in the accident caused by damage to Columbia's heat shield.

Soyuz is due to dock with the space station tomorrow morning.

Ansari will return to Earth September. 28 with Williams and Pavel Vinogradov, who, after six months on the station, will be replaced by Tyurin and Michael Lopez-Alegria.

The space station had a brief emergency today when a chemical spilled from an oxygen generator and caused a noxious odor, but it was cleaned up without problem.

REUTERS DKA RK1610