Seema Hakhu Kachru in Houston

Houston, Jun 21: Indian-American astronaut Sunita Williams' homecoming is just hours away after her six-month sojourn in space.

The shuttle's heat shield is safe to return to earth provided there is no weather-related hitch.

A day before the shuttle's planned landing in the US, the mission managers said the Atlantis crew is preparing for landing during its scheduled final full day in space.

They said Atlantis' heat shield is safe to return to Earth but also added that the weather may hamper the shuttle landing. Two opportunities are available for the shuttle Atlantis to land at Kennedy Space Centre Thursday.

Preparations on Wednesday included stowing equipment and checking out systems that will be used to deorbit Atlantis and begin the descent to Earth. Also, the seven crew members took time out of their schedules to talk to NBC News, ABC News and CNN Live.

The first landing opportunity available is on Orbit 202, which calls for the deorbit burn to occur 12:50 p.m. EDT on Thursday with a 1:55 p.m. (local time) touchdown. The final opportunity of the day is on the next orbit. It begins with the deorbit burn at 2:25 p.m. and ends with a 3:30 p.m. landing.

Weather forecasts call for a possibility of thunder showers in the area. Flight controllers and forecasters with the Spaceflight Meteorology Group will continue to monitor the weather at Kennedy Space centre.

The STS-117 crew members are returning home from a construction mission to the International Space Station [Images]. They installed the Starboard 3 and 4 (S3/S4) truss segment and conducted four spacewalks to activate it.