Washington: All countdown activities are proceeding normally toward the Dec 7 launch of Space Shuttle Discovery that would fly Indian American astronaut Sunita Williams to the International Space Station, her new home for the next six months.

"Our systems are in great shape," said NASA Test Director Steven Payne yesterday (Dec 5, 2006) at the Kennedy Space Centre in Florida.

"The teams are ready," he said.

A cold front moved through Central Florida Monday and the forecast calls for clear skies for the next two days, according to Shuttle Weather Officer Kathy Winters.

However, another front is headed toward the spaceport on Thursday, and although it's expected to pass through the area prior to launch time, there is a possibility of isolated showers and low cloud ceilings lingering through the evening.

There is a 40 percent chance of weather prohibiting the flight of Williams, who will become the second person of Indian origin to go into space since the Columbia disaster killed Indian born Kalpana Chawla and six other astronauts in 2003.

She will replace German Thomas Reiter as a flight engineer on the space station. Reiter, a European Space Agency astronaut, who flew aboard Discovery July 4 to take up residence at the Space Station, will return to Earth with STS-116 Shuttle's six other crew after its 12-day mission.

Since weather is expected to deteriorate on Friday and Saturday, weather on Thursday will be the most favourable.

The launch countdown began at 11 p.m. Monday at the T-43 hour mark. Included in the countdown are nearly 28 hours of built-in hold time prior to a targeted 9:35 p.m. EST launch on Thursday (8:05 am Friday).

The STS-116 mission is the 33rd for Discovery and the 117th space shuttle flight. During the 12-day mission, the crew will continue construction on the International Space Station, rewiring the orbiting laboratory adding a segment to its integrated truss structure.