Shuttle to fly over Chantal for landing

Coming home: Susan Helms, left, Yury Usachev, center and Jim Voss

By Richard Stenger
CNN

(CNN) -- The space shuttle Discovery will race over the tropical depression that was Chantal if it lands during the first opportunity on Wednesday.

But the orbiter, returning with the old crew of the international space station, should pass safely over the top of the once mighty storm in the Gulf of Mexico.

And the latest forecast predicts clear skies at the Florida landing site for the scheduled 12:46 p.m. EDT touchdown.

"It's looking really nice," a NASA ground controller told the shuttle crew Wednesday morning.

"Sounds like a great day to come on home," replied Discovery Commander Scott Horowitz.

Should the shuttle miss the first opportunity to return home, it could complete one more orbit and try again 90 minutes later. But weather conditions might worsen. There is a slight chance that storms could move closer to the Kennedy Space Center later in the afternoon.

The landing forecast for Thursday looks promising. If necessary, the shuttle could use an alternative runway in California or remain in space another day before returning.

Gravity a weighty challenge

Space station Alpha

During an 11-day mission, Discovery delivered a fresh crew to space station Alpha and picked up Americans Jim Voss and Susan Helms and Russian Yury Usachev, who had spent almost six months aboard the orbiting outpost.

The returning Alphanauts can expect weeks of physical therapy to regain muscle and bone strength lost during their weightless flight, the second longest in NASA history.

But the recovery could be minimal since they used specialized exercise equipment onboard Alpha.

"We have a pretty good program for keeping ourselves in good shape. We have two bicycles, a treadmill and an exercise device that simulates weightlifting," Voss told CNN in an interview Tuesday.

Usachev could have an easier time mending, having spent two long-duration missions on the retired Russian space station Mir. When he returns from his latest flight, he will have spent 553 cumulative days in orbit, the fifth highest total in history.

Only fellow cosmonauts have stayed in space longer, including the long-duration champion, Sergey Avdeyev, who on three missions spent 747 days off the planet.

The third Alpha crew, composed of U.S. skipper Frank Culbertson and Russians Vladimir Dezhurov and Mikhail Tyurin, will spend four months aboard the modular complex.

A project of the United States, Russia, Canada, Europe and Japan, space station Alpha could cost $100 billion when completed later this decade.