Animation of Atlantis docking to ISS. Photo: NASA TV/Spaceflight Now

The astronauts aboard shuttle Atlantis are gearing up to undock from the international space station late this evening after six days of grueling work to move some three tons of supplies and equipment on board for use by the lab's first full-time crew.

U.S. space station managers say so far, the 99th shuttle mission has been virtually flawless and that the station's first crew, scheduled to arrive in early November, will be in good shape to begin the lab's permanent occupation.

"The reports from the (Atlantis) crew are very positive, they have good things to say about the environment they find there, the conditions relative to temperature, humidity, cleanliness, etc.," said former astronaut and shuttle manager Brewster Shaw, now vice president and general manager of Boeing's space station program.

"And of course, they've brought on board supplies and a lot of equipment, equipment for the generation of oxygen, the reduction of carbon dioxide, exercise equipment, etc.," Shaw said. "So they're pretty much turning down the blanket and putting chocolate on the pillow for those guys when they show up."

Atlantis skipper Terrence Wilcutt and his six crewmates floated out of the space station for the last time early Sunday, closing a final hatch a few minutes past 8 a.m. to wrap up five days nine hours and 21 minutes of station outfitting and activation.

With pilot Scott Altman at the controls, the flight plan calls for Atlantis to undock form the now-dormant space station at 11:44 p.m. as the two spacecraft pass over Russian ground stations.

Before leaving the lab for good, Altman plans to fly the shuttle through two complete loops at a distance of around 400 feet for a detailed exterior photo survey.

Finally, at 1:34 a.m. Monday, Atlantis will leave the scene for good and the astronauts will set their sights on landing early Wednesday at the Kennedy Space Center, weather permitting.

Entry flight director Wayne Hale said early today the preliminary forecast calls for generally acceptable weather in the wake of Hurricane - now Tropical Storm - Gordon, which buffeted the Cape with high winds and heavy rain Sunday.

"The outlook - and of course, this is Sunday morning and we're looking out to Wednesday - the weatherman tells us that following the storm, weather conditions in Florida should be pretty good," Hale said.

"When we come around to Wednesday morning, we'll take a good hard look at the weather in Florida. If at all possible, we'd like to land back in Florida. If the weather's not good in Florida, we'll have a decision to make whether or not we want to go to California or wait a day and try to go back to KSC a day later."

The international space station as seen by Atlantis during the rendezvous last weekend. Photo: NASA

For now, however, the astronauts have their sights set on this evening's undocking, a carefully choreographed procedure that will give pilot Altman a chance to try his hand at the controls for an extended bit of manual flying.

"Traditionally, the program has had the pilot do the flyaround, to get a little bit of extra 'stick time,' we call it, flying around the station," Altman said in a pre-flight NASA interview.

"I'll be standing at the aft (flight deck) station looking out an overhead window up at the station and watching it go away," he said. "And it's not like it's a long ways away - it's right over the top of your head as you undock for the first time.

"It's really amazing when I looked at that in the simulator and I just know it's going to be even more so when I see the real thing right there in front of me."

Astronaut Daniel Burbank will actually push the buttons that cause Atlantis to undock from the space station. Powerful springs then will push the shuttle gently away and once at a safe distance, Altman will fire small steering jets to move out to the fly-around starting point.

"We're going to go out to about 400 feet and then start this flyaround where we go all the way around the station two times," Altman said. "It's a challenge I'm really looking forward to and think will be an incredible, incredible event."

Wilcutt said the primary goal of the flyaround is to shoot high resolution photos and video of the space station and its new Zvezda command module to give ground engineers a record of the lab's current condition.

By making two complete orbits the astronauts will ensure good lighting at some point on all sides of the station.

"We'll be documenting the outside of the station with photography, and we have engineers back here that study those photographs and study whether, for instance, even the paint would be peeling on the station or any other things that look different or out of configuration," Wilcutt said.

"And we use that on the ground for future EVA (spacewalk) planning as well as more or less documenting how the station is doing in that environment."

After final separation, the astronauts will hold a crew news conference at 3:11 a.m. Monday to discuss the flight with reporters at the Johnson and Kennedy space centers. A Russian media event is planned for 3:51 a.m. The astronauts will go to bed around 10:46 a.m. and wake up at 6:46 to begin readying Atlantis for Wednesday's return to Earth.