The shuttle Endeavour glided back to Earth today, bringing three space station astronauts back to a starkly different post Sept. 11 world and leaving a fresh crew behind in orbit for a nearly six-month tour of duty.

Dropping like a stone through a somewhat cloudy sky, Endeavour settled to a high-speed touchdown on runway 15 at the Kennedy Space Center at 12:55:10 p.m. EST to close out a 12-day voyage spanning 186 complete orbits and 4.9 million miles.

A few moments later, commander Dominic Gorie brought the spaceplane to a stop on the runway centerline and along with it, NASA's 107th shuttle mission.

"Houston, Endeavour, wheels stopped," Gorie radioed.

"Endeavour, Houston. Nice job on the approach and landing there, Dom," replied astronaut James Kelly from mission control in Houston.

Mission duration was 11 days 19 hours 35 minutes and 42 seconds. It was the 57th shuttle landing at the Kennedy Space Center, the 44th to occur in daylight hours.

The returning space station crew - Expedition 3 commander Frank Culbertson, Vladimir Dezhurov and Mikhail Tyurin - made the trip back to Earth resting on their backs, strapped into recumbent seats on Endeavour's lower deck.

U.S. and Russian flight surgeons were standing by to help them off the shuttle as required. Russian flight surgeons forbid their cosmonauts from attempting to walk immediately after landing, but U.S. medical officers leave it up to the astronaut.

For his part, Culbertson sounded healthy and in good spirits when he called Houston about 25 minutes after touchdown.

"To everyone who helped make this mission possible and bring us home, thanks very much, we're very grateful to be home for Christmas," Culbertson radioed. "We're really grateful for all the great work everybody did."

"Frank, those are great words, we'll pass 'em on and welcome back to Earth," Kelly replied. "We're happy to have you back."

"Thanks. Looking forward to seeing everybody."

After medical exams and their first hot showers in 129 days, the returning station fliers looked forward to reunions with friends and family and a bit of food and drink not available in space.

Culbertson told flight controllers last week he was especially eager for a taste of ice cream while Tyurin said he was looking forward to "a big glass of cold beer."

"Living in space had always been a goal of mine and we had the opportunity to do it and it was a great experience," Culbertson said Sunday. "We felt like we accomplished a lot and as Mikhail has said, this may end up being one of the most significant parts of our lives.

"So it's sad when something like that comes to an end. But of course, we've got a lot of good things ahead of us and we'll be very, very happy to see all our family and friends."

Flight surgeon Stephen Hart said the crew will get a brief chance to visit with their families prior to medical exams and then "afterwards, after we finish out testing initially, they'll get back to the most important activity of sort of quietly getting some family time."

NASA plans to interview Culbertson and his crewmates later this evening and videotape will be broadcast on NASA television shortly thereafter.

All three Expedition 3 crew members will spend Tuesday at the Kennedy Space Center and fly back to Houston on Wednesday. Following U.S. protocols, Culbertson will move back into his home while he begins physical therapy to continue his re-adaptation to gravity.

Dezhurov and Tyurin, as is the Russian custom, will check into crew quarters at the Johnson Space Center where they will remain in quarantine for several days. Both men plan to fly back to Moscow later this month to ring in the new year with their families in Russia.

But first, the crew faces another eight days of intense "biomedical and research activity and, most important, rehab," Hart said. "And we'll be doing that to build up gradually the strength and flexibility and balance skills that have basically been on vacation the past four months. The first week of that period is really the steepest part of the curve, but thereafter things are really pretty much back to normal."

Maybe from a daily activity standpoint. But it typically takes returning station astronauts as much time on Earth as they spent in space to fully recover from the effects of prolonged weightlessness.

Endeavour blasted off on the year's final shuttle mission Dec. 5 and docked with the station two days later. The following day, Dec. 8, Culbertson's crew was officially replaced by Expedition 4 commander Yury Onufrienko, Daniel Bursch and Carl Walz, who plan to remain aboard the outpost for nearly six months. They will return to Earth in mid May.

In a formal change-of-command ceremony a few days later, Culbertson said "it's been a great ride. and it's now time to say goodbye."

"We feel like we've accomplished a lot, we feel our mission has been successful," he said. "However, the most important thing for everybody to remember is the journey continues, the work continues, the research continues and it will for many, many years thanks to good people here and good people on the ground. ... It's been a wonderful experience for all of us."

Next up for NASA: Launch of the shuttle Columbia at 1:43 p.m. on Feb. 14 to service the Hubble Space Telescope. Hubble Servicing Mission 3B features five back-to-back spacewalks by alternating two-man teams to install two new solar arrays, a new power control unit, a new camera and a high-tech cooling system to revive a dormant infrared camera/spectrometer.

"We're going to put on a new camera, the Advanced Camera for Surveys, which has two times the field of view and five times the sensitivity of the current Wide-Field Planetary Camera 2," said program scientist David Leckrone.

"It will be about 10 times more efficient, which means in a given amount of observing time it'll go fainter by quite a bit and also cover a broader field of view with better resolution. So it's going to be a gang busters camera, it will become the work horse camera supplanting WFPC."

After the Hubble mission, NASA plans five station assembly, resupply and crew rotation flights, beginning with mission 8A in late March to install the anchor section of what will become a huge cross truss that ultimately will support the station's four sets of solar arrays.

While NASA faces a shuttle flight reduction in 2003 and other measures to bring space station costs in line with budget projections, next year promises to be just as ambitious as the one now concluding.

"I think we've accomplished an awful lot this year," said Milt Heflin, chief of NASA's flight directors office. "Since we've had continuous human presence on board the station, which is about 13 months or so, it's been a remarkable year. ... In the past year, we've put up about 45 tons of new equipment and modules and this brings the total mass to around 184 tons. What's interesting is we're probably going to double that this next year as we begin to add more truss segments ot the station.

"Since this continuous human presence, we have flown a total of 15 visiting vehicles to the international space station. That's seven shuttle flights, five Russian Progress flights, two Soyuzes and the docking compartment. That's a remarkable amount of activity that we have handled safely, developed procedures for and managed throughout the last year."

Astronauts and cosmonauts from six nations visited the station and given the international participation in the program, "I really think we're building a zero gravity United Nations," Heflin said.

"This last year, we have accomplished on the order of 18 spacewalks to assemble and maintain the international space station," he said. "That basically doubles what we did last year. And hang on. Because this coming year, we plan to do somewhere in the neighborhood of 20 spacewalks. ... People here at the Johnson SPace Center talk about the 'wall of EVA.' Well, the wall of EVAs is getting steeper and I think the team of people here on the ground and the folks who are going to be on board have been able to get prepared for all that.

"Over the past year, I'm told we accomplished something on the order of 50,000 hours of experiment operating time, that's both including the crew-tended experiments as well as the remote telescience operations. So that's a very busy year."

Heflin said NASA accounts for less than 1 percent of the U.S. budget per year and "it's my belief that by building this international space station, this little agency is providing tangible proof of a real beacon of international cooperation. And goodness knows, we ought to take advantage of all that that we can, today."