Astronaut Jeff Williams at work inside Zarya on Thursday. Photo: NASA

Turning out the lights and dogging the hatches, the Atlantis astronauts methodically exited the international space station early today, leaving a healthy, refurbished spacecraft behind after a near-flawless repair mission. If all goes well, Atlantis will undock from the space station at 7:07 p.m. EDT (2307 GMT) this evening, setting the stage for arrival of a new Russian command module in July.

"I can't be happier with the way the mission has gone," flight director Phil Engelauf said during a 2:30 a.m. EDT (0630 GMT) status briefing. "We're at more than 100 percent of the planned objectives accomplished, the crew is still in great spirits, everybody's doing good and everything's just been perfect so far. I couldn't be happier."

Said space station flight director Paul Hill: "It is a good night for space station. Atlantis and her crew did wonders for us. They refurbed the vehicle and they'll be leaving a pristine ISS behind. All the equipment this crew installed for us is performing beautifully."

Almost all. Two of the 10 new smoke detectors installed in the Russian Zarya module are giving false readings and have been shut down. Engineers suspect they are detecting dust or fibers kicked up by the astronauts during their repair work. The detectors will be turned back on later, after Atlantis departs and the air settles "down" a bit.

Three of Zarya's four new batteries, meanwhile, are performing normally and the fourth will be brought on line later today after it finishes a 20-hour charging cycle. For the first time in months, the Russian module is equipped with six healthy batteries, giving flight managers confidence the station will remain healthy through the end of the year and certainly through arrival of the long-delayed service module in July.

Astronaut Mary Ellen Weber floats through one of Zarya's hatches. Photo: NASA

"All of our objectives have been completed, all of our get-ahead tasks for future flights have been completed," said Sharon Castle, launch package manager. "Our projection is we will have delivered over 3,300 pounds of cargo on this flight. ... I could not be any happier. This is just a great day."

Earlier Thursday evening, the astronauts completed one of their major objectives, carrying out a third and final series of rocket firings to increase the space station's altitude using spare propellant aboard the shuttle. During the 54-minute procedure, Halsell and Horowitz fired Atlantis's steering jets 26 times to put the station in an orbit with an apogee, or high point, of 237.7 statute miles and a perigee, or low point, of 229.4 miles. When the shuttle docked with the space station early Sunday, the outpost had an apogee of 209 miles by 203 miles. As a result of three shuttle reboost maneuvers over the past three days, the station's orbit was raised an average of 27.6 miles, exactly what flight planners were hoping for.

The space station is one of the most complex - and expensive - engineering projects in history. But unlike the Apollo moon program of the 1960s, the station hasn't generated the same level of public support and enthusiasm. Mission specialist Mary Ellen Weber said in an interview today that was to be expected in a program designed to utilize space rather than explore it for the first time.

"We're entering a whole new era in space travel," she said. "It's like now, when you get on an airplane, you don't have the same twinkle in your eye that I'm sure the Wright brothers had when they took their first flight. We're now using air travel as part of our daily lives, we're having productive lives as a result of it. That's what space travel is turning into, we're now not just going up for the thrill of it, for the challenge of it, but to make use of space. And certainly when we enter that stage, people's attitudes are going to change as well."