It was a graceful ending to a strange flight, reports CBS News correspondent Bob Orr. First there was trouble getting off the ground — Launch was delayed four times, twice by weather and twice by technical glitches — and then more trouble coming home. Several objects seen floating near the orbiter after it left the space station.
For NASA, the station was a first step in resuming the construction of the space station which was stopped more than three years ago by the loss of Columbia. Now, Atlantis clears the way for a rapid-fire series of flights.
"This had to go by clockwork so all the others could proceed," says Orr. "NASA is under the gun to finish the space station by 2010. Now they are on track."
"Nice to be back. It was a great team effort. Assembly is off to a good start," said commander Brent Jett immediately after touchdown at Kennedy Space Center at 6:21 a.m. EDT.
From 220 miles above Earth, astronaut Jeff Williams watched from the space station, where Atlantis had departed on Sunday.
"Spectacular lightning flashes just below the orbiter," Williams said as the space shuttle slowed from traveling at 17,000 miles an hour and entered Earth's atmosphere about an hour before landing. "The glow of the orbiter itself is getting dimmer but the contrail is still pretty bright."
The landing 48 minutes before sunrise was a day later than planned because NASA ordered up more inspections of the spacecraft's delicate skin to make sure it was safe to come home. The fear was that a mysterious piece of debris spotted floating nearby on Tuesday might have hit the spacecraft. Astronauts later saw other debris.
"We've seen a new standard in NASA vigilance," said shuttle program manager Wayne Hale.
After numerous cameras took pictures above and below, some of them maneuvered robotically by the shuttle astronauts, NASA proclaimed the spacecraft damage-free.
The unplanned drama threatened to overshadow what had been a nearly flawless mission filled with strenuous spacewalks and rigorous robotics work that placed the international space station back on a path to completion after a 3½-year hiatus.
NASA officials said their best guess was that the most worrisome object was a plastic filler placed in between thermal tiles which protect the shuttle from blasting heat. Four other pieces of debris, including a possible garbage bag, floated near the shuttle over the next day.
"We were not very concerned," Jett said several hours after landing. "We just assumed whatever objects came out had come from the payload bay. What we were trying to do is make the folks on the ground comfortable."
In a news conference, NASA administrator Michael Griffin downplayed the litter in space problem, saying debris coming out of the shuttle cargo bay happens because people are not perfect. He and launch director Mike Leinbach said Atlantis came back as clean, if not cleaner, than Discovery did in its previous two landings.
Atlantis' return avoided a near traffic jam at the space station, as a Russian Soyuz spacecraft arrived at the space station less than two days after Atlantis had departed.
Of 114 successful landings, it was the 21st in darkness. Not once has the shuttle had to use the entire three-mile runway at KSC, reports CBS News correspondent Peter King.
The Atlantis mission was the first of 15 tightly scheduled flights needed to finish constructing the half-built space lab by 2010.