Russian spotters found the capsule on the scrub-covered steppe north of the Aral Sea after a nerve-racking, two-hour air search. The three crewmen had opened the hatch and climbed out of the spacecraft, and stood waving at the search plane.
It was the first time ever that U.S. astronauts had landed on foreign soil and in a foreign spacecraft and one of the Americans had trouble walking after what a NASA official said was steep descent.
Arriving at the airport in the Kazakh capital Astana for the ride back to Star City, the cosmonaut training center outside Moscow, U.S. astronaut Kenneth Bowersox told U.S. and Russian space officials that the crew was feeling fine.
"Just normal return to Earth," he said with a broad smile.
Though they looked pale and squinted in the bright sunlight, he and Russian cosmonaut Nikolai Budarin got out of the sedans that had carried them from the helicopter and walked to the waiting plane with sure strides. The other U.S. astronaut, Donald Pettit, looked queasy and weak and could hardly walk. Several people had to help him go from the helicopter to the plane, and then up the steps. When he made it to the top, the crowd of about 50 space officials from both countries applauded.
The crew's arrival in Astana, following the lengthy search, ended a mission already severely shaken by the Columbia catastrophe on Feb. 1, which led to the grounding of the U.S. shuttle fleet and forced a change in travel plans for the astronauts left stranded in space.
The head of the U.S. space agency NASA, Sean O'Keefe, admitted he had been nervous but he put a positive spin on the landing and lauded the Russian-U.S. cooperation that had allowed the space program to continue.
"At the time when we needed them most, Russia, our partners, have excelled," O'Keefe told reporters at Russian mission control outside Moscow. "Today's challenge further demonstrates that space exploration is a very, very risky business. Today's success story is that the international space station goes on because of their (the Russians') commitment."
Russian aerospace agency Sergei Gorbunov said a special commission will investigate the circumstances of the landing, the ITAR-Tass news agency reported.
Rather than gliding to Florida in a shuttle, the three crewmen rode in a Soyuz TMA capsule, just over two meters by two meters (two yards by two yards) in size.
Ten search helicopters carrying NASA doctors, Russian space agency and military officials and journalists set out from the Kazakh capital Astana to find the capsule. Crew members listened in to radio updates on the progress of the Soyuz's descent, and everything appeared to be going well.
But at the appointed touchdown time, o parachutes or capsule could be seen in the clear sky or on the barren steppe. In one helicopter, two Russian air force officers huddled together, each holding half of one headset to an ear. As the minutes wore on, they gestured to the others on board that nothing had been heard from the spacecraft or seen on the ground. The helicopters finally headed back to Astana leaving the spotting to other aircraft.
"Nervous. Nervous. This landing was unusual," said Talgat Musabayev, a cosmonaut who had accompanied American space tourist Dennis Tito to the space station two years ago and was in one of the helicopters that returned to Astana.
At mission control, elation over the landing turned to confusion. There were conflicting reports of where the capsule had landed and whether communications had been established. Russian space officials retreated to their offices, leaving NASA officials and journalists in the dark.
Finally, mission control announced that the capsule had landed just north of the Aral Sea. The landing site was some 460 kilometers (287 miles) southwest of the target, said NASA spokesman Rob Navias. The capsule had landed on its side and apparently been dragged about 12 meters (40 feet), probably by the main parachute.
"The mission was a complete success," said Jim Newman, an astronaut in charge of NASA's human spaceflight program in Russia who was stranded in Astana, waiting for helicopters to pick up the crew.
"Hey, they're alive."
Allard Beutel, a NASA official at mission control, said the capsule had landed on a steeper trajectory than expected, falling short of the target landing site.
A Russian ballistic researcher, Nikolai Ivanov, said such a descent would have increased the force of gravity to G-9, well above the maximum planned G-7 but still within a range the astronauts could tolerate. He also said that the so-called ballistic descent could have adversely affected the capsule's communications system, hampering the search-and-rescue efforts.
Yuri Semyonov, director of RKK Energiya, the company that builds Russian spacecraft, said human error could not be excluded: Someone could have pulled one lever when they intended to reach for another. It was the first time the new Soyuz model had gone through a descent.
"We very often get used to the fact that everything will work as normal," said Russian space agency chief Yuri Koptev. "But space is a new horizon."
"The most important thing is 'a happy end,' he told reporters at mission control, switching to English.
The three crewmen spent 5 1/2 months aboard the space station two months longer than planned because after the Columbia accident extra time was needed to bring their replacements aboard another Soyuz.
Astronaut Edward Lu and cosmonaut Yuri Malenchenko checked in last week for a six-month stay that promises to be a challenge, given the reduction in crew size to conserve supplies until shuttle flights resume.
Handing over command to Malenchenko before floating into he Soyuz for the flight home, Bowersox told the new crewmen, "You guys have to be the two luckiest guys who come from planet Earth today. Over the next six months you get to live aboard this beautiful ship."
"Yuri, I'm ready to be relieved," he added.
EDITOR'S NOTE Associated Press writer Mara D. Bellaby contributed to this report from mission control outside Moscow.