But amid the smiles and salutations, questions remained unanswered about a section of peeled-back thermal blanket on the shuttle. Engineers continued to review photographs of the affected area to determine whether it could pose a problem when Atlantis returns to Earth next week.
Hatches between the two spacecraft opened about 1 1/2-hours after the shuttle docked with the space station following leak checks.
"Atlantis arriving," U.S. space station resident Sunita Williams said after the traditional ringing of a bell.
Atlantis' astronauts floated into the space station's Destiny laboratory and hugged each of the station's residents, which besides Williams includes commander Fyodor Yurchikhin and cosmonaut Oleg Kotov.
After exchanging greetings and receiving a safety briefing from Yurchikhin, both crews resumed working.
Before reaching the space station, Atlantis commander Rick Sturckow told Yurchikhin that shuttle astronaut Clayton Anderson was ready to relieve Williams on the station.
"Are you sure Clay is onboard?" Yurchikhin said.
"Yes we checked before we launched from Florida," Sturckow said amid laughter.
Sturckow eased the shuttle into the space station's docking port. Latches fastened the shuttle and orbiting space lab together at 3:36 p.m. EDT. The shuttle's two-day chase of the space station ended about 210 miles above southeastern Australia.
It was the first visit this year by a shuttle to the space station. The shuttle was delivering Anderson, the newest member of the space station's crew, as well as a new segment to the orbiting outpost.
Prior to Atlantis' arrival, astronaut Danny Olivas took additional photographs from inside the shuttle of the area where the thermal blanket had peeled back. The images were sent to Mission Control for analysis.
NASA engineers are focusing their attention on a gap about 4 inches by 6 inches that was discovered after Friday's launch from Kennedy Space Center.
Engineers weren't sure whether stitching on the blanket came loose or whether the blanket, covering a pod of engines near the shuttle's tail, was hit by debris during launch.
The rest of the vehicle appeared to be in fine shape, NASA said. Sensors reported six hits on the wing during launch but engineers were not concerned about them.
Astronauts inside the space station also took photographs of the shuttle's belly when Atlantis was 600 feet below the orbiting outpost.
The pictures were taken when Sturckow maneuvered the shuttle into a 360-degree back-flip — part of an inspection technique. Engineers want to make sure there is no damage from launch like the kind that doomed Columbia in 2003.
After the hatches were opened Williams and Anderson were to trade out seatliners on the Russian emergency vehicle attached to the station. The seatliner exchange marks the official replacement of Williams by Anderson as a space station resident.
The shuttle astronauts' wake-up song Sunday, "Riding the Sky," written by two Johnson Space Center employees, was dedicated to Anderson in honor of his move to the space station.
Williams will return to Earth aboard Atlantis after more than six months in space.
NASA engineers want to study more photos of the torn blanket, including images taken by cameras attached to the solid rocket boosters that separated from Atlantis after launch.
On Saturday, astronauts took photographs of the thermal blanket and heat shield using a camera attached to the end of a robotic arm and boom.
Engineers can build models from the images and perform tests to determine whether the peeled-back blanket would be problematic when Atlantis returns to Earth.
Thermal blankets came unstitched during flights of Discovery in 2005 and 2006 with no problems, and thermal tiles were lost in the same area where the blanket is on Atlantis on two of the earliest shuttle flights.
The area does not get hotter than 1,000 degrees Fahrenheit during the shuttle's re-entry, compared with other vehicle parts, where temperatures can reach 2,900 degrees Fahrenheit.
If the blanket needs to be fixed, Atlantis' astronauts could trim it off, tuck it back into protective tiles or cover it with a plate held in place by adhesive goo during three planned spacewalks or an extra one that could be added.
After the Columbia disaster, a shuttle repair kit was included in all shuttle missions.
During the 11-day mission, Atlantis will also deliver to the station a new segment, which includes a third pair of solar arrays. The new addition was expected to be attached to the station Monday during the first spacewalk.