HOUSTON - The shuttle Atlantis and its seven-astronaut crew cast off from the International Space Station (ISS) early Monday to begin the trip home after adding a new European module to the orbiting laboratory.

Atlantis undocked from the space station at 4:24 a.m. EST (0924 GMT) as the two spacecraft flew 219 miles (354 km) above eastern New Zealand.

"We just wanted to thank you again for being a great host and letting us enjoy your station for about a week," Atlantis commander Steve Frick told station commander Peggy Whitson. "We had a great time over there."

Frick and his crewmates delivered the European Space Agency's (ESA) Columbus laboratory and a new crewmember to the ISS during almost nine days docked at the station. They are also returning U.S. astronaut Dan Tani back to Earth after nearly four months stationed aboard the ISS.

"Well, thank you guys," said Whitson, who rang the station's bell to mark Atlantis' departure. "It is a great new room you have added on and we really appreciate it. Get Dan home safe and thanks."

Atlantis is due to land in Florida early Wednesday to complete its 13-day spaceflight.

Station astronaut heads home

Atlantis ferried ESA astronaut Leopold Eyharts of France to the ISS, where he replaced Tani as a member of the station's Expedition 16 crew. Tani is returning to Earth two months later than planned after delays to Atlantis' launch in December extended his mission.

"It certainly will be sad to leave," Tani said, adding that he will miss his Whitson and flight engineer Yuri Malenchenko of Russia's Federal Space Agency. "I've gotten to know Peggy and Yuri quite well."

Mission Control woke the Atlantis crew at 12:53 a.m. EST (0553 GMT) to a ukulele version of "Somewhere Over the Rainbow" bIsrael Kamakawiwo Ole. The song was chosen for Tani by his wife Jane and their two young daughters, Keiko and Lilly.

"I can't wait to get back home," Tani said after hearing the tune. "I've had such a wonderful time here, but it's time to get back to my family."

Before Atlantis pulled away from the space station, shuttle pilot Alan Poindexter flew the shuttle on a victory lap of sorts to allow his crewmates to observe their construction handiwork.

"It was a real pleasure to fly around the station," Poindexter said. "It was a beautiful sight."

Poindexter's crewmates photographed and recorded video of the space station's new look as he flew Atlantis.

"We're just looking for a complete survey," ISS flight director Bob Dempsey said Sunday, adding that the station's new Columbus lab would be likely target. "One of the main reasons we do this is to monitor the exterior of the space station over time."

Even as Atlantis departed the ISS, NASA's next space shuttle to fly made the trek out to its seaside launch pad. Riding atop its massive crawler carrier vehicle, the shuttle Endeavour ambled out to Pad 39A at the Kennedy Space Center (KSC) in Cape Canaveral, Fla., the same launch site where Atlantis lifted off on Feb. 7.

Endeavour and its STS-123 crew are slated to launch to the ISS on March 11 to deliver a new addition to the station's Canadarm2 robotic arm and the first segment of Japan's massive Kibo laboratory.

Heat shield inspection up next

Today's undocking was only the start of a busy day in space for the Atlantis crew. The shuttle flyers will conduct a second full inspection of their orbiter's heat shield covering its nose cap and wing leading edges.

Known as a late inspection, the four-hour survey will begin at 8:40 a.m. EST (1340 GMT). The now-standard chore is aimed at ensuring that Atlantis' heat shield has not suffered damage from orbital debris or micrometeorites during flight. Engineers have already cleared the shuttle of any concerns related to external fuel tank debris from launch.

NASA has kept a close watch on shuttle heat shield health since the 2003 loss of Columbia and its crew due to a wing damage sustained at launch.

Aboard the space station, the three Expedition 16 astronauts have a light couple of days ahead to rest up after the frenetic pace of last week's construction work. Eyharts is expected to spend some of that time activating science racks aboard Columbus, while Whitson has volunteered to perform extra experiments for researchers on Earth.

"It's definitely a lot quieter already," she said late Sunday.

Frick and his crew are due to land at KSC on Wednesday at 9:07 a.m. EST (1407 GMT), though NASA is activating a backup runway in California to return Atlantis as soon as possible and give the U.S. military enough time to shoot down a falling spy satellite laden with half a ton of toxic rocket fuel.

"We are still planning on landing on the 20th," Dempsey said. "The weather is looking promising at the Kennedy Space Center."

NASA is broadcasting Atlantis' STS-122 mission live on NASA TV. Click here for SPACE.com's shuttle mission coverage and NASA TV feed.