Discovery docks with space station

SPACE CENTER, Houston -- Discovery docked at the international space station Thursday after performing an unprecedented back flip to allow those aboard the outpost to photograph the shuttle's belly for signs of damage.

The digital camera images will be analyzed by NASA to spot any signs of trouble. It wasn't immediately clear how long that analysis will take.

Discovery was just 600 feet beneath the station when Commander Eileen Collins manually steered the shuttle's nose up and slowly flipped the spacecraft over.

Collins then repositioned the shuttle and locked onto the station just after 7 a.m.

About two hours later, following leak and pressure checks, Discovery's astronauts entered the orbital lab, where they were greeted with hugs and bread and salt -- a Russian tradition thought to bring good luck when visiting another's home.

The station's crew then took Discovery's astronauts on a tour.

"We're looking forward to seeing you guys," Collins told station Commander Sergei Krikalev when the shuttle was a little more than 5,000 feet from the station. "Your space station looks ab-solutely beautiful from the outside."

The astronauts' greetings in-side the lab weren't picked up by microphones.

Flight director Paul Hill said the docking was "picture perfect."

Discovery was the first shuttle to return to orbit in the 2 1/2 years since Columbia broke apart over Texas as it returned to Earth on Feb. 1, 2003. All seven astronauts aboard died.

The space agency believed it had solved problems associated with the foam on the external fuel tank, but learned Wednesday that it was wrong. The foam prevents the formation of ice on the fuel tank.

"We have got to go take a look at this, and we have got to go find a solution to this problem. And we will," shuttle program manager Bill Parsons said.

It was the first time a shuttle hitched to the station in almost three years. A crew last visited the outpost in November 2002.

Flight director Paul Hill said the docking was "picture perfect."

"It even looked easy to us in Mission Control," Hill said. "Everything was just right on the rails, right out of a textbook."

Discovery arrived loaded with 15 tons of much-needed supplies, including a replacement gyroscope for one that failed in March. Gyroscopes help steer the station. The shuttle crew planned to leave with 13 tons of trash stowed aboard the station since shuttles were grounded.

Krikalev, a Russian cosmonaut, and astronaut John Phillips used two digital cameras -- one with a 400 millimeter lens and another with an 800 millimeter lens -- to snap 100 seconds worth of photos of the shuttle as it flipped backward, exposing its thermal tile belly. The photographs were expected to provide resolution similar to a person standing within a few inches of the shuttle's tiles.

The digital photos, downloaded after docking, are what NASA officials said they're most interested in. A team of special analysts at NASA's Johnson Space Center in Houston plan to examine them for any indications of damage.

In addition to the chunk of foam that broke from Discovery's external fuel tank during launch, several smaller pieces broke away as well. A thermal tile on Discovery's belly was also damaged soon after liftoff.

One tile near the doors for Discovery's landing gear -- a particularly vulnerable spot -- lost a 1 1/2-inch piece that was repaired before the flight.

Deputy shuttle program manager Wayne Hale said none of the tile damage looked serious and likely wouldn't require the use of untested repair techniques in orbit designed after Columbia.

"We don't really have a mechanism for knowing why a part of that tile came off," Hale said.

A planned inspection of Discovery's wings and nose using a new 50-foot, laser-tipped extension to the shuttle's robotic arm turned up nothing alarming, he said.

However, analysis will continue for the next four to five days.

Hale and Parsons said despite attention to the agency's decision to ground future missions, NASA's focus remains on Discovery's mission and bringing its crew home at the end of its 12-day mission.

"We have had some extremely great successes within this mission," Parsons said.