Shuttle Discovery pays last visit to space station

Space shuttle Discovery arrived at the International Space Station on Saturday on its final mission before the United States retires its three-ship shuttle fleet later this year.
Carrying 10 tons of cargo and a crew of six to help get the orbital outpost ready for a future without shuttle support, Discovery blasted off Thursday on an 11-day mission that marks its 39th and last flight.
Sister ships Endeavour and Atlantis are scheduled for their final voyages within six months.
Before pulling into the shuttle's parking spot at 2:14 p.m. EST, commander Steven Lindsey back-flipped the ship so the station crew, headed by NASA astronaut Scott Kelly, could photograph Discovery's heat shield.
NASA analyzes the images to check for damage from debris impacts during launch, a routine inspection since shuttle flights resumed after the 2003 Columbia accident.
The U.S. space agency expects no issues with Discovery, the oldest surviving shuttle, despite evidence that four large pieces of foam popped off the ship's disposable fuel tank about halfway through Thursday's 8-1/2-minute ride to orbit.
At that point, there is not enough force for flyaway foam to damage the shuttle on impact, unlike the chunk that fell off Columbia 82 seconds after launch, while the atmosphere was still thick.
Originally, Kelly expected to meet his identical twin brother, astronaut Mark Kelly, in orbit. But technical delays launching Discovery on its final voyage bumped back Endeavour's mission -- which Mark Kelly is commanding -- to April. Mark Kelly is the husband of Gabrielle Giffords, the Arizona congresswoman who was critically wounded in an assassination attempt last month.
ORBITAL PHOTO SHOOT
Discovery's launch delay also cost the crew its lead spacewalker, Tim Kopra, who was sidelined last month after a bicycle crash. NASA tapped Stephen Bowen to replace Kopra. He and spacewalker Alvin Drew are scheduled for two outings to work on the station during Discovery's week-long stay.
The Discovery crew, which also includes pilot Eric Boe and astronauts Michael Barratt and Nicole Stott, is delivering a new storage and research module, an external stowage platform, a spare radiator and a prototype humanoid robot named Robonaut 2, or R2, built in partnership with General Motors Co.
NASA expects to decide Tuesday whether to extend the mission one day for an unprecedented photo shoot. With Discovery's arrival, six spaceships -- the shuttle, three cargo ships from Russia, Japan and Europe, and two Russian Soyuz capsules -- are parked at the international outpost, a $100 billion project of 16 nations.
If approved, Kelly and two cosmonauts would board one of the Soyuz capsules for a 75-minute ride to photograph the station as it nears completion after 12 years of construction 220 miles above Earth.
After landing and post-flight cleanups, Discovery, which first flew in 1984, will be prepared for its new life as a museum piece.