CAPE CANAVERAL, Fla. — Space shuttle Discovery performed a slow back flip and then docked at the international space station yesterday, delivering a mammoth lab and two new occupants: a NASA astronaut and Buzz Lightyear.

Back at the launch site, meanwhile, NASA hurriedly set up an investigation to figure out why the launch pad suffered its worst damage in 27 years of space shuttle flight. Bricks and mortar flew off the pad during Discovery’s liftoff Saturday.

Discovery was not struck by any of the debris — engineers pored over the launch pictures to be sure of that, the chairman of the mission management team, LeRoy Cain, said. When asked by a reporter if NASA got lucky in that regard, he said: “I don’t like to think in terms of luck.”

Commander Mark Kelly pulled up to the space station and parked as the two spacecraft soared 210 miles above the South Pacific.

Discovery carried Japan’s prized Kibo lab, a 37-foot-long, 16-ton scientific workshop. The seven shuttle astronauts and three station residents will combine forces to install the bus-size lab today.

The shuttle crew also brought a spare toilet pump for the orbiting outpost. The space station’s Russian-built toilet broke nearly two weeks ago — forcing the crew to perform manual flushes with extra water several times a day — and engineers hope the new pump will take care of the problem.

Astronaut Gregory Chamitoff got his first look at what will be his home for the next six months. He is replacing Garrett Reisman, who has been living at the station since March.

“Garrett, you have a beautiful house,” Mr. Chamitoff said. “Oh my God, it’s so beautiful.”

The two men hugged once the hatches between them swung open. It was a group embrace, actually, with the space station’s two Russian residents joining in as well.

Also moving in for a half-year is a 12-inch action figure familiar to children almost everywhere: Buzz Lightyear, the character from the 1995 film “Toy Story” that’s always yearning to blast off “to infinity and beyond.” Disney sent up the toy as part of NASA’s toys-in-space educational program.

Right before linking up with the space station, Kelly guided Discovery through a 360-degree somersault from 600 feet out, allowing Mr. Reisman and one of the space station’s Russian residents to take zoom-in photos of the shuttle’s belly. The back flip became standard procedure for shuttle flights following the 2003 Columbia tragedy; Columbia was brought down by a hole in the wing, left there by flyaway fuel-tank foam.