HOUSTON — Space shuttle Discovery docked with the international space station today, and its crew prepared to embark on the most challenging construction work ever attempted in a single mission.

With commander Pamela Melroy at the helm, Discovery snuggled up to the space station and latched on after performing a giant somersault to give engineers a close look at the ship’s belly.

The engineers were paying special attention to see whether ice that formed just before launch on the shuttle’s fuel tank plumbing hurt the ship during liftoff. Some of the ice apparently shook free and hit a door on the underside, but engineers were not sure if damage occurred.

NASA gave the go-ahead for launch, saying the ice chunk was too small to pose a serious hazard. It appeared to be melting as the countdown entered its final minutes.

The docking marked the historic meetup of the first two spacecraft simultaneously commanded by women. Space station commander Peggy Whitson is the first woman to be in charge of the orbiting lab.

NASA engineers didn’t spot anything significant in a preliminary look at images captured during yesterday’s meticulous examination of Discovery’s nose and wings, the head of the mission management team, John Shannon, said.

Officials will need even more data and analyses before they can be sure the shuttle’s thermal shielding made it through the launch damage-free.

Photos taken during Endeavour’s pre-docking backflip in August allowed engineers to spot a worrisome gouge in that ship’s belly. The shuttle landed safely after several days of debate over whether in-flight repairs were needed.

Inspections like the one yesterday became standard procedure after a piece of foam broke off Columbia’s external fuel tank during liftoff and gashed a wing, allowing hot gases to penetrate the spacecraft during its return to Earth. The shuttle disintegrated, killing all seven astronauts aboard.

About six pieces of foam broke off Discovery’s external fuel tank during launch and one or more may have hit the shuttle, but it happened late enough to be of little or no concern. Ms. Shannon said nothing appeared to come off the tank’s brackets, which were modified after Endeavour’s landing.

Later today, astronaut Daniel Tani will ceremoniously change places with Ms. Anderson, who has been living on the station since June and will return to Earth aboard Discovery. Mr. Tani will remain on board until the next shuttle flight, slated for December.

“I can’t wait to settle into my new home,” Mr. Tani said after being awoken to the song “Dancing in the Moonlight.”

The Discovery crew won’t have much time to get comfortable with an action-packed schedule that calls for a record-tying five spacewalks.

The astronauts have to install Discovery’s primary payload, a pressurized compartment that will be a docking port for European and Japanese laboratories being launched on the next three shuttle flights.

An Italian astronaut making his first spaceflight, Paolo Nespoli, is personally delivering the chamber, named Harmony by schoolchildren who took part in a national competition.

The astronauts also have to move a massive girder and set of solar wings on the station and pull out the solar wings and radiators.