The two craft linked up 220 miles above Australia.
"Welcome to the space station, Discovery, we're glad you're here," said Mike Fincke, the station's skipper.
Before pulling up, commander Lee Archambault guided Discovery through a 360-degree back flip so the station astronauts could photograph its belly. Fincke said even though the station residents didn't hear the go-ahead to take pictures because of communication system trouble, they got some good shots and the shuttle looked "clean, very nice."
The digital pictures — more than 200 of them — were immediately transmitted to Earth. Experts will scrutinize the images for any signs of launch damage, standard procedure following the 2003 Columbia disaster. A chunk of fuel-tank foam insulation smacked Columbia's wing at liftoff, dooming the shuttle and its crew during re-entry two weeks later.
Fincke and his two station crewmates were thrilled to finally get some company. Discovery and its crew of seven were supposed to show up last month, but launch delays kept the shuttle grounded until Sunday. The postponements resulted in a shortened visit.
Loaded aboard Discovery are two solar wings that will be installed at the space station later this week. The electricity-producing panels will join six others already in place — four on one side and two on the other — and finally make the outpost look balanced and like the artist renderings.
"It's huge, isn't it?" space station resident Sandra Magnus radioed to the shuttle astronauts as they were 30,000 feet away. "But asymmetric," said one of Discovery's crew. "But not for long," Magnus replied.
The 115-foot solar wings are folded on a framework that also holds a radiator. Altogether, the $300 million segment is the last major American-made space station piece needed.
Discovery also is dropping off badly needed equipment for the space station's new water-recycling system — a spare urine processor and iodine flush to kill bacteria. NASA would like to have the system working before the crew at the orbiting outpost jumps from three to six at the end of May.
The system is designed to convert astronauts' urine and condensation into drinking water. It arrived in November.
The space station also is getting a new crew member, Koichi Wakata, who will become the first Japanese to live there. When the hatches between the spacecraft are opened, he will trade places with Magnus, who has been on board since the last shuttle visit in November.
Discovery will spend eight days at the space station, and its crew will perform three spacewalks. That's two days and one spacewalk less than originally planned. Discovery needs to be gone by the middle of next week so a Russian spacecraft can bring two fresh station crew members. That launch is set for March 26.