That's because the lab must be successfully mounted in place on the station before NASA and its international partners can proceed with an intricately orchestrated outpost assembly scheme.

"We really need to get this done. It's a very critical operation that has to get done tomorrow," NASA lead flight director Robert Castle told SPACE.com during a news briefing Friday.

"It's probably equivalent to the Hubble Space Telescope's original deployment in terms of criticality and challenge. It's one of the more challenging and difficult things that we've done."

Considered the prime goal of NASA's 102nd shuttle flight, the effort to attach the lab to the station will come less than a day after Atlantis and its four-man, one-woman crew arrived at the international outpost.

Flying tail-first some 200 miles (320 kilometers) above Western Pacific northeast of New Guinea, the shuttle eased its way up to the station at 11:51 a.m. EST (16:41 GMT) before docking mechanisms gently kissed and then pulled the craft together in a metallic embrace.

"Atlantis, Houston: Great job, guys, on a smooth approach and docking," NASA astronaut Mario Runco told the shuttle crew from the agency's Mission Control Center in Houston. "It's nice to have Destiny closer to home there."

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Spectacular color footage beamed back from the station showed Atlantis approaching the outpost from below. Puffy white clouds hovering over the blue planet Earth served as a remarkable backdrop.

"Beautiful birdie," a Russian ground controller called up to the station crew as video played on a massive screen in the Russian Mission Control Center outside Moscow. "Very beautiful. Very beautiful views."

Also outstanding were images of the station and its glimmering gold-and-blue solar wings against the pitch black vacuum of deep space - footage relayed back from Atlantis as it closed in for a midday rendezvous at the outpost.

Circular hatches between the craft swung open about 2 p.m. EST (19:00 GMT), enabling the Atlantis astronauts to meet up with station commander Bill Shepherd and his two Russian colleagues, Yuri Gidzenko and Sergei Krikalev.

The joined crews then scrambled to haul food, water, clothing and critical equipment into the station from Atlantis - work that kept the astronauts and cosmonauts too busy to immediately beam back video of a traditional welcome ceremony.

The Atlantis crew will spend the next week carrying out three spacewalks required to attach and activate the Destiny lab, the first of six science research facilities that ultimately will be launched to the station.

The second spacewalk - which is scheduled to take place next Monday - will involve moving a shuttle docking port to the forward end of the lab, where it will serve as a parking place for visiting construction crews.

The last excursion is set for next Wednesday. Curbeam and Jones, who will perform all three spacewalks, will stow a spare communications antenna outside the outpost during that foray.

Atlantis is scheduled to depart the station Friday, Feb. 16, after a final farewell and hatch-closing ceremony now scheduled for 7:18 a.m. EST (12:18 GMT) that day.

The ship and its crew are due to land at Kennedy Space Center at 12:52 p.m. EST (17:52 GMT) Sunday, Feb. 18.