Located on the exterior of the station's U.S. Destiny lab, the fixture will serve as an initial home base for the 57.7-foot (17.5-meter) crane, which is designed to crawl end-over-end to outpost construction sites that can't be reached with the shuttle's fixed robot arm.

"Congratulations. You've just added a new part to the station," astronaut Lisa Nowak told the joined crews from NASA's Mission Control Center in Houston, Texas.

"A lot of excited people up here," station flight engineer Susan Helms replied.

"And down here, too," Nowak said. "You guys did a great job."

The rest of the visiting shuttle crew -- which includes astronauts from the United States, Russia, Canada and Italy -- took advantage of an opportunity to make a zooming tour of the station's linked segments, which stretch 171 feet (52 meters) from end to end.

"Just flying up through the station was an incredible experience," shuttle pilot Jeff Ashby said. "I think we each took three or four laps before we went back to work."

Station flight engineer Jim Voss reported that the robot arm -- which will play a crucial role in finishing the station -- passed its initial orbital testing without problems.

"Four certified arm operators have all had a chance to use the arm, and I think that we all agree that it is an extremely fine piece of hardware," Voss told ground controllers. "It's very smooth, very precise, and it's just a joy to operate and to work with."

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An advanced version of the shuttle's Canadian-built robot arm, the so-called Space Station Remote Manipulator System is four times stronger, longer and more flexible than its predecessor.

Combined with a mobile rail cart and a smaller, more dexterous two-armed robot, the new construction crane comprises the bulk of Canada's $900 million station contribution.

What's more, the robot arm and its associated control systems must be up and operating properly before the $60 billion outpost construction project can continue with the planned launch in June of a station airlock for staging spacewalks.

And it will play a key role in adding bus-sized laboratories, electrical power towers and skeletal truss segments to the growing outpost, which ultimately will span an area nearly as large as two football fields.

The activation of the 3,600-pound (1,620-kilogram) arm will continue Tuesday as Canadian astronaut Chris Hadfield and crewmate Scott Parazynski carry out a spacewalk that's scheduled to begin at about 9 a.m. EDT (13:00 GMT).

The spacewalking duo will finish up the wiring work required to ready the crane for 15 years of anticipated operations at the station - a job they are looking forward to after an excursion outside the station on Sunday.

During that sortie, Hadfield and Parazynski did some initial wiring work with the Canadian crane, which had been folded up and firmly latched to a pallet-like shuttle cargo bay packing crate for the ride up to the station.

The two spacewalkers also unfurled the lengthy crane, locking its hinges in place as they soared some 240 miles (384 kilometers) above Earth -- an exhilarating experience that Parazynski found hard to articulate.

"I think the English language lacks the descriptive words to describe what we experienced," he said. "It's really beyond belief."

The planned six-and-a-half-hour excursion Tuesday will follow the temporary mounting of an Italian moving van to a port on the station's American Unity module, which serves as a pressurized passageway to all parts of the outpost.

Wielding the shuttle's robot arm, Parazynski hoisted the cargo carrier from Endeavour's cargo bay and attached it to the cylindrical module.

Dubbed Raffaello after 16th-century artist Raphael, the pressurized craft is filled with several tons of supplies and equipment for Voss, Helms and station commander Yuri Usachev, who are in the midst of a four-month tour of duty aboard the complex.

All the gear and goods -- which includes two hefty science research racks as well as food and clean clothes -- will be unloaded over the next several days before the Italian freighter is stowed back in Endeavour's bay for a return trip to Earth.

Endeavour's astronauts are scheduled to depart the station Saturday. The shuttle and its seven-member crew are due back at NASA's Kennedy Space Center at 10 a.m. EDT (14:00 GMT) April 30.