The prime job at hand: Routing power, data and video cables from the Canadian robot arm to the station's U.S. Destiny science laboratory, which will serve as the crane's initial operating base at the outpost.

A string of similar cables linking the robot arm and its pallet-like launch mount also will be disconnected so that the latter can be stowed in the shuttle's cargo bay for a return trip to Earth.

And once the chores are complete, the new crane largely will be ready for up to two decades of construction and maintenance work required to finish and then operate the growing outpost.

"We're going to be doing some rewiring work so that it can live and work here for the next 15 or more years," Parazynski said in a space-to-ground interview Monday.

The job calls for the two spacewalkers to remove a shield-like panel the size of a kitchen table from the side of the Destiny lab. Parazynski then will attempt to hook up two dozen electrical cables, about half of which are fragile fiber optic wires.

"I'll spend the next hour and a half or so doing some fairly delicate work -- surgery almost -- rewiring some very delicate fiber optics cables to enable the space station arm to live permanently at the station," Parazynski said.

The meticulous work will be followed by yet another job that's deemed key to the future of the $60 billion station construction project, which involves 100,000 people from 16 nations on four continents.

Hadfield and Parazynski plan to unbolt a box-shaped communications antenna from the exterior of the station's American-made Unity module, which serves as a pressurized passageway to all parts of the station.

The 100-pound (45-kilogram) antenna no longer is needed at the station and must be removed to clear the way for an airlock that is scheduled to be hauled up to the outpost aboard shuttle Atlantis in June.

Shaped like a giant thimble, the airlock will serve as a staging area for spacewalking work that will be carried out at the complex during five more years of construction and a subsequent decade of orbital operations.

A small laundry list of other work also is planned for the spacewalk, which is expected to last about six-and-a-half hours. The spacewalkers also will stow a spare electronics box and a video signal converter in an external storage box.

The rest of the shuttle crew, meanwhile, will spend the day either overseeing the spacewalk from Endeavour's cockpit or unloading an Italian moving van that was temporarily mounted to the outpost on Monday.

The shuttle-borne cargo carrier is filled with several tons of supplies and equipment ferried to the station for its current resident crew, which includes Russian commander Yuri Usachev and two American flight engineers, Susan Helms and Jim Voss.

The three station tenants are in the midst of a four-month tour of duty that began in March.

Made up of astronauts from the United States, Russia, Canada and Italy, Endeavour and its seven-member crew are scheduled to depart the station Saturday. Launched last Thursday, NASA's 104th shuttle flight is scheduled to be capped with a 10 a.m. EDT (14:00 GMT) April 30 landing here at Kennedy Space Center.