"It's an amazing view up here," the Australian-born Thomas, a native of Adelaide, said as the station and shuttle Discovery flew in tandem in low Earth orbit.

"I'm passing over South Australia, and I can see the coastline [and] my hometown all very clearly," he added. "Quite extraordinary."

Richards was just as impressed during a high-flying pass over a landmass covered with snowcapped mountaintops and meandering blue rivers.

"Where are we flying over now?" the first-time shuttle flier asked veteran astronaut Susan Helms, who was directing the spacewalking work from within Discovery's crew cabin.

"We're over Europe," Helms said.

"From this vantage point, any view is beautiful," Richards replied. "Everything that everybody said about being out [on a spacewalk] and looking down is true."

Added Helms, who performed her first career spacewalk Sunday: "I can relate, Paul."

Tallied up, the spacewalkers saw four colorful orbital sunrises and sunsets as they carried out a hodge-podge of jobs outside the station. The most important: electrical work left undone Sunday after a comparatively difficult excursion during which Helms and astronaut Jim Voss set a new record for the longest spacewalk in U.S. history.

During that 8-hour, 56-minute sortie, a metal tray laced with electrical wiring harnesses was attached to the underside of the station's $1.4 billion U.S. Destiny laboratory. But Helms and Voss ran out of time before they could connect the cables.

Richards and Thomas breezed through the deferred work, and that was good news for NASA and its project partners: The cable connections are key to operating the station's 57-foot (17-meter) robot arm, which is to be delivered to the outpost in mid-April.

Said NASA lead space station flight director Rick LaBrode: "Until you mate those connections, you have no power or command and control of the arm."

No further construction work can be done until the Canadian crane is set up outside the station and then activated by Helms, Voss and incoming outpost commander Yuri Usachev.

The sophisticated crane will be able to inch-worm from work site to work site outside the growing outpost, crawling to places the shuttle's fixed robot arm cannot reach.

That capability will be vital as NASA and its 15 global partners add new labs, solar power wings and support trusses to the outpost, which eventually will span an area nearly as large as two football fields.

The wiring work came on the heels of some successful outfitting chores outside the bus-sized Destiny lab, which was delivered to the station by a visiting shuttle crew last month.

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Working some five stories above shuttle Discovery's cargo bay, Richards and Thomas mounted a stowage platform on the lab's cylindrical hull.

That job called for Richards first to unfasten the pallet from a shuttle cargo bay carrier with a pistol-grip power tool he invented 10 years ago when working as an engineer at NASA's Goddard Space Flight Center in Greenbelt, Md.

"Paul, if you need any help with how to work that tool, just let us know," shuttle pilot Jim Kelly said from Discovery's flight deck.

The joke evoked laughs from both Richards and Thomas.

"Well, I designed it hoping to use it some day, and today is the day," Richards said.

Added Helms: "This is a momentous moment."

The rail-like platform was designed to hold spare parts, and it was quickly put to use.

Thomas stored a 250-pound (112.5-kilogram) cooling system pump on the pallet before moving on to the wiring work, which took place near the lab's Earth-facing window on the world.

Peering into the 20-inch (51-centimeter) lab porthole, Thomas asked: "Is anybody home?"

"I have a feeling someone is there," said Helms.

She was right. Usachev, Voss and outgoing outpost skipper Bill Shepherd were busy hauling equipment into the lab from an Italian-built moving van that was mounted to the complex Monday.

The Leonardo cargo carrier ferried up five tons of supplies and equipment that Voss, Helms and Usachev will need during a four-month station tour.

Power converters, space-to-ground communications gear and computerized robot arm work stations were unloaded from the module Monday and early Tuesday, kicking off five days of so-called transfer operations.

The spacewalkers, meanwhile, scaled to the top of the 171-foot (52-meter) station stack, which now includes the Destiny lab, a pressurized U.S. passageway, Russian crew quarters, a Russian space tug and a Soyuz lifeboat.

From that perch, Thomas was able to fix a metal latching bar that failed to snap firmly into place when a U.S. electric power tower was erected at the station last December. The repair job turned out to be relatively easy. Thomas simply tapped the bar into a fully extended position with a standard spacewalking tool.

"You got it, Andy. Good job," Richards said.

"That is absolutely outstanding," fellow astronaut Shannon Lucid told the pair from NASA's Mission Control Center in Houston, Texas.

Floating nine stories above the shuttle at that point, Thomas and Richards also inspected a balky device designed to measure the electrical environment near the station's giant U.S. solar wings, which stretch some 240 feet (73 meters) from tip to tip.

In doing so, they noted that light emitting diodes that were supposed to be blinking were not on at all -- an indication that the device, which has been operating intermittently, apparently is not getting a steady stream of electrical power.

NASA engineers will mull over that problem in the coming weeks to determine whether troubleshooting work can be done on a future spacewalk.

Thomas and Richards, meanwhile, both were exhilarated by the spacewalking experience. For six hours and 21 minutes, both were flying higher than any other human being.

"Well, Andy, we were on top of the world there," Richards said.

Added Thomas: "We were for awhile, yeah."