CAPE CANAVERAL, Fla. -- Spacewalking astronauts waltzed through six hours of construction work at the International Space Station Sunday, whistling while they wired up a new metal truss at the orbital outpost.

They chuckled. They chatted. They sang songs about Jedi Knights and mimicked "The Three Stooges." And when it was all said and done, they also had successfully set up two key communications antennas and stowed a toolbox for future outpost assembly workers.

The two spacewalkers work around the station just as the sun rises, a visible sign of their handiwork evident in the deployed boom with the antenna dish jutting out from the right side of the Z-1 truss.

"Just think, they pay us $2 a day to be up here," jovial Bill McArthur joked as the astronauts ambled around an orbital construction site some 240 miles (384 kilometers) above Earth.

"Nyuk, nyuk, nyuk -- yes they do," spacewalking partner Leroy Chiao bantered back.

"What a deal!" McArthur said.

The first of four spacewalks planned for NASAs 100th shuttle flight got off to a lighthearted start about 10:30 a.m. Eastern Daylight Time (1430 GMT) Sunday as first Chiao and then McArthur floated into Discoverys cargo bay.

"Okay, Bill, you can come on out now," Chiao, a veteran of two previous spacewalks, said.

Linked to the shuttle and looming above them was the 13-story international station, which now comprises three permanent wings and a Russian supply ship.

"Woo-hoo! This is too cool," McArthur, a rookie spacewalker, said as he drifted into open space for the first time. "Its huge."

"Its gorgeous," added Chiao. "Just wonderful."

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Enjoy your work

McArthur and Chiao clearly had fun cruising around the planet at 25 times the speed of sound, taking a moment every once in awhile to do a bit of extraterrestrial sightseeing.

Discovery astronaut Bill McArthur is at the end of the robot arm while Leroy Chiao is seen in the foreground in the early stages of the first spacewalk.

"Look at the moon up there! Is that the moon?" an awed McArthur said at one point. "The moon illumination is incredible."

The shimmering rainbow curtain of light that comes with every orbital sunrise -- or once every 45 minutes -- was just as impressive.

"You guys should see the sunrise coming -- pretty awesome," crewmate Jeff Wisoff told the spacewalkers midway through the 6-hour, 28-minute foray.

"Ah, yes indeedy!" McArthur exclaimed.

Added Chaio: "Wow, this is really cool."

Working at a steady pace all day, the spacewalking electricians first wired up a new nine-ton truss that was added to the outpost Saturday.

Now sitting atop a docking module dubbed "Unity," the aluminum truss houses four dome-shaped gyroscopes designed to reduce the amount fuel needed to keep the station properly positioned in orbit.

It also will serve as a mounting platform for a pair of giant solar arrays to be delivered to the station on NASAs next outpost construction mission, which is scheduled for launch on shuttle Endeavour Nov. 30.

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High wiring act

The wiring work called for Japanese astronaut Koichi Wakata to hoist McArthur to a point three stories above Discovery with the shuttles 50-foot (13-meter) robot arm.

Discovery astronaut Leroy Chiao works outside the International Space Station during the first spacewalk.

"Lets go for a ride," McArthur said as Wakata lifted him to a work site on the far side of the station -- a vantage point that blocked the spacewalkers view of Discovery.

"I was wondering what it was going to be like being out on the end of the arm, not being able to see the shuttle," McArthur said. "Its a strange feeling. My toes are curling right up."

The chitchat continued as Chiao and McArthur used pistol-like electric screwdrivers to remove a dish-shaped antenna from the side of the truss.

The 190-pound (85.5-kilogram) antenna -- which will be used beam television and voice communications from the station back to Earth -- then was mounted on the end of a lengthy boom and swung into place outside the outpost.

A smaller, less capable radio and data transmission antenna also was put in place, and the astronauts set out a toolbox for future spacewalking construction crews.

"It was quite an adventure," McArthur said.

"It sounded that way, Bill," astronaut Ellen Ochoa replied from NASAs Mission Control Center in Houston, Texas. "We enjoyed all your commentary."

"It entertained everybody up here as well," McArthur said.

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Plan ahead

Up next for Discoverys crew: The addition of a new shuttle docking port to the station.

Mission Discovery

Look here for the latest news from NASA's STS-92.

Plucking the cylindrical port from a shuttle cargo bay carrier with the robot arm, Wakata will carry that job out Monday with an assist from spacewalkers Wisoff and Michael Lopez-Alegria.

Chiao and McArthur will be at it again Tuesday, installing a pair of bulky electrical voltage converters on the new station truss during the missions third spacewalk.

The final spacewalk -- to be carried out by Wisoff and Lopez-Alegria -- will include test-flights of jet backpacks that outpost construction workers would use to fly back to the station if inadvertently cast adrift in orbit.

The crew also will spend a day inside the station, delivering supplies for the outposts first full-time tenants, who are due to take up residence at the station in early November.

The shuttle and its crew are to depart the station Friday and then land back at Kennedy Space Center at 2:10 p.m. EDT (1810 GMT) next Sunday.