Two spacewalking astronauts took on cable and antenna work at the international space station in their final trek outside, but encountered last-minute difficulty with a connector and had to leave one job undone.

Lead spacewalker Danny Olivas and his partner Christer Fuglesang unreeled 60 feet of cable for a new room that will be added to the orbiting complex early next year. The pair also hooked up a couple of Global Positioning System antennas and replaced some electronic equipment in their second excursion in three days.

Everything went well until near the end of the seven-hour spacewalk, when the two had trouble hooking up one of the cable connectors to a panel on the space station. What's more, Fuglesang's helmet camera came loose and it was difficult for flight controllers to watch him work, given the wobbly, upside-down pictures.

"We thought you were doing tremendous acrobatics," Mission Control radioed.

Mission Control told Fuglesang to wrap insulation around the loose power connector and leave it like that. But then the camera and light assembly on his helmet came off entirely. Olivas removed the still-tethered assembly for him.

With darkness looming, Fuglesang was ordered back to the space station's air lock, while Olivas took over the insulating job late Saturday night (early Sunday GMT).

"Christer, no need to rush but hurry every chance you get. Sunset in about six minutes," astronaut Patrick Forrester urged from inside.

Mission Control advised Fuglesang to use his helmet light as a flashlight if necessary; he was carrying the unit. He made it back safely and speculated he may have bumped his helmet while struggling with the connector. But officials at Mission Control later said it was likely a latch problem.

The cables were routed in advance of the Tranquility live-in chamber that's supposed to be launched in February aboard shuttle Endeavour.

Flight director Heather Rarick said early Sunday that repairs to the connector would be attempted on a future mission, possibly Atlantis' flight in November. The problem could be a thermal issue or sticky mechanism, and the astronauts might have to splice into the connector or seek out an alternate path to get power, when the time comes, to Tranquility.

"We definitely have some time" to deal with it, Rarick said.

On Saturday evening, the two spacewalkers got off to a fast start, making their way out along a girder and pulling open a shelf that will be used to store big spare parts later this year. Olivas helped install the framework on the right side of the space station two years ago.

"It's like old times, huh, Danny?" Forrester asked from inside.

"You're right, Pat, this is like being at home," Olivas replied.

An identical shelf on the opposite side of the space station jammed when astronauts tried to pull it open back in March. It took a special tool and another mission to get the shelf open. Olivas and Fuglesang had the tool with them in case they ran into trouble, but the job went smoothly.

NASA loaded Saturday night's spacewalk — the third and final one of Discovery's space station visit — with all sorts of odds and ends, most of them mundane.

During the first two spacewalks, astronauts gave the orbiting complex a fresh tank of coolant.

Fuglesang, a Swede, is the only non-American on Discovery's seven-person crew. But the space station has one Belgian, one Canadian, two Russians and two Americans living on it. The combined crews make for a record-tying crowd of 13 in space.

Saturday night's spacewalk was the last major job for the shuttle astronauts before they depart Tuesday. Their 13-day flight is scheduled to end with a landing back in Florida on Thursday.