In this image from NASA television astronaut Barry "Butch" Wilmore, left, and Terry Virts during their second spacewalk outside the International Space Station Wednesday Feb. 25, 2015. Wednesday's spacewalk is the second in five days for Butch Wilmore and Terry Virts. In all, three spacewalks are planned in just over a week to prepare the orbiting lab for future American crew capsules. (AP Photo/NASA-TV)

(AP)—Spacewalking astronauts breezed through a lube and cable job outside the International Space Station on Wednesday.

It was the second spacewalk in five days for NASA astronauts Butch Wilmore and Terry Virts. In all, three spacewalks are planned in just over a week to prepare the orbiting lab for future American crew capsules; the final spacewalk in the series is this weekend.

Wilmore and Virts installed two more cables, for a two-day total of 364 feet. They unreeled the first eight cables Saturday.

Then Virts began the long, tedious lubrication of screws, brackets and tracks on the end of the space station's giant robot arm. The snares had gotten a bit creaky over the past year, and engineers hoped the grease would make operations smoother.

Virts used a long, slender tool to reach deep into the snares. It was messy work: The grease got on Virts' gloves and nearby equipment, and a few little gobs of oil even floated away.

"This is definitely not a precision tool, I will say that," Virts radioed.

"Nor a clean tool," Mission Control replied.

The spacewalkers managed to squeeze in a few extra tasks. They also took a moment to savor the view.

"I don't think I've seen blue that blue," said Wilmore, the space station's commander, as the complex soared 260 miles above the Caribbean.

In this image from NASA television astronaut Barry "Butch" Wilmore, upper left, and Terry Virts, center, begin their second spacewalk outside the International Space Station Wednesday Feb. 25, 2015. Wednesday's spacewalk is the second in five days for Butch Wilmore and Terry Virts. In all, three spacewalks are planned in just over a week to prepare the orbiting lab for future American crew capsules. (AP Photo/NASA-TV)

By the end of their third spacewalk scheduled for Sunday—which features more cable work—Wilmore and Virts will have routed 764 feet of power and data lines on the station's exterior. NASA considers it the most complicated cable job ever at the 16-year-old orbiting outpost.

The extensive rewiring is needed in advance of this year's arrival of a pair of docking ports, designed to accommodate commercial crew capsules still in development. NASA expects the first port to arrive in June and the second in December.

SpaceX and Boeing are designing new capsules that should start ferrying station astronauts from Cape Canaveral in 2017. Manned flights have been on hold at the cape since NASA's shuttles retired in 2011. SpaceX already is launching station cargo.

NASA has contracted out space station deliveries so it can concentrate on getting astronauts farther afield in the decades ahead, namely to Mars.

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