CAPE CANAVERAL, Fla. — Spacewalking astronauts successfully completed a three-day cable job outside the International Space Station on Sunday, routing several hundred feet of power and data lines for new crew capsules commissioned by NASA.

It was the third spacewalk in just over a week for Americans Terry Virts and Butch Wilmore, and the quickest succession of spacewalks since NASA’s former shuttle days.

The advance work was needed for the manned spacecraft under development by Boeing and SpaceX.

A pair of docking ports will fly up later this year, followed by the capsules themselves, with astronauts aboard, in 2017.

Sunday’s 260-mile-high action unfolded 50 years to the month after the world’s first spacewalk.

Soviet Alexei Leonov floated out into the vacuum of space on March 18, 1965, beating America’s first spacewalker, Gemini 4’s Edward White II, by just 2 1/2 months. Leonov is now 80; White died in the Apollo 1 fire on the launch pad in 1967.