CAPE CANAVERAL, Fla. — Astronauts took their second spacewalk in two weeks Thursday, taking care of some long overdue radiator work outside the International Space Station.
Commander Jeffrey Williams used a power drill-type tool to fold up a 44-foot-long thermal radiator that's no longer in use. Spacewoman Kate Rubins floated nearby, making sure Williams was clear of the panel as it slowly retracted, accordion style.
With the radiator closed all the way, they cinched it down in four spots for safekeeping. NASA wants to preserve the radiator as a spare. Outstretched, it was at greater risk of getting hit with space junk.
The radiator was extended in 2012 to help stop a coolant leak. But the leak ended up being elsewhere. Another team of astronauts attempted the radiator retraction late last year, but couldn't complete the job, so it fell into Williams and Rubins' gloved hands. The radiator is part of the 250-mile-high lab's heat-dispelling system.
The two U.S. astronauts installed a new docking port during a spacewalk Aug. 19.
Williams returns to Earth next week. He already holds the NASA record for most accumulated time in orbit; his tally will reach 534 days over four missions by the time he's back on Earth.
Just over an hour into the spacewalk, meanwhile, a massive explosion rocked the SpaceX launch site at Cape Canaveral, Florida. SpaceX said it was conducting a test firing of its unmanned Falcon rocket on the pad before Saturday's planned launch of an Israeli satellite.
Mission Control said it did not tell the two astronauts about the explosion while they were on the spacewalk.
SpaceX is one of two companies supplying the space station for NASA. It's also working on a crew capsule to ferry station U.S. astronauts; that first flight was supposed to come as early as next year.