Spacewalk 2 for NASA's 1-Yr Spaceman

CAPE CANAVERAL, Fla. (AP) -- NASA's one-year spaceman, Scott Kelly, ventured back outside the International Space Station on Friday morning for some radiator work.

It was the second spacewalk in 1 1/2 weeks for Kelly, who's more than halfway through a U.S. record-setting yearlong flight, and fellow American astronaut Kjell Lindgren. They got started an hour early, eager to make the home improvements.

"Going off grid for spacewalk," Kelly said via Twitter before heading out. "I'll be back w you again soon!"

Friday's excursion involved work on the space station's cooling system. The spacewalkers needed to undo jury-rigged repairs made to a leaky cooling line three years ago. The ammonia leak subsequently was fixed another way --- by replacing a failed pump --- so NASA wanted the system back in its original setup.

Kelly and Lindgren kept a close lookout for any ammonia flakes that might escape and contaminate their suits.

Their Oct. 28 spacewalk featured a robot-arm lube job and other mundane maintenance.

Kelly has been at the 250-mile-high outpost since March, and isn't due back until next March. Friday marked his 224th day in orbit, already a U.S. record. His companion for the long haul is Russian Mikhail Kornienko.

Four other astronauts are on board for the typical six months: Lindgren along with a Japanese and two other Russians.

This was the 190th spacewalk in the station's 17-year history. Astronauts have been on board, continuously, for 15 years.