A pair of Atlantis shuttle astronauts ended the mission's third spacewalk at 1:13 pm (1713 GMT) Friday after replacing large batteries outside the International Space Station (ISS), dpa reported.
Spacewalkers Michael Good and Garrett Reisman completed one of the heaviest chores of the farewell mission of the Atlantis - swapping out the old batteries that store energy collected by the station's massive solar panels. The spacewalk lasted 6 hours, 46 minutes.
Three of the six batteries were replaced in a spacewalk on Wednesday. On Friday, the astronauts swapped the remaining two batteries and installed one battery that was left in a temporary stow position from the last spacewalk.
The space walkers were helped by the space station's robotic arm in moving the 170-kilogramme batteries, which were delivered by Atlantis when it docked over the weekend.
The old batteries will be transported back to Earth when Atlantis undocks on Sunday.
In the mission's first spacewalk on Monday, astronauts started work on the battery exchange by loosening the bolts that hold the old ones in place.
After its planned landing on Wednesday, the Atlantis shuttle is to be retired after 25 years of service.
NASA's Endeavour and Discovery shuttles are scheduled to make their final journeys later this year, as the US space agency retires the ageing fleet.
Atlantis will be kept flight-ready during the final two flights in case of an emergency rescue before being decommissioned.
Atlantis astronauts replace batteries at space station
