Astronauts go on six-hour spacewalk to replace ageing batteries on International Space Station

US astronaut Shane Kimbrough left the station’s airlock at about 3.30pm UAE time on Friday to begin his second spacewalk this month. He was joined minutes later by French crew-mate Thomas Pesquet, who was making his first spacewalk.

European Space Agency astronaut Thomas Pesquet makes his first spacewalk at the International Space Station on Friday. EPA

Two astronauts floated outside the International Space Station on a six-hour spacewalk on Friday to replace ageing batteries for the laboratory’s solar power system, Nasa said.

An upgrade was needed to keep the outpost running into the next decade.

American astronaut Shane Kimbrough left the station’s airlock at about 3.30pm UAE time on Friday to begin his second spacewalk this month. He was joined minutes later by Frenchman Thomas Pesquet, who was making his first spacewalk.

The pair breezed through work on the batteries and completed several maintenance chores before returning to the station just before 9.30pm UAE time, 30 minutes earlier than planned.

“Thanks for all the help,” Kimbrough radioed to Nasa’s mission control in Houston.

The men continued work started during a spacewalk earlier this month to hook up an array of 194 kilogram lithium-ion battery packs – about the size of a small refrigerator – to the station’s solar power system. They replaced nickel-hydrogen batteries that were losing the ability to hold a charge.

The first six of the 24 new lithium-ion batteries arrived at the station aboard a Japanese automated cargo spacecraft last month. The remaining 18 new lithium-ion battery packs will be flown to the station on future Japanese resupply missions.

Nine of the old batteries will be loaded aboard the cargo ship that will depart the station this month and burn up in the atmosphere.

Three defunct batteries will be stored outside the station.

Nasa expects it will take about three years to complete the space station’s power system upgrade, which will keep it operational until at least 2024.

Before this month’s spacewalks, ground control teams used the station’s robotic arm to move the new batteries into position and remove the old ones. This robotics work cut the number of spacewalks needed for the project from six to two, Nasa said.

The solar-powered station draws power from the batteries when it flies in darkness, circling about 400 kilometres above Earth.

The space station, about the size of a five-bedroom house, is a US$100 billion (Dh367bn) research laboratory that is owned and operated by 16 countries.

* Reuters