Two American astronauts are taking a spacewalk to replace aging batteries on the International Space Station
NASA's Anne McClain and Nick Hague are scheduled to work in space Friday several hours to out three old nickel-hydrogen batteries with more powerful lithium-ion batteries.
The station's robotic arm did much of the heavy work already, but the astronauts have to lug 300-pound adapters the size of a large coffee table and reconnect attachments.
Even when the chore is complete, there will still be more of the 20-year- old station's original batteries to replace.
Next week's spacewalk will include the first all-female crew, including McClain.