Astronauts take spacewalk to swap space station's batteries

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 for several hours to swap 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 still have to lug 300-pound adaptors the size of a large coffee table and reconnect attachments.Even when the chore is complete, t