Astronauts take the exit in space to exchange the batteries of the space station | WBNS-10TV Columbus, Ohio

Two US astronauts make an exit into space to replace used batteries of the International Space Station.

Anne McClain and Nick Hague of NASA are expected to work in space Friday for several hours to replace three older nickel-hydrogen batteries with more powerful lithium-ion batteries.

The robotic arm of the station was already doing a lot of the work, but the astronauts still had to carry 300-pound adapters the size of a large coffee table and reconnect the props.

Even when the chore is over, there will still be more batteries from the original 20-year-old station to replace.

The exit in the space of Friday is the first of three planned excursions to replace batteries and perform other maintenance work. The release in space next week will include the first all-female crew, including McClain.