File photo: AFP

 Two female US astronauts wrapped up a spacewalk out of the International Space Station (ISS) on Monday, upgrading the battery for one channel on one pair of the station's solar arrays.

Astronauts Christina Koch and Jessica Meir finished their spacewalk at 1:33 p.m. US Eastern Time (0633 GMT), which lasted about six hours and 58 minutes, according to the US space agency NASA.

This is the third all-female spacewalk. Koch and Meir completed their first one in October last year. They conducted their second one last week, also to replace batteries.

They removed the last two nickel-hydrogen batteries from the station's backbone near the port solar array and moved them to an external platform. The batteries will be stored there until they can be disposed of in the next Japanese cargo spacecraft.

The duo also installed the sixth and final new lithium-ion battery, according to NASA. The ground controllers verified the new batteries powered up successfully to provide an improved and more efficient power capacity for station operations.

The lithium-ion batteries provide an improved power capacity for operations with a lighter mass and a smaller volume than the nickel-hydrogen batteries, according to NASA.

The International Space Station crew members have now conducted 226 spacewalks in support of the assembly and maintenance of the orbiting laboratory.

NASA astronaut Andrew Morgan and space station commander Luca Parmitano of European Space Agency will conduct the next spacewalk on Jan. 25, to finish installing the Alpha Magnetic Spectrometer's new cooling apparatus and lines and to verify they are ready for use.