Oct. 7 (UPI) -- October is spacewalk month for astronauts aboard the space station. By the end of the month, crew members will have completed a total of five spacewalks. Most of their time outside will be spent making upgrades to the space station's power system.
The first of the five trips occurred over the weekend. Expedition 61 flight engineers Christina Koch and Andrew Morgan spent more than seven hours outside the International Space Station on Sunday.
"The two NASA astronauts began the replacement of nickel-hydrogen batteries with newer, more powerful lithium-ion batteries on the far end of the station's port truss," according to a NASA news release.
The new lithium-ion batteries are lighter and more energy efficient than than the old nickel-hydrogen batteries. Over the last several spacewalks, astronauts have worked to remove the old batteries and install the new ones.
Morgan and Koch will continue their battery swap work later this week, on Oct. 11. The spacewalk will be broadcast live on NASA TV.
Additional spacewalks are scheduled for Oct. 16, 21 and 25.
Astronauts conducted a similar battery swap in 2017. As more new batteries arrive and are installed, the old batteries will get shipped back to Earth for proper disposal.
Earlier this year, astronauts prepared the truss for the several new batteries, the installation of which is expected to be completed by the end of the month. Sunday's spacewalk was the first of five scheduled for October.