On Sunday, ahead of their historic joint spacewalk, Koch will complete another battery replacement spacewalk.
In an interview from the station earlier in the week, Koch and Meir said they were aware it would be possible for the two of them to be assigned to the same spacewalk, although no formal decisions had been made at that time.
The upcoming spacewalks will help replace solar array batteries and upgrade them to lithium-ion batteries, as well as refurbish the Alpha Magnetic Spectrometer, a scientific instrument "that explores the fundamental nature of the universe", according to NASA.
Finally, Koch and Morgan moved another of the new lithium-ion batteries from the pallet to the truss, where they installed it in the empty slot vacated by the second nickel-hydrogen unit.
Astronauts Christina Koch and Andrew Morgan have just returned to the ISS after changing over a pair of old batteries. These new batteries are so powerful that only one is needed for every two old ones.
Astronauts Christina Koch and Jessica Meir are set to do the first-ever all-female spacewalk on October 21. The two additionally repositioned battery moving apparatuses and relaxed the torque on jolts verifying two nickel-hydrogen batteries in anticipation of the following spacewalk. "Instead of the large, she would need a medium-sized hard upper torso - what NASA calls 'the shirt of the spacesuit'".
The first five scheduled spacewalks will upgrade the space station's power systems and the last five, planned for November and December, will fix the alpha magnetic spectrometer, which analyses cosmic ray events.
(Koch also is a member of the 21st class of astronauts.) Before that, Meir was rejected for NASA's 20th class of astronauts.
Koch is two-thirds of the way through a mission of more than 300 days.
"You have the battery", affirmed Morgan.
Sunday's EVA was both Koch's and Morgan's second spacewalks.
ME astronaut Jessica Meir is scheduled to take part in the first all-female spacewalk later this month.
The space station is fueled by eight huge sun oriented cluster wings, four on each side of the bracket.
Koch, who served as EV1 (or lead spacewalker) and wore the Extravehicular Mobility Unit (EMU) spacesuit with red stripes now has now logged a total of 13 hours and 46 minutes on her two spacewalks.
This was the 219th spacewalk given to the International Space Station since get together of the station started in 1998. Astronauts and cosmonauts have now spent 1,374 hours and 27 minutes, or 57.3 days, working outside the orbiting complex.