CBS News's Third all-female spacewalk completes job of swapping out batteries says:

NASA is in the process of replacing 48 older-generation nickel-hydrogen batteries in the station's solar power system with 24 more powerful lithium-ion units, along with circuit-completing "adapter plates" to fill in for batteries that were removed but not replaced.

During spacewalks in 2017 and 2018, astronauts replaced half the nickel-hydrogen power packs with 12 lithium ion units. During two spacewalks in October, Koch and Drew Morgan installed three of the left outboard array's six lithium-ion batteries.

Shortly thereafter, however, engineers discovered one of the three battery charge controllers in that circuit had failed, sidelining one of the new batteries. Koch and Meir then staged the first all-female spacewalk last October 18, removing the failed controller and installing a replacement.


With the battery charge controller in place, Koch and Meir pressed ahead with the battery replacement work January 15, removing four older nickel-hydrogen batteries and installing two new lithium-ion units and one adapter plate.

During Monday's spacewalk, the women removed the two remaining nickel-hydrogen batteries and installed the final lithium-ion battery needed by the station's left-side outboard set of solar arrays. A final set of six batteries will be installed in the station's far right-side set of arrays later this year.

While this is interesting to read, I can't figure out how many of the 48 nickel-hydrogen batteries are still there. So I'd like to ask the following:

Question: How many "main" batteries does the ISS have right now? How many are still nickel-hydrogen?

For background, the ISS' main batteries are discussed in question and answer posts and comments on:

  • 1
    $\begingroup$ I think the answers are here: nasaspaceflight.com/2020/01/… $\endgroup$
    – amI
    Commented Jan 21, 2020 at 7:17
  • $\begingroup$ @amI I think you may be right, there's even some helpful graphics $\endgroup$
    – uhoh
    Commented Jan 21, 2020 at 7:21

1 Answer 1


Each of the eight power channels originally shipped with six Nickel-Hydrogen Battery ORUs (Orbital Replacement Units), making 48 battery ORUs. These are gradually being replaced with Lithium Ion Battery ORUs, at a ratio of 1:2. Six channels have been completed to date, making the total number of active batteries 30 as of the date of this answer. By the end of 2020, all Nickel-Hydrogen batteries should be replaced, making the total 24.

Status: Complete. Spacewalkers Complete Multi-Year Effort to Upgrade Space Station Batteries


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