H-II Transfer Vehicle KOUNOTORI (HTV)

The International Space Station is refreshed with Japanese lithium-ion batteries cells transported by H-II Transfer Vehicles "KOUNOTORI" (HTV)

Batteries and cables being replaced during an extravehicular activity (Credit: NASA)

NASA astronauts Christopher J. Cassidy and Robert Behnken replaced the batteries on the S6 truss during their 6 hours of Extravehicular Activity (EVA) on July 17, 2020. This EVA was the eleventh and final work of the battery replacement mission started in January 2017. The 48 nickel-hydrogen batteries have been replaced with 24 new batteries based on Japanese lithium-ion batteries cells. The International Space Station (ISS), refreshed with the Japanese technologies such as "KOUNOTORI" and Japanese lithium-ion batteries cells, is getting ready for supporting further experiments under the space environment.

These new battery cells were transported by "KOUNOTORI". The old batteries of ISS had to be replaced since ISS operations were extended until 2024. Utilizing its maximum payload capacity compared with other space cargos, each of the 4 "KOUNOTORI" (HTV6 to HTV9) transported 6 batteries, taking three and a half years in total to complete the entire battery replacement mission.

*All times are Japan Standard Time (JST. UTC + 9 hours)