When NASA astronauts Mike Hopkins and Victor Glover took a spacewalk on Feb. 1, they embarked on a multi-year effort to replace the obsolete nickel-hydrogen batteries on the ISS with new lithium-ion models. The International Space Station Program approved the development of lithium-ion batteries to replace the station’s obsolete energy storage system in 2011. Battery production began in 2014 and the first lithium-ion replacements flew to the station aboard JAXA’s Kounotori 6 resupply flight in December 2016 Now, four years after that flight and 14 spacewalks with 13 different astronauts later, the upgrade is finally complete.
Ground controllers used the Canadarm2 robotic arm to position a number of batteries for installation. However, some required extra spacewalks for the locations the arm could not reach. The batteries are not quite like the lithium ion we are used to, with their lithium ion cells for space and a radiation barrier. Because lithium-ion technology has a higher energy density than nickel hydrogen, only 24 new batteries were needed to replace the 48 old ones.