When NASA astronauts Mike Hopkins and Victor Glover went on a spacewalk on February 1st, they wrapped up a multi-year effort to replace the aging 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 aging power storage system back in 2011. Battery production started 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 some of the batteries for installation.