Astronauts Mike Hopkins and Rick Mastracchio are currently on the first of three scheduled urgent spacewalks to repair the cooling system on the International Space Station. You can watch the event live online thanks to NASA TV.
Hopkins and Mastracchio are replacing the faulty pump module in the cooling system over the course of their three scheduled extravehicular activities. During the current spacewalk, they are preparing the pump module for removal and prepping the spare pump. During the next spacewalk, scheduled for December 23, they will work to remove the faulty pump and install the spare. If necessary, they will complete the installation during a third spacewalk, scheduled for December 25th.