Preparing Pirs for the arrival of a new Russian module called the Mini-Research Module 2, or MRM2

The EVA crew replaced a hatch with a docking point.
Taking place entirely inside the Zvezda Service Module, with the spacewalkers' suits still attached to umbilicals, it has been called an "internal" spacewalk, but is nonetheless considered a spacewalk because Michael Barratt and Gennadi Padalka worked in a depressurized space.

NASA says today's spacewalk lasted due to a water leak only 31 minutes; that's the time between the switch to battery power and the moment the crew reconnected to station power.