Preparing the Columbus module for installation on Harmony. Originallly it was planned that Walheim and Schlegel had to do this EVA, but Schlegel became ill (propably he suffered on the space adaption syndrome), so Love had to do the first EVA. They installed the Power Data Grapple Fixture on Columbus, which allowed the space station’s robotic arm to grab the module and move it from the shuttle’s payload bay to Harmony at the end of this spacewalk. Preparing work to remove the Nitrogen Tank Assembly, a part of the station’s thermal control system, from the P1 truss. The tasks took more time than planned. At time they were one full hour behind the timeline.

Installing two payloads on Columbus' exterior: SOLAR, an observatory to monitor the sun; and the European Technology Exposure Facility (EuTEF) that will carry eight different experiments requiring exposure to the space environment. Moving a failed control moment gyroscope from its storage location on the station to the shuttle's payload bay for return to Earth.