Two astronauts have performed the third and final spacewalk, or Extra-vehicular activity (EVA), of the STS- 122 mission. Rex Walheim and Stan Love began the spacewalk at 13:07 GMT, departing the Quest airlock of the International Space Station (ISS). The EVA ended with their return to the airlock, seven hours and 25 minutes later, at 20:32 GMT.

The goals of the spacewalk were to install two experiments onto the outside of the newly delivered Columbus module of the space station, and to load a failed gyroscope onto the visiting Space Shuttle, Atlantis, for return to Earth next Wednesday. The gyroscope, CMG-3 was one of four used to control the space station's attitude. It was replaced during an EVA made by the STS-118 crew during August 2007. It has been stored outside the Space Station since then, awaiting collection.

The experiments installed on the Columbus module are a solar observatory, SOLAR, and a materials research experiment, EuTEF. Subsequent to this, the astronauts fitted handrails to the Columbus module, to assist with future EVAs. Following the successful completion of these primary tasks, the astronauts performed several other tasks, which included collecting safety tethers from previous EVAs, and inspecting micrometeroite damage on a handrail.

This is the 104th spacewalk conducted as part of the International Space Station programme.