NASA astronauts Greg Chamitoff (right) and Mike Fincke perform the fourth spacewalk of STS-134. It is also the final spacewalk of the Space Shuttle era. During this historic milestone, Canadarm2 manoeuvred the Inspection Boom to Chamitoff and Fincke who then tethered it to the Station. They also added a power and data grapple fixture to make the boom compatible with Canadarm2. May 27, 2011. Credit: NASA