On August 16, 2010 American astronauts Douglas Wheelock and Tracy Caldwell Dyson completed the third contingency spacewalk to install a spare ammonia pump module on the S1 Truss.
Flight Engineer Shannon Walker assisted the spacewalkers from inside the International Space Station and operated the Canadarm2. Flight Engineers Wheelock and Caldwell Dyson were outside during the third repair spacewalk for 7 hours and 20 minutes. Attachments: | 
