During the outing, Cassidy and Parmitano teamed to place grapple fixtures on thermal control system radiators that jut from the starboard and port sides of the station’s vaulting U.S. solar power truss. The fixtures were pre-staged to hasten efforts, if needed, to remove a failed radiator using the station’s Canadian robot arm.
Parmitano secured himself to the tip of the 58-ft.-long robot arm for the grapple bar installations. NASA astronaut Karen Nyberg maneuvered her colleague on the end of the mechanical limb from a control post inside the ISS.
The spacewalkers also started the installation of external jumper cabling on the solar power truss to permit astronauts inside the station to reconfigure the flow of solar power to control moment gyros, thermal control system hardware, Ku-band communications gear and other critical systems in response to possible external switching unit failures.
Cassidy and Parmitano replaced a failed Ku transceiver controller box and retrieved a failed external camera as well as a pair of U.S. Naval Research Laboratory materials exposure experiments. The samples of optics, electronic components and other candidate materials for spacecraft fabrication were deployed two years ago.
Parmitano applied an orbital debris shield across the docking mechanism once used by NASA’s shuttle fleet. The Pressurized Mating Adapter 2 docking port, last used in July 2011, will be configured for use by future U.S. commercial crew vehicles now in development under NASA Space Act agreements.