U. S. and Italian spacewalkers sailed through a list of upgrade activities outside the International Space Station on Tuesday, including a solar power cable extension that will flow electricity to Russia’s Nauka Multipurpose Laboratory Module following the compartment’s launch later this year.
Italian astronaut Luca Parmitano rides end of the International Space Station's Canadian robot arm during Tuesday's space walk. Photo Credit/NASA TV
The 22 ton Nauka MLM will mark the first major addition to the station since 2011, when U. S. segment assembly of the space station came to an end.
Spacewalking cosmonauts will complete the power cable extension to a Russian segment berthing port for Nauka later this year.
Tuesday’s near seven hour spacewalk marked the first for an Italian, Luca Parmitano, a European Space Agency astronaut, and the fifth for Chris Cassidy, of NASA. They will team for a second spacewalk on July 16 to continue their work.
The two men installed grapple bars on radiators extending from the right and left sides of the station’s long U. S. solar power truss.
The grapple fixtures would permit the use of the station’s 58-foot-long Canadian robot arm to accelerate the replacement of a failed thermal control system radiator. Adequate cooling is critical to the distribution of solar power throughout the station, including life support equipment and science experiments.
Cassidy and Parmitano began the installation of jumper cables on the power truss that would permit astronauts inside the station to re-route electricity in response to possible external switching unit failures. That could prevent prolonged loss of power to space station guidance, communications and thermal control hardware.
Another power and data cable extension, a task handled by Cassidy, would permit Canada’s robot arm to be anchored on the station’s Russian segment, where the mechanical limb could serve as a cherry picker style platform for spacewalking cosmonauts and astronauts.
Parmitano collected a pair of external science experiments and a failed video camera that will be returned to Earth, repaired and re-launched. Cassidy replaced a controller box for a transceiver, part of the Ku video communications link between the station and the Earth.
Parmitano covered the station’s former space shuttle docking port with a cover to prevent damage from orbital debris. The port will likely be reconfigured for use by U. S. commercial crew vehicles now in development under NASA space act agreements.