Wednesday, April 10, 2019

U.S. and Canadian Astronauts Perform Power Upgrades Spacewalk

Expedition 59 Flight Engineers Anne McClain of NASA (red stripes) and David Saint-Jacques of the Canadian Space Agency are seen while working outside the International Space Station. In a six and a half hour spacewalk, McClain and Saint-Jacques successfully established a redundant path of power to the Canadian-built robotic arm, known as Canadarm2, and installed cables to provide for more expansive wireless communications coverage outside the orbital complex, as well as for enhanced hardwired computer network capability. The duo also relocated an adapter plate from the first spacewalk in preparation for future battery upgrade operations. Credit: NASA

Expedition 59 Flight Engineers Anne McClain of NASA and David Saint-Jacques of the Canadian Space Agency concluded their spacewalk at 2 p.m. EDT on April 8. During the six-and-a-half-hour spacewalk, the two astronauts successfully established a redundant path of power to the Canadian-built robotic arm, known as Canadarm2, and installed cables to provide for more expansive wireless communications coverage outside the orbital complex, as well as for enhanced hardwired computer network capability. The duo also relocated an adapter plate from the first spacewalk in preparation for future battery upgrade operations.

Floating in the Quest airlock, NASA flight engineer Anne McClain, call sign EV-1, and Canadian astronaut David Saint-Jacques, EV-2, switched their spacesuits to battery power at 7:31 a.m. EDT, officially kicking off what turned out to be a six-hour 29-minute excursion, the 216th since station assembly began in 1998.

During the spacewalk on March 29, Hague and Koch helped with the installation of another three li-ion batteries. But during testing after the first EVA, engineers ran into problems with one of the initially installed li-ion batteries and an electronics component called a battery charge-discharge unit, or BCDU.

After attempts to correct the problems failed, NASA managers opted to remove the faulty battery and replace it with two of the recently removed nickel-hydrogen batteries. They also decided to replace the BCDU with a spare.

Using the station’s robot arm, flight controllers removed the suspect battery and the BCDU and then re-installed one of the recently removed nickel-hydrogen batteries. They also robotically replaced the failed BCDU.

With that work out of the way, McClain and Saint-Jacques removed an adapter plate that was installed during the first spacewalk to make room for the installation of a second nickel-hydrogen battery.

This was the third spacewalk in just under a month on the space station. The first two spacewalks installed powerful lithium-ion batteries for one pair of the station’s solar arrays. On March 22, the first spacewalk was completed by McClain and fellow NASA astronaut Nick Hague. On March 28, the second spacewalk was completed by Hague and NASA astronaut Christina Koch.

Saint-Jacques became the first Canadian Expedition astronaut to walk in space and the fourth Canadian astronaut to spacewalk overall.

Space station crew members have conducted 216 spacewalks in support of assembly and maintenance of the orbiting laboratory. Spacewalkers have now spent a total of 56 days 10 hours and 53 minutes working outside the station.



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