posted 07-16-2020 07:59 AM               

ISS Expedition 63: U.S. Spacewalk 67

NASA astronauts Bob Behnken and Chris Cassidy began the first of two final spacewalks to finish a 3.5-year effort to upgrade the International Space Station's power system on Thursday (July 16). They are working to replace batteries on one of two power channels on the station's far starboard truss (S6 Truss).

Behnken and Cassidy switched their spacesuits to battery power at 7:10 a.m. EDT (1110 GMT) to begin the spacewalk, which is expected to last between six and seven hours.

The spacewalkers will be removing five existing nickel-hydrogen batteries and replacing them with three new lithium-ion batteries that arrived on a Japanese HTV cargo ship last month. The batteries store electricity for one pair of the station's solar arrays, and the swap will upgrade the station's power supply capability.

The batteries store power generated by the station's solar arrays to provide power to the microgravity laboratory when the station is not in sunlight as it circles Earth during orbital night.

This is the 230th spacewalk in support of space station assembly and maintenance. Behnken is extravehicular crew member 1 (EV 1), wearing the spacesuit with red stripes, and using helmet camera no. 20. Cassidy is extravehicular crew member 2 (EV 2), wearing the spacesuit with no stripes and helmet camera no. 18. It is the ninth spacewalk for both astronauts.

posted 07-16-2020 01:18 PM               

Behnken, Cassidy conclude spacewalk

Bob Behnken and Chris Cassidy concluded their spacewalk on Thursday (July 16) at 1:10 p.m. EDT (1710 GMT), after precisely six hours. The two NASA astronauts completed all the work to replace batteries that provide power for the station's solar arrays on the starboard truss of the complex.

The spacewalkers removed six aging nickel-hydrogen batteries for the second of two power channels for the starboard 6 (S6) truss, installed three new lithium-ion batteries, and installed the three associated adapter plates that are used to complete the power circuit to the new batteries. Mission control reports that all three new batteries are working.

The work nearly completes a 3.5-year effort to upgrade the International Space Station's power system. At completion, 24 new lithium-ion batteries and adapter plates will replace 48 aging nickel-hydrogen batteries.

In April 2019, one of the newly installed lithium-ion batteries on the near port truss blew a fuse, so two nickel-hydrogen batteries were re-installed to take its place. A new replacement lithium-ion battery arrived to the space station in January 2020 aboard the SpaceX Dragon on its 19th commercial resupply services mission and is stowed on the station's truss until it can be installed during a future spacewalk later this year.

This was the ninth spacewalk for each astronaut. Behnken has now spent a total of 55 hours and 41 minutes spacewalking. Cassidy now has spent a total of 49 hours and 22 minutes spacewalking.

Space station crew members have conducted 230 spacewalks in support of assembly and maintenance of the orbiting laboratory. Spacewalkers have now spent a total of 60 days, 6 hours, and 34 minutes working outside the station.