Astronauts Have Begun Spacewalk Live on NASA TV

NASA astronauts Robert Behnken and Chris Cassidy have begun the first of two final spacewalks to finish a 3.5-year effort to upgrade the International Space Station’s power system. They will replace batteries on one of two power channels on the station’s far starboard truss (S6 Truss).

The spacewalkers switched their spacesuits to battery power at 7:10 a.m. EDT to begin the spacewalk, which is expected to last between six and seven hours.

Watch the spacewalk on NASA TV and on the agency’s website.

The spacewalkers will be removing five existing nickel-hydrogen batteries and replacing them with three new lithium-ion batteries that arrived on a Japanese 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 #20. Cassidy is extravehicular crew member 2 (EV 2), wearing the spacesuit with no stripes and helmet camera #18. It is the ninth spacewalk for both astronauts.

Learn more about station activities by following the space station blog, @space_station and @ISS_Research on Twitter as well as the ISS Facebook and ISS Instagram accounts.