Power upgrades at space station nearly complete

CAPE CANAVERAL, Fla. — Spacewalking astronauts completed their part of a three-year power upgrade to the International Space Station on Thursday, replacing six more outdated batteries with powerful new ones.

It was the third spacewalk in as many weeks involving battery work by NASA’S Bob Behnken and Chris Cassidy.

Running more than an hour ahead of schedule, they managed to complete the battery swaps in a single spacewalk rather than two. Their fourth spacewalk next week will now focus on other chores.

“Great job,” Mission Control radioed. Behnken and Cassidy swiftly removed six of the remaining old nickel-hydrogen batteries and plugged in three new lithium-ion units.

The lithium-ion batteries — big, boxy units with a mass of more than 400 pounds — are so powerful that only half as many are needed. The batteries store power gathered by the station’s solar panels for use on the nighttime side of Earth.

The effort to replace all of the space station’s 48 aging batteries began in January 2017, requiring 11 spacewalks to date.

One new battery shorted out in 2019 and the old ones had to be re-installed. One more spacewalk remains, likely this fall. NASA is putting it off instead of tackling it next week because it would involve powering down that power channel.

Besides, the two remaining old batteries are working well with all the new ones, said Rob Navias, a spokesman at Johnson Space Center in Houston.

“We are fat with power and there is no rush,” he said in an email.