Astronauts Mike Hopkins and Victor Glover floated back outside the International Space Station Monday for a planned six-and-a-half hour spacewalk to complete solar array battery replacement work, to install a new high definition camera and to replace two other degraded units.
Sealed inside the station’s Quest airlock, the astronauts switched their spacesuits to battery power at 7:56 a.m. EST, officially kicking off the 234th spacewalk, or EVA, devoted to station assembly and maintenance. It is the second so far this year, the fourth for Hopkins and the second for Glover.
Both men carried out a joint spacewalk last Wednesday to electrically connect an external European experiment platform and to make preparations for future solar array upgrades. As with last week’s EVA, Hopkins, call sign EV-1, wore a suit with red stripes Monday while Glover, EV-2, used an unmarked suit.
During solar array battery replacement work in March 2019, a newly installed lithium ion power pack supporting the station’s left-side inboard set of arrays failed and was replaced with one of the older nickel hydrogen batteries that had been removed.
Over the weekend, flight controllers operating the station’s robot arm by remote control disconnected the old battery and robotically installed a fresh lithium ion unit.
The first item on the agenda Monday was for Hopkins and Glover to electrically connect the new battery. They also planned to loosen a bolt holding another electrical component in place so it can be robotically replaced later.
The batteries are critical to station operation. They are recharged by the arrays when the lab is in sunlight and then provide that stored power during periods of orbital darkness.
Starting in 2017, spacewalking astronauts began work to replace all 48 of the station’s aging nickel-hydrogen batteries with 24 smaller, more powerful lithium ion units. With Monday’s spacewalk, that work is finally complete.
Before leaving the battery worksite, Hopkins and Glover planned to remove a no-longer-needed solar array ground handling fixture to make way for the eventual attachment of new solar blankets to boost the lab’s power.
The remainder of the spacewalk was devoted to upgrading the station’s external camera system.
With Glover now riding on the end of the station’s robot arm, the astronauts first planned to remove and replace a camera group mounted on a stand attached to the right side inboard solar array truss segment.
Glover then planned to ride the arm to the Destiny laboratory module to attach a high definition camera to an existing set while Hopkins headed out to the Kibo laboratory module to install a new wrist camera on the lab’s small Japanese robot arm.
Two more spacewalks are planned later by the current Expedition 64 crew.
Glover and veteran spacewalker Kate Rubins will work outside the lab to make more preparations for attachment of new solar blankets. Two sets of “ISS roll up solar array” blankets will be carried up later this year aboard SpaceX Dragon cargo ships.
Rubins and Japanese astronaut Soichi Noguchi, also a veteran spacewalker, will carry out a variety of station upgrades during the current crew’s final spacewalk.