STORY WRITTEN FOR CBS NEWS & USED WITH PERMISSION
Up to date 2:39pm EDT (1839 GMT)
Two astronauts floated exterior the Worldwide Area Station Monday for NASA’s third spacewalk in lower than three weeks, this one to assist change a defective photo voltaic array battery that was put in in the course of the first tour, to route ethernet cabling to increase wi-fi connectivity and to put in backup energy traces for the lab’s robotic arm.
Floating within the Quest airlock, NASA flight engineer Anne McClain, name signal EV-1, and Canadian astronaut David Saint-Jacques, EV-2, switched their spacesuits to battery energy at 7:31 a.m. EDT, formally kicking off what turned out to be a six-hour 29-minute tour, the 216th since station meeting started in 1998.
The spacewalkers completed all of their major goals with none main issues. McClain had a little bit of hassle clearly listening to mission management towards the tip of the tour and reported moisture on her helmet visor after returning to the airlock. However she stated there have been no indicators of an precise water leak that may pose a security risk.
Saint-Jacques initially deliberate to conduct Monday’s spacewalk with NASA astronaut Nick Hague. Hague and McClain carried out the primary of the three spacewalks March 22 whereas McClain and Christina Koch deliberate to hold out the second on March 29, turning into the primary all-female spacewalk group in house historical past.
However after the primary tour, McClain determined she was extra snug carrying a medium-size swimsuit, the identical one Koch wanted. As a result of it will take almost a full crew day to re-size a spare swimsuit to suit McClain, Hague took her place on the second spacewalk and McClain changed him for the third outing.
Because it turned out, the crew swaps have been simply one of many adjustments the crew needed to take care of.
Through the March 22 spacewalk, McClain and Hague adopted up work with the station’s robotic arm to exchange six older nickel-hydrogen batteries within the lab’s solar energy system with three extra environment friendly lithium-ion batteries. The astronauts put in “adapter plates” allowing a single li-ion battery to take the place of two of the older nickel-hydrogen energy packs.
Through the second spacewalk March 29, Hague and Koch helped with the set up of one other three li-ion batteries. However throughout testing after the primary EVA, engineers bumped into issues with one of many initially put in li-ion batteries and an electronics element referred to as a battery charge-discharge unit, or BCDU.
After makes an attempt to right the issues failed, NASA managers opted to take away the defective battery and change it with two of the just lately eliminated nickel-hydrogen batteries. In addition they determined to exchange the BCDU with a spare.
Utilizing the station’s robotic arm, flight controllers eliminated the suspect battery and the BCDU after which re-installed one of many just lately eliminated nickel-hydrogen batteries. In addition they robotically changed the failed BCDU.
With that work out of the way in which, McClain and Saint-Jacques eliminated an adapter plate that was put in in the course of the first spacewalk to make room for the set up of a second nickel-hydrogen battery.
After the spacewalk, flight controllers will use the robotic arm to re-install the second nickel-hydrogen battery, restoring energy channel 4A to its regular output.
Kenny Todd, house station operations and integration supervisor, stated the defective lithium-ion battery will likely be discarded whereas the BCDU will likely be returned to Earth for inspections to search out out what went unsuitable. A brand new lithium-ion battery will likely be flown as much as the station on a future cargo flight and finally put in instead of the 2 older batteries.
As for utilizing a mixture of outdated and new batteries in energy channel 4A, “we anticipate we will run that configuration for fairly a while and get us again to our nominal energy functionality on channel 4A,” he stated. “So we really feel actually good about the place we’re going to finish up on the again aspect of those EVAs and robotics actions.”
With the adapter plate transfer out of the way in which, McClain and Saint-Jacques pressed forward with work to attach ethernet cabling on the ahead finish of the station’s Future laboratory module that can lengthen wi-fi connectivity for science devices mounted exterior the station.
A cable run out to the suitable aspect of the station’s solar energy truss was deferred to find time for the adapter plate relocation.
The ultimate main activity on the crew’s agenda Monday was to run energy traces from the central Unity module to the central S0 phase of the facility truss to offer a backup energy supply for the lab’s robotic arm.
Whereas the arm already has redundant energy sources, the cables put in by McClain and Saint-Jacques will permit the arm to proceed working even when a type of different energy provides fails.
Saint-Jacques additionally labored on the ahead finish of the station where4 the European Area Company’s Columbus laboratory module is connected to put in fittings wanted for the eventual addition of a business payloads platform that will likely be used to carry quite a lot of remotely operated science devices.
He efficiently put in a secondary attachment becoming, however was unable to mount the first unit due to sudden interference points. He took documentary images to assist engineers higher perceive the difficulty earlier than a further try is made on a future spacewalk.