During the walk, Hoshide and Pesquet will install a modification kit, or support bracket, that will prepare the outside of the station for future Roll-Out Solar Array installation work. The two astronauts will be working on the inward port side of the station’s backbone truss structure called P4. This is close to the space station’s living space.
When new solar arrays are sent to the space station, the modification kit will allow astronauts on a future spacewalk to install the third new Roll-Out Solar Array (which arrive rolled up like carpet).
The solar array upgrades will help upgrade the station’s power channels.
This will be the first spacewalk conducted out of the orbiting laboratory’s Quest airlock by two international partner astronauts at the space station, according to NASA. A 360-degree virtual reality camera will film Hoshide and Pesquet during their spacewalk.
During the spacewalk, Hoshide will be extravehicular crew member one, wearing the spacesuit with red stripes, and Pesquet will be extravehicular crew member two in a white unmarked suit.
It’s the fourth career spacewalk for Hoshide, the sixth spacewalk for Pesquet. This is the 244th spacewalk to help assemble, maintain and upgrade the station.
Upgrading solar power
While the current solar arrays on the space station are still functioning, they have been supplying power there for more than 20 years and are showing some signs of wear after long-term exposure to the space environment. The arrays were originally designed to last 15 years.
Erosion can be caused by thruster plumes, which come from both the station’s thrusters as well as the crew and cargo vehicles that come and go from the station, said Dana Weigel, deputy manager of the International Space Station Program.
“The other factor that affects our solar arrays is micrometeorite debris. The arrays are made of a lot of small power strings, and over time those power strings can degrade if they’re hit by debris,” she said.
“The exposed portion of the old arrays will still be generating power in parallel with the new arrays, but those new Iris arrays have solar cells on them that are more efficient than our original cells,” Weigel said. “They have a higher energy density and together in combination may generate more power than what our original array, when it was new, did on its own.”
The new arrays will have a similar 15-year expected life span. However, since the degradation on the original arrays was expected to be worse, the team will monitor the new arrays to test their true longevity because they may last longer.
Rescheduling a spacewalk
The September 12 spacewalk was rescheduled from August 24, with some changes. The original spacewalk plan included NASA astronaut Mark Vande Hei working alongside Hoshide.
During the spacewalk, Vande Hei will be providing support from inside the space station as he continues to recover.
The agency also provided an update on the detection of smoke on the space station earlier this week.
A Russian spacewalk continued as scheduled on Thursday despite the fact that the space station crew was awakened by a fire alarm around 10 p.m. ET Wednesday night. The alarm sounded for a minute after sensors detected smoke in the Russian Zvezda module. The smoke and burning plastic smell was also present in the US parts of the space station.
The crew reacted quickly, replaced air filters, scrubbed the atmosphere, and all signs of smoke dissipated, according to NASA. However, the source of the smoke was not identified at the time.
The Russian cosmonauts have been investigating the issue, and believe they have discovered a connection. They had a piece of equipment running in the module that has since been turned off. After that, the smell dissipated.
“Everything is returned back to normal, and they haven’t had any recurrence of any issues,” Weigel said. “So everything is stable and great onboard.”