Solar array upgrade planned for 3rd ISS spacewalk June 25
Watch the solar array upgrade online June 25
NASA plans to install two new solar arrays on the International Space Station (ISS) in June 2021. The third and final spacewalk aimed toward this goal will take place on June 25. The space agency said:
Live coverage will begin at 6:30 a.m. EDT (10:30 UTC) on NASA Television, the agency’s website, and the NASA app, with the crew members scheduled to exit the station’s Quest airlock around 8 a.m. The spacewalk will last approximately 6 hours, 30 minutes.
The first of the new solar arrays was to be installed June 16, but was not, due to various technical difficulties. Then, on Sunday, June 20, a second spacewalk by two astronauts did result in the successful installation of the first of six new ISS Roll-Out Solar Arrays (dubbed iROSAs). And now the June 25 spacewalk will aim at installing a second iROSA. NASA said in a statement that the third spacewalk will continue power system upgrades:
… that are already increasing output and proving the technology that will enable NASA’s future Gateway lunar outpost.
Again, iROSA stands for ISS Roll-Out Solar Arrays. They’re needed because ISS has been in orbit a while. The first humans to inhabit the station – Expedition 1 – came aboard in November 2000.
The ISS has eight power channels that have been in action since the Space Shuttle program delivered them between the years 2000 to 2009. Boeing designed them with a lifespan of 15 years. Thus they have degraded.
The arrays will upgrade the station’s existing power system, and NASA plans to send six eventually.
According to Spaceflight Now, when all six iROSA units are deployed on the station the power system will be capable of generating 215 kilowatts of electricity to support at least another decade of science operations. That’s about a 20% to 30% boost in power. They’re only about half the length and width of the solar panels currently outfitted to the station but will generate the same amount of electricity.
iROSA installed during June 20 spacewalk
The two astronauts started their assignment by retrieving the iROSA from a temporary holding fixture installed earlier in the year. The iROSA had arrived at the station via a SpaceX Cargo Dragon capsule just two weeks earlier, on June 7.
Kimbrough and Pesquet bolted the array into place and connected the appropriate cables to the ISS power supply.
Canadian astronaut Jenni Sidey-Gibbons radioed the team from Mission Control in Houston:
Good news, you two. You can probably see most of what we can see. We’re tracking a full and good deploy of that solar array, so well done, both of you.
Before retreating back inside the ship, the astronauts also prepared hardware to be used when they return to install the second iROSA during the June 25 spacewalk.
The June 20 spacewalk marked the eighth for Kimbrough, and fourth for Pesquet, and the fourth they’ve conducted together.
Technical difficulties at June 16 spacewalk
June 20 was initially planned to deploy the second iROSA, but the schedule changed when June 16’s spacewalk was cut short.
The spacewalk on June 16 lasted a long time, as spacewalks go: 7 hours and 15 minutes. Kimbrough and Pesquet performed the EVA on that day, too. According to SciTechDaily, Kimbrough’s spacesuit experienced technical issues with its display module. There also appeared to be a glitch with its sublimator, the suit’s cooling system. Finally, they attempted to unfold iROSA. But an interference issue with the array mechanism prevented them from extending the new panel as planned. And because they were already running behind schedule, Mission Control decided to postpone the installation to June 20.
Fortunately, Kimbrough was able to don a different spacesuit for the June 20 EVA.
June 25 spacewalk ahead
Kimbrough and Pesquet are expected to complete installation of the second of the six new iROSAs on June 25.
Pesquet will be designated extravehicular crew member 1 for the spacewalk. Look for him in a spacesuit with red stripes. Kimbrough will be extravehicular crew member 2, wearing a suit with no stripes.
Hundreds of experiments have been conducted on the ISS in human research, space medicine, life sciences, physical sciences, astronomy, and Earth science. In NASA’s words, ISS provides:
… opportunities for unique research and technological demonstrations that help prepare for long-duration missions to the moon and Mars and also improve life on Earth.
Bottom line: Astronauts Shane Kimbrough and Thomas Pesquet successfully upgraded the International Space Station with a new solar array – called an iROSA – on June 20, 2021. They are scheduled to install the second iROSA on June 25. NASA TV’s live coverage of the spacewalk will begin that day at 6:30 a.m. EDT (10:30 UTC). The spacewalk itself begins at around 8 a.m. EDT (12:00 UTC) and will last about 6 1/2 hours. Watch here.