NASA astronaut Shane Kimbrough and ESA (European Space Agency) astronaut Thomas Pesquet concluded their spacewalk at 2:10 p.m. EDT, after 6 hours and 28 minutes. In the eighth spacewalk of the year outside the International Space Station, the two astronauts completed the deployment of a new ISS Roll-Out Solar Array (iROSA) on the far end of the left (port) side of the station’s backbone truss structure (P6).
Kimbrough and Pesquet successfully unfolded the solar array, bolted it into place, and connected cables to the station’s power supply to complete deployment. Additionally, the astronauts removed and stowed hardware in preparation for releasing the second iROSA from the flight support structure for installation. The pair will work toward the second solar array upgrade – this one on the P6 truss’ 4B power channel – during another spacewalk, tentatively scheduled for June 25.
NASA is augmenting six of the eight existing power channels of the space station with new solar arrays to ensure a sufficient power supply is maintained for NASA’s exploration technology demonstrations for Artemis and beyond as well as utilization and commercialization.
The new solar arrays are being positioned in front of current arrays, which are functioning well but have begun to show signs of expected degradation as they have operated beyond their designed 15-year service life. The first pair of legacy solar arrays were deployed in December 2000 and have been powering the station for more than 20 years.
The new solar array is positioned in front of the current solar array on the same plane and rotary joints, but not directly on top of the primary solar arrays. The new arrays are 60 feet long by 20 feet wide (18.2 meters by 6 meters) and will shade a little more than half of the original array, which is 112 feet long by 39 feet wide. Each new iROSA will produce more than 20 kilowatts of electricity, while the current arrays generate, on average, 17 to 23 kilowatts each.
This was the eighth spacewalk for Kimbrough, the fourth for Pesquet, and the fourth they have conducted together. Kimbrough has now spent a total of 52 hours and 43 minutes spacewalking, and Pesquet’s total spacewalking time is 26 hours and 15 minutes.
Boeing, NASA’s prime contractor for space station operations, its subsidiary Spectrolab, and major supplier Deployable Space Systems (DSS) provided the new arrays. The technology was developed and proven by NASA’s Space Technology Mission Directorate during a demonstration on the space station in 2017, and the same solar array design will be used to power elements of the agency’s Gateway lunar outpost.
Space station crew members have conducted 240 spacewalks in support of assembly and maintenance of the orbiting laboratory. Spacewalkers have now spent a total of 63 days and 56 minutes working outside the station.
In November 2020, the International Space Station surpassed its 20-year milestone of continuous human presence, providing 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. In that time, 244 people from 19 countries have visited the orbiting laboratory that has hosted nearly 3,000 research investigations from researchers in 108 countries and areas.