Over the next few weeks, astronauts aboard the International Space Station (ISS) will undertake a series of three spacewalks. This is part of a long-term plan to upgrade the space station’s aging electrical system.

The ISS uses large solar panels to capture energy from the Sun and convert it into usable electricity. Energy is used for everything on board, from life support and temperature control to communications with Earth and even the propulsion system to allow the station to avoid space debris.

The ISS’s electrical system consists of eight solar arrays that extend outside the main terminal area like wings. For so long, they have been able to meet the ISS’s power needs by generating an average of 84 to 120 kilowatts of electricity. However, some battery arrays are more than 20 years old and were originally designed for a use life of only 15 years, so there are signs of deterioration.

That doesn’t mean the old battery arrays will suddenly break or stop working - although the station has had power problems in the past - but it does mean that they are slowly becoming less efficient over time. . And with the large number of increasingly complex scientific experiments performed on the station, power requirements are also increasing.

Anthony Vareha, who will lead the first spacewalk on November 15, explains:  “Some of the chains that generate power on those battery arrays have gone offline. However, that is what was expected from the original energy construction plan.”

To meet the ever-increasing demand, the ISS has continuously upgraded its electrical system, including replacing battery arrays during previous spacewalks. Now, however, new battery arrays need to be added, and that is the main goal of the upcoming series of spaceflight.

An iROSA solar array was deployed in 2001. Solar arrays are gradually being added to the ISS space station to increase its energy availability.

Upgrades to the power system include the addition of six new battery arrays, which will sit ahead of the old battery arrays, and allow power to be drawn from both. At 18 meters long and 6 meters wide, the new arrays, known as the ISS Roll-Out Solar Array, or iROSA for short, will be smaller than the old arrays, 34 meters long and 11.8 meters wide. . However, developments in solar panel technology mean that the new arrays can generate the same amount of electricity as the original arrays.

However, this will not be a simple process. Before an iROSA array can be added, it needs a support structure, which is mounted on the outside of the station. Vareha describes a two-part process, first installing the scaffolding and then installing an array. Currently, the ISS has two of the new iROSA arrays installed. Scaffolding is ready for two more arrays and scaffolding for the last two will be installed soon, starting with the upcoming spacewalk on November 15. This will be the first spacewalk of two NASA astronauts, Josh Cassada and Frank Rubio.

Two subsequent spacewalks are scheduled for November 28 and December 1, with the task of installing two more arrays onto the existing scaffold. The ultimate goal is for all six arrays to be installed and operational by the middle of next year.

Chris Mundy, space operations officer, said the new arrays will be stacked on a transport ship during the SpaceX CRS-26 resupply mission, which will launch on November 18. The arrays will then need to be installed, integrated into the electrical system and deployed. The implementation involved unpacking the arrays which took 6 to 10 minutes.

To integrate with the electrical system, astronauts need to install cables to link both the old and new arrays to the electrical system. “Once they are fully connected, we will be able to route power from the legacy array and the new iROSA array into the ISS power system,” Mundy said  .

NASA says these new arrays are being tested for use in future missions like the Artemis Moon program, as well as helping the space station continue to operate. As for the ISS space station, its future remains unclear. While NASA announced late last year that it intends to continue operating the ISS until 2030, Russia, another major partner, has repeatedly threatened to withdraw its cooperation, leaving the ISS in a fragile position. even if it is heavily upgraded.

“Every new array brings new strength,” said  Fiona Turett, NASA’s flight director.  “The ISS continues to grow and we have more scientific research and more systems online. This additional power source will ensure we can operate the ISS at full capacity in the years to come.”