NASA Previews Upcoming Spacewalks to Complete ISS Solar Array Installation

NASA announced two upcoming spacewalks, scheduled for October 29 and November 5, to complete the installation of solar arrays and augment power for the International Space Station (ISS). These are the final pair of arrays, which were delivered to the station last week via SpaceX-35.

The first spacewalk marks the 285th in support of station assembly, maintenance, and upgrades, while the second on November 5 will be the 286th. Gaurang Patel, operations integration manager for the Low Earth Orbit Program, stated that these rollout arrays are projected to increase the ISS's power generation capability by up to 30%, elevating the total power from 160 kW to as much as 215 kW.

During the first spacewalk on Thursday, October 29, NASA astronaut Anil Menon and Canadian Space Agency (CSA) astronaut Joshua Kutryk will exit the Quest airlock. Their mission is to install and deploy the seventh International Space Station Roll-out Solar Array (iROSA) on the 2A power channel.

This upcoming spacewalk will be Anil Menon's fourth and Joshua Kutryk's first. This will be the eighth spacewalk conducted outside the station this year, and the fifth for the Expedition 75 crew, who arrived in July.

The following week, on Thursday, November 5, astronauts Anil Menon and Joshua Kutryk will perform their second spacewalk to install and deploy the eighth and final set of iROSAs on the 3B power channel. This installation will complete the power augmentation upgrades for the International Space Station.

This will mark Menon's fifth spacewalk and Kutryk's second, concluding the series of power upgrades for the station.

Last week, on October 8, Crew 12 successfully splashed down. Crew 13 has since been busy, supporting the release of the Northrop Grumman NG-24 cargo mission on October 9, which safely deorbited on October 12. They also observed the docking of SpaceX-35 last week, which delivered over 6,300 pounds of supplies, science, and the critical iROSA arrays.

Looking ahead, the fall remains busy for the space station, with additional cargo flights and a Progress spacecraft planned for late November. These missions include the Northrop Grumman NG-25 cargo vehicle.

Garrett Hehn, spacewalk flight director, and Greg Whitney are leading the execution team for the final iROSA array installations. Hehn noted that approximately 20% of the 99 prior U.S. EVAs have been dedicated to power upgrades, an experience the team is leveraging for these upcoming missions. Miranda Nelson, lead EVA Officer, and J. Ray, lead robotics officer, developed an efficient and robust plan that is designed to withstand real-life challenges.

An animation was presented to outline the specific sequence for transporting the rolled-up arrays from the Dragon trunk to the truss for attachment. The team highlighted their focus on setting up support equipment for both EVAs during the first spacewalk to optimize the process.

During the spacewalk, the first solar array, currently pointed out of the screen, will be carefully slid off its rails. This process involves working through numerous bolts to release it from its support equipment.

Additionally, launch locks, which protected the array during its ascent through the dynamic environment, will be disengaged once the array is safely in zero gravity. The array will then be handed over to a crew member for further positioning.

Garrett Hehn likened the deployment of the solar array to a snap bracelet. He explained that these arrays feature a series of magnets along their sides, enabling them to deploy with sufficient energy to steadily roll out.

The entire deployment process is anticipated to take approximately ten minutes on the day of the extravehicular activity (EVA).

Anil Menon will ride the robotic arm, after getting into position on its platform, while Josh Kutryk releases the final bolts securing the array. Menon will then transport the array, weighing approximately 750 pounds in its folded configuration and about ten feet long, to the power channel at Alpha outboard.

The team implemented a refined series of maneuvers, learned from previous EVAs, to rotate around the array's center of mass rather than the crew member's. This adjustment aims to minimize fatigue for Menon as he handles the substantial array.

Josh Kutryk and Anil Menon will collaboratively slot the rolled-up, folded array onto a modification kit, which was installed during a previous EVA. After structurally attaching the array with a series of bolts, it will be released to unfold, expanding from approximately ten feet long to about twenty feet long. This unfolding is described as one of the key points of the EVA.

Following deployment, the astronauts will structurally attach the rollout solar array in its new position. They will then move to access the power cables beneath the array's cylinder. This critical step requires the team to work in eclipse conditions, ensuring no sun is on the arrays while handling the 'hot' cables.

A jumper will be used to integrate the power from both the legacy arrays and the new rollout solar array, significantly augmenting the station's power generation capability. Training teams have thoroughly prepared for these critical moments and potential contingencies.

The second extravehicular activity (EVA) will move to the starboard side of the International Space Station, the opposite side from the first EVA which is on the port side. The sequence of operations for the second EVA will be very similar to the first. The second array is already stowed in the equipment area, and preparations for its installation will be made during the first EVA to ensure completion within the limited duration of the spacewalk.

Between the two EVAs, all robotics equipment, including the mobile transport system to which the array is currently attached, will be relocated to the starboard side. The team aims to move in one axis at a time during robotic maneuvers, which is expected to make the process less strenuous for Anil Menon. The robotic arm is capable of reaching the outboard set of arrays where the installation will take place.

Spacewalkers will employ a technique referred to as the 'leapfrog' to bridge the final distances that the robotic arm cannot cover independently. This maneuver involves one astronaut moving their platform about 180 degrees to allow the other to exit and then ingress their own platform, closing the gap to the installation site. The mission aims to complete the installation of the final iROSA arrays, achieving full power generation capability for the station.

The overall preparation for these spacewalks is a significant team effort, involving robotic arm operators, mission control in Houston, and dedicated training teams. This comprehensive collaboration ensures that all aspects, from timeline management to anticipating and solving potential issues, are meticulously addressed.

Spacewalks inherently involve risks, particularly with aging equipment like spacesuits, which, while robust, are not entirely redundant and have known 'quirks'. Garrett Hehn emphasized that these spacesuits function as personal spacecraft, providing essential life support systems such as oxygen and CO2 scrubbing.

Flight controllers prioritize crew safety above all else, making every decision with a thoroughly prepared team. Hehn expressed full confidence in Anil Menon and Joshua Kutryk, noting that backup crew members are also trained and ready if needed.

NASA selected Anil Menon and Joshua Kutryk to perform both spacewalks due to the significant hardware commonality between the two mirror-image EVAs, which occur on opposite sides of the station. This approach leverages the extensive study and preparation undertaken by the astronauts to navigate the complex environment efficiently.

Keeping the same team ensures efficiency and minimizes the need for additional training for new personnel. While multiple crew members are trained and ready, maintaining the same team for similar tasks is a strategic advantage.

Gaurang Patel provided an update on the status of the station's robotic and mobile systems. The Canadarm2 is currently operating nominally, with no tracked issues regarding its performance.

However, for the mobile transporter, Channel A experienced transaction errors earlier in the year. Consequently, Channel B has been designated as the prime channel for current operations. Channel A remains available as a redundant option, based on ongoing checkouts that confirm its usability if needed.

Garrett Hehn highlighted that one of the most challenging aspects of spacewalks is managing motion inertia, particularly avoiding maneuvering in two axes simultaneously. Astronauts like Anil Menon, whose feet are locked into the robotic arm while manipulating a large object, rely on clear communication protocols to prepare for single-axis movements. This allows them to get ready, bias, or start moving an array before their feet catch up.

Hehn explained that while massive objects in zero gravity have no weight and don't need to be lifted, astronauts must still combat their significant inertia and reluctance to rotate when the astronaut themselves is rotating. The focus is on ensuring controlled and efficient movement despite these physical challenges.

Gaurang Patel explained that the Low Earth Orbit (LEO) program management collaborates with the astronaut office to select crew members for spacewalks. The selection process primarily focuses on identifying the specific skills required to execute the EVAs and matching those needs with the strengths of available crews.

These decisions are made in a timely manner, synchronized with the overall EVA preparation schedule, to ensure the chosen astronauts are well-prepared for their missions.

Garrett Hehn highlighted the Neutral Buoyancy Laboratory (NBL) at NASA's Johnson Space Center as an invaluable asset for spacewalk training. The NBL provides a unique capability to replicate nearly the entire EVA, end-to-end, in full-scale chunks. This 3D simulation, involving personnel and all necessary equipment, builds significant trust in the mission timeline.

While the pool has physical size limitations that require some simulated 'flying,' it remains a highly effective training environment. Hehn noted that equipment for the current iROSA spacewalks has been staged and ready for training in the NBL for several years, providing extensive experience for astronauts like Anil Menon and Joshua Kutryk.

Gaurang Patel outlined future spacewalk plans, stating that the next baseline EVAs are scheduled for early January. These spacewalks will support the Alpha Magnetic Spectrometer, a payload receiving an upgrade onboard, with the enhancement, known as the tracker layer zero, set to launch on SpaceX 36. This is the current planned target timeframe.

Patel also confirmed that NASA maintains readiness to reassess and launch EVAs for critical failures or emergency situations if they arise, ensuring that crew members are prepared to go out as needed.