NASA Astronauts Complete Critical Power Prep for New ISS Solar Array

NASA astronauts Jessica Meir and Chris Williams concluded a significant extravehicular activity (EVA) on Wednesday, March 18, 2026, marking the first U.S. spacewalk of the year and the 278th in support of the International Space Station's (ISS) ongoing assembly and maintenance. The spacewalk, designated U.S. Spacewalk 94, lasted seven hours and two minutes, commencing at 8:52 a.m. EDT and concluding at 3:54 p.m. EDT. The primary objective involved critical preparatory work on the 2A power channel, which is essential for the forthcoming installation of International Space Station Roll-Out Solar Arrays (iROSA) by installing a necessary modification kit and a jumper cable to the power system.

This endeavor is part of a larger effort to augment the ISS power grid, as the station's original solar arrays have degraded beyond their initial 15-year service life. Meir, completing her fourth EVA, and Williams, on his inaugural spacewalk, executed the external tasks on the port side of the station's backbone truss. Inside the orbiting laboratory, Expedition 74 crewmates Jack Hathaway and ESA astronaut Sophie Adenot provided crucial support, assisting with the spacesuit operations and participating in post-spacewalk debriefing with ground teams. The successful completion of this preparatory work on the 2A channel sets the stage for a subsequent spacewalk, U.S. Spacewalk 95, which will focus on preparing the 3B power channel for its own iROSA deployment.

Following the demanding EVA, the Expedition 74 crew transitioned to routine station upkeep and debriefing sessions on Thursday, March 19, 2026. While the spacewalkers conducted follow-up procedures, other crew members focused on internal maintenance, including inspecting modules and stowing cargo. Furthermore, the crew continued advanced scientific research, including testing the EchoFinder-2 system, which utilizes augmented reality and artificial intelligence to enable autonomous medical diagnostics, such as ultrasound scans, a capability vital for future long-duration missions to the Moon and Mars.

This infrastructure upgrade using iROSA technology, developed by Redwire, involves lightweight, flexible power sources designed to restore and ultimately increase the ISS's power generation capacity by 20% to 30% once all planned arrays are installed. Previous iROSA installations, such as the one on the 1B power channel in June 2023, demonstrated the technology's effectiveness, with each new array producing over 20 kilowatts of electricity. The successful preparation of the 2A channel signifies a tangible advancement toward securing sufficient power to support continuous scientific research and operations through the planned end of station support, potentially extending through 2030 with the addition of new lithium-ion batteries.

Expedition 74, which commenced on December 8, 2025, is balancing these critical maintenance tasks with a demanding research schedule, including studies on vascular health and the effects of microgravity on biological samples. The successful execution of Spacewalk 94, which occurred 61 years after Alexei Leonov's first human spacewalk, underscores the continuous evolution of human capability in the vacuum of space, paving the way for the Artemis missions and beyond.