Cosmonauts Sergei Prokopiev and Dmitry Petelin were slated to depart the International Space Station on November 25 to relocate the radiator-heat exchanger from the Rassvet module to the Nauka module, the Russian segment’s new laboratory. Moments before the scheduled EVA launch, Roscosmos announced a cancellation due to an emergency in progress.
During the spacesuit preparations, engineers found anomalous readings from the cooling-system pumps in one suit. A decision was made to halt the spacewalk at the airlock while the issue was investigated. The agency said the reasons for the abnormal readings were under examination and that a new EVA date would be set once the investigation reached a conclusion.
Sergei Pozdnyakov, who leads the Zvezda research and production enterprise that manufactures the Orlan spacesuits, stated that their technicians would address the cooling pumps to restore reliable operation for future excursions. He explained that the system includes a main pump and a standby pump, with an automatic switch that activates the standby pump if the main pump encounters problems, and vice versa. Pozdnyakov noted an instability in how the pumps were operating and promised a resolution.
The planned EVA timeline called for a start at 14:20 Moscow time. For Petelin and Prokopiev, this would have been their second spacewalk during this mission, with live coverage expected on the Roscosmos website.
The core objective was clear: move the radiator-heat exchanger from Rassvet to Nauka to manage the extra thermal load generated by ongoing scientific experiments in the MLM Nauka module. Controlling this heat is essential to maintain the performance and safety of on-board systems during extended research operations.
Remote manipulation of the exchanger was to be handled by the European Robotic Arm, operated from the orbital outpost by cosmonaut Anna Kikina. Her role was to secure the radiator with the manipulator so that Prokopiev and Petelin could perform the handover. After detaching and inspecting the wiring, engineers would ensure the radiator was properly interfaced with Nauka before reevaluating the station’s thermal balance. TASS reported that Kikina had completed her preparatory work with the manipulator by early afternoon Moscow time.
The spacewalk was planned to last a little more than six and a half hours. Petelin and Prokopiev were to wear the red and blue-striped Orlan-MKS spacesuits, a modernized lineage of suits used by Russian cosmonauts since 2017. The Orlan-MKS design supports extravehicular activity for up to seven hours, with a polyurethane shell designed to withstand the rigors of space. As used in multiple expeditions, these suits are intended for rapid donning and reliable life support during complex exterior tasks.
Incidents involving Orlan-MKS suits are not new in recent years. Earlier in the mission year, a malfunction forced an EVA to be paused when a suit revealed a battery voltage drop, jeopardizing contact with the craft. In that episode, one cosmonaut descended to safety while a partner continued essential external work. The episode underscored ongoing concerns about the age and supply chain of the suit family and the demands of sustained space operations.
Looking back, the broader context includes discussions from the previous year about the long-term viability of the Orlan-MKS fleet. The general director of Zvezda warned that the warranty period for these suits was nearing its end and that new production agreements had not yet been finalized. The concern reflected broader questions about Russia’s ability to produce new spacesuits promptly, given supplier dissolution and the high costs involved in developing fresh components. The commentary also touched on bureaucratic hurdles, with observers noting that approval processes could slow the introduction of new hardware. In historical remarks from around that period, a prominent space agency official indicated that an alternative manufacturing path might be necessary if the standard route proved too slow. These remarks framed the ongoing conversation about resilience in spaceflight gear and the steps needed to ensure continued, safe access to the vacuum of space.