Two Russian cosmonauts spent more than six hours outside the International Space Station on May 27, 2026, pulling science experiments off one module and bolting new instruments onto another while NASA broadcast every minute of it live. Sergey Kud-Sverchkov and Sergei Mikaev, both Roscosmos flight engineers, worked their way across three segments of the station’s Russian section in a carefully choreographed excursion that ended at 4:23 p.m. EDT with all primary objectives complete.
Kud-Sverchkov, a veteran cosmonaut who previously served as a flight engineer on Expedition 64 in 2020-2021, has logged months of experience aboard the station. Mikaev, also a trained engineer within the Roscosmos cosmonaut corps, is building his own spaceflight record during this rotation. Their pairing for this spacewalk reflects the standard Roscosmos practice of assigning EVA duties to crew members who have completed the agency’s full extravehicular-activity training pipeline.
The spacewalk is the latest sign that the Russian orbital segment remains fully operational for hands-on science work, even as the ISS enters the final stretch of its planned service life. NASA and Roscosmos continue to coordinate joint operations aboard the station under an ongoing cross-flight agreement, a partnership that persists despite broader tensions between the two countries on the ground.
What the cosmonauts did outside
Kud-Sverchkov and Mikaev tackled three distinct tasks during the 6-hour, 5-minute spacewalk, according to NASA’s post-spacewalk summary. They removed a microorganism exposure study from the exterior of the Poisk module, retrieved a materials-science cassette from the Nauka module, and installed a solar-flare radiation measurement device on the Zvezda service module.
Each objective sat on a different part of the Russian orbital segment, which meant the pair had to translate along the station’s outer hull between work sites. That kind of multi-module traverse adds complexity to any spacewalk because it requires careful tether management and coordination with flight controllers monitoring the crew’s path from the ground.
The cosmonauts had been preparing for the excursion for at least a week. Earlier in May, they moved their Orlan spacesuits into the Poisk airlock and rehearsed hatch procedures, a standard pre-EVA step for Russian spacewalks that confirms the outing was part of a planned operations cycle rather than an emergency response.
What the retrieved experiments were studying
The three pieces of hardware the cosmonauts handled touch on questions relevant to both basic science and future spaceflight. The microorganism study from Poisk exposed biological samples to the vacuum of space, cosmic radiation, and temperature extremes. Research like this helps scientists understand how life survives in harsh environments, data that could inform astrobiology and the design of life-support systems.
The Nauka cassette had been collecting materials-science data. NASA’s summary describes it as related to semiconductor formation, though the exact experimental parameters and the precise terminology used by Roscosmos for the study have not appeared in the English-language updates cited here. The new radiation sensor mounted on Zvezda will track solar-flare activity, giving ground teams better data on the radiation doses crews absorb during periods of high solar activity. With the current solar cycle near its peak, that kind of monitoring carries added urgency.
No raw results from the retrieved experiments have been released yet. Roscosmos and its partner research institutions will need to analyze the returned samples and data before publishing findings, and no timeline for that release has been announced.
How NASA covered the spacewalk
NASA streamed the full spacewalk through its NASA+ platform and affiliated channels, with English-language commentary running over the cosmonauts’ Russian radio communications. Live coverage of Russian EVAs by NASA is routine but still operationally notable. Broadcasting these events in English likely involves close coordination between Mission Control in Houston and its counterpart in Moscow, though the specific workflow between the two centers during live coverage is not detailed in the cited NASA updates.
The agency’s pre-spacewalk update had listed a planned start time of approximately 10:15 a.m. EDT. Based on the confirmed end time of 4:23 p.m. and the logged duration of 6 hours and 5 minutes, the cosmonauts appear to have opened the hatch within minutes of that target.
Where this spacewalk fits in the 2026 ISS calendar
The exact number of spacewalks conducted from the ISS so far in 2026 is not specified in the cited NASA blog posts, so a precise count is not available from the sources used here. What is clear is that both the U.S. and Russian segments continue to host active experiments and maintenance work, and the station’s operational calendar between now and its planned controlled deorbit in the early 2030s remains busy.
All descriptions of this spacewalk’s objectives and outcomes in this article come from NASA’s ISS program blog. Direct statements from Roscosmos leadership or from Kud-Sverchkov and Mikaev themselves have not appeared in the available English-language record. That means any interpretation of why these particular hardware moves were scheduled for this window, rather than a future one, rests on inference rather than on-the-record explanation from the Russian agency.
The practical picture is straightforward: the Russian crew is actively maintaining and upgrading science hardware on the station’s exterior, and U.S.-Russian ground teams are still running joint operations smoothly enough to broadcast them live to the public. The open question is whether the data Kud-Sverchkov and Mikaev brought back inside will produce published science, and how quickly. Until Roscosmos or its research partners release results from the Nauka cassette and the Poisk microorganism samples, the full scientific value of this spacewalk will remain incomplete.
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*This article was researched with the help of AI, with human editors creating the final content.
