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NASA is bringing some of the crew aboard the International Space Station (ISS) back to Earth early due to medical concerns with one the astronauts.

That shouldn't cause any delays in the preparations to rollout and launch the agency's Space Launch System (SLS) rocket for Artemis 2 — the first crewed mission to the moon in over 50 years — NASA Administrator Jared Isaacman said Thursday (Jan. 8).

"These would be totally separate campaigns at this point," Isaacman said during a Jan. 8 press conference to provide an update on NASA's decision to end Crew-11 early. "There's no reason to believe at this point in time that there'd be any overlap that we have to deconflict for."

His reassurance of Artemis 2's timeline, which is slated to roll to the launchpad for a liftoff no earlier than Feb. 5, comes amid NASA's decision to cut short an ISS crew rotation due to medical concerns for the first time ever.

On Wednesday (Jan. 7), NASA officials announced they had decided to cancel an upcoming spacewalk due to a medical issue with an undisclosed crew member. Hours later, the agency indicated that it wasn't ruling out an early end to Crew-11's mission, and confirmed that the unnamed crew member was in a stable, non-emergency condition. NASA officials finalized the decision to bring the astronauts home in an announcement Thursday (Jan. 8).

NASA astronauts Zena Cardman and Michael Fincke, Japan's Kimiya Yui, and Oleg Platonov of the Russian space agency Roscosmos launched to the ISS atop a SpaceX Falcon 9 rocket on Aug. 1, 2025. Ferried to the ISS aboard SpaceX's Crew Dragon Endeavour, the Crew-11 astronauts were expected to carry out a six-month stint before replacement astronauts on SpaceX's upcoming Crew-12 mission rotated in.

Crew-12 is currently scheduled for a mid-February launch, with Crew-11 previously slated for departure a handful of days after their arrival. Their early departure, however, has raised questions of NASA's ability to handle the logistics of sandwiching the Crew-11 return and Crew-12's launch around what is arguably NASA's biggest mission in over 50 years.

Artemis 2 is the second installment for NASA's Artemis program, which aims to return astronauts to the moon to establish a permanent presence on the lunar surface. The program's first launch, Artemis 1, launched in November 2022, and flew an uncrewed Orion spacecraft to lunar orbit on a mission that lasted about one month.

Artemis 2 will be Orion's first venture into space with astronauts aboard, and will fly humans around the moon for the first time since 1972 and the end of NASA's Apollo missions. The spacecraft will carry NASA astronauts Reid Wiseman, Victor Glover, Christina Koch and Canadian Space Agency astronaut Jeremy Hansen on a roughly 10-day mission once around the moon and back, and will set the stage for Artemis 3 — the mission intended to land astronauts back on the moon's surface.

Both missions have faced years-long delays, and NASA's ambitious goal to launch Artemis 2 during its first window of opportunity isn't being thwarted by recent events aboard the ISS.

Ideally, just as in a nominal crew turnover, NASA would prefer to launch Crew-12 prior to Crew-11's departure. Such overlaps have been standard procedure since the station's continual occupation for more than two decades of operation. And even with SLS rollout expected within the next two weeks, NASA is investigating the possibility to move Crew-12's launch up the calendar to avoid the crew gap in low Earth orbit.

"We're still evaluating what earlier dates would be achievable, if any, for Crew-12," Isaacman said. "We're going to look at ... all of our standard process to prepare for Crew-12, and look for opportunity if we can bring it in while simultaneously conducting our Artemis two campaign."