4 astronauts to depart ISS, leaving behind just 3 crewmates to staff the orbiting lab

Four astronauts are about to make an abrupt exit from the International Space Station amid a health concern — and their unprecedented early departure will leave behind a bare-bones staff to look after the outpost.

When the crew boards the SpaceX capsule that will bring them home, only three people will remain on the orbiting laboratory: Roscosmos cosmonauts Sergey Kud-Sverchkov and Sergei Mikaev of Russia and NASA astronaut Chris Williams.

The US space agency will livestream the departure of the SpaceX Crew capsule on NASA+ starting at 4:45 p.m. ET Wednesday, with the capsule set to undock from the space station around 5 p.m. ET.

It’s a less-than-ideal scenario. NASA has repeatedly signaled that keeping the ISS fully staffed is a top priority, as the agency aims to maximize the amount of scientific research it can conduct on the aging station before it’s permanently retired early next decade.

NASA’s new administrator, Jared Isaacman, made the decision last week to bring the four-person crew home early when the agency canceled a January 8 spacewalk slated to be carried out by American astronauts Mike Fincke and Zena Cardman.

“For over 60 years, NASA’s set the standard for safety and security in crewed spaceflight,” Isaacman said during a news conference last week. “In these endeavors, including the 25 years of continuous human presence on board the International Space Station, the health and the well-being of our astronauts is always and will be our highest priority.”

Fincke and Cardman, along with astronaut Kimiya Yui of the Japan Aerospace Exploration Agency, or JAXA, and Roscosmos cosmonaut Oleg Platonov, are part of the Crew-11 mission that’s leaving the space station. NASA did not say which crew member is experiencing a medical concern — nor did the space agency provide any details about the nature of the condition, citing privacy concerns. However, NASA has said the affected astronaut is in stable condition.