Four astronauts are set to return from the International Space Station (ISS) on Wednesday night, departing weeks earlier than originally planned due to health concerns.

NASA astronauts Zena Cardman and Mike Finke, alongside Japanese cosmonaut Kamiya Yui and Russian cosmonaut Oleg Platonov, will make their journey back to Earth aboard the same SpaceX Dragon capsule that previously transported them to the ISS. This group, known as “Crew-11,” is expected to undock at around 5:05 p.m. ET.

This incident marks the first time in the ISS’s 25-year history that a mission has had to be cut short due to a medical issue while in orbit. Though NASA has not disclosed specifics regarding the affected crew members or the nature of their medical issues, citing privacy concerns, officials reassured the public that the situation is stable and does not warrant an emergency evacuation.

“First and foremost, we’re all okay,” Finke stated in a LinkedIn post over the weekend. “Everyone on board is stable, safe, and well cared for. This decision allows for a comprehensive medical evaluation on the ground where all diagnostic capabilities exist. This is the correct decision, even if it feels somewhat bittersweet.”

If undocking proceeds as scheduled, Crew-11 astronauts are anticipated to splash down in the Pacific Ocean off California’s coast around 3:41 a.m. ET on Thursday. The journey back will take approximately 11 hours, including a deorbit burn to slow the spacecraft before it re-enters Earth’s atmosphere, culminating in a parachute landing underwater.

Arriving at the ISS in August, Cardman, Finke, Yui, and Platonov were initially slated to remain until the end of February. However, a recent medical incident involving a crew member led NASA to cancel a planned spacewalk, which Cardman and Finke were set to conduct for station exterior renovations. Following this, the decision was made to expedite the crew’s return as a precautionary measure.

“After thorough consultation with Chief Medical Officer Dr. J.D. Polk and various agency leaders, we concluded that it is in the best interest of the astronauts to return Crew-11 ahead of the original schedule,” stated NASA Administrator Jared Isaacman on Thursday.

The astronauts are expected to land on Earth before the next space station crew takes off, but NASA confirms that Flight Engineer Chris Williams and two Russian cosmonauts will remain aboard. NASA officials are exploring options to expedite the next launch. The upcoming mission, known as Crew 12, is planned for a launch by February 15, but Williams will presumably be the sole NASA astronaut managing U.S. scientific experiments and operations on the ISS for several weeks.

During a “change of command” ceremony prior to departure on Monday, Finke officially handed over command of the space station to cosmonaut Sergei Kud-Sverchkov.

“Sergei, it is both an honor and a pleasure to hand over command to you,” Finke remarked.

He referred to the crew’s unexpectedly early departure as “an interesting time,” reminiscing positively about their experience in orbit.

“We come from diverse places around the globe and work collaboratively,” Finke concluded. “This is a fantastic representation of what humanity can achieve together.”