MELBOURNE, FL — NASA conducted its first medical evacuation from the International Space Station on Wednesday, Jan. 14, after a Crew-11 astronaut developed a health issue last week.

The astronauts are set to return to Earth in the early hours of Jan. 15. The crew will splashdown at 3:41 a.m. ET off Southern California. Areas along the California coast could hear a sonic boom as the spacecraft reenters Earth's atmosphere faster than sound.

Instead of waiting for Crew-12's arrival, the four-person Crew-11 will return to Earth early via the SpaceX Dragon they traveled up in. SpaceX released a reentry trajectory map. Dragon will pass directly over Santa Barbara, California, past Los Angeles and Long Beach, California, heading for a splashdown off the coast of San Diego.

The departure marked the first time in the station's 25-year history that a crew on the orbital outpost has cut a mission short to be medically evacuated. NASA has emphasized that there is no emergency, but that the problem one of the astronauts experienced requires monitoring on the ground.

NASA's decision to return the crew early was swift and unprecedented, but the space agency said astronauts and teams on the ground prepared for every possible situation. NASA has not identified the astronaut or the medical issue due to privacy concerns.