Life at 17,500 mph: ISS astronauts juggle 16 sunrises, sleep schedules, and celebrations

ISS crews live by UTC, not by the sun, because the station sees 16 sunrises a day.

To protect sleep and circadian health, astronauts follow fixed routines and carefully engineered lighting.

Religious observance and personal celebrations are adapted to Earth-based anchors, mission rules, and ritual workarounds.

The story highlights how long-duration spaceflight reshapes both the body’s timekeeping and cultural life.