ISS Crew Sees 16 Daily Sunrises as Station Circles Earth Every 90 Minutes
Updated
Updated · spacedaily.com · Jun 7
ISS Crew Sees 16 Daily Sunrises as Station Circles Earth Every 90 Minutes
1 articles · Updated · spacedaily.com · Jun 7
Summary
Sixteen sunrises and sixteen sunsets a day are visible from the International Space Station because it completes about 16 Earth orbits in 24 hours, not because astronauts live through 16 separate days.
At roughly 400 kilometers above Earth, the station flies near 28,000 kilometers an hour, producing an orbital period of about 90 to 93 minutes; the public-facing count of 16 is a rounded average.
That average can briefly fail during high-beta-angle periods above about 70 degrees, when the station may stay in continuous sunlight for days and orbital sunsets stop for about a week each summer and winter.
UTC—not the Sun—sets the crew's schedule: astronauts follow a normal 24-hour routine with work, meals, exercise and about 8.5 hours of sleep, supported by adjustable LED lighting and dark sleep compartments.