NASA Installs 3-Mode ISS LED Lights to Counter 16 Daily Sunrises
Updated
Updated · spacedaily.com · Aug 1
NASA Installs 3-Mode ISS LED Lights to Counter 16 Daily Sunrises
3 articles · Updated · spacedaily.com · Aug 1
Summary
NASA replaced the ISS’s fluorescent fixtures with adjustable LED panels designed to keep astronauts on a 24-hour sleep-wake schedule despite 16 sunrises and sunsets each day in orbit.
The system cycles through three modes—daytime white light, blue-enriched alerting light, and amber pre-sleep light—while station windows are covered during scheduled sleep to block orbital dawns and dusks.
A 2016 study of 21 astronauts across 3,248 nights found crews slept an average 6 hours 5 minutes in space, with less than 6 hours on 43.8% of nights and frequent use of sleep medication.
That sleep loss was tied to circadian misalignment and measurable drops in cognitive performance, underscoring how long-duration spaceflight still depends on engineered countermeasures to offset human biology.