Our sleep patterns on Earth are influenced by our environment and a 24-hour cycle called circadian rhythms. These rhythms regulate our alertness and sleepiness, impacting various bodily functions. The cues in our environment, such as light, affect these rhythms. Light signals our bodies to wake up, while darkness signals sleep.

However, in space, there is no natural 24-hour day cycle. To address this, the International Space Station (ISS) follows Greenwich Mean Time to establish a consistent schedule for astronauts’ sleep and wake cycles. Nevertheless, researchers aim to enhance the astronauts’ sleeping conditions within this cycle. One approach is to use lighting that simulates different times of day, with a soft red glow at night resembling a sunset and a bright blue light in the morning similar to the sky.

The European Space Agency has initiated an experiment called Circadian Light. Astronaut Andreas Mogensen will test this experiment to investigate if changing light conditions can improve his sleep. The lighting not only changes color, but it also varies from day to day, simulating diverse weather conditions. This variability aims to provide a more engaging experience in an otherwise monotonous environment.