Light Side of the Moon

What should lighting design look like for a lunar habitat?

SAGA Space Architects, a Danish design practice specializing in outer space habitation research, wondered the same thing. With the goal of developing a Moon habitat suitable for regular people, not just trained astronauts, SAGA built and tested one for an analog Moon mission conducted near Moriusaq, Greenland in the high Arctic. From September to November 2020, Sebastian Aristotelis and Karl-Johan Sørensen deployed LUNARK and lived in it for 60 days, completely isolated.

A key factor to be considered for their psychological and physical well-being was the need for a stable circadian rhythm. In space, where every day is the same, senses become numb, cognitive abilities deteriorate and out-of-sync circadian rhythms make astronauts lethargic and unproductive. However, on the Moon, the sunlight environment is different. At the Moon’s equator, one will experience a 28 day-night cycle of 14 sunlit days followed by 14 days of darkness. At the Moon’s south pole there is almost always sunlight. The crew of LUNARK experienced similarly difficult light conditions by being close to Earth’s North Pole in the Artic Circle. To combat this, SAGA partnered with Danish lighting brand Louis Poulsen to create custom-made Circadian Light Panels that bathed the interiors in pseudo-natural daylight and accurately emulated Earth’s subtle hourly variations of dawn, sunrise, daylight, sunset and dusk.

Simulating a healthy circadian rhythm stimulates natural sleep and wake hormone production in the body. Lowering the intensity of blue light towards the evening promotes production of the sleep hormone melatonin production, and likewise waking up to increasing blue light suppresses melatonin and promotes cortisol. To combat monotony even further, the panels were also programmed with variations between the days to mimic the different weather patterns we experience on Earth, from overcast and low light intensity to brighter, high intensity warm light.