To work in conjunction with the eye’s nonvisual system, the International Space Station’s high-precision LED lighting system will offer three main settings:
1) high alertness (blue-enriched light): suppresses melatonin, accelerates the shifting of the circadian clock, and boosts reaction times and performance.
2) general illumination: a bright and full spectrum of evenly distributed light — like that of daytime — improves visibility and maintains alertness and cognitive function.
3) pre-sleep, or bedtime (red-enriched white light): de-emphasizes blue light and promotes relaxation and sleep.
The lighting is being designed to help the astronauts relax, sleep, awaken feeling refreshed, and quickly shift their body clocks to better handle dangerous unpredictability in a line of work where one wrong move can mean mortal disaster.
The lights are designed to provide the right light at the right time, from blue-enriched alerting light in the morning, to lighting to maintain good vision during the working day, and then a blue-depleted and lower intensity light before bed to help relaxation and facilitate sleep.
Circadian neuroscientist Steven W. Lockley explains that along with the new lighting, we also need a new way to measure light as the current standards and meters are concerned only with light for vision. Light meters — along with current industry lighting standards — are attuned to the peak light sensitivity of the eye’s daytime color vision system.
The field is designing new ways to describe light so that the nonvisual benefits are also captured, Lockley says, allowing lighting designers and architects to start to incorporate the benefits of light into their designs. The spectral fingerprint of all lighting design should be based on optimizing both the visual and nonvisual benefits of light.
Safety-sensitive occupations, such as those found in the law enforcement and military fields, can benefit from this technology as well. Submarine crews, for example, just like astronauts, lack access to natural light-dark cycles.
A research article published in Acta Astronautica (George C. Brainard, et al., 2012, “Solid-state lighting for the International Space Station: Tests of visual performance and melatonin regulation”) describes the future of lighting.
As the article details, the development of specialized lighting for long-duration space exploration “will ultimately revolutionize how our public facilities, work places and homes are illuminated in the coming decades. … By refining multipurpose lights for astronaut safety, health and well-being in spaceflight, the door is opened for new lighting strategies that can be evolved for use on Earth.”
Everywhere electric light is used, Lockley says, we can do a better job of it. We’re only at the start of understanding what this photoreceptor system does. And as the general public becomes aware of the multipurpose lighting being developed for astronauts, he predicts an explosion in the availability of LED technology on Earth.