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NASA astronaut Mike Fincke holds an early prototype of the lighting that will be implemented aboard the space station.
It's not every day that the reach of one's research extends into space.
But the work of BWH's Charles Czeisler, MD, PhD, Elizabeth Klerman, MD, PhD, and Steven Lockley, PhD, is doing just that and will be implemented aboard the International Space Station (ISS) later this year, improving astronauts' ability to sleep soundly and stay alert.
Sleep is largely managed by the body's circadian clock, which regulates our production of the sleep-promoting hormone melatonin, and cortisol, a hormone that promotes wakefulness and is associated with stress. On Earth, people's circadian clocks are reset each day by exposure to natural light. In space, however, different light cues disrupt astronauts' circadian rhythms.
Czeisler, Klerman and Lockley learned in 2008 that NASA was planning to replace the florescent lighting on the entire ISS with next-generation solid-state lighting-longer-lasting energy-efficient lighting made up of light-emitting diodes (LEDs). They encouraged NASA to incorporate their research on the biological effects of light on sleep and circadian rhythms into the design of the lighting. That required that the wavelength and intensity of the lighting be controllable, instead of just the intensity, as NASA had planned.
In response, NASA formed the Space Station Lighting Assembly Design Revision Team, which consisted of Czeisler, Klerman, Lockley, George Brainard, PhD, of Thomas Jefferson University, and several colleagues at NASA. Based on the research conducted at BWH, the team advised NASA to re-lamp the entire ISS with LED lamps that would allow the wavelength and intensity of the lighting to be adjusted, in order to help synchronize astronauts' circadian rhythms with their necessary schedules in space. This will improve the soundness of astronauts' sleep and their waking performance.
The fixtures are composed of a rainbow of more than 100 LED bulbs cloaked by a diffuser, so they appear to be a single panel of white light. They have three modes, each with a different hue: white light for general vision, a cooler blue-enriched light that promotes alertness and a warmer red-enriched light that reduces the alerting effects of light and the suppression of the sleep-promoting hormone melatonin. LEDs have the additional bonus of being lighter, cooler, more durable, less toxic and more energy-efficient than fluorescent lights.
The Space Station Lighting Assembly Design Revision Team recently won the prestigious NASA Johnson Space Center Director's Innovation Award for its work. The award recognizes individuals and teams that have shown innovation through the development or implementation of positive changes in the operations or programs of NASA or the Johnson Space Center and in business practices, science, technology, engineering, medicine and education within the center.
Czeisler, Klerman, Lockley and the team accepted the award at a Jan. 14 celebration near the Johnson Space Center in Texas.
"Installation of this new lighting technology aboard the ISS represents the culmination of 25 years of basic and applied research on the effects of light on sleep and circadian rhythms, much of which was supported by NASA and conducted here at BWH," said Czeisler. "We are thrilled that this technology will be introduced aboard the space station in 2015 and hope that it will soon be available here on Earth as well."
Fun Fact
This is not the first foray into space for Czeisler and his team: In 1990, they convinced NASA to introduce a bright light countermeasure into the astronaut crew quarters for use during the quarantine interval before launch. The team designed the lighting at BWH, which NASA has since used for all crews requiring a pre-launch shift in the timing of their sleep-wake cycles.