Can Research on Astronauts Lead to a Good Night’s Sleep on Earth?
As NASA, SpaceX and other groups plan for voyages to the moon and Mars, researchers are working to figure out the secret of an essential for life on any planet: a good night’s sleep.
Scientists and NASA engineers are coming to grips with how the body’s natural biorhythms are affected by artificial light, whether from a bedside lamp, the overhead fixtures of a hospital room or the cramped quarters of a space capsule in the twilight between planets.
Tests aboard the International Space Station—including $11 million worth of adjustable LED lighting that mimics the changing spectrum of natural sunlight through the day—may help the next generation of astronauts sleep soundly on space flights. The research also may improve the quality of slumber for shift workers, bleary business travelers and insomniacs.
Many astronauts lose sleep because they have severed an intimate connection with the natural 24-hour cycle of sunset and sunrise under which humankind evolved on Earth, researchers discovered. Like many body functions, sleep is regulated by exposure to light, which sets a biological tempo called the circadian rhythm.
To address the problem, spacecraft engineers and sleep physiologists are trying to put things in a different light. For the past 18 months, astronauts have been replacing the 85 fluorescent lights aboard the International Space Station—similar to those used in hospitals, warehouses and office cubicles—with energy-efficient LED lighting that can help reset the body clock because their light can affect production of a sleep-related hormone called melatonin.
“It is like the sun in a box,” said flight surgeon Smith Johnston at NASA’s Johnson Space Center in Houston, who supervises astronaut medical matters.
The experimental fixtures have three settings that simulate changes in natural sunlight throughout the day. The first is rich in blue wavelengths of light like the noonday sun, for normal work lighting. The second setting is brighter and more intensely blue to heighten alertness during emergencies. The third is low in blue and rich in red, like the afterglow of the setting sun, to promote sound sleep.