The lights that NASA is testing on sleep-deprived astronauts in space may also help people on planet earth get more rest, reports The Wall Street Journal.

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.