Astronauts Measure Sleep in Orbit

Getting a good night’s rest can be difficult in your own bed, but imagine being over 200 miles from home, sleeping strapped down in a spacecraft orbiting earth, and at any moments notice you could be asked to perform a critical mission operation. Astronauts onboard the International Space Station spend anywhere from 14 days to 6 months in such conditions. Now NASA is conducting a study to monitor the sleep-wake patterns of crew members while onboard the space station in hopes of improving the quality and duration of sleep in space—a gravity free environment .

Astronauts will wear a wristwatch called an Actiwatch that monitors their sleep/wake activity using accelerometers, sensors that record movement. The device will also measure the ambient light conditions. In addition, astronauts will have to keep a daily sleep log. At least 20 crew members are expected to participate in the study. Prior to launching in space, each crew member will submit baseline data from her sleep patterns on Earth.

Sleep deprivation has a real effect on human health, a person’s ability to focus and perform task, and his or her mental state. Medical research has also shown that chronic sleep loss can lead to hypertension, diabetes, obesity, cardiovascular disease, and multiple psychiatric disorders. The manager of the Behavioral Health and Performance Element Human Research Program Space Medicine Division at NASA’s Johnson Space Center in Houston, Lauren Leveton, points out the importance of the impact of sleep loss to the crew in the agency’s press release. “When you consider the risky business of spaceflight,” said Leveton, “We want to reduce the risk of performance decrements and optimize people’s performance capabilities.”

NASA says that data and feedback from a few astronauts already using the device has lead to changes in schedule and countermeasures like naps or caffeine intake. The agency hopes that the information they gather can be used for planning future exploration missions that could last twice as long and in more constrained environments. The data will also be valuable on Earth to improve the sleep of police officers, shift workers, and military personnel, for example.