Sleep Disorders Are the Greatest Threat to Successful Space Travel

If the Mars500 project has taught us anything, it's that the human brain can't handle the sensory deprivation chamber-like conditions of space for more than just a few months at a time.

Houston, we have a sleep disorder. That's essentially the greatest issue that faced astronauts who volunteered for a 17-month space simulation called the Mars500 project. It's not exploding oxygen tanks or a malfunctioning command module or a broken space heater or, shit, HAL. The failures were physiological, not mechanical.

Mars500 brought together three Russians, two Europeans and one Chinese crew member--all men--who volunteered to test the limits of the mind in the ultimate sensory deprivation chamber, a replica spaceship without windows, nestled in Moscow. Researchers studying the crew ran nearly 100 experiments on the men to gauge the impacts of protracted space travel. They even simulated the days-long lag in radio communications between Earth and Mars. Results of the sleep study are the first to be released since the project wrapped, and some of them read like science-fiction horror stories.

One crew member, for example, lost his circadian rhythm within days. Having evolved on Earth, humans are intrinsically in tune with both the revolutions of the planet around the Sun and the natural cycle of day and night. In space, that light-dark cycle disappears. The crew member wound up falling into a 25-hour day, which after a few days had dragged his rhythm far out of sync with those of his space buddies, making collaboration on basic tasks impossible. Their day was his night.

"He became somewhat isolated," said Mathias Basner, a sleep expert at the University of Pennsylvania involved in the sleep study, told the BBC. "For 20 percent of the time, this crew member was either the only crew member awake or the only person sleeping, which could potentially be a problem for team cohesion."

Well? How else did you expect they'd pass 520 days? Mars500 crew inside the deprivation ship (via)

Another crewman began sleeping less and less as his fellow mates slept more and more. He eventually developed chronic sleep deprivation, and wound up accounting for the most errors in the crew's weekly performance tests. A third crew member became depressed. Only two of the crew members coped successfully, Basner said. The crew members who began sleeping more were essentially slipping into a kind of hibernation, one researcher said. 

"This looks like something you see in birds in the winter," said David Dinges, another sleep expert at the University of Pennsylvania and lead author of the study, published in the journal Proceedings of the Natural Academy of Sciences.

The rules of space travel currently mandate that astronauts will not spend more than six months aboard the International Space Station. Largely, that's because the human brain, delicate as it is, can't handle the psychological stresses of being taken out of our natural, gravity-filled, sun-up/sun-down habitat. In fact, a bunch of studies have shown that the main impediment to a successful space mission is low crew morale stemming from living in a cramped environment with the same few souls, day-in and day-out. One cosmonaut wrote in his personal space journal that, "All the conditions necessary for murder are met if you shut two men in a cabin measuring 18 feet by 20 and leave them together for two months." Spooky.

Of course, one simple way to combat this kind of sleep-deprived space mania is to install brighter and more effective fluorescent lights, like the ones Earthlings in Scandinavia and the Pacific Northwest use to counteract Seasonal Affective Disorder

"This is one of the take-home messages," Basner said. "There has to be adequate lighting and it has to be strong enough to get the day/night cycle going and the time that the crew exposes itself to the light also has to be optimal."