To fend off vision problems some astronauts experience while living in space, scientists have developed a high-tech sleeping bag that effectively sucks fluid from the head to the feet, countering pressure build up.
Earth’s gravity keeps liquid from accumulating where it shouldn’t, but in the vacuum of space, more than half a gallon of body fluids can gather in the head, squeezing the eyeballs. The condition, known as Space-Associated Neuro-Ocular Syndrome (SANS), is thought to involve multiple factors—including increased pressure in the head, as well as overfilling of blood vessels, inflammation, elevated levels of carbon dioxide, radiation, genetics, and vitamin B status.
“The pressure in zero-g is always lower than the pressure in one-g,” Benjamin Levine, professor of internal medicine at University of Texas (UT) Southwestern Medical Center, told the BBC. “But it’s not as low as when you’re standing up.
Levine is part of a team of researchers working to get their fluid-sucking sleeping bag deployed on the International Space Station. “Normally, we spend one-third of our time lying down at night and two-thirds upright during the day,” he explained. “NASA astronauts can’t stand up during flight.”
Roughly 70 percent of ISS crew members develop vision problems of varying degrees. In 2005, for instance, John Philips returned from a half-year stint aboard the floating laboratory with his vision reduced from 20/20 to 20/100, The Washington PostThe Washington Post previously reported.
“We don’t know how bad the effects might be on a longer flight, like a two-year Mars operation,” Levine said in a statement. “It would be a disaster if astronauts had such severe impairments that they couldn’t see what they’re doing and it compromised the mission.”
Unlike a traditional camping bedroll, this new sleeping device, developed with outdoor equipment manufacturer REI, attaches at the waist and encloses the lower body in a solid frame. Just like your home vacuum cleaner, a built-in suction system creates a pressure difference, drawing fluid down to the feet and preventing build up in the brain.
Don’t expect to see the next set of ISS astronauts sporting these cocoon-like bags, though. Scientists must first determine things like optimal time spent in the sleeping bag each day, and whether it’s fit for everyone or just those at risk of developing SANS.
