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A new sleeping bag could reduce eyesight difficulties on long space missions. The invention aims to alleviate tension that builds up driving the eyes for the duration of lengthy intervals of reduced gravity. Astronauts expertise this microgravity in house.
The high-tech snooze sack appears like a big sugar cone and addresses only the lower 50 % of the human body. The idea for it arrived from a technique researchers use to review blood tension, notes Christopher Hearon. He’s a physiologist at the College of Texas Southwestern Healthcare Center in Dallas. He and many others explained their new creation in JAMA Ophthalmology on December 9, 2021.
The sleeping bag’s style aims to prevent some thing regarded as SANS. That stands for spaceflight-linked neuro-ocular syndrome. On Earth, gravity pulls fluids in the system down into the legs. But without having the pull of Earth’s gravity, also significantly fluid stays in the head and upper overall body.
This extra fluid “presses on the back again of the eye” and modifications its condition, describes Andrew Lee. He was not element of this examine. As a neuro-ophthalmologist (Op-thuh-MOL-uh-gist), he’s a professional medical health practitioner who specials with the nerves in the eye. He works at Houston Methodist Medical center and at a new Weill Cornell Health-related College or university method. Both of those are in Texas.
“You get much more far-sighted,” Lee describes. The stress also causes a component of the eye’s optic nerve to swell. “Folds can form in the back of the eye as effectively. And the extent of the outcomes depends on how lengthy people today shell out in microgravity. “The a lot more time persons invest in place, the far more fluid stays in the head,” Lee claims. “So a extended-period space flight — like 15 months — could be a dilemma.” (That interval is how extended it would just take to get to Mars.) Lee and other people explained SANS in npj Microgravity in 2020.
And here’s in which Hearon and his team enter the tale. Before studies on blood pressure used techniques that sucked out air to generate destructive stress all around the lessen physique, Hearon suggests. Some teams had tried out to harness that strategy to stop SANS. But they ran into challenges, Hearon notes. So his team resolved try an technique that would deal with astronauts when they weren’t performing. That is why bedtime seemed great.
The workforce understood that tucking anyone into a standard sleeping bag and sucking out air wouldn’t perform. At some position the bag would collapse and push in opposition to the legs. That would backfire, pushing more fluid into the head. “You truly need to have to have a chamber,” states Steve Nagode. He’s a mechanical and innovation engineer in Kent, Wash. He commenced operating with Hearon’s crew when he was with REI, a sporting-products organization.
The sleeping bag’s cone receives its framework from rings and rods. Its outer shell is major vinyl, like that used on inflatable kayaks. The seal all-around the sleeper’s midsection is tailored from a kayaker’s skirt. (The cosy in shape keeps h2o out of a kayak.) And a platform like a tractor seat keeps an astronaut from being sucked in far too considerably when the device’s reduced-electrical power vacuum is on. “You experience like you are receiving sucked into the sleeping sack a tiny bit,” admits Hearon. “Otherwise, it feels seriously regular after you get settled in.”
His team analyzed a prototype with a small team of volunteers on Earth. “We had 10 subjects who each and every completed two bouts of 72 several hours of bed relaxation,” he points out. At the very least two months separated each 3-working day exam interval. Except for small lavatory breaks, the volunteers stayed flat. Earlier analysis had revealed that was enough time to trigger fluid shifts like all those astronauts would knowledge.
The volunteers used the 3 days in 1 test session laying usually in mattress. They stayed on the exact same mattress for 3 days in the other exam session. But their reduced overall body was in the sleeping sack for eight hrs every single night time. In the course of every single test period, health-related personnel measured heart premiums and other factors.
They calculated blood stress, for instance, as blood fills the coronary heart. Recognized as central venous pressure, this CVP is large when there is a ton of blood in the higher entire body, as comes about in place. CVP also went up when people stayed flat. But it came down at night time when the rest sack was on. That “confirms that we have been pulling blood down to the legs, absent from the heart and head,” Hearon says.
People’s eyeballs also showed tiny changes in shape when they stayed flat on the 3 days that they did not use the unit. Shape improvements like those are an early indication of SANS. The modifications were being substantially smaller sized when men and women utilised the system.
Lee at Weill Cornell and Houston Methodist says he hopes the design would protect against SANS in microgravity, but “It might not. We don’t know mainly because we have not analyzed it in place.” He also miracles about doable facet outcomes from extended-expression use. It is just one factor to reverse improvements in fluid tension, Lee states. “It’s one more issue to do it safely.”
Hearon and his team agree much more testing is necessary. “Missions are likely to be significantly lengthier than 3 times,” he notes. Potential do the job also will investigate how lengthy the gadget must run to give the best benefits.
Nagode may perhaps also attract on his competencies from designing backpacking equipment to make long term tweaks. The group may perhaps want to make the cone condition collapsible, for illustration. Soon after all, he states, “Anything heading up into house has to be lightweight and compact.”
This is 1 in a series presenting news on technologies and innovation, designed attainable with generous assistance from the Lemelson Foundation.