WEBVTT - Why Would We Need Artificial Gravity in Space?

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<v Speaker 1>Welcome to brain Stuff, a production of I Heart Radio,

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<v Speaker 1>Hey brain Stuff Lauren Vogel Bomb Here. Imagine that you're

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<v Speaker 1>inside a vehicle or other machine this spinning around so

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<v Speaker 1>fast that the force presses your body against the wall

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<v Speaker 1>or seat. As you spin faster and faster, the pressure

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<v Speaker 1>forcing you against the wall increases, and conversely it decreases

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<v Speaker 1>as the spin slows down. The weight feels just like

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<v Speaker 1>the force of gravity that keeps your body grounded to

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<v Speaker 1>the Earth. If you're like many people, your most dramatic

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<v Speaker 1>experience with this type of spinning forces probably from an

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<v Speaker 1>amusement park ride, maybe the classic rotor ride that has

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<v Speaker 1>produced a great deal of joy and yes, vomit since

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<v Speaker 1>the middle of the eight hundreds, But a handful of people,

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<v Speaker 1>including astronauts and military pilots, experience the same phenomenon in

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<v Speaker 1>a human rated centrifuge, which is a machine that spins

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<v Speaker 1>to produce these high G forces, which can be summarized

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<v Speaker 1>as forces that cause the perception of weight like acceleration,

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<v Speaker 1>deceleration and quick shifts and direction like on a roller coaster,

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<v Speaker 1>aboard high performance aircraft during high speed turns, during launches

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<v Speaker 1>into space, and when spacecraft's rapidly slow as they re

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<v Speaker 1>enter Earth's atmosphere, and like in these rotating machines, in

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<v Speaker 1>a very real sense, this type of rotation produces gravity,

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<v Speaker 1>artificial gravity to be precise. It provides weight to your body,

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<v Speaker 1>a weight that your bones and muscles can't distinguish from

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<v Speaker 1>the weight that Earth or another planet provides on account

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<v Speaker 1>of its sheer mass. Consequently, for decades, science fiction writers

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<v Speaker 1>have envisioned rotating spaceships that create artificial gravity for astronauts

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<v Speaker 1>during the longest phases of space missions. These phases are

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<v Speaker 1>when they are not extra heavy due to the ship

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<v Speaker 1>accelerating to build up speed or decelerating in the atmosphere,

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<v Speaker 1>but when they feel relatively weightless due to the craft coasting,

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<v Speaker 1>negating the effects of gravity. Two examples of such artificial

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<v Speaker 1>gravity and science fiction are the film The Martian and

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<v Speaker 1>the nineteen sixty eight film two thousand one, a Space Odyssey.

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<v Speaker 1>The Martian features an interplanetary craft, the Hermes, with a

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<v Speaker 1>large wheel shaped section that rotates on its journey between

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<v Speaker 1>Earth and Mars, and you notice that up for the

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<v Speaker 1>astronauts inside the Hermes is always towards the center of

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<v Speaker 1>the wheel. While down or the floor is the outer

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<v Speaker 1>rim of the wheel. In two thousand one, a Space

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<v Speaker 1>Odyssey space station five is a spinning station that generates

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<v Speaker 1>artificial gravity equal to that of the Moon's gravity. Apart

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<v Speaker 1>from mere comfort, there are good reasons why we need

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<v Speaker 1>artificial gravity on long distance space missions. For one, experiencing

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<v Speaker 1>relative weightlessness for long periods of time changes our bodies

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<v Speaker 1>in ways that could be harmful. When astronauts arrive at

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<v Speaker 1>their destinations such as an asteroid or Mars, or when

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<v Speaker 1>they return to Earth after some time in low gravity,

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<v Speaker 1>bones lose mineral content, meaning they soften, becoming vulnerable to fracture.

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<v Speaker 1>Muscles atrophy meaning they shrink and weaken. The fluids shift

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<v Speaker 1>toward the head and are also excreted from the body,

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<v Speaker 1>causing changes in the cardiovascular system in the lungs, the

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<v Speaker 1>nervous systems thrown out of whack, and in recent years,

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<v Speaker 1>space medicine researchers have found what could be permanent eye

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<v Speaker 1>damage in some astronauts due to the reshaping of the

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<v Speaker 1>eyes lenses. Add to that, research suggesting that gravity may

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<v Speaker 1>be required for humans to have a normal pregnancy in space,

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<v Speaker 1>and it seems almost like a no brainer that any

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<v Speaker 1>spacecraft carrying humans around the Solar System should either rotate

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<v Speaker 1>or have some part of the ship that does so.

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<v Speaker 1>Are NASA and others researching this possibility. The answer is yes, absolutely.

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<v Speaker 1>Since the nineteen sixties, NASA scientists have been considering the

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<v Speaker 1>prospect of artificial gravity by way of rotation. However, the effort, funding,

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<v Speaker 1>and overall enthusiasm has waxed and waned through the decades.

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<v Speaker 1>There was a surge in research in the nineteen sixties

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<v Speaker 1>when NASA was working on sending people to the Moon,

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<v Speaker 1>though the budget for NASA at that time was nearly

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<v Speaker 1>five percent that of the entire federal government, ten times

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<v Speaker 1>what it is today. While NASA has not emphasized research

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<v Speaker 1>on artificial gravity over the past half century, scientists both

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<v Speaker 1>inside and outside of the Space Agency are studying a

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<v Speaker 1>range of situations. Mice spinning in a small centrifuge aboard

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<v Speaker 1>the International Space Station survived with no problem, and earthbound

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<v Speaker 1>humans are learning how to adapt in spinning rooms. For example,

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<v Speaker 1>the DLR Institute of Airspace Medicine in Cologne, Germany, is

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<v Speaker 1>home to the DLR Short Arms Centrifuge Module one. It's

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<v Speaker 1>the only one of its kind in the world researching

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<v Speaker 1>the effects of altered gravity, especially as it pertains to

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<v Speaker 1>health risks that occur in microgravity, and the University of

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<v Speaker 1>Colorado Boulder is studying waste design revolving systems that could

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<v Speaker 1>fit in a room of a future space station or

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<v Speaker 1>moon base. Astronauts could crawl into these rooms for just

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<v Speaker 1>a few hours a day to get their daily dose

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<v Speaker 1>of gravity. But if the need for artificial gravity is

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<v Speaker 1>so clear, why bother with research in space or on Earth.

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<v Speaker 1>Why don't engineers simply get to work designing spinning ships

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<v Speaker 1>like the fictional Hermes. The answer is that artificial gravity

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<v Speaker 1>requires a trade off because all that spinning creates problems.

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<v Speaker 1>As on the rotor ride, moving your head while you're

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<v Speaker 1>spinning that fast causes nausea. It impacts the fluid in

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<v Speaker 1>your inner ear and any other body parts that you

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<v Speaker 1>move while you're in a rotating environment, and that nausea

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<v Speaker 1>and disorientation worsen the faster you rotate. That is, as

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<v Speaker 1>you increase the number of revolutions per minute or r

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<v Speaker 1>p ms, and the amount of artificial gravity that can

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<v Speaker 1>be produced depends on both those RPMs and the size

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<v Speaker 1>of whatever is rotating to experience a given amount of gravity,

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<v Speaker 1>for example, one half the usual amount that you feel

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<v Speaker 1>on Earth. The length of the radius of rotation, that is,

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<v Speaker 1>the distance from you standing on the floor to the

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<v Speaker 1>center of whatever is spinning, determines how fast you need

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<v Speaker 1>to spin. Build a wheel shaped craft with a radius

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<v Speaker 1>of seven and thirty eight feet that's two d and

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<v Speaker 1>twenty five, and you'll produce the equivalent of normal Earth

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<v Speaker 1>gravity known as one G, rotating at just one revolution

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<v Speaker 1>per minute. That's slow enough that scientists are pretty sure

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<v Speaker 1>that nobody would get nauseated or disoriented. Other than the

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<v Speaker 1>floor being a bit curved, things aboard such a craft

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<v Speaker 1>would feel pretty normal, but building and flying such an

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<v Speaker 1>enormous structure in space would entail a lot of engineering challenges.

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<v Speaker 1>This means that NASA and any other space agencies or

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<v Speaker 1>organizations likely to send people around the Solar System in

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<v Speaker 1>the future must either settle for a lower amount of gravity,

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<v Speaker 1>faster rotation that is more RPMs, or both. The Moon

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<v Speaker 1>has a surface gravity of about six that of Earth's surface,

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<v Speaker 1>which makes it a great place to research the effects

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<v Speaker 1>of low gravity, but there are no laboratories on the

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<v Speaker 1>Moon it. There simply isn't enough data to know how

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<v Speaker 1>much gravity humans may need for long term space missions

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<v Speaker 1>or in space colonies, which means more research is needed,

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<v Speaker 1>as is data on how much rotation humans can reasonably tolerate.

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<v Speaker 1>Today's episode was written by David warm Flash and produced

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<v Speaker 1>by Tyler Clang. For more on this and lots of

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<v Speaker 1>other heavy topics, visit how stuffworks dot com. Brain Stuff

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<v Speaker 1>is production of I heart Radio. For more podcasts to

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