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Hank Green: So some people, and I'm not gonna say who, might find themselves sometimes laying on a hill at night, staring up at the moon and wondering, maybe even fantasizing, about what it would be like to walk around on that glorious lunar surface.  Only ten people have actually set foot there, making it look pretty fun, even if it was a little bit slow-goin', but a new NASA study has found that walking on the moon might be a lot easier and faster than we thought.  The Apollo astronauts just sorta galumphed around because their suits weren't designed with mobility in mind.  To see how people could move in lunar gravity, NASA physiologists conducted a weird experiment involving two pieces of equipment that I would be happy to never get anywhere near: a reduced gravity aircraft, also known as a vomit comet, and a treadmill.  

The scientists put eight people aboard a DC-9 tricked out with exercise equipment and sent them flying in a barf inducing parabolic pattern, going up sharply and then down to create low-G environments similar to that of the moon, where the effect of gravity is about 1/6 of that on Earth.  During the 20 second spells of low gravity, the test subjects started walking on treadmills, and scientists measured how quickly they could walk, as well as the speed at which they transitioned from walking to running.  On Earth, that transition happens when you're going about 2 meters per second, just fast enough that both of your feet are briefly off the ground at the same time, which is the technical definition of running.  Based on their calculations, the researchers thought that low gravity would make subjects hit that threshold while still going pretty slowly, about .8 meters/second.  But it turns out that they were able to walk a lot faster and keep walking at higher speeds until they broke into a run, reaching almost the same speed that they would here on Earth, about 1.4 meters/second.  Now, the subjects weren't wearing big bulky 1970s era space suits, which probably helped, but the researchers think that they key factor could be the motion of our limbs while we walk.  The swinging of our arms and legs creates its own slight G-force, as our limbs accelerate, which generates a small amount of what the researchers call "effective gravity" that pulls us to the ground.  This happens here on Earth, too, though its effect is negligible, but on the moon, the extra force could be enough to make walking feel a lot more familiar than Buzz and Neil made it look.  

And according to some other new research, you probably don't have to be as physically fit as the Apollo astronauts were if you wanna go into space.  With commercial ventures making space travel more accessible to the average person, or at least, the average millionaire, doctors at the University of Texas at Galveston wanted to see what it really means these days to have "the right stuff."  So they recruited 86 volunteers, ranging from age 20 to 78, with everyday health problems, like high blood pressure, diabetes, asthma, and common neck and back ailments, and they put them through the paces of space flight simulation along with a control group.  The test involved 7 stints over two days in a centrifuge, which simulates the high G-forces of launch and re-entry, and according to their results, none of the subjects suffered any serious negative physical effects from simulated space flight, not even that 78 year old.

But of course, this was more than just a ride on some carnival tilt-a-whirl, almost all of the subjects experienced some discomfort.  69% experienced grayout, a blurriness of vision caused by temporary loss of blood circulation the brain, 20% reported nausea, which is not at all surprising, and at least 6% felt pressure in the chest.  But those results are pretty typical, suggesting that, as one of the doctors put it, "the dream of spaceflight is one that most people can achieve."  So there's hope for all of us!

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