On the desiccated desert planet Arrakis in Frank Herbert's novel Dune, the native Fremen use their water-conserving Stillsuits to recycle their bodies' fluids. They drink their own pee. Then they sweat and pee it out. Then they drink it again.
We see Astronaut Frank Poole going for a jog on the Jupiter-bound ship Discovery One, in Stanley Kubrick's 2001: A Space Odyssey.
In the report Nutritional Biochemistry of Space Flight, NASA scientists describe the cuisine enjoyed by early space pioneers:
"Early U.S. space food was highly engineered to minimize mass and volume and to prevent any possibility of food contaminating the small cabins... ...It consisted primarily of pureed foods in squeeze tubes, small cubed food items coated with an edible film to prevent crumbs from escaping, and freeze-dried, powdered food items. It was agreed by most that this early space food was unappetizing"
If one is to live and travel in space, there are some things one simply must do. You brush your teeth every day of course, because if you didn't you'd get a painful cavity. It's mindless now, a routine. Space explorers, real and fictional, know that without certain practices, supplements, and technology--bad things would happen.
Space--from the surface of other planets, to the vacuum of the interstellar void--is a harsh, foreign, and dangerous place. We humans like the conditions on our tiny speck of a bubble hurtling through space. Traditionally, on average, things have been just right for us. We like our goldilocks orbit, roughly 93 millions miles from the sun. We like our air with its 20% oxygen, our 1g gravity, our atmosphere and magnetic field letting in just the right amount solar radiation (maybe a little too much for our skin, but that's what shade trees and beach umbrellas are for), our water fresh, and our average global temperature around 50 ?F (though we'll soon kiss that goodbye).
Our physiology developed in and for these conditions: the way our lungs are calibrated just for this air pressure, allowing us to breathe without even thinking about it; the way our bones react to navigating a 1g environment by continually replenishing and turning over the mineral-rich tissue at just the right rate; the way our skin cells produce melanin and our irises contract to protect us from the damaging light of the sun. Our bodies are finely tuned for this environment, yet we have this desire to leave, to explore, to pack ourselves into little earth-like bubbles, without which we'd pretty quickly suffocate, freeze, burn, die of thirst, waste away, or get squashed or ripped apart by the tidal forces of massive planets and stars.
Even when we're in one of our high-tech bubbles, like the International Space Station (ISS), things can get pretty rough. NASA's Human Research Roadmap includes a list of risks to human health that come from spending long periods of time beyond low-earth orbit. There are 32 risks on the list. These include: bone fracture, decompression sickness, radiation carcinogenesis, cardiac rhythm problems, inadequate nutrition, adverse behavioral conditions and psychiatric disorders, early onset of osteoporosis due to spaceflight, renal stone formation, and spaceflight-induced intracranial hypertension/vision alterations. Among others.
As you can imagine, astronauts need to take certain precautions. In this super-cool NASA video from 2011, astronaut Sunni Williams shows how ISS residents exercise--an interesting challenge in zero g--for two hours every day! Resistance and cardiovascular exercises are necessary, she explains, for avoiding muscle atrophy, bone density loss, and cardio vascular issues (the heart is muscle too).
Many of us would balk at the prospect of doing two hours of exercise a day, but to the ISS astronauts, this is as normal a part of their daily routine as flossing. It's a small price to pay when one has the privilege of being at the front line of human technological advancement.
So you have to be fit to be a spaceman (or spacewoman). That's not so surprising. We send the best of our best into space, we want our fittest and our brightest test-driving the technology of the future.
However, imagine life two or three hundred years from now. If we haven't blown ourselves up or fried the planet by then, it's likely that a lot more everyday people will be spending time in space. For future asteroid miners, mars and lunar settlers, scientists, tourists and explorers, precise dietary and exercise practices will be a mundane but necessary part of daily life.
That may seem like long way off, but maybe we should start looking at conditions here on earth today. If you think about our way of life in its historical context, you start to realize that we're already living a fantastic future. To us, bubble cities on mars, space cruises and asteroid mines seem like bizarre and amazing technological feats, the stuff of science fiction novels. Go back a few thousand years, and you'd find that an over-abundant food supply, automated transportation and manufacturing, and a sedentary workforce would be viewed as similarly awesome and impossible.
Just as we evolved as a species specialized to an environment characterized by the constant force of earth's gravity, so too did we evolve in an environment characterized by the constant pressure to seek out, consume and store energy, often in conditions where such energy was scarce. This scarcity affected the way we developed as a species. Many aspects of our physiology and even our psychology are fine-tuned to thrive even in an energy-deficient environment.
Our bodies start to break down when confronted with a low gravity environment. So too do our bodies start to break down when confronted with a high energy and low-physical activity environment. We see this in the drastic increase in obesity, type II diabetes, heart disease, stroke, depression, liver and gallbladder disease, sleep apnea, osteoarthritis, and certain types of cancer.
NASA is working on risk mitigation strategies for dealing with the harsh realities of life in space. The Centers for Disease Control and Prevention have already developed strategies for dealing with the risks of living in a sedentary, energy-rich, consumer society. The dangers are just as real, but thankfully, the solutions are much simpler. We don't need to use shock-mounted zero-g exercise bands and gravity-simulating treadmill harnesses for two hours every day (by the way, ISS's space treadmill is named after none other than TV comedian Stephen Colbert). We don't need to calculate exactly how much rocket fuel we can afford to burn to carry the precise amount of food weight we'll need for a multi-month mission. We just need to incorporate a bit more physical activity into our daily lives, eat more fresh fruits and vegetables, and eat a little less overall, even though every part of our beings is telling us to eat more and more.
These things are certainly not easy. But maybe it would help to start seeing physical activity and healthy eating simply as those things that we just have to do as a result of living in a science fiction story. We have flying machines. We have the ability to access and transfer unimaginable volumes of information over massive distances in no time at all. We have unmanned flying drone taco delivery. We have robots that care for our elderly and disabled. We live in the future! We also live in an energy environment that is completely foreign to our genes, and to our natural disposition.
What would you be willing to do to take care of your body if you got to go to space? To the future? What are you willing to do to take care of your body now? Maybe you can walk or bike to work. Maybe you can get a salad instead of the fries. You'll be happy you did, and you'll feel good. Plus, it's much better than drinking your pee.
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