Space is a great place to visit (we’re told). But it’s tough to live there. Unlike say, Miami, it wasn’t meant for human habitation or extended loitering.
Barring radiation poisoning and direct exposure to the -454.8 degree temperatures and the airlessness, one of the biggest menaces to the fluid-sacks that we call our bodies is zero-gravity. From sudden peeing to dams of sinus-packing mucus, space is hardly a pleasure cruise. Here are the weirdest, and most painful, side effects to consider before your journey.
On Earth, your bladder tells you when to go. As it fills, the pressure on the bottom increases and, when they’re about two-thirds full, that’s when you feel that awkward urge. In space you don’t feel that because of zero G. It’s only when you reach max capacity that you may start to feel it. By then, you’re already going.
Consider Astronaut John Glenn. In 1962 he voided 27 ounces of pee during his—and the nation’s—first orbital flight, with no advance warning. Luckily, he was wearing a roll-on cuff attached to a bag that let him pee hands free. (A great idea, we think, for long road trips or movie theaters).
NASA deemed this innovation necessary after Glenn’s predecessor, Alan Shepard, had to sit on the launch pad for five hours before his fifteen minute spaceflight. Shepard had no option but to pee in his suit; he short-circuited his heart rate monitor in the process. Nowadays, astronauts on the International Space Station are prepared with a high-tech solution: adult diapers, ones that can absorb the urine and recycle it for drinking water later. Yum.
As the stomach breaks down food, it produces gas. (That’s why you burp). On Earth, that air naturally rises. In space, gases stay trapped in the stomach. Any attempt to burp can result in vomiting. ISS astronaut James Newman has found a little push provides the necessary assistance for vomit-proof belch production. His “push and burp” strategy entails pushing off a wall, forcing the gas in one direction (out through the esophagus) and the stomach fluids in the other.
The problematic gas-trap is one reason NASA does not allow carbonated drinks like soda or beer in space. Think about it: The only thing worse than an inebriated astronaut is an inebriated astronaut who keeps vomiting.
The body’s natural ability to reabsorb calcium into the bones doesn’t function in zero G. So in space we lose bone density at a rate ten times faster than osteoporosis. Muscles also atrophy because you’re not using them much: you can get anywhere with a tiny push. For both reasons, you need to exercise a couple hours a day. But then there’s the sweat, which sticks around. If you exercise vigorously enough, sweat clings to you in blobs. You could float around like that all day, to the annoyance of your fellow astronauts, and the sweat will never roll off. You need to towel it off. And then you need to collect it. Why? It’s a valuable source of water that can be reclaimed for drinking. We guess Douglas Adams was on to something when he said a towel is the most massively useful thing to have in space.
Like sweat, tears ball up in space. They do not cinematically roll down your cheeks. Instead, they coat your eyes until you can’t see. ISS astronaut Andrew Feustel experienced this problem, in 2011, during a seven-hour spacewalk. His helmet’s anti-fogging solution caught in his eye and he started to tear up and he could not wipe it from inside his suit. His spacewalk partner Mike Fincke could offer only a consolatory “Sorry buddy.” So Feustel had to scratch his eye on a device used to protect the nose during pressure adjustments. We’re guessing it couldn’t have been pleasant. But it did scrape the solution and the tears out of his eye. Other astronauts who have teared up say that, thanks to the salt content, it stings quite a bit.
Here on Earth, gravity drains your sinuses. As you produce mucus, it empties through the nose and drains down the throat. (Yes, it does this all day long, you’re just not aware of it. Now try to un-know that!). In zero G, the gluey stuff piles up, giving you the symptoms of a minor cold–headache, stuffy nose, a diminished sense of smell and taste. The only relief is to blow. A lot. That can hurt the mucous membranes and be really annoying to boot. So most astronauts turn to a delicious coping mechanism: hot sauce and other spicy foods. While it won’t clear up the sinuses, at least they can taste their food again.
The feeling, and the concept, of “up” and “down” rely on our sense of gravity, which in turn rely on two small organs in each inner ear. The utricle and saccule use sensory hairs in a membrane layer. When we tilt over, the membrane shifts, and the hairs bend, informing us of the change in balance.
In weightless environments there’s no reason for the membrane to shift, so the system goes a little haywire. This can be completely disorienting until you adapt to it. And until then, you’ll be space sick. Incapacitating discomfort, nausea, headaches, and more vomiting.
Technically it’s known as Space Adaptation Syndrome, and it is informally measured on what’s called the Garn Scale. It’s named after former U.S. astronaut and former U.S. Senator, Edwin “Jake” Garn. He served as payload specialist congressional observer on a 1985 shuttle mission and as a specimen for fellow astronauts to perform medical experiments on motion sickness. Fortunately for his crew members, Garn did not adapt well to space. Upon his return to Earth, other astronauts jokingly developed the informal Garn Scale to indicate how much an astronaut is incapacitated by space sickness. Garn experienced one Garn, which according to astronaut trainer Robert E. Stevenson, “represents the maximum level of space sickness that anyone can ever attain.” Garn suffered from each of the ailments listed above—although he insists he never vomited.
As far back as Apollo 11, in 1969, astronauts have reported seeing bright flashes of light in the dark–and when their eyes are closed. Shuttle astronaut Don Pettit, who also spent time on the ISS, said it was like seeing “luminous dancing fairies.” He said he often saw them when falling asleep.
The lights are still kind of a mystery, but here’s what we know: When we see a thing on Earth, light from the object hits photoreceptors in the back of our eye. The photoreceptors signal our brain about what happened so that it can begin to put a picture together. But in space, high-energy cosmic rays originating from beyond the solar system are everywhere; NASA scientists suspect the fairy lights phenomenon is caused by those cosmic rays passing directly through the eyelid to hit the photoreceptors, but the exact cause isn’t understood. For decades, NASA didn’t even believe it was a real phenomenon and insisted the astronauts were imagining it, which may have been another reason they didn’t want beer up in space.
Zero G disrupts the body’s blood flow. No longer pulled down towards the feet, blood is free to flow toward the upper torso. The head is a welcoming receptacle. During the first few days in space, the blood vessels of the head and neck swell, giving you a puffy-faced look. The astronauts call it “Moon face.” It takes about four days for the circulatory system to adapt and prevent so much blood from flowing to the upper body. At that point, the swelling (mostly) disappears, leaving only a lingering puffiness until the astronaut returns to Earth.
The International Space Station orbits Earth every 90 minutes, which means anyone on board experiences 16 sunrises and sunsets every 24 hours. These rapid light-to-dark transitions mess with the body’s circadian rhythm—normally maintained by regular intervals of light exposure—and short circuits the ability to sleep. On average, astronauts sleep two hours less per night than they do on the ground. If left alone this puts them in a perpetual state of jet lag, which can lead to exhaustion, increasing irritability, and decreasing reaction times and concentration. And a distracted astronaut is a careless astronaut. NASA combats the sleep problem by regularly adjusting when the astronauts’ alarms go off to ensure they get proper rest.
Try this experiment: Don’t look at your arm. You don’t see it, but you sense where it is in relation to your body. Even that awareness relies on gravity. Your proprioceptive system is a series of sensors in your muscles, tendons, and joints. The stresses that your joints experience from the regular pull of gravity informs that system, which tells your brain the location of your limbs. Without those stresses in zero G, and the tendency of limbs to float into unexpected positions, you can easily lose track of your own arms and legs. Many astronauts from Apollo to the present have woken up startled by someone’s hand in their face, only to realize it’s their own. Spooky.