Space weather is a fickle and unforgiving mistress. An unprotected astronaut could freeze his nuts off in the shadows, yet fry like an egg in the sun's harsh rays. Which is why his space suit almost has to be a kind of mini-spaceship, one that can protect him from both extreme heat and extreme cold at the same time. And why the space suit itself looks like a body diaper -- it's stuffed with multiple layers of insulation and an elaborate cooling system for maintaining the astronaut's body temperature.
Go ahead and pee in it. No one will notice.
The insulation isn't going anywhere, so the astronaut isn't really going to need to worry about losing much body heat during a short spacewalk, but if the cooling system breaks down, that's a whole other ball of death wax.
Sorry, little Timmy, but you'd boil alive in seconds with that suit.
Wait ... How Can That Kill Me?
In 1966, astronaut Gene Cernan (the same guy who gave his buddy space fever with moondust) became the third person to attempt an EVA, or extra-vehicular activity, in space. But unlike his Soviet and American predecessors, Cernan actually had work he was supposed to do during his three-hour spacewalk, including testing the first Astronaut Maneuvering Unit, or rocket pack. Unfortunately, those tasks were next to impossible to complete in microgravity, and Cernan found himself heating up like a two-dollar whore at a 1920s tent revival.
Gene Cernan, seen here humping a globe.
His air-cooled suit was unable to keep up with his body heat, so his faceplate fogged up so bad that he found himself blind in space. His pulse raced to 195 beats per minute. NASA doctors on the ground watched his vitals and worried that he was going to lose consciousness, so the three-hour walk was aborted after two hours. Had he stayed out much longer, he would have been a goner.
If you're going to die of heatstroke, it might as well be somewhere pretty.
The scary part is that it doesn't even take a completely broken suit to have space heatstroke. After Cernan's hot mess of a spacewalk, space suit makers switched to a water-cooled system, meaning the astronauts have tubes of water running through their suits to keep them from overheating. When Russian cosmonaut Alexander Kaleri started overheating during his 2004 spacewalk, it wasn't a broken suit that did him in -- it was one bent tube. In other words, it doesn't take much more than a wonky piece of plastic to condemn future astronauts to a death by body heat.
#2. Being Unable to Stop
One surprising thing about traveling through space is that you don't actually need a lot of fuel to do it. All that a spacecraft really requires is enough fuel to reach its top speed and enough to stop. Once ships attain their top speed, they can shut off their engines, because any object will stay at its speed unless a force is applied to it, aka Newton's First Law of Motion.
Making interstellar road trips very affordable.
In space, there are no resistive forces, and a ship does not need any fuel to stay in motion. It needs fuel to maneuver, yes, and fuel to slow down, but not fuel to move. Space is not a country drive in your pickup; you can't just kill the engines and cruise to a standstill.
You could totally fit, like, 20 mattresses in there, though.
Wait ... How Can That Kill Me?
A ship that runs out of fuel will go on continuously, forever and ever, in a singular direction. You don't even get to go out in a blaze of glory, because 99 percent of the observable universe is a heaping bowl of nothing. So running out of gas in space isn't a matter of sputtering to a stop, then calling home for somebody to fly up with a gas can. No, it's the opposite: Running out of gas in space is more like losing your brakes -- you'll shoot right past Earth and continue streaking out into nothingness, never stopping, ever, until you either get sucked into the orbital pull of another object or crash into something that kills you.
Above: Space emergency brake.
As for a cosmic gas truck coming to your rescue, fat chance. If you were already traveling at your top speed, you'd better hope that they built the refueling ship to be the fastest thing ever made. And if you're going, say, the speed of the Apollo spacecraft (about 24,000 miles per hour) and it takes them a week to get the rescue mission together, you'll be 4 million miles away before they even get off the launch pad.
#1. Kidney Stones
There's nothing like a rollicking kidney stone tale to remind you of the preciousness of good urinary health. Just the thought of passing a rock through your pee hole is enough to send a shiver up your back, and certainly enough to send you for the nearest glass of water.
"Painful, shitting death from cobra poison would be a mercy right now."
But still, it's a kidney stone, something usually reserved for grandpas and people who weren't manly enough to catch a real disease, like herpes. But what can start off as an excruciating inconvenience here on Earth can do some killing damage up in space.
Wait ... How Can That Kill Me?
First off, astronauts are waaaaay more vulnerable to kidney stones than the rest of us because they're losing bone density in space. And that lost calcium isn't just seeping off their bodies like bone sweat; it's ending up in their urine. And extra calcium in urine is one of the causes of kidney stones.
Robert R. Wal
So don't overdo it with the milk, OK?
So astronauts start the game with a stony target on their backs (or pee holes). Plus, peeing in space is no walk in the park to begin with, so astronauts are less likely to take in a lot of fluid, because they don't want to mess with space toilets. Lower fluid intake coupled with higher concentrations of calcium in their urine equals a very serious risk of getting a kidney stone on an extended journey. In fact, between 2001 and 2006, 14 American astronauts developed stones after they got back to Earth. That's a whole lot of pebble passing.
"It's like I'm passing a razor blade made of nails!"
Second, getting rid of that kidney stone in space is a totally different ballgame from passing it here on Earth. No gravity, no X-rays and no high-quality pain medication, so an especially big kidney stone is going to incapacitate its victim, at the very least. And if the stone drifts the wrong way for some reason, or if the astronaut develops stones in both kidneys, which, once again, is very likely -- forget it. Blocked kidneys are totally a death sentence in space. And if House is to be believed -- and you know it is -- kidney failure is not a pretty way to go. But at least it's not getting hit by space trash, right?
Ethan Lou is a freelance writer. He blogs at ethanethan.tumblr.com, his Twitter is twitter.com/Ethan_Lou and you can reach him at firstname.lastname@example.org.