Packing for Mars

by Mary Roach

“Of course, exploration to Mars will be a different story,” says Tachibana. “You need someone aggressive, creative. Because they’ll have to do everything by themselves.” With a twenty-minute radio-transmission lag time, you can’t rely on advice from ground control in an emergency. “You need again a brave man.”

Isolation and confinement are issues of no small concern to space agencies. The Canadian, Russian, European, and US space agencies are spending £9.5 million on an elaborate psychology experiment that puts six men in a simulated spaceship on a pretend mission to Mars.

If technologies being tested on Mars500 pan out, spacecraft – and other high-stress, high-risk workplaces like air-traffic control towers – will be outfitted with microphones and cameras hooked up to automated optical and speech-monitoring technology. The robotic spies can detect telltale changes in facial expressions or speech patterns and, hopefully, help those in command to avert a crisis.

Laveikin confides that there were moments when he thought about suicide. “I wanted to hang myself. Of course, it’s impossible because of weightlessness.”

(Here on Earth, were there no atmospheric drag to slow you down, gravity would accelerate you at the rate of twenty-two miles per hour faster for each second that you fall.)

Crazy! Never knew this.

Every time NASA develops a new piece of hardware – be it a pump or a heating element or a toilet – someone has to haul it up on a plane out of Ellington Field near Houston to see what sort of problems might develop in zero gravity. Twice a year, something even more problematic gets hauled up there: college students and journalists.

YOU NEVER THINK about the weight of your organs inside you. Your heart is a half-pound clapper hanging off the end of your aorta. Your arms burden your shoulders like buckets on a yoke. The colon uses the uterus as a beanbag chair. Even the weight of your hair imparts a sensation on your scalp. In weightlessness, all this disappears. Your organs float inside your torso. The result is a subtle physical euphoria, an indescribable sense of being freed from something you did not realize was there.

Overheating equipment is a common theme in zero G. Anything that generates heat tends to overheat, because there are no convection currents in the air. Normally, hot air rises – because it’s thinner and lighter; the livelier molecules are all bouncing off each other and spreading out more than they do in cooler air. When hot air rises, cooler air flows in to fill the vacuum left behind. Without gravity, nothing is any lighter than anything else. It’s all weightless. The heated air just sits where it is, getting hotter and hotter and eventually causing damage to the equipment.

What has aeromedical science learned from the combined tortures of motion sickness research? For starters, we now know what causes it: sensory conflict. Your eyes and your vestibular system can’t get their stories straight. Say you are a passenger belowdecks on a heaving ship. Since you are moving along with the walls and floor, your eyes report to your brain that you are sitting still in the room. But your inner ear tells a conflicting story.

In the case of motion sickness, vomiting is an impressive lot of bother for no apparent reason. Vomiting makes sense as a bodily response to poisoned or contaminated food – gets it out of you ASAP – but as a reaction to sensory conflict? Pointless, says Oman. He says it’s just an unfortunate evolutionary accident that the emetic brain happened to evolve right next to the part of the brain that oversees balance. Motion sickness is most likely a case of crosstalk between the two. “Just one of God’s jokes,” says Pat Cowings.

How many excess G’s the human body can tolerate without injury depends upon how long it’s exposed. For a tenth of a second, people can typically hack between 15 and 45 G’s, depending on what position they’re in relative to the force. When you get up into the range of a minute or more, tolerance drops alarmingly. Your heavy blood has enough time to pool in your legs and feet, depriving your brain of oxygen, and you black out. If it goes on long enough, you die.