If space were not so incredibly awesome, going there would really suck. You have to be "on" all the time, dealing with conditions best described as hot, close, smelly, dirty and noisy, all while being stressed and sleep-deprived. It's unending, and you don't dare flinch, lest the folks back at mission control boot you or scrub the mission, so you become skilled at displacing or repressing your anger. Meanwhile, you're dealing with the frustration of equipment, weightlessness and possibly cultural and language barriers.
You can't quit; you can't go home; you can't even crack a window.
Under such conditions, the best of us can keep our heads for a few days or even weeks. Give it a couple of months, though, and we start imploding into depression or exploding with anger -- which raises the question: What about years? What about when your crew finds itself alone in the black, or on some distant world where they can barely pick Earth out of the star field?
NASA has a history of selecting steely-eyed missile men (and women) based on guts, instincts and reactions under pressure. With the dawn of the shuttle era, NASA added one more requirement: a knack for tolerating boredom and low levels of stimulation [source: Roach]. You have plenty to do -- mission control lays tasks out in an unbroken series of 15 to 20 minute time slots -- but flipping toggles or tightening bolts, even in space, can't quite compete with test-piloting an experimental fighter [source: NASA].
Perched on the shoulder of every astronaut is a tiny devil called Frustration, and he grows a little bigger with every task performed in cramped, weightlessness conditions. On spacewalks, they must struggle with weightlessness, bulky space suits and awkward, pressurized gloves that tire out their hands within minutes, all while their air supply ticks down and they hover on the precipice of doom. Handling such pressures long term, even inside the ship, requires a different level of cool than most of us possess.
Although some astronauts say weightlessness becomes natural after a week, it never stops causing petty annoyances. Without gravity, dust doesn't settle; nor does spilled food, drink, vomit or excrement. You can't just put something down -- you must tether it to a hook or Velcro it to a surface. Without weight, you must concentrate just to hold an object, and if you let it go, it might drift off, never to be found. Relearning how to use eating utensils and a bathroom: It's like going through preschool all over again.
This constant vigilance, and these minor annoyances, add up to seriously frayed nerves, setting the stage for rage, panic, jumpiness and a whole host of related stress reactions.
In some cases, they've pushed spacers over the edge.