NASA is so selective for two reasons. First, it can be. With so many wannabes, the federal agency doesn’t have to settle for anything less than the best of the best of the best. After all, the government entrusts astronauts not only with the lives of their crewmates, but also with hardware worth hundreds of billions of taxpayer dollars — and with the United States’ reputation as the world leader in space exploration.

Second, the job is way harder than you think. Flying space missions demands a rare combination of intellectual and physical skills, plus special personality traits. NASA looks for technical expertise surpassing that of an airline pilot, the valor of a special forces soldier, the forbearance of a kindergarten teacher, and the stamina and decisiveness of a mountain climber — all in one person. And did we mention advanced training in medicine, engineering, or physics?

Earlier this month, NBC News MACH made the trip to Houston and sat down with NASA astronauts Karen Nyberg (#478), Kjell Lindgren (#542), and Sunita Williams (#450) to dig deeper into what it takes to join the corps, train for the job, and then perform well under enormous pressure. Like the others we have met, these spacefarers seem normal enough in conversation. But as astronauts describe all they have accomplished, it becomes abundantly clear that they simply are not like you and me.

Astronauts come in every shape, size, and skin color. They hail from small towns and big cities, rising through the ranks in the military, academia, industry, and medicine. But all share the same program of intense training that has them making emergency repairs in spacecraft simulators both physical and virtual, testing their skill in notoriously unforgiving supersonic jets, and logging long hours underwater in full space gear — over and over, until their responses are automatic.

An Extravehicular Mobility Unit (EMU) space suit and glove. Dan Winters

As the experiences of Nyberg, Lindgren, and Williams show, it’s this combination of innate character and relentless training that prepares them for the challenges and hazards of spaceflight: the chaotic scenarios, but also the unnerving tedium of weeks or months spent with crewmates in an airtight container where even simple tasks like washing your hair and cooking become absurdly complicated. A spacecraft is, without a doubt, the most bizarre home office on the planet — or off it.

NEXT CHAPTER: Saving a Spaceman from Drowning

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