It takes imagination. It takes imagination to fathom the awe-inspiring, regal rings of Saturn. The icy moons of Jupiter. The desert wastelands of Mars. The bone-chilling nitrogen glaciers of Sputnik Planita on Pluto.
It takes courage, the special kind of courage to go boldly where no man has gone before. The special kind of courage to peer into the darkness, to explore the unknown. To seek what has not been found.
It takes perseverance. When Robert Goddard said that liquid fuelled rockets would one day taken man to the Moon and beyond, the New York Times laughed at the idea. Literally posting an article ridiculing him.
It takes a inherent, genuine interest in space. While a child may dream about becoming an astronaut, only genuine enthusiasm can make the mind dream of the Earth rising above the limb of the pale Moon, a grand oasis in a vast void.
And it takes a US citizenship, a 20/20 vision, the ability to pass a NASA astronaut physical, a Bachelor's degree in a STEM field, 1000 hours of jet aircraft flight time or 3 years of professional career in said STEM field.