https://www.scientificamerican.com/article/do-you-have-what-it-takes-to-be-an-astronaut/ > As of December 4, 2019, 565 people from 41 countries have gone into space. That’s it. 565 out of more than 7 billion of us currently on this planet. And that's using the definition of space travel to include any flight over 62 miles or about 100 kilometers. > Many of these space travelers are, of course, NASA astronauts. That means they went through a rigorous application and training process. So, what exactly does it take to be an astronaut?