Hello, SFIA audio listeners. In this month's Nebula exclusive, big alien theory,

we're asked at the reason alien civilizations might be rare is because most aliens are huge.

To hear it and every episode early and ad-free, plus hours of bonus content,

check out go.nebula.tv slash Isaac Arthur and use my code, Isaac Arthur.

In the future, we will travel to strange new worlds, but who will pilot the

spaceships that take us there?

Possibly one of the most dreamed-of jobs in modern times and in science fiction is to be an

astronaut and to crew a spaceship, and today will be

looking at various selection criteria and discussing them.

I should emphasize we won't be trying to say what is best or right today, as it's likely

to be highly dependent on both your technology and cultural or physiological aspects that we

cannot anticipate well right now.

We know what the big ones are for nowadays, every astronaut is expected to have a degree

in something relevant, typically STEM fields, and a lot of professional experience in that

field. Extensive background as a pilot is appreciated, especially on experimental vehicles as a

test pilot, but that's likely to drop away as a major consideration.

Nowadays, every spaceship flight, even a reusable spacecraft that's flown before, is essentially

an experimental one, and your crew is rarely more than a handful of people. Down the road, a crew of dozens,

or hundreds, or even hundreds of thousands, is not going to require piloting scale as a major

criteria for astronauts in general, any more than a chef's background would matter for roles

beyond ships cook. When you only have a crew of three or four, or maybe a bit more, everyone has to wear a bunch

of different hats, and so one thing you're looking for is a knack for quickly picking up some

...