Astronauts must have a wide variety of skills and spend a lot of time training.

What do astronauts do when they aren’t in space? They spend most of their days training, taking classes and studying. So if all you want to do is whip around the earth in a spaceship, you’d hate being an astronaut.

Astronauts need a tremendous range of skills. Some are more obvious, like piloting the rocket, walking in space, repairing pieces of the space station and monitoring the experiments on board.

Since they’re away from civilization for so long, however, astronauts also need to prepare for some less obvious tasks. They have to be able to perform basic surgery and dentistry, program their computers, rewire any electrical panels and conduct a press conference. They also have to get along with their colleagues while living with them 24/7 in a confined space!

Astronauts must be prepared to respond to any crisis that could occur in space. When they’re orbiting the Earth at 400 km, they certainly can’t expect a rescue crew to come get them.

There are many dangerous potential situations. Toxic gas could start leaking or a fire break out, for instance.

Fires aren’t hypothetical situations, either. In 1997, an oxygen-generating canister started a fire on the Russian space station Mir. The astronauts managed to put it out by throwing wet towels on the canister. Their spacecraft filled with smoke, but thankfully everyone survived.

The ratio of time spent in space vs. time spent preparing for space is quite low: for each day in orbit, you have to train for several months. It takes several years of training before you’re assigned to a mission, and then training for a specific missions takes between two and four more.