How does NASA ensure that astronauts going into space for months at a time don’t get sick?

Question

I assume the astronauts are healthy, thoroughly vetted by doctors, trained in basic medical principles, and have basic medical supplies on board.

But what happens if they get appendicitis or kidney stones or some other acute onset problem?

In: 2048

Answer 1

They’re quarantined before launch to weed out any infectious diseases and they’re health screened.

Of course you can never be 100% sure someone won’t have a brain aneurysm or some other bizarre health emergency. It hasn’t happened yet, but it surely will eventually.

I’m sure there are contingency plans on paper for such a thing happening, but space travel is still isolated and dangerous. Just like traveling to the south pole or the bottom of the ocean, there’s an inherent risk involved that the people are accepting when they sign up to ride a gigantic missile at 12,000 mph into a vacuum.