US astronauts are government employees and their pay is mostly determined by the US government's pay scale (GS) which itself is based on experience, academic qualifications, seniority and other factors.

The starting salary for an astronaut is GS11, which means they currently earn $64,724 per year (this is taken from the NASA website, and of course the pay scale could change). A top level astronaut will be on the GS14, which takes them up to $141, 715 per year.

So this is a highly paid job even at the lower levels. But this is no surprise given that nearly all astronauts are graduates in science or mathematics, plus with three or more years of relevant experience. The job itself is also extremely demanding and has to be well paid.

Figures for other countries tend to be similar, allowing for different cost of living in different countries - in Europe, for example, a starting salary of 55,000 euros is typical.