There is only truly one reason to be an astronaut. Space is well beyond International Borders, so gambling is way legal. You could totally play craps all night! Except there would be no literal night, just a time period when you’re way tired.
This, I believe, is why NASA should start sending up crews with astronauts from nations that are currently enemies to NASA’s country. They could then gamble against the enemy crews and, assuming they win, bankrupt the enemy space programs. It’s so devious it must work.