Would-be space tourists beware: You may regret it.

“It’s not like riding a commercial aircraft . . . and I can see all these problems with people up there throwing up and messing up somebody’s flight that they paid $250,000 for,’’ former astronaut Anna Fisher told Britain’s Telegraph newspaper.

“I was lucky I never threw up . . . if you think throwing up is bad on the ground it’s really bad in space.”

Space travel can also seriously affect metabolism and eyesight as well as the respiratory and immune systems. Astronauts who braved deep space were five times more likely to die from cardiovascular disease than those who went into low orbit.