Space travel for regular folks is almost here. But before jumping on board the nearest spacecraft, amateur astronauts and their doctors might want to consider the health risks.

“Practically only the healthiest people have flown in space so far,” says Marlene Grenon, a vascular surgeon at UCSF who researches the effects of microgravity on the body. Government astronauts go through extensive medical testing and training. But even these extra-fit fliers have suffered ailments ranging from cardiac dysrhythmia to good old-fashioned vomiting. What’s in store for the rest of us?

Grenon is the lead author of a paper in BMJ asking that question. The researchers say that doctors will have plenty to consider before sending their patients to boldly go where no civilian has gone before.

Photo Credit: The space shuttle Atlantis launches in May 2009. Matthew Simantov / Flickr.com