News flash to those who weren’t aware: humans are not meant for space.

According to scientists, the human body is made up typically of about 60 percent water, which floats upward in space where there’s no gravity. As the fluids move up toward the chest and head, faces get puffed, pressure in the skull rises and leg cells begin to die.

“Your head actually feels bloated,” said Mark E. Kelly, a retired NASA astronaut who flew on four space shuttle missions. “It kind of feels like you would feel if you hung upside down for a couple of minutes.”

Another newsflash: throughout human history, people never managed to evolve for living out in space. Researchers will to take some giant scientific leaps to make up for the last hundred thousand years of our lack of evolution.

That’s not to say none of the trouble associated with space living have been solved. One example is how bones become brittle, which has been overcome. NASA scientists have also discovered other problems such as astronauts being unable to sleep enough or having difficulty eating.

One quandary has totally stumped scientists since the very first space launch 50 years ago; some astronauts’ eyeballs become squashed (not too bad) during flight.

The first real attempt to understand this phenomenon was made in 2009 by physician and astronaut Dr. Michael R. Barratt during a space mission. He noted that both he and a team member struggled to read words close up. They decided to perform eye exams on each other, confirming they had farsightedness.

The also saw blemishes on their retinas and that their optic nerves were slightly swollen. NASA sent up a high-resolution camera on the next cargo mission so the two could take clearer images of their eyes, which that their eyes had become slightly squished.

“It is now a recognized occupational hazard of spaceflight,” Dr. Barratt said. “We uncovered something that has been right under our noses forever.” NASA now checks astronauts’ eyesight before, during and after space trips.

Dr. Barratt said the farsightedness did not impede ability to work out in space. He is wondering whether the shift in eyesight is actually a symptom of a much more serious problem caused by the astronauts living in space. “What are the long-term implications?” he said. “That’s the $64 million question.”