Sleeping in space is more difficult than you think
Since March of 2015, Astronaut Scott Kelly has been living on the International Space Station as part of the One Year Mission. He and Russian cosmonaut Mikhail Kornienko will ultimately spend 365 days in orbit to see how the human body copes with extended periods of microgravity — research that could help agencies prepare for future missions to Mars. (Kelly's identical twin brother, Mark, is staying on Earth as a control.)
Many Earth-dwellers might assume it's entirely pleasant to sleep in space. You just float. But Kelly points out that this actually makes snoozing more difficult.
"Sleeping is harder here in space than on a bed," Kelly writes, "because the sleep position here is the same position throughout the day. You don't ever get that sense of gratifying relaxation here that you do on Earth after a long day at work. Yes, there are humming noises on station that affect my sleep, so I wear ear plugs to [bed]."
He's not the first to lodge this complaint. A 2014 study found that a large portion of astronauts on the space station suffer from sleep deprivation — with many resorting to sleeping pills. This is one problem NASA will have to solve before sending people to Mars, since that journey is likely to take years and it'd be no good if the astronauts are perpetually exhausted.
And what about dreams? "My dreams are sometimes space dreams and sometimes Earth dreams," Kelly wrote. "And they are crazy."