Catchin' Zs in Micro-G

It’s the little things we take for granted here on Earth; things like being able to lie down on a bed and not have it float away, or wake up without suffocating on our own exhaled carbon dioxide. While interning at the Museum, I’ve spent time researching several of those things we take for granted but astronauts in space cannot. I’ve explored the effects of microgravity on the human body, and the various technologies we’ve developed to keep astronauts healthy.

What began as an interest in the intersection of biology and space, ended with a plethora of interesting facts not only about the science behind sleep and space, but also personal accounts from astronauts about how it feels, routines they follow, experiments completed, and some of the discoveries made. Here is a compilation of six of my favorite findings.

1. Astronauts feel like their limbs disappear.
One Apollo astronaut recalled that when he would begin to fall asleep in space, the microgravity prevented him from feeling the weight of his limbs, thus tricking his brain into thinking they had disappeared. When he "consciously commanded an arm or leg to move, it instantly reappeared -- only to disappear again when [he] relaxed."

 2. Science says you should nap longer.
Sleeping in space can be pretty difficult for astronauts. Because of this, NASA has conducted numerous sleep studies attempting to find ways to counteract the sleep deficit of their astronauts. One such way is with naps. Researchers determined that the longer the nap, the more beneficial to cognitive function.

3. Alarm clocks in space are better than yours.
Starting with Gemini VI-A and progressing through the Shuttle era, astronauts received wake up calls from Mission Control in the form of popular music. Wake up calls included anything from Louis Armstrong's Hey Look Me Over on Gemini VII to Tom Petty's Free Fallin’ on STS-101.

4. Cosmic rays let astronauts fall asleep to fireworks every night.
Without the protection of Earth's atmosphere, astronauts are exposed to high amounts of cosmic radiation. Sometimes, this results in bright flashes of light when astronauts shut their eyes. Such phenomenon can make sleeping extremely difficult. One astronaut described the experience as trying to fall asleep to fireworks inside your head.

5. You can thank NASA for that white noise app you use.
Seth Horowitz, a neuroscientist who researched various aspects of sleep in space, discovered that astronauts often suffer from Sopite Syndrome, a form of motion sickness that results in drowsiness. Using his findings, Horowitz and his colleagues developed the smartphone app Sleep Genius, so everyone can utilize low frequency vibrations to induce Sopite Syndrome and thus sleepiness.

6. In space, sleeping may literally take your breath away.
On Earth, the hot air you breathe out moves upward and is replaced by fresh air. But in space, up or down doesn’t really exist. If astronauts don't sleep in areas with good air circulation, as they breathe out, the carbon dioxide from their breath doesn't move away. Astronaut Danny Olivas describes this phenomenon from his perspective, describing how the buildup of a carbon dioxide bubble can cause a headache, or even suffocation.  

Curious to know more about life in space? We’ve got a tour for that. Download our free app GO FLIGHT to get access to our newest tour “Biology of Space Flight.” While the tour starts in our Moving Beyond Earth gallery, the information can be enjoyed anywhere.