This fall, NASA’s Scott Kelly broke the record for longest consecutive time spent in space by a U.S. astronaut. He made history again earlier this week when he became the first-ever person to conduct a Reddit AMA from space.

Kelly recently passed the 300-day mark of his unprecedented One-Year Mission, so he’s the perfect person to ask about all the fascinating—and sometimes nasty—details that come with life in orbit. “A year is a long time to live without the human contact of loved ones, fresh air, and gravity, to name a few,” said Kelly in his introduction. “While science is at the core of this groundbreaking spaceflight, it also has been a test of human endurance.” Here are nine of Kelly's most out-of-this-world revelations.

1. HIS ARMS ARE ALWAYS FOLDED FOR A REASON.

If you’ve watched any of the videos Scott Kelly has made aboard the International Space Station, you may have noticed he has a habit of folding his arms. No matter how cool he looks while doing it, Kelly insists that the pose is less about aesthetics and more about practicality. "Your arms don't hang by your side in space like they do on Earth because there is no gravity,” he told Redditors. “It feels awkward to have them floating in front of me. It is just more comfortable to have them folded. I don't even have them floating in my sleep, I put them in my sleeping bag.”

2. SPACE DOES WEIRD THINGS TO YOUR FEET.

When asked to share an unusual part of life in space that most people don’t think about, Kelly definitely did not disappoint. “The calluses on your feet in space will eventually fall off. So, the bottoms of your feet become very soft like newborn baby feet,” he said. “But the top of my feet develop rough alligator skin because I use the top of my feet to get around here [in the] space station when using foot rails.”

3. SLEEPING IN ZERO GRAVITY IS NO PICNIC.

According to Kelly, zero-g conditions don’t make for a relaxing night’s sleep. “Sleeping is harder here in space than on a bed because the sleep position here is the same position throughout the day,” he said. “You don't ever get that sense of gratifying relaxation here that you do on Earth after a long day at work.” And it probably doesn’t help that Kelly was a poor sleeper long before he ever left the planet. “I don't think I have ever slept eight hours straight in the last 20 years. I wind up waking up a couple of times. My dreams are sometimes space dreams and sometimes Earth dreams. And they are crazy.”

 4. A TON OF WORK GOES INTO EACH MISSION.

When asked about the biggest misconception people have about space travel, Kelly cited the public's underestimation of the amount of work that’s required for each mission. “I think a lot of people think that, because we give the appearance that this is easy, that it is easy,” he said. “I don't think people have an appreciation for the work that it takes to pull these missions off, like humans living on the space station continuously for 15 years. It [takes] a huge army of hard-working people to make it happen.” 

5. HIS FAVORITE DAVID BOWIE SONG ISN’T "SPACE ODDITY."

Though you’d think the cosmic anthem would be an easy choice for Kelly, he said he’d pick “Modern Love” as his favorite Bowie song.

6. THE ISS HAS A DISTINCT SMELL.

If you’ve ever wondered what it smells like aboard the International Space Station, the answer is: not particularly pleasant. Kelly described some segments of the structure as having an “antiseptic smell,” while other areas have an odor that “smells like garbage.” He also claimed that outer space has a distinctive scent: “[The] smell of space when you open the hatch smells like burning metal to me.”

7. SPACE TOILETS PRESENT A WHOLE NEW SET OF ISSUES.

Kelly was asked by one Reddit user to recall the creepiest thing he has ever encountered on the job, and the answer he gave highlights one of the less glamorous aspects of space life. “Generally it has to do with the toilet,” he said. His most recent custodial endeavor involved cleaning up a “gallon-sized ball of urine” mixed with acid used to keep the piping clear. 

8. EARTH-BASED SNEEZING ETIQUETTE APPLIES IN SPACE.

Sneezing in a zero gravity environment sounds like a recipe for disaster, but the protocol astronauts follow to keep sneezes contained is the same one they learned on Earth. "I just sneezed twice coming into my crew quarters. And I do what I do on Earth and cover my mouth with my hand," said Kelly. "If I didn't do that, it's possible the sneeze could be found floating in another module. I generally don't sneeze into open air on Earth or here in space."

9. SPACE HAS CHANGED HIS ATTITUDE TOWARD NATURE.

According to Kelly, the one thing he will forever do differently after he safely returns home is “appreciate nature more.”