1. He saw numerous sunrises and sunsets each day.
Cruising along at over 17,000 miles per hour, the International Space Station circumnavigates Earth once every 90 minutes. Kelly and his Russian counterpart Mikhail Kornienko therefore had the opportunity to witness an astounding 10,944 sunrises and sunsets over the course of their 340-day mission. All told, they each traveled some 144 million miles, or just about the average distance between Earth and Mars.
2. Kelly grew noticeably taller.
Spinal discs expand without gravity pushing them down, meaning astronauts can actually grow taller during their time in space. Kelly, for example, gained 1.5 inches. But, alas, he shrank back to his normal size almost immediately after touching down in Kazakhstan on March 1. Thanks to something called the time dilation effect (which Albert Einstein predicted in his theory of relativity), Kelly also returned to Earth 0.01 seconds younger than he otherwise would have been.
3. Since coming back, he’s experienced full-body discomfort.
Despite constantly exercising aboard the International Space Station—he ran about 650 miles on the treadmill alone—Kelly suffered the unavoidable ill effects of cramped living conditions and extremely low gravity. In addition to complaining of extreme muscle soreness and fatigue, Kelly told reporters Friday that his skin burned every time he sat or walked since returning to Earth, and that he couldn’t make a single shot playing basketball. “It seemed like I lived there forever,” Kelly said. Yet he also maintained that he could have stayed longer and that even a two-and-a-half year round trip to Mars is “doable.”
4. He didn’t shower for the entire mission.
Since the International Space Station lacks running water, Kelly was unable to shower for 340 straight days, a streak he finally broke on his way back from Kazakhstan to the United States. Perhaps unsurprisingly, he leapt into his swimming pool fully clothed the moment he returned home on March 3. “You want to get that water around you,” Kelly told reporters. “We make due with not having a shower onboard, and it’s not like you feel dirty, but you definitely feel like you would like to jump in a pool. So I did.”
5. Kelly stayed up-to-date with current events.
The lack of a shower notwithstanding, Kelly had access to many of the same entertainment options as his fellow Americans on Earth. In his spare time, he said he watched TV shows and movies, talked on the phone, snapped photographs, sent out emails and posted constant updates to his followers on Twitter, Facebook and Instagram. Most of all, he intently followed the news, which he said remained on virtually the entire time in orbit. In fact, as soon as he exited the landing capsule on March 1, Kelly asked who had won the Super Tuesday presidential primaries.
6.Kelly may have his next vacation planned out.
Among Earth’s many beautiful locations, Kelly singled out the waters of the Bahamas as appearing “just striking” from space. Yet he expressed the most interest in visiting a group of differently colored lakes that dot the northeastern side of the Himalayas. Now, he said, he just has “to look into what these lakes are called and what country actually owns them.”
7. Kelly lamented humankind’s destructive impact.
From space, Kelly said he could see “large swaths of pollution” hovering over Earth, particularly in Asia, as well as weather systems in areas you wouldn’t expect to find them. Moreover, “you just notice how thin the atmosphere is, how fragile it looks,” he said. “It makes you more of an environmentalist after so much time looking down at our planet.”
8. He is being studied in conjuncture with his twin.
To learn more about the effects of long-term spaceflight, Kelly’s organs, bones, DNA, stomach microbes and state of mind are being compared to those of his identical twin brother, Mark, a former astronaut. The two will continue to be poked and prodded for up to an additional year, after which the results will come in. So far, Kelly hasn’t noticed any obvious changes (other than his temporary bump in height and slightly impaired vision). “He’s got a better tan,” Kelly quipped. “I think it’s because he plays too much golf and has too much time on his hands.”
9. The twins study is being conducted with Mars in mind.
NASA says that the so-called twins study, as well as other research performed aboard the International Space Station, will help it reach its goal of sending a manned spacecraft to Mars by the 2030s. “We are going to go to Mars—there’s no doubt about that,” White House science advisor John Holdren told Kelly following his return to the United States. “We are committed to it. We are going to get it done, and you really have established the latest milestone on that very challenging pathway.”
10. His first food back was a fitting choice.
During one of his last few days in space, Kelly posted a video of himself in a gorilla suit chasing around another astronaut. “Needed a little humor,” he tweeted at the time. The joke got new life on Friday, when Kelly revealed that a banana was the first thing he ate back on Earth. “It looked so good,” Kelly said, adding that he only recognized the irony of his choice after finishing half of it.
11. Kelly now holds two NASA records.
Over the course of four missions, Kelly has now spent 520 days in space, more than any other NASA astronaut (the worldwide record is 879 days, held by Russian cosmonaut Gennady Padalka). Kelly also holds the NASA record for most consecutive days in space (the worldwide record is 438 days, held by Russian cosmonaut Valeri Polyakov). Kelly said he hopes both are broken soon. “Pushing the envelope,” he said, “is what makes our society progress.”