One of the first tourists to travel in outer space can be a bit of a buzzkill. Sure, he loved every minute—even if he was physically miserable part of the time. The next wave of space tourists will need a high tolerance for discomfort.

If all goes according to plan, Elon Musk's Space Exploration Technologies Corp. will send two paying civilians around the moon and back some time next year. "My advice to them would be to medicate early and often," says Richard Garriott de Cayeux, the video game developer and entrepreneur who paid $30 million to Russia's Space Adventures to spend 12 days aboard the International Space Station. His moon-voyaging counterparts have put down a "significant deposit," according to a post last week on SpaceX's website, but the total price and the identities of the tourists have not been disclosed.

The microgravity that permits what Garriott de Cayeux describes as  "joyous, free-feeling" motion we associated with astronauts also takes a serious physiological toll. "Body fluids stop flowing normally, which is why, in space, people's faces look puffy, and they generally have somewhat bloodshot eyes," he says. "It feels sort of like lying on a children's slide, head down. In the first days, you get very stuffed up and have a bit of a headache." These symptoms can be easily remedied with common drugs, such as aspirin and Sudafed.

Another side effect comes from the floating fluid in your inner ear, which normally helps a person detect motion and stay balanced. In space, of course, it also begins floating. "So if you move your head forward, it will slosh to the back and make you feel like you're falling backwards," says Garriott de Cayeux. "There's a disagreement between what you see that you're doing and what your body thinks it's doing—and that often causes sea sickness."

That perceptual disconnect tends to last for about three days before your brain begins compensating. When you get back to Earth it takes another three days to readjust. This is another downside of space tourism that can be treated with drugs.

Other physical challenges are more difficult to address and also less acute. Humans in space suffer muscle and bone atrophy. Space travel requires exposure to increased levels of radiation, which can lead to surprising visual effects. "All of a sudden you will see this really intense, bright white … and then it will fade back out," says Garriott de Cayeux. "That is basically you being damaged by radiation, it triggers the impression of light even though there is no light."

His time in space required a year of difficult preparation, although physical fitness wasn't a focus. "If you're going on a space walk, you need to be in excellent physical condition, because an inflated space suit is hard to bend. But if you're not, you just need to be healthy," he says. Still, SpaceX's tourism clients will likely be studied head to toe, undergoing a battery of medical tests they've probably never heard of before. "In my case, they found I was missing a vein on one lobe of my liver," says Garriott de Cayeux. "On Earth that's irrelevant, but in space it could have led to internal bleeding, which is why I ended up having surgery to remove that lobe."

Training and preparing mentally will likely be the main challenge for the next generation of space tourists. "This is not like an airplane where the pilots sit up front and there's a passenger cabin where you're being serve tea and coffee," says Garriott de Cayeux. "I went through all the exact same classes as every other astronaut and cosmonaut." That included learning how to operate every piece of equipment aboard the craft, including radios and safety systems, and studying a long list of potential malfunctions. 

Garriott de Cayeux's team also trained extensively for potential disaster scenarios, including open sea survival. "If there was an emergency in orbit and you had to come to ground immediately [in a capsule], you might land in the ocean," he says. "You would probably sit in the capsule until somebody came and picked it up. But it's also possible that the capsule might start to sink." He learned to change out of a space suit and into special thermal wetsuits—all while crammed in a space roughly the size of the front two seats of a Volkswagen bug. The first time they attempted the feat, while bobbing in a capsule in the ocean, he and his colleagues began overheating to the point where doctors stepped in and aborted the mission. "Our heart rates and core body temperatures were going up to a level that was so dangerous, they literally understood that we'd be doing ourselves medical harm to continue," says Garriott de Cayeux.

But mini-hardships such as this are crucial for assessing what is perhaps the most important factor in traveling to space: mental fortitude. "You need to make sure that the people on the vehicle are … serious, confident, positive, and will work to address situations that come up," says Garriott de Cayeux. "Every person has a psychologist assigned to them, from Day 1 until launch, to make sure they'll be a safe crew member."

Despite the discomforts and hardship of space travel, Garriott de Cayeux, now 55, says his trip to space was worth every penny. His father, Owen Garriott, was an astronaut. He grew up learning and thinking about space and felt his life change when he looked at the planet from inside the International Space Station. "There's something called the Overview Effect," he says. "Up there you really realize, 'Yeah, of course we are polluting the Earth. Of course CO2 is a problem. Of course particulate matter is a problem. How could you possibly doubt it when we can see it so self evidently?'"

While Garriott de Cayeux got to observe the Earth, SpaceX's voyagers will see both Earth and the Moon up close. "For them, the Earth will slowly recede into the distance to become much like the moon," he says. "That is a whole other level of awe that no one has experienced in over 50 years."

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