Chris Crisman

One day last summer, while the citizens of Mojave, California, were still eating breakfast, Brian Binnie lit a hybrid rocket above a nearby airfield and shot 21,650 metres into the pink desert sky.

Binnie, a 61-year-old test pilot for Virgin Galactic -- and the man piloting the experimental spaceship that won the $10 million (£6m) Ansari X Prize in 2004 -- is testing rocket vibrations on SpaceShipTwo, the plane Virgin hopes will begin ferrying civilians into space later this year. "Rocket stability is still a pretty big deal," says Binnie, five minutes after landing. "How the vibration of that motor translates into the crew cabin, the effect on the ability to read the instruments, control the vehicle and the ergonomic effect on the passengers."


That last part is an acknowledgment of the bone-rattling, nerve-battering, adrenaline-pumping sensations that a violently shaking metal tube, breaking the sound barrier at Mach 1.4, will inflict on untrained civilians riding it into space. "If you are not used to the g-forces it can really mess with you," says Binnie, a former US Navy fighter pilot, who has since left Virgin Galactic for XCOR Aerospace. "There's this overwhelming power that sweeps through the cabin. Your senses get pegged out.

You're looking for comfort or safety but you won't find any. All you can do is keep breathing."

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As commercial space outfits such as Richard Branson's Virgin Galactic and Elon Musk's SpaceX race to send paying customers heavenward, health officials, regulatory commissioners and the industry itself are grappling with ways to screen passengers for health issues and to train them for the ride. Since Yuri Gagarin in 1961, only 536 people have made it to space. "That's an elite group of extremely healthy, well-prepared and well-trained people," says Vernon McDonald, vice president of science, technology and engineering at Texas aerospace giant Wyle, which trains Nasa astronauts and military pilots on its g-force-generating centrifuges. "Now we want to send the general public to space. And we don't know how they will take it." It's no easy ride: WIRED's Robert Luesson experienced five g on Wyle's San Antonio centrifuge. "Up to three g was kind of fun," he says. "But five was difficult.

I was greying out. A tumbling into nothingness feeling you can't shake."


According to a 2006 Nasa-funded Survey on Public Space Travel, space tourism could generate £390 million in annual revenue by 2021 -- while sending 13,000 paying civilians into space each year.

These flights will make enormous physical, mental and emotional demands on passengers. Virgin plans to drop its spaceship, known as Enterprise, from the belly of a twin-fuselage commercial jet, called Eve, at 15,240 metres. Enterprise will then rocket its way into sub orbit, 110km above Earth (roughly the edge of what we consider space). It will hit 4,500kph on its way up and exert as much as six g -- enough to force blood from passengers' heads and toward their feet, putting them on the edge of blacking out. And the plunge back to Earth will be as taxing as the ride up.

So far, 630 customers have paid $200,000 apiece (early bird) or $250,000 (current price). The roster ranges from Finnish poker players to Justin Bieber and Stephen Hawking, and Princess Beatrice to Branson and family.

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Despite the physical and mental demands, Virgin does not require the majority of its space passengers to undergo training. Julia Tizard, its vice president of operations, explains that Virgin requires this of only a select few -- mostly those with previous heart or lung problems. "Our mantra is that everybody who wants to go to space can get to space," Tizard says at Virgin Galactic's hanger and fabrication facility in Mojave, where it is building its space planes and conducting final tests on SpaceShipTwo. "My personal goal," adds the British astrophysicist, "is to take civilisation to space."


Of course, those making up civilisation are an imperfect and fallible lot. Many of Virgin's "astronauts" are ambitious professionals, well into their fifties and sixties, with the personal wealth to pay for such a trip, and the attendant indignities of age that got them there. In addition to full physicals, Virgin, working with Nasa-affiliated doctors, will make sure that anyone with, say, diabetes, has taken their insulin and has the proper blood-sugar levels before takeoff.

Beyond that, training is up to the ticket holder. You don't want to lay out a life's savings only to black out, throw up, "or take an elbow to the ribs", says Binnie, because the other guy floating around next to you didn't receive instruction. For all these reasons, Virgin -- whose ship will carry six passengers -- recommends two types of preparation: zero-gravity training and experiencing g-forces. The first is to help you manoeuvre in weightlessness. The second is to keep you conscious.

Michael Mills, an aerospace physiology specialist, in the centrifuge at Wyle's San Antonio facility. It is capable of 30 g Chris Crisman

Just north of Philadelphia, amid the cornfields turned to strip malls and lone dental clinics, sits a hulking warehouse. This is home to the US National Aerospace Training and Research (NASTAR)

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Center, a facility that trains military pilots and private citizens using a large centrifuge, testing them against the extreme accelerations known as g-forces.

The flight centrifuge is a high-fidelity simulator with mock-up altimeter, surround sound, a seat that shakes with the force of a rocket blast and a video feed of Earth receding behind you. It's the closest thing to being there.

For a year, Rebecca Blue, a space medicine doctor and researcher with the University of Texas Medical Branch, brought volunteers here -- 87 in all -- to conduct the largest study on the effects of simulated space travel on civilians. She looked at people with five common ailments, the problems many of us suffer, or will suffer, in our lifetimes: high blood pressure, heart and respiratory disease, diabetes and back or neck problems. "We've gotten pretty good at flying people on normal airline flights, but what happens when you take normal people from the back row of aeroplanes and put them into space?" says Blue, who conducted the research for the US Federal Aviation Administration's (FAA) Center of Excellence for Commercial Space Transportation. "How do normal people, and by that I mean people who suffer everyday ailments, deal with the acceleration forces when you ride a rocket?"

To understand that, you first have to know that the human body is a sack of liquid. Gravity pulls our blood to our feet when we're upright. Our hearts work hard to keep pumping it to our brains. In a 2006 report, the FAA noted that rapid acceleration stress from rocket travel can cause changes in cardiac rhythm and conduction.

Also, the head, neck and spine need to be stabilised to reduce the potential for musculoskeletal injury.

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Blue's subjects, aged 18 to 75, were first taught about the types of g-forces they would encounter when blasting into space.

NASTAR's centrifuge can be set up to mimic Virgin Galactic's flight profile. When Virgin's mother ship releases Enterprise from its belly at 15,240 metres, the smaller craft drops away and then blasts forwards horizontally, pushing passengers back into their seats, like a speeding race car, and creating what's called a Gx force -- or what pilots commonly call "eyeballs back" for the sensation it causes. The ship then pulls up, blasting its way toward space "and pulling you down into your seat", says Blue, as it reaches 4,500 kilometres per hour within three seconds. The force then becomes Gz, or "eyeballs down". "When that rocket lights up, you know it," Blue says. "It's really a hard kick in the pants."

That's where it gets tricky, because your blood is now forced toward your feet at up to four g -- four times gravity's usual hold on you. So, if you're a guy weighing 75kg, that's 300kg of internal drag on your organs. Your heart has to pump extremely fast just to keep the blood up around your brain. Without that blood, your eyes lose the ability to see, causing you to "grey out", and you can lose consciousness, a condition known as g-loc.

Rebecca Blue, a space medicine doctor researching the effects of g-forces on civilians Chris Crisman

Go to YouTube, type in g-loc, and you'll find hilarious clips of pilots in centrifuges and passengers on fighter jets, going all rubber-faced and blacking out from massive g-forces. It's a temporary condition that subsides when the g-forces drop away, but it can stress the heart. To combat g-loc, Blue's test subjects were taught the same anti-g straining manoeuvre fighter pilots use. "You tense the muscles in your legs and in your abs to artificially push the blood back to your heart, so it can send it to your brain so you don't pass out," Blue says.

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Virgin's flight will use a parabolic trajectory -- like a roller coaster climbing a hill, cresting at the top and then free falling.

It will linger at its apogee of 110km for four or five minutes, providing passengers with the experience of weightlessness during this time. (Virgin's closest rival, XCOR Aerospace, which hopes to launch within the next two years, will do the same.) As passengers float around the cabin, they can take in stunning views of Earth -- continental shelves, the oceans, vast weather systems, 2,400km in every direction -- then plunge back to Earth for a runway landing.

Re-entry will be fast and noisy. Binnie likens it to the sound of a tornado in the cabin. During a 20-minute free fall, up to six forces of Gz, "eyeballs down", will press down on the passengers.

If they remained upright, most would almost certainly black out.

Virgin's seats will recline to help them absorb the pressure. But it will feel like "a very heavy adult, six times their weight", says Blue, sitting on their chests. It will squeeze their lungs and they could suffer a panic attack. Anti-g straining and steady breathing alleviate it, as does this sort of training. "Once you can experience it," says Blue, "it won't scare you."

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During her study, Blue's researchers gradually ratcheted up the g-forces, whipping their subjects around slowly at first, and then steadily faster, so they could acclimatise to the feeling. Her researchers monitored volunteers' pulse rates, blood pressure, oxygen concentration and other vitals before, during and after the centrifuge simulations. They talked to their subjects as they rode the simulators about what they felt and watched them over video.

They noticed that most people need to start straining manoeuvres around three g. But Blue says it mostly depended on three unique variables: your initial resting blood pressure; the elasticity of arteries and veins; and your level of motivation to make it work.

Simply put, a low resting blood pressure means you have to start the anti-straining manoeuvre earlier. And high motivation merely means you'll try hard and stay focused. But vascular elasticity is something of a surprise. "Think of your vasculature like those long skinny balloons at a carnival. Imagine you stretch it out, but instead of with air, you do it with water," says Blue. "If the balloon is super stretchy, or elastic, all the water falls to the bottom and you're left with this empty top. But if it's stiff, you can hold it by the top and it will stay even throughout." So, stiff vasculature, as in older people with hardened arteries, makes it easier to not black out. "Age stiffens vessels and you need less straining than a young person," Blue says. "In some ways, you can say age is protective."

Blue -- an eager and excitable talker with a scientist's grasp of facts and layman's way of explaining them -- is careful to note that her subjects were all in controlled stages of their ailments.

That means, if they had diabetes or high blood pressure, they responsibly took their medication, and if they had suffered ruptured discs and had undergone surgery for it, they now performed rehabilitation and worked out to strengthen their core muscles. "What we concluded was that these people did great, the ones who were motivated and took care of themselves," Blue says. "Every one of them did fine, despite their diseases."

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In other words, despite prior heart and lung trouble, diabetes, and back and neck injuries, every single person Blue tested made it through suborbital training without a problem, signalling to the industry and to regulators that the general public is flyable.

Yet, when her findings are finally made public this summer, in the aerospace journal Aviation, Space and Environmental Medicine, Blue expects criticism for focusing on this cohort of controlled diseases and ignoring, say, at-risk passengers with potential strokes just around the corner. "It's easy to read our study and say everybody can do this, but that's not what we're saying," Blue says. "We're not saying you don't need screening before you fly.

You should be screened, but it doesn't have to be as exhaustive as with Nasa."

Scientists on Zero Gravity's "vomit comet" conduct tests in microgravity such as vestibulo-ocular examinations Chris Crisman

Richard Branson is many things, but he is not (yet) an astronaut. Despite agreeing to send hundreds of people into space -- for a collective £76 million in ticket sales -- he hasn't experienced what it is he's selling. So, in February, to prepare for the inaugural flight, which he and his family say they will be on, he hopped into a modified Boeing 727 that had been stripped of seats and outfitted with a padded interior. The plane, run by the Zero Gravity Corporation in California, performs parabolic arcs (pulling up and then diving) to create weightlessness.

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It's not cheap (£2,700 per passenger, for 12 to 15 parabolas) and is nicknamed the vomit comet. "After about 12 parabolas on the plane, some people started looking slightly green," Branson later tweeted. Virgin recommends that its passengers train here to make the most of their roughly four minutes in space. "You don't want to spend that time figuring out how to manoeuvre," says Terese Brewster, president of Zero Gravity, which has flown dozens of Virgin's clients and trains Nasa astronauts as well. "You want your brain and body to be ready for this."

Some 70 per cent of trained astronauts suffer motion sickness while flying in space for the first time, mainly due to sensory conflicts -- not knowing what's up or down (there is no up or down in space). If you look out the portal, the Earth might be overhead, not below you, which could easily create a sense of vertigo.

Dizziness, pallor, sweating and vomiting can occur without warning.

The Aerospace Medical Association, looking at health issues on commercial space flights, noted in a 2011 issue of Aviation, Space, and Environmental Medicine that "vomiting can crescendo quite suddenly... In a multi-passenger vehicle, one passenger becoming nauseated can potentially trigger nausea in the other vehicle occupants." They advise not moving your head around too quickly.

It's also not a good idea to eat heavily or drink beforehand, a messy fact of zero gravity that dawned on Ashton Kutcher too late.

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During his Zero Gravity training in November, he told talk-show host Ellen DeGeneres, he didn't get the "no drink or food" memo. "I think there were, like, 18 parabolas and I threw up for about 12 of them," he said. And although Virgin, like Zero Gravity, will supply fliers with zip-shut vomit bags, Kutcher helpfully noted that "vomit behaves differently in zero g. When you throw up in the vomit bag, it just kind of stays there, with you, when you're flying."

Virgin's spaceship is 18 metres long with a two-metre diameter cabin. If you push off too hard while in microgravity, you'll go flying fast, likely smacking into another passenger. It might not injure you, but as Binnie says, "it can spoil an otherwise memorable experience."

Blair LaCorte, the global president of the theatrical Production Resource Group, and an early ticket holder on Virgin (he's passenger 197), "smashed" into walls and other people during his zero-g training flight last year, as he attempted somersaults. "That's my goal for the actual space flight," he says, "to complete a full somersault."

He has not yet undergone g-force training, but he considers it as a necessary step. "I know when I see that space ship, my adrenaline is going to spike and it would be easy to pass over into panic mode," says LaCorte, 51, who is a flight junkie and former CEO of private airplane company XOJET. "I want to be ready."

NASTAR is the only company in the US, and one of few around the world, that trains civilians on centrifuges to prepare them for the g-forces of space flight. (Cost: £1,800 for a two-day training session.) Another company, Wyle, trains clients for the Virginia-based firm Space Adventures, the company that sends civilians to the International Space Station for a fee of about £6 million. Wyle helped train American entrepreneur and technologist Dennis Tito, the first civilian to fly to space in 2001, as well as billionaire software executive Charles Simonyi, who enjoyed the experience so much he did it twice.

Although Wyle does not offer regular civilian training, like NASTAR, it has consulted on the issues of safety and training with the FAA as well as with the major commercial space providers, including Virgin Galactic and SpaceX. Advice includes giving passengers hydrating gel packs and energy bars, rather than water or food -- as yet, there are no toilets in civilian space -- and developing emergency procedures. Rather than give passengers bulky, oxygen-equipped space suits, Virgin plans to offer a "shirt-sleeve" environment in space. In the unlikely event of depressurisation, riders will use small scuba-style oxygen tanks.


As commercial space flight gets closer to becoming a reality, the business of training citizens as astronauts will also take off.

This summer, a company called Waypoint 2 Space says it will open the first comprehensive civilian training facility in the world (offering both a g-force centrifuge and zero gravity training), on a par with Russia's Star City. It will target both the sub-orbital and orbital markets, running month-long sessions for the latter. "The question for commercial space flight providers is what do you recommend and what do you require?" says Vernon McDonald of Wyle, who has worked with the FAA and the flight companies. The FAA, which oversees Spaceport America in New Mexico, where Virgin and several other outfits will launch from, is looking to the companies to help figure it out. "As we get closer," McDonald says, "you will see these companies coming forward and saying, 'OK, if you want to fly on our spacecraft we require you to do X, and we recommend you to do Y.' Where Y is drawn is now open to evaluation and discussion."

It's an important point not just for safety and health reasons, says McDonald, but for passenger comfort and liability. "What happens when the guy paying $250,000 gets elbowed or maybe ends up with someone's breakfast on him? You want to do everything you can to make sure 100 per cent of your customers enjoy the experience."