First Person: How I Trained to Fly in Space (Without Leaving Earth)

Last week, a private spaceship designed to take passengers for joy rides in suborbital space made its first glide flight above California's Mojave Desert. The stage is set for space tourist flights as early as next year, but what will those intrepid space tourists feel during the flight?

That's what I found out in a recent training session, and wow, was it a wild ride.

The spaceship, of course, is Virgin Galactic's SpaceShipTwo: an eight-person space plane designed to drop from a huge mothership at high altitude, launch into suborbital space and then glide back to Earth for a runway landing. The trip, including views of Earth from space and a few minutes of weightlessness, costs a cool $200,000. [Photos: My Training for Suborbital Spaceflight]

Training day

As someone who's been to Space Camp and witnessed four space shuttle launches to date, I've long considered myself a space geek. But my space cred was put to the test as never before when I took a stab at suborbital launch practice.

This summer, I underwent a spaceflight training course culminating in a centrifuge ride that packed on a walloping six times the normal force of gravity. The run was meant to simulate a flight on Scaled Composites' SpaceShipOne suborbital spacecraft, the progenitor of SpaceShipTwo, which was also designed by Scaled founder Burt Rutan.

Virgin Galactic plans to launch people into suborbital flights aboard SpaceShipTwo vehicles as early as 2011. But space tourism is only part of the company's plan.

Scientists hoping to conduct microgravity experiments are also potential customers ? that's where the training course comes in.

Taking science to space

I was one of eight trainees at the three-day Suborbital Scientist Training course at the National Aerospace Training and Research Center in Southampton, Pa.

I joined a group of researchers, including at least one aspiring astronaut, who are working on experiments to take on commercial suborbital space trips like the ones soon to be offered by Virgin, as well as XCOR Aerospace, and Armadillo Aerospace.

These experiments could range from studies on how weightlessness affects the human body to projects to observe how dust grains interact without the force of gravity.

The $3,000 NASTAR training program, run by a Pennsylvania company, Environmental Tectonics Corp., was designed to familiarize the scientists with the rigors of spaceflight to help prepare them and their experiments for the journey to space.

Me, I was just along for the ride.

Making do with less oxygen

When we arrived on site for our first day, we donned NASTAR flight suits and settled in for some instruction by trainer Glenn King on how altitude affects the human body. Commercial suborbital spaceflights will fly to extreme heights ? high enough to reach space, but not high or fast enough to enter low-Earth orbit like NASA's space shuttles.

At high altitudes, the atmospheric air pressure is lower than at sea level, which can affect the body in myriad ways. To learn what it's like, we went through a simulated flight to 18,000 feet (5,486 meters) using a hypobaric chamber, where the air was slowly sucked out of a closed room to recreate the low pressure of attitude.

I admit, my palms were a bit clammy going in. Specifically, it was this phrase in the training materials that gave me pause: "This altitude is high enough that it will induce the onset of hypoxia, but not high enough that any serious injury should occur."

Hypoxia occurs when the human body doesn't get enough oxygen. We were on the lookout for symptoms such as blurred vision, loss of color and peripheral vision, numbness and tingling, headache, dizziness, nausea, hot and cold flashes, and poor judgment and mental confusion.

Clearly, this was going to be fun.

Luckily, we were fitted with oxygen masks that reminded me of what Tom Cruise wears while flying jets in Top Gun. If we started to get symptoms, we could take a hit of oxygen from the masks to perk us back up.

As it turned out, we mostly faired fine. Sure, I felt a little strange when we got to our peak altitude. And our collective performance on a series of mental tasks showed we probably were not functioning at our best.

For example, trainers passed around a child's puzzle ? a ball with differently shaped holes that we had to fit corresponding blocks into.

For whatever reason, it seemed harder than it should have been! And I hold the simulated high altitude completely responsible for my subpar performance on a set of math problems we completed on a worksheet while in the chamber.

Ultimately, I gave myself a pat on the back for enduring my first day of spaceflight training. I knew it was only uphill from there.

Packing on the Gs

Day Two began our introduction to NASTAR's centrifuge Space Training Simulator, the STS-400 Phoenix.

The machine has a 25-foot (7.6-meter)-long arm attached to a gondola holding a cockpit simulator, where terrified volunteers like me can be strapped in and spun.

As the arm twirls around in a circle at greater and greater speeds, the rotation creates an outward-pointing force that multiplies the weight bearing down on the person in the cockpit. The orientation of the cockpit can be rotated so that the force is pointing from your head to your toes (the so-called Gz direction) or from your front to your back (the Gx direction) ? or both. Yikes.

I was almost shaking with fear when I strapped into the comfy seat in the cockpit and heard the loud click of the door locked behind me. King's calm voiced warned me the rotation was about to begin.

I would like to state for the record that I did not lose my lunch on the centrifuge (even though I was reminded repeatedly there were bags inside the cockpit in case I felt the need). The first day wasn't quite as bad as my worst fears, but it wasn't as easy as any amusement park centrifuge I've ever been on either.

It helped that they worked us up slowly. On that day each trainee went on a few rides where we felt Gs in each direction separately, in increasing amounts. The trainers ratcheted up the Gs we felt to 3.5 Gs in the Gz direction, and 6 Gs in the Gx direction.

Elephant on my chest

When I got up to 6 Gs in the Gz direction (head to toes), it felt like an elephant was sitting on top of me.

At this force, breathing is difficult, as it takes a Herculean force just to push your chest out enough to take air into your lungs. I did put to use the pressure-breathing technique King taught us to help keep our lungs expanded and taking in air.

And Gz, for me, was even worse. This force tends to pull the blood from the top of your body down into your extremities. So while my toes weren't starving for blood, my brain certainly was.

King taught us to be on the lookout for loss of peripheral vision ? the so-called tunneling effect where your vision tends to go black around the edges and your field of view becomes smaller and smaller as your brain runs out of oxygen from lack of blood.

Within seconds of packing on the Gz force, I experienced the beginnings of this effect. As the centrifuge pummeled my body, I had to squeeze my muscles ? especially legs, feet and arms ? to constrict the veins and arteries there, forcing the blood out of my limbs and back to my head.

This worked, surprisingly well, and I could quickly see again.

The real deal

Day Three brought my greatest test.

Riding the centrifuge, I would undergo the full flight profile of SpaceShipOne, the first privately funded reusable manned spacecraft that won the $10 million Ansari X Prize in 2004.

The ride was actually designed to simulate what passengers should feel on Virgin Galactic's SpaceShipTwo suborbital flights, though data from that craft is not yet available, so NASTAR used readings from SpaceShipOne to design the centrifuge program.

This ride would subject me to 3.5 Gs in both the Gx and Gz directions during launch, then a period of simulated "weightlessness" (while it's really still 1 G because we're on the ground, in comparison it almost feels like microgravity), and then up to 6 Gx and 1.5 Gz during reentry.

The G-forces build just like during a real flight, on the same time scale. The experience is made even more lifelike by a seat that shakes just like a real rocketship, and a domed display that shows a control panel and visuals simulating the forward and aft view at all times.

G force unleashed

I have to admit I was pretty much petrified.

I watched my seven compatriots go before me. While it helped that they all appeared to have fun, I was sobered by the fact that even some of the most stalwart among them cried out in alarm when the spaceship dropped from its carrier plane in mid-air and then the rocket engines ignited for a speedy climb to space.

First, we went through one flight where all the Gs were at only 50 percent strength. That helped to prepare me for the full-on throttle, but even the half-way version was intense. I knew a kick was coming when the rocket lit, yet still it caught me off guard. I screamed out loud like I was riding the upside-down portion of a roller coaster (which, by the way, I try to avoid at all costs).

Frankly, after that it all felt bearable.

Then I had a few minutes at rest before I took the full 100 percent G ride. If I thought the ascent was tough the first time, it was nothing to the real thing.

This time, it felt like what I imagine characters in sci-fi movies experience as they twist and whirl through a wormhole.

My body was pulled with extreme force, and within seconds my peripheral vision started to black out. King's reassuring voice guiding me through it reminded me to "squeeze, squeeze, squeeze" my leg and arm muscles to force blood back to my head.

Luckily, it worked, and soon I was in "space."

Ah, the relaxing release as the Gs lifted and I saw a gorgeous view of glittering stars and shining Earth below. Yet I was still feeling apprehension for my return journey coming up in a couple of minutes.

Soon, a disembodied female voice counted down the seconds and I braced myself for reentry.

The Gs during this portion come in two waves ? a rapid increase to 6 Gs pointing into my chest, which quickly let up, followed by a milder push to a little over 2 Gs. The z-direction Gs during this phase were mercifully low.

If I make it sound agonizing ? well, that's not untrue. But it was also one of the most thrilling sensations I've ever felt in my life. And it was fascinating to learn about techniques to fight the G forces ? and see that they really worked when I had trouble.

Who knows? Those skills could come in handy when I take a real ride to space!

• Photos: Suborbital Spaceflight Training with SPACE.com
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