You might be surprised to find out that the gravitational pull of the Earth is nearly the same hundreds of kilometers or miles above our planet as it is on its surface But as a space traveler in Earth orbit you’ll get to feel the sensation of weightlessness while your spacecraft is falling around Earth fast enough to cancel most of gravity’s influence Actually there is still a tiny amount of gravity called microgravity that varies a little depending on where you are in your spacecraft But beyond the orbit of the Moon the gravitational pull from the planets and their moons is much much less In fact you could think of this space between planets and beyond as having zero gravity Getting Ready for the Greatest Show Off Earth Simulations are among the most useful tools for space training Whether it’s a computer program or a full-scale model spaceship a simulation is designed to imitate elements of your space adventure Simulations help you gain experience without posing real-world danger To prepare for the sensation of weightlessness one kind of zero-gravity simulation happens inside a specially modified passenger jet with an empty padded area in place of the plane’s usual seats Using current rocket technology a trip to the Moon and back will take days a trip to a comet will take anywhere from one to four years depending on how far it is from Earth to get to the planets of the inner solar system such as Venus or Mars and back will take months or even years depending on the distance between the planet and Earth at the time of the trip a journey to the planets of the outer solar system such as Jupiter or Saturn and back could take up to ten years
These vomit comets you can guess how they got this nickname climb as fast as they can up to an altitude height above the ground of about the same as a typical airplane flight As the plane gets close to its maximum altitude you start to feel lighter and lighter Finally your feet arms and then your whole body rise off the floor to float in mid-air for 20 to 30 seconds Then the plane dives downward to its starting altitude before leveling out for its next run During a session of zero-gravity training you’ll get to do this about a dozen times Another way you might train for the feeling of weightlessness is to jump into a giant specially designed pool of water Weights will be attached to you so that you neither float up to the surface nor sink down to the bottom instead you hover in place like an astronaut in space NASA runs the world’s largest underwater training facility which is 60 m 200 ft long and 12 m 40 ft deep and is used to train astronauts for space walks Above Zero-G’s Airbus A300 climbing toward a weightlessness simulation Below Astronauts Rick Mastracchio left and Koichi Wakata right train for a space walk in the waters of NASA’s Neutral Buoyancy Lab NBL
Once you’ve trained for a lack of gravity it’s time to prepare for the additional gravity you’ll experience during launch and upon your return simulator you’ll also need to practice Why would you need to train for this The ship’s rapid acceleration increased speed causes g-forces to build up and pile on several times more weight than the gravity you’re used to You and your body are used to living in 1g a g is equal to normal gravity on the surface of the Earth You can experience dozens of gs for a split second without suffering any real damage but if you were to undergo as little as 5 gs for more than a minute you could pass out To prepare for these extra gs you’ll need g-force training which might not be as fun as it sounds In a high-g simulator you’ll spend a few minutes at a time strapped into a seat inside a sealed capsule at the end of a giant centrifuge arm swinging around at the speed of a car on the highway As well as spending time in the high-g exercises that help you tolerate more gs such as flexing your arm and leg muscles and controlling your breathing After several days of getting used to high g-forces don’t worry you won’t be spinning around in the centrifuge the whole time it’s a good idea to try out a machine that can simulate both the movements your ship might make and extra g-forces One option is to take a high-altitude flight in a military fighter jet which is almost like going on a suborbital trip Or some of today’s space tourism companies use copies of the insides of their spaceships built inside real aircraft For example Virgin Galactic has a SpaceShipTwo suborbital craft replica built inside its WhiteKnightTwo jet That way before actually going up into space you can fly around and get used to the motions space adventurers will feel during a trip to or from space The 20-G Centrifuge at the Ames Research Center can produce forces up to 20 times that of terrestrial gravity
G-Suits for Super-G-Forces High g-forces can force blood away from important parts of your body such as your head and chest causing you to faint get seriously injured or in extreme cases die During some of your final pre-space simulations you may get to wear a g-suit a kind of anti-g-force jumpsuit G-suits have special sacs that inflate to press on different parts of your body keeping blood from draining the wrong way when g-forces increase Today’s g-suits take up to two seconds to inflate That means that you’re still going to feel some of the effects of the g-forces when your craft launches makes a hard turn or slows quickly Next-generation g-suits being perfected for future flights will inflate almost instantly The 37-million horsepower main engines of a space shuttle fire just before liftoff From the intense vibrations you’ll feel at the start of a space shuttle launch to the violent movements of a space capsule as it enters the atmosphere and all the way to the extreme gravity you may experience along the way you’ll be glad you trained well for your upcoming space adventure There’s a test you can take to see how you’ll react to your return to gravity after a trip in space For this tilt test you’re strapped to a special table lying down and then quickly tilted upward into a standing position Believe it or not this helps to see how likely it is you’ll faint from the rapid changes in position upon your return But don’t try this at home
