Before the astronauts going to space, they must be trained in a capsule, which is devoid of gravity, right? My question is how this room or capsule become devoid of gravity, and what is its machanism?
A person feels weightless when he is undergoing free-fall; for example a person who is diving from a high platform will feel weightlessness till he/she hits the water. NASA uses a modified KC135 four engine jet to fly on a parabolic orbit so that for a certain period of time, it is falling freely towards Earth. In this period, astronauts practice eating, drinking and using various kinds of onboard shuttle equipment. Training on these (called vomit comet) normally lasts from 1 to 2 hours.
Update from Ann: In addition to the "vomit comet" (which was recently retired), astronauts get very creative during their training. The Neutral Buoyancy Laboratory at NASA's Johnson Space Center, for example, is basically an enormous tank of water. Astronauts wear special suits that don't float, to mimic the microgravity environment of outer space, so they can practice living and maneuvering. They need to practice working in microgravity, of course, but they also need to practice working in the bulky, inflexible suits that they wear for extravehicular activities. Before undertaking complex missions at the space station, like the 2009 servicing mission to the Hubble Space Telescope, astronauts use the Neutral Buoyancy tank to practice over and over and over again.
Page last updated on June 24, 2015, by Ann Martin.