Before an astronaut is granted the rare privilege of spaceflight, she or he must undergo years of education and training.

In particular, getting ready for the alien sensation of microgravity requires a battery of preparations.

Throughout the 1960s, NASA developed a variety of training simulators to mimic the intense G-forces of liftoff and reentry, the weightlessness of space and the one-sixth gravity of the moon.

The simulations were designed not only to give astronauts a sense of what microgravity feels like, but also to rehearse specific portions of their slated missions. The simulations often introduced unexpected problems to train the astronauts to respond to contingencies that might arise in space.

Astronauts were also trained in desert and jungle survival, should their reentry capsules miss the ocean.

Today, astronaut training also includes detailed virtual reality simulations, instruction in physiology and medicine, and courses on language and culture for multinational missions.