How is zero gravity simulated on Earth for astronaut training?

Zero gravity is simulated on Earth using special planes called "parabolic flights" or "vomit comets." These planes fly up and down in curves called parabolas. During each curve, people inside the plane feel weightless for short periods (about 20-25 seconds). This helps astronauts train for space. Another way is dropping objects or experiments in tall towers called "drop towers," where they experience free fall for a few seconds. Scientists also use water tanks, where being underwater reduces the feeling of weight, to help with training for spacewalks.​