Explanation : Weightlessness in space is caused by the simple physical factors that cause the limitation of gravity. While on Earth, external forces are pushing or pulling on a person's body, but when a spacecraft enters orbit, the people and objects aboard the craft enter a state of free fall. Essentially, the vehicle and all of its contents are falling towards the Earth causing the sensation of weightlessness similar to the state a person feels when enjoying the amusement park ride. Many people believe that a lack of gravity is the root cause for weightlessness in space. However, a spacecraft needs gravity in order to orbit around the Earth. Gravity supplies necessary centripetal force responsible for the orbital motion, this means that the spacecraft is falling towards the Earth without colliding with it due to tangential velocity. Despite this fact, spacecraft in orbit around Earth still experience a certain amount of weighted force. ....Read more