Weightlessness occurs when a body in a gravitational field changes places to neutralise its gravitational force.
Astronauts orbiting the Earth in a space station experience zero gravity or weightlessness because their spacecraft continuously undergoes changes in velocity in its orbit in order to prevent it from being pulled into the atmosphere.
This acceleration, which is often known as a centrifugal force, counterbalances gravity. Hence, they experience Zero Gravity or weightlessness.
This floating around in space looks like such an incredible thing to experience it had to be added to my bucket list!