Question

Explain why an astronaut in an orbiting satellite has a feeling of weightlessness.

Answer 1

The sense of weightlessness in orbiting satellite is because of the lack of any contact-forces. The only force that acts upon humans in space is the force of gravity, which acts at a distance; but as there is no counter-force, we do not experience the sensation of weight over there. The counter or force-of-contact is missing because everything that floats on space does so due to the acceleration due to gravity being the same. Thus, both the astronaut and the satellite have the same value of $g$, which is again equal to the centripetal acceleration of the satellite. These two neutralize each other, causing everything to appear weightless.