An astronaut is said to be weightless when they travel in the satellite. What does this mean?

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.

moving ball hits still ball. mover stops, hit ball moves. momentum transfer.