Both  the  person  and  the  satelite are  in a  continual  state  of  free  fall  towards the  earth, at  the  same  rate,  so that  the astonaut  does not  feel  a  sense  of  support  and  appears  weightless.  The  person  exerts  no force  on the  floor,  and there  is no normal  reaction experienced by  the  person.

Introduction:
When a satellite is in a circular orbit around the Earth, the person inside the satellite experiences a weightless sensation. This is due to the specific conditions and forces at play in the satellite's orbit.

Gravity's Role:
Gravity is the force that attracts objects towards the center of the Earth. When a satellite is in orbit, it is constantly falling towards the Earth due to gravity. However, its forward velocity is precisely balanced with the gravitational pull, causing it to continuously fall but never hit the Earth's surface.

Centrifugal Force:
In a circular orbit, the satellite's motion creates a centrifugal force that counteracts the gravitational force. The centrifugal force is directed away from the center of the orbit and is equal in magnitude to the gravitational force. This creates a balance between the two forces, resulting in the sensation of weightlessness for the person inside the satellite.

Effect of Height:
The height of the satellite above the Earth's surface also plays a role in the feeling of weightlessness. As the satellite moves higher, the gravitational force decreases due to the inverse square law. At a height of 100 km, the gravitational force is significantly weaker compared to the surface of the Earth. This further enhances the weightless sensation experienced by the person in the satellite.

Freefall and Weightlessness:
In essence, the person inside the satellite is in a state of freefall. The gravitational force and the centrifugal force cancel each other out, resulting in no net force acting on the person. Without a supporting force, the person does not experience any sensation of weight.

Conclusion:
The feeling of weightlessness experienced by a person inside a satellite in a circular orbit at a height of 100 km above the Earth's surface is due to the balance between the gravitational force and the centrifugal force. The person is essentially in a state of continuous freefall, where the absence of a supporting force leads to the sensation of weightlessness.