What is the effect of being in free fall for an astronaut inside the Space Shuttle?

When an astronaut is in free fall inside the Space Shuttle, they experience what is known as apparent weightlessness. This occurs because both the astronaut and the Shuttle are falling towards Earth at the same rate due to the force of gravity. This creates a condition where the astronaut does not feel the normal force that would be felt when standing on solid ground, leading to the sensation of weightlessness.

In free fall, the astronaut's body and the Shuttle are accelerating towards Earth at 9.8 m/s², which means they are not experiencing any resistance that would normally provide a sense of weight. This is similar to how we feel weight when standing on the ground; without that supporting force, the sensations we associate with weight disappear.

The other options do not accurately describe the effect experienced during free fall. There is no change to mass or gravitational pull itself; gravitational force is still present but acts equally on the astronaut and the Shuttle, which is essential to their simultaneity of motion. Though loss of coordination can be a challenge in a microgravity environment, it is not the defining or primary experience of free fall, which is best characterized by the sensation of weightlessness.