<h2>Answer: The astronauts are falling at the same rate as the space shuttle as it orbits around earth</h2>
The astronauts seem to float because they are in free fall just like the spacecraft.
However, although they are constantly falling on the Earth, they do not fall because the ship orbits at a sufficient speed (in the same direction of rotation of the Earth) so that the centrifugal force is balanced with the Earth's gravitational pull.
In other words:
The spaccraft and the astronauts are in free fall but the Earth's surface will never be reached as long as they does not decrease the speed.
Then, as they accelerate toward Earth (regardless of their mass), it curves beneath them and never comes close.
That's why astronauts, having the same acceleration as the spacecraft, feel weightless and see themselves floating.
