Answer:
Rmmbr... Absolute gravity means zero gravity..
No, and we don't have a zero gravity environment in space, either.
On the ISS, gravity is very much working. Here on the surface, we experience an acceleration of gravity of about 9.81 m/s^2. On the space station they experience a slightly reduced acceleration (about 9.2 m/s^2) because of their increased distance from the center of the Earth (gravity is a 1/r^2 law).
What we are actually experiencing on the ISS is a state of free-fall. Gravity is pulling the astronauts down, just as if they had stepped out of an airplane, but it is also pulling the ISS down. We feel weight on the ground because gravity pulls us down and the ground, not wanting to move, pushes back up at us.
We call the environment on the ISS weightlessness. An astronaut could stand on a scale and appear to have no weight because the scale is falling, too, and therefore can't push back up at us.
The two ways that we best simulate this environment on the Earth is by using airplanes that fly in (approximately) parabolic paths to put the inhabitants and vehicle into free-fall and by working in swimming pools where the neutral buoyancy feels similar to being in free-fall.
