Why do astronauts feel weightless in space?

Weightlessness has nothing to do with being outside Earth's reach. A spacecraft in low orbit sits deep inside Earth's gravitational field, and gravity is precisely what keeps it there: the vehicle is permanently falling towards the planet. What saves it is sideways speed. It moves fast enough that the surface curves away beneath it as quickly as it drops, so the fall never ends and never arrives. Crew, cabin, cameras and loose crumbs all follow the same curved path at the same rate, so nothing drifts away from anything else.

What the body senses is not gravity but the force that resists it. Standing on the ground, the floor pushes up through the feet; the skeleton, the inner ear and the pressure in the tissues all register that push, and the brain reads it as weight. In free fall nothing pushes. The seat falls with the astronaut, so it applies no force, the fluid in the inner ear stops pressing against its sensors, and the body reports the absence of support as floating. The same sensation appears in a dropping lift or over the crest of a roller coaster.

Agencies prefer the term microgravity because the environment is never perfectly still. Atmospheric drag, thruster firings, crew movement and the slight difference in pull between one end of a large station and the other all leave tiny residual accelerations, and they matter for sensitive work in crystal growth or fluid physics. Aircraft flying parabolic arcs reproduce the same condition for a few seconds at a time, and they do it well inside the atmosphere — proof that free fall is a trajectory, not a place where gravity ends. Orbit simply makes that trajectory permanent.