This condition, also called 'Zero-Gravity' is actually not the negation of gravity, but is, instead, its local cancellation in a small region of space due to a counteracting 'fictitious force' called centripetal force which is directed opposite to gravity. When an astronaut is in a stable, circular orbit around the Earth at any altitude, the force of gravity inside the spacecraft, is countered by the centripetal force so that the nearly balance:
mV^2 G M(earth) m ---- = ------------- R R^2This gives a 'weightless' condition to the astronaut throughout the orbit. However, if the capsule is large enough, the astronaut can begin to detect the 'tidal' force from the Earth which is due to the fact that the geometry of the gravitational field is radial, but like the spokes on a wheel, the radial gravitational force has a divergent or convergent geometry to it within any volume large enough. In a circular orbit, the majority of the Earth's local gravitational field inside the spacecraft is canceled, except for a 'micro-gravity' force due to its tidal effects.