How much gravity is in space compared to earth?

Short answer

It depends entirely on where in space you are, and near Earth the answer surprises people: at the International Space Station's 400 km altitude, gravity is still about 90 percent of its surface strength. On the Moon it is roughly one sixth of Earth's, on Mars about 38 percent, and only far from any massive body does it approach zero.

Published: September 23, 2026 · Updated: September 23, 2026 · Edited by Above Ten Thousand · Editorial policy

How much gravity is in space compared to earth?

Apollo 15 Commander Dave Scott — First to Drive an EV on the MoonSteve Jurvetson from Los Altos, USA (CC BY), vía commons

Near Earth, almost all of it remains

Gravitational acceleration falls with the square of the distance from a body's centre, and orbital altitudes are small compared with planetary radii. Earth's mean radius is about 6,371 km; a station at 400 km sits some 6,771 km from the centre. The resulting acceleration is close to 8.7 m/s² against 9.81 m/s² at sea level — around 90 percent. Crews float because the whole vehicle is in free fall, not because the pull has gone.

At geostationary altitude, 35,786 km above the equator, the picture changes. Distance from the centre grows roughly sevenfold and gravity drops to something near 0.22 m/s², a little over two percent of the surface value. Even there, it is what keeps a satellite in place.

Standing on other worlds

Surface gravity varies with a body's mass and radius together, which is why intuition based on size alone misleads. The Moon offers about 1.62 m/s², roughly one sixth of Earth — the reason Apollo crews adopted a loping gait. Mars gives about 3.72 m/s², close to 38 percent. Jupiter, despite being gaseous, presents about 24.8 m/s² at its cloud tops, some 2.5 times Earth's.

The genuinely weightless case

True absence of gravity does not exist anywhere in the observable universe, because the field of every mass extends without limit. What exists is negligible field strength: deep interstellar space, far from any star, where residual accelerations are vanishingly small. Aboard a spacecraft the practical condition is microgravity, typically around a millionth of Earth gravity, produced by drag, tidal gradients along the vehicle and the movement of the crew themselves.