# Accleration of gravity

1. May 4, 2007

### delta_simon

About what is the value of the acceleration of gravity
in low earth orbit? <9,8m/s² ?

2. May 4, 2007

### Janus

Staff Emeritus
Somewhere in the order of 9m/s^2

3. May 4, 2007

### Meir Achuz

g(H)/g=[R/(R+H)]^2.

4. May 4, 2007

### rcgldr

A typical low orbit shuttle travels around 17,235 mph, or 25,280fps, every 91.38 minutes or 5483 seconds. Orbital length is about 26250 miles = 138,600,000 feet, with a radius of 4178 miles = 22,060,000 feet. Earth radius is about 3959 miles, so the orbital radius is about 1.0553R, or about 219 miles altitude. The altitude actually ranges from 185 miles to 250 miles depending on the mision (space station is 250miles up). Centrifugal acceleration is v^2/r = 28.97 ft / s^2. Gravitational acceleration is 32.264ft / s^2 = 9.822m / s^2 (once earth rotational effects are eliminated), so the shuttle in low orbit experiences about 89.8%g. or 8.82 m / s^2. This corresponds with g at shuttle radius = g/R^2) = g/(1.0553^2) = 89.8% g.

Geostationary sattellites are high orbits, speed around 6880mph=10,091 ft/s, altitude 22,240miles, radius about 26200 miles = 138,330,000 ft, for only 2.28% g. v^2 / r = .736ft/s^2 => 2.28% g which checks.

Last edited: May 4, 2007