To calculate the radius of a geostationary orbit, the centripetal force must **equal **the gravitational force on the satellite or mass..

r³ = G (m2) T² / 4π²

We know that (m2) is the mass of the earth at 5.98×10^24 kg, T is the time period and G the universal gravitation constant at 6.67 x10^-11 kg^-2 .

## Radius Of A Geostationary Orbit

r = 4.23×10^7 metres.

However this is the radius to from the **center of the Earth**. Therefore, we will need to deduct the radius of the Earth from this number: the height of the satellite from Earth = r – r(E) where r is the distance of the satellite from the center of the Earth and r(E) is the radius of the Earth.

## Summary

- A geostationary orbit is an orbit which is fixed in respect to a position on the Earth. Therefore, the time period will always be 24 hours.
- From combining the centripetal force, gravitational force and basic velocity force equations, we can deduce that the radius required for a geostationary orbit is 3.6×10^7 meters.