# What determines the orbital period of a satellite?

Feb 3, 2018

For artificial satellites, it depends upon height of the orbit.

#### Explanation:

For the earth,

• Artificial satellite:-

1.The time to complete one revolution around the planet depends upon the height of the orbit.

2.When height of orbit is 1000 km it takes 1.8 hours,when the height of orbit is 20,000 km the time taken is 12 hours.

Feb 3, 2018

The orbital period of a satellite depends on the mass of the planet being orbited and the distance of the satellite from the centre of the planet.

#### Explanation:

The orbital period of a satellite $T$ can be obtained from Newton's form of Kepler's third law.

${T}^{2} = \frac{4 \pi}{G M} {a}^{3}$

Where $a$ is the semi minor axis, which is the distance of the satellite's orbit from the centre of the planet it is orbiting. $G$ is the gravitational constant and $M$ is the mass of the planet. The product $G M$ is called the gravitational parameter.

In the case of the Earth, the gravitational parameter $G M = 3.986 \cdot {10}^{14} {m}^{3} {s}^{-} 2$.