How to calculate the Period of a circular orbit (Aerospace engineering Pt.2)
In the previous lesson, we looked at how to calculate the velocity of an object with a simple formula. Now let’s finish this segment by learning how to calculate the period of orbits using the orbital velocity.
Once we have the orbital velocity of the satellite, then we can apply it in a formula to calculate the period of this orbit.
What does “period” even mean? A period is the time a satellite needs to orbit an object ONCE
Let’s start the calculation
In easy words, the period of revolution is given by the circumference of the orbit divided by the circular/orbital velocity.
Formula:
Quiz Time: Orbital Period
Let’s consider a satellite in a circular low Mars orbit, 300 km above the planetary surface.
- Radius of Mars = 3396 km
- Mass of Mars = 6.419 * 1⁰²³ kg
- Universal gravitational constant: G = 6.674 * 10-¹¹ m³/kg/s²
What is the orbital period of the satellite? The answer should be given in minutes:
First of all, we need to find out the circular velocity of this satellite. Have a look at my other story, where I explain how to calculate the velocity.
In this case, the circular velocity is about 3.40 km/s.
So let’s insert 3.40 km/s and the radius in our formula.
Note: The radius = Radius of the planet + satellite altitude
Answer: The satellite orbits the object every 114 minutes with a velocity of 3.40 km/s
END:
Hopefully, you’ve seen how easy it is to calculate the orbital period of a satellite. Thanks for reading and stay safe :)