When launching a satellite into space, you have an infinite number of orbits to choose from.
For the vast majority of satellites, what matters is Earth, since that is what they interact with. To be effective, they must be placed in an orbit that considers both their movement around Earth and the Earth’s rotation on its axis.
Only a few specific orbits optimize these factors, and we’re going to explain why in this lesson.

This is an orbit that perfectly matches Earth’s rotation. As a result, satellites placed in this orbit appear “stationary” above a fixed point. Since they move in sync with Earth, they complete one orbit in 24 hours (23h 56min 4s exactly).
We’ll use satvis to illustrate this, taking for example the weather satellite GOES-17.

In this image, you can see that this satellite has a huge field of view covering the two American continents , nearly an entire hemisphere 🌎.
In 2D view, the satellite coverage looks like:

And you can even obtain images useful for weather forecasting, for example:

Though this orbit is ideal for many activities, its major drawback is its distance from Earth , about 35786km (at the equator)! This not only makes it very expensive to launch a satellite so far, but also introduces a 22-second delay for signals to travel between the satellite and Earth, complicating certain operations ⏳.

Let’s move closer with Medium Earth Orbit, which lies between Low Earth Orbit and Geostationary Orbit.
This orbit is ideal for navigation satellites operating in a constellation. In this orbit, each satellite can view about 38% of Earth’s surface while orbiting quickly enough to cover the globe. Their orbital periods vary between 2 and 12 hours.
For instance, check out satvis to see, for example, the Galileo constellation composed of 30 satellites, where each satellite’s coverage helps determine your position at all times.

Feel free to check out right here my course on GPS/GNSS to understand how it works :)

Let’s get as close as possible to our surface with Low Earth Orbit, the most populated region, where around 85% of all satellites reside. These are satellites roughly within 2000km of Earth.
This orbit is so popular mainly because it takes minimal resources to place satellites here, making space accessible to smaller players. Additionally, communication delays are almost negligible compared to the 22 seconds in geostationary orbits.
Because they are nearby, these satellites orbit Earth very quickly , in only about 90 minutes. That’s why astronauts aboard the ISS (which travels at about 28,000km/h) see 16 sunsets per day 🌅.
Although a LEO passes over many areas rapidly, its coverage is limited, which necessitates multiple ground stations for continuous contact.

In fact, the mega constellation of Starlink satellites from SpaceX is in LEO, now totaling over 6000 satellites (more than half of all satellites), and growing.

A polar orbit (a type of low Earth orbit) circles over the poles with an inclination of 90°. Because Earth rotates, satellites in this orbit can cover the entire globe very quickly.

On our diagram, the scale relative to the Sun is simplified, but it clearly shows that the advantage is satellites always facing the Sun , ensuring continuous energy reception ☀️.

A sun-synchronous orbit is a near-polar orbit that is selected to allow the satellite to observe every part of Earth at the same local time. This is particularly useful for climate studies.

This is the orbit used by the NOAA satellites from which we retrieved images in this project.

A unique orbit characterized by an elliptical path, meaning the satellite swings from very near to Earth to extremely far away.

This orbit is used, for example, by Russian satellites. On such an orbit, they move slowly during apogee to provide prolonged coverage at northern latitudes and rapidly during perigee near southern latitudes. This example refers specifically to the Molniya orbit.
There’s also the Tundra orbit, but generally, HEOs are particularly useful for telecommunications in polar regions.

And that’s it for the main types of orbits. Today, there are over 10,000 satellites orbiting Earth. It isn’t easy to know the exact number, but you can get a good overview at Orbiting now 🔍.