Satellites: Types of Orbit

There are four primary types of orbit for satellites

  • Low Earth Orbit (LEO)
  • Geosynchronous Earth Orbit (GEO)
  • Medium Earth Orbit (MEO)
  • Elliptical

 

 The vast majority of satellites (just over 72%) are in Low Earth Orbit a breakdown of what orbit satellites, by numbers, is shown below. 

Satellites - by Orbit

  • GEO
  • Elliptical
  • LEO
  • MEO
[vcj_heading_simple content2=”Low Earth Orbit (LEO) – 160km to 2,000 km” alignment=”left” color_text=”#000000″ italic=”” size=”default” animation_speed=”2″ animation_delay=”0″]

Typically LEO satellites have an orbit time of around 90 to 120 minutes. Almost all human activity in space is LEO, including the ISS. The ability to get close to Earth for reconnaissance, the high speed of orbit and the fast transfer of data makes this the most popular area of satellites with over 72% of satellites in this space

 

Satellites - Low Earth Orbit

Low Earth Orbit Image from ESA

[vcj_heading_simple content2=”Geosynchronous Earth Orbit (GEO) – around 36,000 km” alignment=”left” color_text=”#000000″ italic=”” size=”default” animation_speed=”2″ animation_delay=”0″]

Due to the nature of their orbit, these satellites effectively stay in the same point. Most GEO satellites are actually geostationary, with zero incline above the equator, meaning they are in the same point all of the time.  This makes them very useful for communication satellites – hence this is the second most common orbit with over 20% of the spacecraft (554 satellites) in this orbit.

Satellites - Geostationary Orbit

Geostationary Orbit – image from ESA

[vcj_heading_simple content2=”MEO – Medium Earth Orbit” alignment=”left” color_text=”#000000″ italic=”” size=”default” animation_speed=”2″ animation_delay=”0″]

MEO refers to satellites between the LEO ad GEO orbits yet, despite the huge range distances only 5% of satellites operate in this space. This area is used largely by navigation satellites, like the European Galileo system (pictured below

 

Galileo Constellation of Satellites

Galileo Constellation for Navigation – Image by ESA

[vcj_heading_simple content2=”Elliptical Orbits – Various” alignment=”left” color_text=”#000000″ italic=”” size=”default” animation_speed=”2″ animation_delay=”0″]

This is the least common of the satellite orbits, with just 2% in this place. The vast majority of these are military or government missions, with just three that for commercial use.

The orbit for these is shown below

Molniya orbit - an eliptical satellite orbit

Molniya orbit, from NASA.