|Types of Satellite Orbits
A geostationary orbit, often referred to as a geosynchronous equatorial orbit, is a circular geosynchronous orbit 35,786 km above Earth's
equator and following the direction of Earth's rotation. An object in such an orbit appears motionless, at a fixed position in the sky,
to ground observers. This equates to an orbital velocity of 3.07 km/s (1.91 mi/s) and an orbital period of 1,436 minutes, which equates to
almost exactly one sidereal day (23.934461223 hours).
Low Earth orbit (LEO) - objects in low-Earth orbit are at an altitude of between 160 to 2,000 km (99 to 1200 mi) above the Earth’s
surface. Objects below this altitude will begin to suffer from orbital decay and will rapidly descend into the atmosphere, either burning
up or crashing on the surface. Objects at this altitude also have an orbital period (i.e. the time it takes for the object to circle the earth
once) of between 88 and 127 minutes.
Medium Earth orbit (MEO) - sometimes called intermediate circular orbit (ICO), is the region of space around Earth above low Earth
orbit (altitude of 2,000 km (1,243 mi) above sea level) and below geostationary orbit (altitude of 35,786 km (22,236 mi) above sea level).
The most common use for satellites in this region is for navigation, communication, and geodetic/space environment science.
A polar orbit - is one in which a satellite passes above or nearly above both poles of the body being orbited on each revolution. It
therefore has an inclination of 90 degrees to the body's equator. A satellite in a polar orbit will pass over the equator at a different longitude
on each of its orbits.
A Sun-synchronous orbit (SSO, also called a heliosynchronous orbit) -is a nearly polar orbit around a planet, in which the satellite
passes over any given point of the planet's surface at the same local mean solar time. A Sun-synchronous orbit can place a satellite in
constant sunlight, which allows the solar panels to work continually. This orbit is also useful for imaging, spy, and weather satellites.
An elliptical orbit, also called an eccentric orbit - is in the shape of an ellipse. In an elliptical orbit, the satellite's velocity changes
depending on where it is in its orbital path. The satellite is moving the fastest at the low point of an elliptical orbit. The low point of the orbit
is called the perigee. The high point of the orbit, when the satellite is moving the slowest, is called the apogee.
An elliptical orbit can be useful to a communications satellite because it allows the satellite to travel over a specific region for a long portion
of its orbit, and it is only out of contact with that region for a short time when it is zipping quickly around the other side of the Earth.