Telecom Satellites

Factual Questions
#1

Does anyone know their usual distance from Earth’s surface?

Thanks. :slight_smile:

#2

They are in geo stationary orbit, That’s at about 22,000 miles.

#3

Not all satellites are in geosynchronous orbit. Satellites that a consumer mounted dish is to be aimed at are (satellite TV, etc). Low Earth Orbit (LEO - about 100 to 500 miles - it varies somewhat from different sources) is employed for a lot of telecommunications services such as mobile phone - you can have stations which track the satellites, it doesn’t take as much power to get a signal up to the LEO satellite, and you have less lag time to cope with.

Here’s a table of orbital distances and their uses:

http://www.inetdaemon.com/tutorials/satellite/orbits.html

#4

In fact, if you want to dig through a mountain of data on the satellite “constellations” for various services, here’s a registry somebody maintains:

http://www.ee.surrey.ac.uk/Personal/L.Wood/constellations/

There’s an interesting picture on the “overview” page, illustrating the orbital heights of some of the services:

http://www.ee.surrey.ac.uk/Personal/L.Wood/constellations/overview.html

#5

The CelesTrak site has information on the orbits of specific satellites.

#6

The J-Track site plots the positions of lots of satellites, with orbits and ground tracks.

#7

yabob’s first link is inaccurate in at least one detail: geostationary and geosynchronous are not the same thing. The former is a sub-class of the latter. Geosynchronous orbits are ones in which an object remains over a single longtitude of the earth, but it might vary in latitude. A geostationary orbit is a geosynchronous orbit directly over the equator, so that the latitude never changes.