How are sattallites controled from one place to another in orbit?

Question

Like those used by D.O.D (Department of Defence)

Answer 1

This depends on the type of orbit the satellite has

Low Earth Orbit - obits the earth in 90min

They are controlled via different earth stations all over the globe where the controllers download and upload the data when the sats are visible to them. All the earth station can form a large network. One such is the Deep Space Network which is used for space exploration communications http://deepspace.jpl.nasa.gov/dsn/

Sometimes like for the ISS where permanent contact is required for a LEO spacecraft satellites in geostationaty orbit are used to relay the signal back to earth. So because the satellite is so far away only a small number is required to achieve coverage of all space surrounding the earth. With this method only one earth station is enough to have constant communication to the satellite. The project was designed mainly to support manned missions and is called "TDRS network" or Tracking and Data Relay Satellite network.

Oh by the way radio amateurs(http://www.arrl.org) that have satellites in orbit control them by cooperating together around the globe and upload and download data on the satellite whenever it is available to them. They use radio frequencies all over the radio and microwave spectrum that they are licenced to use by the amateur radio licence and it is really cool! I as a radio amateur have communicated numerous times with the international space station and have helped in deploying the antenna of one amateur microsatellite by forwarding telemetry I was receiving to the internet for the operations controllers to use.

Answer 2

Some have little gas thrusters. Some have ion engines. The DOD's have small rocket motors. They would only change orbit for a major cause since it burns so much fuel. Ion engines take too long for CIA and DOD satellites.

Answer 3

Software plus radio link.

Answer 4

A network of radio communications.