Communications satellite of a GEO satellite. Like LEOs, these satellites don’t maintain a stationary distance from the earth. This is in contrast to the geostationary orbit, where satellites are always approximately from the earth. Typically the orbit of a medium earth orbit satellite is about above earth. In various patterns, these satellites make the trip around earth in anywhere from 2 to 8 hours. In 1962, the first communications satellite, Telstar, was launched. It was a medium earth orbit satellite designed to help facilitate high-speed telephone signals. Although it was the first practical way to transmit signals over the horizon, its major
Transit (satellite) similar to the system used by emergency locator transmitters, except that in the latter case the transmitter is on the ground and the receiver is in orbit. Each Transit system satellite broadcast two UHF carrier signals that provided precise time hacks (every two minutes), plus the satellite's six orbital elements and orbit perturbation variables. The orbit ephemeris and clock corrections were uploaded twice each day to each satellite from one of the four Navy tracking and injection stations. This broadcast information allowed a ground receiver to calculate the location of the satellite at any point in time. Use of two