Definition
An unmanned spacecraft placed in orbit around the Earth that receives radio signals from a ground station, amplifies them, and retransmits them to one or more receiving stations elsewhere on Earth. Communications satellites are used to relay voice, data, and video signals over distances that would otherwise be blocked by the curvature of the Earth or by terrain.
Plain English
A satellite in space that acts as a relay for radio signals, picking them up from one place on Earth and sending them back down to another place, allowing communication across great distances.
Context Anchor
Seen in discussions of aircraft satellite communication systems, especially for oceanic, remote-area, or long-range flights.
Derivation
From Latin communicare, meaning 'to share' or 'to make common,' and Latin satelles, meaning 'attendant' or 'companion.' A satellite originally meant a follower; in space terms it means a body that travels alongside or around another. So a communications satellite is literally a 'sharing companion' orbiting the Earth — a relay station that keeps signals moving between distant points.
Why Pilots Care
Provides reliable communication beyond VHF line-of-sight range, essential for transoceanic flights, position reporting, and weather updates.
Analogy
It is like a radio repeater placed very high above Earth: one station sends a signal up to it, and the satellite sends that signal back down where it is needed.
Intuition Check
A communications satellite is not the same thing as a navigation satellite. Its main job is to pass communication signals, not to tell the aircraft where it is.
Example Sentence 1
On the transatlantic crossing, the crew used a communications satellite link to send their position reports to oceanic control.
Example Sentence 2
Dispatch coordinated the diversion routing through the communications satellite link when the aircraft was well beyond VHF coverage.