A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth. Communications satellites are used for television, telephone, radio, internet, and military applications. Many communications satellites are in geostationary orbit 22,236 miles (35,785 km) above the equator, so that the satellite appears stationary at the same point in the sky; therefore the satellite dish antennas of ground stations can be aimed permanently at that spot and do not have to move to track the satellite. Others form satellite constellations in low Earth orbit, where antennas on the ground have to follow the position of the satellites and switch between satellites frequently.

दूरसंचार के प्रयोजनों के लिए संचार उपग्रह अंतरिक्ष में तैनात एक कृत्रिम उपग्रह है। आधुनिक संचार उपग्रह भू-स्थिर कक्ष, मोलनीय कक्ष, अन्य दीर्घवृत्ताकार कक्ष और पृथ्वी के निचले कक्ष सहित विभिन्न प्रकार के परिक्रमा-पथों का उपयोग करते हैं।