Satellite Communications
From Telstar's transatlantic television to modern high-throughput satellites, satellite communications connects the world. Today, LEO constellations like Starlink compete with traditional GEO satellites for broadband.
How SatCom Works
Satellite communications uses radio frequencies (C-band, Ku-band, Ka-band) to transmit data between ground stations and satellites. Ground stations (gateways) connect to terrestrial networks, while user terminals (VSATs, mobile phones) connect directly to satellites or through intermediate satellites in the constellation.
Frequency Bands
- L-band (1-2 GHz): Mobile satellite services, GPS
- S-band (2-4 GHz): Weather radar, communications
- C-band (4-8 GHz): Traditional satellite TV (4-8 GHz)
- Ku-band (12-18 GHz): Direct-to-home TV, VSAT
- Ka-band (26-40 GHz): Modern HTS, Starlink, Viasat
VSAT Networks
Very Small Aperture Terminal (VSAT) networks provide satellite internet to businesses, ships, and remote locations. A typical VSAT has a 0.75-2.4m dish and provides 1-10 Mbps. These networks use hub-and-spoke topology, with all traffic routing through a central hub.
High-Throughput Satellites (HTS)
Modern HTS satellites use spot beams and frequency reuse to achieve capacities of 100+ Gbps—10-20x traditional satellites. ViaSat-3 (Ka-band) promises 1 Tbps capacity. This enables consumer broadband, aviation, and maritime services competitive with terrestrial options.