What is HTS?
High Throughput Satellite (HTS) refers to a satellite design philosophy rather than a specific orbit. Instead of illuminating large regions with a few powerful wide beams, an HTS satellite uses dozens or hundreds of narrow spot beams — each covering an area of 200–500 km diameter — and reuses the same frequency spectrum across geographically separated beams. This cellular-like approach multiplies effective capacity dramatically.
Frequency reuse: the key mechanism
A traditional Ku-band GEO satellite might have 24 transponders, each using 36 MHz of bandwidth once across a continental footprint. An HTS satellite with 200 spot beams and a frequency reuse factor of 4 uses the same 36 MHz in 50 groups of beams, multiplying capacity 50× over the traditional design. ViaSat-3 (2023) achieves over 1 Tbps total capacity using this approach — compare this to ViaSat-1 (2011) at 140 Gbps, which was already revolutionary at launch.
Gateway requirements
Frequency reuse requires a gateway station for each beam cluster. A 200-beam HTS satellite might need 20–40 geographically distributed gateway sites, each with large Ka-band antennas connecting to fibre infrastructure. This distributed gateway requirement is one of the main operational complexities of HTS systems.
HTS and the cost-per-bit revolution
HTS reduced the cost of satellite bandwidth from over $3,000 per Mbps/month in the early 2000s to under $10/Mbps/month by 2020, enabling satellite broadband, cellular backhaul, and maritime connectivity services that were previously economically unviable. LEO mega-constellations are now further accelerating this trajectory.