Starlink linked 12,000 planned satellites with lasers to beat fiber latency

Geostationary internet satellites orbit far enough away that round-trip latency is physically higher than fiber's, and fiber already crosses oceans on circuitous routes. SpaceX's answer, filed with the FCC from 2016, was a constellation in low Earth orbit where the distance itself is short.

To avoid bouncing every long route down to a ground station and back, Starlink satellites connect to each other with laser inter-satellite links: four per satellite, connecting neighbors in the same plane and in adjacent planes. Researchers calculated the mesh could offer lower latency than any possible terrestrial optical fiber network for distances beyond about 3,000 km, valuable enough that a 1 ms advantage can be worth $100 million a year to a major brokerage.

The design traded a few precise, expensive satellites for thousands of cheap ones: Phase I was 1,584 satellites with about 12,000 planned in later phases, each carrying laser terminals that scale from 10 Gbps toward hundreds of Gbps and eventually Tbps per link.