Operations

Ground stations and downlink

Satellites can only send data to Earth when overhead a ground station. Ground station geography drives delivery latency.

equatorGlobal networks (KSAT, AWS, Viasat) — 14–16 downlinks/dayHome-territory networks (e.g. Chinese operators) — 2–4 downlinks/dayGROUND STATION COVERAGE · SCHEMATIC
Fig. 1 Ground station geography sets how quickly captured imagery reaches the ground. Operators using global networks (KSAT, AWS Ground Station, Viasat) can downlink on nearly every orbit. Operators that downlink primarily over their home territory — including Chinese providers — see typical 6–12 hour gaps between passes, which affects delivery latency rather than imagery quality.

A satellite can only downlink data when it is physically overhead a ground station that the operator owns or leases. Western operators use global networks — KSAT, AWS Ground Station, Viasat — with stations in Svalbard, Alaska, Antarctica, Australia, and elsewhere. This means a satellite in a polar orbit gets a downlink opportunity on nearly every single orbit. A typical contact lasts 5–12 minutes and the satellite dumps its data to the ground via X-band radio or laser link.

Why Chinese operators have longer downlink gaps

Chinese operators downlink primarily over Chinese territory for regulatory and sovereignty reasons. The capture itself is usually reliable, but the time between capture and data-in-hand stretches because the image is sitting in orbit waiting for the satellite to pass back over a friendly station — typically a 6–12 hour gap, sometimes longer depending on orbit geometry. This is a planning consideration rather than a quality issue: the imagery when it arrives is fine, it just arrives later than a Western-network equivalent would. Factor delivery SLA — not just revisit — when the use case is time-sensitive.

What this means in practice

If you need rapid delivery, ask about the operator's ground station coverage, not just the satellite's revisit rate. A satellite that revisits daily but downlinks every 18 hours will deliver imagery 1+ day after capture. A satellite that revisits every 3 days but downlinks every orbit can deliver within hours.