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What actually costs the twelve minutes

14.07.2026  ·  6 min read

Downlink is the easy part. We spent a year on the four steps between a raw pass and a tile you can read.

Every conversation about revisit time turns into a conversation about how many satellites you have. That is the least interesting variable. We doubled the constellation in 2024 and the median time-to-tile barely moved, because the bottleneck was never the sky.

Where the minutes actually go

A pass lands as a raw strip with imperfect geometry and no radiometric meaning. Between that and something you can put in a model there are four steps, and three of them used to be batch jobs that ran when a queue felt like it.

A pass over the delta, orthorectified and masked, twelve minutes after the horizon.

Orthorectification against a two-metre elevation model is the expensive one. We moved it onto the ingest path and pinned it to the station that received the pass, which removed a cross-region hop that was costing us four minutes on a good day and forty on a bad one.

What we would not do again

For eighteen months we cached at the wrong layer — after masking rather than before it. Every time we shipped a better cloud mask we invalidated the whole cache. Obvious in hindsight, invisible while you are doing it.

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