Interestingly, other than direct cabled network connections and trying to get ground stations physically closer to the satellites, which is obviously impossible, this is almost exactly what we did for first-level ground processing of geointelligence data for the NRO. Major difference would be data from the sensor platform doesn't even bother with TCP. It's just pure packed structs, but also encrypted with decryption handled by dedicated hardware devices. No need for PKI since it isn't public. The collection metadata from the tasking station still uses TCP.