Sounds good, let’s keep it lean. Put a tiny LTE‑CatM or NB‑IoT module on the stack for low‑power uplink. The rover’s GPS pin gives it a location tag every minute, so the base station can queue an OTA blob that’s split into 1‑kB chunks. When the rover boots, it scans for the nearest beacon—any other rover that’s stuck can act as a relay, forward the packet, and even drop a copy on a local flash. If it finds no neighbor, it powers up the low‑power backscatter and sends a beacon pulse. If a satellite passes overhead, the pulse gets picked up and the update pushes through a quick, opportunistic uplink. Add a watchdog that re‑tries on failure, and you’ve got a self‑propagating update that won’t care if you’re in a canyon or a canyon’s own echo. Good enough for a testbed, and the only thing it’ll kill is your patience with slow firmware cycles.