Engineering a 160-Node Distributed Payload in 3U

Rapid in-orbit technology validation is increasingly constrained by integration effort and spacecraft resource margins. We present a systems-engineering approach for hosting up to 160 low-power experiment nodes within a standard 3U CubeSat as a contained distributed payload. The architecture treats each node as an independently testable endpoint while the spacecraft provides shared power, timing, command and a controlled data path to the downlink.

To bound peak power and reduce coupled interactions between experiments, we implement deterministic polling with a fixed time-division schedule on a master-controlled internal bus. Only one node is granted electrical activity per time slot (power-gated and bus-enabled), flattening peak demand and making worst-case power/thermal behaviour largely independent of experiment count. We describe the supervisory logic, interface constraints for compliant nodes, and a hardware fault-containment layer that detects bus contention and quarantines non-compliant nodes via per-node switching and watchdog-driven lockout, preserving bus integrity for remaining experiments.

We report representative mass, power and data allocations and verification methods covering tray/node interchangeability, end-to-end command/telemetry integrity, and resilience to injected failure modes (hung node, stuck-low bus, repeated reset). The resulting pattern supports high-density, debris-compliant in-orbit validation where modularity, determinism and fault containment are primary drivers.