Extending beacon-based health monitoring to distributed space systems

Beacon-based health monitoring is a technology often noted for enabling drastic reductions in the cost of nominal telemetry monitoring. On board a spacecraft, software filters telemetry to derive a health assessment, and a periodic beacon broadcasts this assessment to the Earth, A network of low cost receiving stations receives the beacon signal and relays it to a central mission control center. At the mission control center, a suite of software responds according to the value of the health assessment; appropriate responses may include operator notification, automatic groundstation rescheduling to accommodate new health operations, and intelligent retrieval of appropriate operational documentation. Conceptually, this system acts as an automated mapping from spacecraft state to high-level operator response. As part of its research programs in distributed space systems, Stanford University and Santa Clara University are extending the standard spacecraft beacon monitoring architecture for use in multi-satellite fleets. Two specific applications are currently being developed. First, a space segment level beacon is being developed as a single communication signal for updating the ground segment with fleet-level health data. Second, inter-satellite beacon broadcasts are being explored as a means of communicating fleet status among individual satellites and indicating operational mode changes in the event of anomalies. This paper will present the beacon monitoring concept and ongoing validation results for single missions. In addition, the aforementioned extensions to distributed space systems will be described in detail. Finally, the incorporation of a distributed beacon system into the two-satellite Emerald spacecraft mission will be presented.