With such dynamic links between the nodes, it was necessary to build a system based on a very dynamic, real-time model that could account for the up-to-date status of the links. The CDG technology makes a clear distinction between the domain model (satellites, communications nodes and links, etc.) and the fault models. It automatically performs diagnostics based on the domain model, fault models, the current system state, real-time events, and events generated by the performance monitoring system. (Please see the white papers on the CDG technology).
The fault management system was under successful development until Iridium ran out of funds, and cancelled Fault Management. Ironically, rumor has it that among the 4 or so satellites that were lost just after launch, some of them might have been saved if the Fault Management system had been fully implemented, and problems were noticed before the satellites lost control to the point that command communications were impossible (e.g., a fault in a thruster starts a satellite spinning. Unless corrected quickly, antennas can’t be aligned for stable command & control.)
CDG technology was productized by us (at Gensym) up to beta software level as a byproduct of our work (while at Gensym) on the fault management system for Iridium. This was incorporated in the overall Integrity Product Line.