  The instrumentation of real systems is often designed for control purposes
and control inputs are designed to achieve nominal control objectives. Hence,
the available measurements may not be sufficient to isolate faults with
certainty and diagnoses are ambiguous. Active diagnosis formulates a planning
problem to generate a sequence of actions that, applied to the system, enforce
diagnosability and allow to iteratively refine ambiguous diagnoses. This paper
analyses the requirements for applying active diagnosis to space systems and
proposes ActHyDiag as an effective framework to solve this problem. It presents
the results of applying ActHyDiag to a real space case study and of
implementing the generated plans in the form of On-Board Control Procedures.
The case study is a redundant Spacewire Network where up to 6 instruments,
monitored and controlled by the on-board software hosted in the Satellite
Management Unit, are transferring science data to a mass memory unit through
Spacewire routers. Experiments have been conducted on a real physical benchmark
developed by Thales Alenia Space and demonstrate the effectiveness of the plans
proposed by ActHyDiag.
