A model based on priority scheduling and state transitions for the automation of Integrated Spacecraft Testing

This Paper presents the design of a mechanism for the automation of the Integrated Spacecraft testing. This model executes the pre-defined sub-system test schedules in parallel with the various activities for the performance evaluation, anomaly monitoring and safety-critical operations on the Spacecraft. It guarantees unmanned testing of the complex spacecraft sub systems in a controlled environment where the sub-system test schedules, auto-actions, safety-critical operations, user-interactions, background activities and all function in harmony. The continuous monitoring and evaluation of the overall spacecraft health will be carried out during all sub-system testing and invokes the appropriate safety-critical test procedure on detection of an anomalous behaviour.There exists only one interface for sending telecommands to the spacecraft. The user submits one or more predefined sub-system test schedules for execution. The subsystem test schedules will contain the execution of a number of test procedures requiring commanding the spacecraft. There will be multiple alert and notification tasks and critical-background tasks running in parallel and performing specific monitoring and evaluation of the spacecraft parameters. These tasks will initiate the execution of certain test procedures on detection of an abnormal condition on the spacecraft. These entire spectrums of activities are asynchronous and nondeterministic in nature. This requires a scheduling scheme for test procedure execution in which the `most important´ one will be taken up for execution at any point of time. This will achieve the automated testing of the complex spacecraft sub-systems This paper covers dynamic spacecraft test environment, the various sources of the test procedures, interrupt handling , the priority assignment mechanism, scheduling algorithm based on priority, the cyclic design of the execution control logic, state model, and state transitions of the test procedure executions.