MS thesis abstract - Chen, Allen

Author:	Chen, Allen
Degree:	Masters of Science
SERC #:	10-02
File type:	PDF, 4244 kB
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Propulsion System Characterization for the SPHERES Formation Flight and Docking Testbed

The MIT Space Systems Laboratory is developing the SPHERES Formation Flight and Docking testbed for the validation of high risk metrology, control, and autonomy technologies. Knowledge of the testbed's actuation system is critical both to the performance of SPHERES as a controls testbed and to the operations of the testbed onboard the International Space Station. This thesis presents work that characterizes the SPHERES propulsion system, the testbed's actuator. The flight design of the SPHERES testbed is presented with particular focus and detail given to the design of the propulsion system. Performance and performance variations of the system are first theoretically determined and then compared to data generated experimentally. Trends in the experimental results are identified and modeled, yielding greater insight into the propulsion system's workings. Better knowledge of the propulsion system allows refinement of the plant control model, resulting in better estimation of propellant consumption and truer performance when evaluating control algorithms. Performance variations resulting from manufacturing, system settings, and usage are identified and quantified. This leads directly to the development of correction schemes that help to mitigate the undesirable and unintended performance variations that affect tracking. Finally, a process for extending the work in this thesis is presented.