ACS air bearing test-bed design

Abstract

This thesis is about the construction and design of a new air bearing test-bed to verify the programmed ACS attitude control algorithm and to validate the ACS MATLAB/SimuLink¬ model of NPSAT1, the second small satellite currently under development at the Naval Postgraduate School Space Systems Academic Group. The software was already verified and validated using a comparable air bearing test-bed. But due to changes in hardware from commercial magnetic torque rods to custom, NPS-built, magnetic torque coils, the changes in the modulated software have to be verified again. Additionally, the use of flight hardware on the test-bed is expanded to also verify and validate the currently available flight hardware. NPSAT1 is a passive, gravity-gradient stabilized satellite. This thesis shows the necessary fundamental requirements on the satellite's mass properties, which has to be met to realize a gravity-gradient stabilized satellite, as well as the basics of pendulum theory, which is required to set up the test-bed on the air bearing for testing. This thesis describes the measurement of the earth's magnetic field taken in the SSAG laboratory and the resulting magnetic field vector field. Restrictions dictatd by the air bearing are followed by a chapter that summarizes and explains all requirements on the new test-bed design. A detailed description of the chosen design approach, layout and available test-bed configurations is given, as well as issues encountered and their solutions.The next step is to verify the ACS MATLAB/SimuLink¬ attitude control algorithm and to validate the MATLAB/SimuLink¬ model using the designed air bearing test-bed. Further, it is suggested to proceed the verification and validiation of NPSAT1's behavior in space by using the custom, NPS-built, Helmholtz coils. With the assistance of Helmholtz coils, custom magnetic field properties can be generated.