Date of Award


Degree Type


Degree Name

Master of Science (MS)


Electrical and Computer Engineering

Committee Chair(s)

Doran J. Baker


Stephen A. Whitmore


Albert Einstein


Attitude control of a prototype satellite bus using fluid mechanical vectoring on an aerospike nozzle is demonstrated. The design achieves thrust vectoring by injecting pro- pellant asymmetrically into the unconstrained aerospike exhaust plume near the nozzle base. The prototype system uses cold-gas thrusters to both spin-up and de-tumble the test article. The system is configured with axially directed annular flows that produce large lon- gitudinal thrusts and smaller secondary lateral-injection flows for side thrusts. Both open and closed-loop attitude control, with and without main aerospike annular flow active, are demonstrated. Proportional, integral, derivative (PID) regulation is used for closed-loop attitude control. When the vectoring ports are operated with no primary plenum flow, very small impulse bits are generated. Based on the results presented in this paper, there exists a significant potential for three-degree of freedom (3-DOF) attitude control without mechan- ical nozzle gimbals. When extended to 3-DOF, the closed-loop control-law will allow the primary satellite propulsion system to be used for both larger-scale orbit change maneuvers and smaller-scale proximity operation maneuvers with the same system.


This work made publicly available electronically on November 21, 2011.