Date of Award

12-2011

Degree Type

Report

Degree Name

Master of Science (MS)

Department

Electrical and Computer Engineering

Committee Chair(s)

Doran J. Baker

Committee

Stephen A. Whitmore

Committee

Albert Einstein

Abstract

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.

Comments

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

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