Masters Theses

Date of Award

12-2006

Degree Type

Thesis

Degree Name

Master of Science

Major

Aerospace Engineering

Major Professor

Gary A. Flandro

Committee Members

Kenneth R. Kimble, Uwe Peter Solies

Abstract

Propulsion driven nutation instability in spin stabilized spacecraft was first observed in the late nineteen seventies. It’s often referred to as the PAM-D coning anomaly, as it first occurred in the McDonnell Douglas Payload Assist Module (PAM-D). Propulsion driven nutation instability is a performance degrading phenomenon that occurs in spin-stabilized spacecraft used for the raising of satellite payloads to geosynchronous orbit. It is characterized by a coning (wobbling) motion that grows to a large degree during the final seconds of motor burn. The instability is clearly related to the increased size of the rocket needed to support the increasing payloads to be taken into orbit. This nutation wastes motor impulse and overtaxes the attitude control system after burn. The remedy to date has been the use of a strap-on attitude control device.

Several mechanisms have been proposed and eliminated due to lack of correlation with observed nutation features. The mechanisms of slag sloshing and jet gain both showed similarities to the observed disturbances. Jet gain shows the most promise in understanding the nutation phenomenon. Neither mechanism has yielded suitable conclusions to establish proper nutation prevention criteria for future designs.

Through analysis of the effects of energy loss due to mass transfer on the spacecraft’s kinetic energy balance, it is shown that nutation can be seen to develop without the need for in depth analyses.

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