Electrodynamic tethers can be employed to effect spacecraft orbital maneuvering outside of Keplerian motion without incurring the mass penalty of traditional propulsion systems. Recently, several studies have been conducted to establish a framework for guidance and control of such orbit maneuvers, including the optimization of a particular maneuver, the orbit transfer. This thesis provides an overview of the concept of electrodynamic tether employment, summarizes research in the field, and catalogues recent proposals. Two minimum-time orbit transfer problems are considered - an orbit raising and a deorbit problem. Both formulations use an identical set of initial conditions for the spacecraft. In the case of the orbit raising problem formulation, the terminal manifold requires an increase in semimajor axis and return to initial eccentricity and inclination values. Other orbital elements are unconstrained. For the deorbit case, optimal control is developed for a minimum time decrease in semimajor axis; the remaining orbital elements are unconstrained. The totality of optimality conditions for both cases of using electrodynamic tethers to maneuver from an initial orbit is examined. Observations and recommendations for future work are presented in the conclusions. / US Navy (USN) author.

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Thesis (Ph. D.)--University of Chicago, 1919. / "Private Edition, distributed by the University of Chicago Libraries, Chicago, Illinois." "Reprinted from the Physical Review, N.S., Vol. 10, No. 2, August, 1917." Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2003. / Supervisor: Linda E. Reichl. Vita. Includes bibliographical references. Also available from UMI.

Inaug.-Diss.--Strassburg, 1902. / Vita.

Thesis (Ph. D.)--University of Chicago, 1919. / "Private Edition, distributed by the University of Chicago Libraries, Chicago, Illinois." "Reprinted from the Physical Review, N.S., Vol. 10, No. 2, August, 1917." Includes bibliographical references. Also available on the Internet.

The self-energy of the free electron at rest Is evaluated without the restriction that the self-interaction be a purely retarded interaction. Both the one-electron theory and the hole theory of the positron are treated. It is shown that in the one-electron theory the normally quadratically divergent transverse part of the self-energy vanishes if the self-interaction is assumed to be one half retarded plus one half advanced, the remaining Coulomb part of the self-energy being only linearly divergent. A similar theorem does not hold for the hole theory. A particular type of self-interaction leads to a vanishing self-energy in one-electron theory. However this does not solve the self-energy problem, as in this case radiation corrections to scattering will vanish as well. The self-energy of a bound electron is evaluated in a similar manner. The decay probability of an excited state is calculated as the imaginary part of the self-energy; the correct value is obtained only for a purely retarded self-interaction in hole theory. In the special case in which the external field is a uniform magnetic field, again only this interaction in hole theory gives the correct value for the anomalous magnetic moment. It is therefore concluded that any solution of the self-energy problem by introducing advanced self-interactions is to be ruled out. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

No description available.

Thesis (M. Sc.)--University of Queensland, 2002. / Includes bibliographical references.

No description available.