Date of Award

Fall 2013

Document Type

Thesis - Open Access

Degree Name

Master of Aerospace Engineering

Department

Aerospace Engineering

Committee Chair

Bogdan Udrea

First Committee Member

Dongeun Seo

Second Committee Member

Timothy Smith

Abstract

This thesis addresses the analysis of the attitude dynamics of pieces of space debris that could result from the fragmentation of a spent upper stage in low Earth orbit (LEO).

Up to now only whole objects of axisymmetric shape have been studied with the purpose of estimating their tumbling rates in LEO. Three shapes have been considered to be representative for the purpose of the study: a thin plate, a monocoque shell, an half conical shell and a spherical shell, and it has been assumed that they are fabricated from aluminum alloy. The motion of conducting body in a magnetic field generates eddy currents which create a torque in the opposite direction of the change in the magnetic flux and thus reduce the rotational rate of the body. The eddy currents that generate torques are described by Maxwell's equations. and the generalized Ohm's law is set up a Poisson problem with Neumann boundary conditions. The electrical potential, solution of Poisson problem and calculated by a finite element solver, defines the density current in the body and thus determines the torque applied on the debris.

The results presented here can be used for the analysis of the initial propagation of a cloud of orbital debris resulting from the explosion of an upper stage or a satellite as well as for orbital debris remediation. Analysis of the attitude dynamics of space debris shows that, for a reasonable initial angular rate, the object is partially stabilized in less than 70 days for the thin plate and totally stabilized in less than 60 days for the monocoque shell, 12 days for the half conical shell, 30 days for an one fourth spherical shell and 90 days an one eighth spherical shell.

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