Forests are important natural resources of Canada. Their renewal has been recognized to be important for continued wood supply and for other benefits. Consequently, the major emphasis of forest management activities focuses upon restocking clearcut forest lands. Effective planning and successful implementation of reforestation programs require efficient techniques for obtaining timely and accurate information regarding restocking status over cutover forest lands. In this thesis the potential of Landsat thematic mapper (TM) data for monitoring reforesting clearcuts was investigated. Landsat-5 TM data covering clearcut forest lands reforesting with lodgepole pine (Pinus contorta Dougl.) were analyzed. To assess spectral separability of various restocking classes and classifying reforestation areas according to their stocking status multivariate distance measures were employed to select the optimum three band subset from six reflective TM bands. Three commonly used vegetation indices, namely the ratio vegetation index, the normalized difference vegetation index, and the infrared index, were also studied for quantitative assessment of vegetation. The main conclusion of the study is that TM bands 3, 4, and 5 are the best for discriminating various restocking classes. The classification accuracy was estimated to be approximately 90 percent. The infrared index appears to be the most suitable vegetation index for quantitative assessment of reforestation. / Forestry, Faculty of / Graduate

A general formulation is presented for the librational dynamics of satellites having an arbitrary number, type, and orientation of flexible appendages, each capable of deploying independently. In particular, the case of beam-type appendages deploying from a satellite in an arbitrary orbit is considered. The governing nonlinear, nonautonomous, coupled system equations are not amenable to any closed form solution, hence are integrated numerically using a digital computer. Effect of important system parameters is assessed through illustrative configurations representing a large class of gravity gradient and spinning spacecraft. Rather than accumulation of a large amount of data, the emphasis is on evolution of a generalized and organized methodology for coping with such complex dynamical systems. The analysis examines the degree of interaction between flexibility, deployment, and attitude motion through systematic variation of system parameters. A study of appendage vibration characteristics suggest that an orbiting beam cannot be treated simply as a rotating beam because of the presence of the gravitational field. Rate of rotation plays a dominant role in stiffening the beam as evidenced by the noticeable straightening of the eigen-functions for even relatively low spin rates (2 rpm). Results also show that the deployment-related Coriolis force can play a major role in causing large in-plane deformations. This implies that, in some cases, deployment should be carried out in stages so as to limitthe time available to build up large amplitude oscillations. Investigation of librational response shows that the coupled character of the motion can significantly affect system dynamics, hence caution should be exercised in utilizing results based on simplified planar analyses. Depending on orbital parameters and physical properties of booms, there are critical values of appendage length and deployment rate for which the satellite can tumble over. On the other hand, in general, appendage offset and shifting center of mass were found to have insignificant effect on response for the cases considered. This may permit considerable simplification of the complex hybrid equations with associated saving in computational time and effort. Also, the small amplitude oscillations evident both with the gravity gradient and spin-stabilized configurations tends to substantiate the adoption of a linear vibration analysis. The simulation of such diverse classes of satellites with relative ease demonstrates the versatility of the formulation. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

The thesis aims at studying the dynamics of single and multibody systems with a variety of spacecraft oriented applications including configuration control for an instrumentation payload deployed from a spacecraft, the Solar Satellite Power Station (SSPS), a Space Shuttle supported tethered payload, etc. The problem is approached in an increasing order of complexity. In the beginning librational dynamics and force distribution for an axisymmetric, gravity oriented, rigid configuration are considered. The governing nonlinear, nonautonomous and coupled equations of motion are analyzed using Butenin's variation of parameter approach in conjunction with the Poincare-type expansion method, and the validity of the solutions established through numerical integration. The closed-form character of the solutions proved useful in identifying periodic solutions and resonance characteristics of the system. Furthermore, they provided considerable insight into the system behaviour over a range of the orbital eccentricity, inertia parameter and initial disturbances. Application of the analysis is demonstrated through the Gravity Gradient Test Satellite (GGTS). Next, general equations of librational motion, force and moment are derived for an arbitrarily-shaped, rigid spacecraft and approximate closed-form solutions obtained for spinning and gravity oriented systems using the Poincare-type analysis. The approach yields useful information concerning response to external disturbances as affected by the system parameters. The method is applied to several configurations: Explorer XX, an instrument package deployed from the Space Shuttle and the SSPS. Finally, a general dynamical formulation for a triaxial multibody system, in a circular orbit, with an elastic interconnecting link in the form of a tether or a beam is developed. The highly complicated coupled, nonlinear, nonautonomous equations of motion are linearized and their exact solution presented. Also expressions for forces and moments required to orient an object in space are obtained. This analytical procedure is applied to several configurations of practical interest. Throughout, the emphasis is on evolving a general formulation of the problem and its acceptable solution. Numerical results are presented only to appreciate significant response characteristics of the system. The general character of the analysis should prove useful in studying the dynamics of a wide range of existing and future spacecraft. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

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