A Method to Predict the Orbital Lifetimes of Free Tethers and Tether-Trailing Satellites using Artificial Neural Networks
Abstract
This dissertation deals with the development of a method to predict the orbital lifetimes of uncontrolled free tethers and tether-trailing satellites originating in low-to-moderate altitude Earth orbits. The problem is solved by application of the empirical method. Two mathematical models to simulate the orbital evolution of tethered systems are developed. In both models the system is discretized into a series of interconnected point masses, orbiting an oblate Earth and transiting an oblate, rotating, temporally and globally averaged atmosphere. For aerodynamic drag calculations, tether segments are modeled as right circular cylinders, and any end-body is modeled as a sphere. Drag coefficients vary as a function of shape and Knudsen number. In the multibody model, connections between masses are elastic, and the system is free to assume any orientation. Newtonian equations of motion are numerically integrated. In the orbital element propagation model, connections between masses are inelastic, and the system is constrained to remain aligned along the local vertical. Gauss' form of Lagrange's Planetary Equations, in terms of equinoctial elements, are used to propagate the orbital elements describing the orbit of the system's center of mass.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 28, 1992
- Accession Number
- ADA258547
Entities
People
- Ted W. Warnock
Organizations
- Auburn University