Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 4 of 4
Full-Text Articles in Astrodynamics
Minimizing Secular J2 Perturbation Effects On Satellite Formations, Jonathan W. Wright
Minimizing Secular J2 Perturbation Effects On Satellite Formations, Jonathan W. Wright
Theses and Dissertations
The purpose of this thesis is to examine the secular effects of the J2 oblateness perturbation on close proximity satellites. The main objective is to analyze the deputy’s position and velocity with respect to the chief and adjust the initial conditions of the deputy in an attempt to minimize the secular effects of J2 perturbations. Previous work has provided a method of obtaining a closed form solution for J2 invariance with co-planar orbits. Therefore, this work will primarily consider deputy orbits that experience motion outside of the chief’s orbital plane. Upon determining the required initial conditions, the …
Modeling Gps Satellite Orbits Using Kam Tori, Rachel M. Derbis
Modeling Gps Satellite Orbits Using Kam Tori, Rachel M. Derbis
Theses and Dissertations
Global Positioning System (GPS) satellite orbits are modeled using Kolmogorov, Arnold, Moser (KAM) tori. Precise Global Positioning System satellite locations are analyzed using Fourier transforms to identify the three basis frequencies in an Earth Centered, Earth Fixed (ECEF) rotating reference frame. The three fundamental frequencies are 1) the anomalistic frequency, 2) a combination of earth’s rotational frequency and the nodal regression rate, and 3) the apsidial regression rate. A KAM tori model fit to the satellite data could be used to predict future satellite locations. This model would allow rapid determination with fewer computational requirements than the typical method of …
Crew Exploration Vehicle (Cev) Skip Entry Trajectory, Emre Kaya
Crew Exploration Vehicle (Cev) Skip Entry Trajectory, Emre Kaya
Theses and Dissertations
This research effort develops a program using MATLAB® to solve the equations of motion for the atmospheric reentry of the Crew Exploration Vehicle (CEV) which is assumed to be in the phase of a lunar return trajectory that could be initiated any time during the mission. The essential reason for this research is to find a solution for the problem of an unplanned lunar return in addition to the normal procedures. Unlike Apollo type missions, the CEV would still be able to land on any preplanned available landing sites without any additional delay. In Apollo type missions, the return phase …
Initial Determination Of Low Earth Orbits Using Commercial Telescopes, Matthew M. Schmunk
Initial Determination Of Low Earth Orbits Using Commercial Telescopes, Matthew M. Schmunk
Theses and Dissertations
Within the last decade, many new technologies have significantly changed the face of private astronomy. Developments such as inexpensive but high-quality sensors, rapid personal computing, and easy networking inspire a reexamination of an old problem: how practical is it to develop initial orbit estimates for Low Earth Orbiting (LEO) satellites using optical tracking? This paper documents the design and implementation of a commercial telescope system used to answer precisely that question. This analysis deter- mined there are some challenging barriers to successful single-site orbit determination, but it is possible given the right conditions. Considering the low cost and small sup- …