Accession Number : ADA306616

Title :   Orbital Perturbation Analysis of Earth-Crossing Asteroids.

Descriptive Note : Engineers thesis,

Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s) : Knudson, Wade E.

PDF Url : ADA306616

Report Date : DEC 1995

Pagination or Media Count : 111

Abstract : Earth Crossing Asteroids (ECAs) are those asteroids whose orbit cross section can intersect the capture cross section of the Earth as a result of secular gravitational perturbations. This thesis provides a framework for understanding the origin, nature, and types of ECAs. The change in velocity requirements to achieve a two Earth radii deflection for long and short term warning scenarios are developed. Next, a method of developing hypothetical Earth colliding asteroid orbits is presented. These hypothetical orbits are used in two ways: (1) to evaluate the ability of Dance of the Planets, a solar system simulation model developed by Applied Research and Consulting, Inc., to accurately propagate orbits of imported asteroid orbits, and (2) to analyze the sensitivity of deflection distance to variation in deflection angle and orbital parameters of a given orbit. Inaccuracies during importation of data precluded the use of Dance of the Planets for the purpose of sensitivity analysis. The program does provide an excellent tool for visualization of ECA scenarios. Consequently, a simpler orbital model was developed to provide a Earth miss distance sensitivity analysis. With one asteroid orbital period warning the minimum change in velocity to deflect an asteroid two Earth radii is approximately 0.135 m/s and the optimal deflection is along the flight path. Maximum deflection occurs when the deflection is applied at perihelion. The miss distance decreases markedly with increase in true anomaly until it is a minimum at aphelion.

Descriptors :   *EARTH ORBITS, *INTERCEPT TRAJECTORIES, *ASTEROIDS, MATHEMATICAL MODELS, SCENARIOS, SIMULATION, ANOMALIES, DEFLECTION, THESES, PERTURBATIONS, RANGE(DISTANCE), EARTH(PLANET), CROSSINGS, RADIUS(MEASURE), WARNING SYSTEMS, MISS DISTANCE, PERIHELION.

Subject Categories : Celestial Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE