Comet dynamics and implications for orbiting spacecraft

Abstract

In this thesis, a comet model is presented and used to analyze an orbiting spacecraft in the presence of outgassing. Simulations are conducted in an attempt to classify the environment around a comet during different orbital periods. The comet is modeled as a discretized triaxial ellipsoid and properties are given to it such that it emulates the comet Churyumov-Gerasimenko. Equations of motion are presented and the comet is simulated with the presence of radiative and outgassing forces. Using the outputs from the simulation, the sublimating jets are parameterized and a satellite is simulated to orbit during perihelion.

It was found that the rotation of the comet is affected mainly by the outgassing jets. On the other hand, the orbital motion, while being affected by the forces, is mainly altered by third body effects. By extrapolating data from the simulation, the remaining lifetime of the comet was found to be about 270 years. Using the environment generated around perihelion, the satellite is then simulated. The pressure from the outgassing jets was found to greatly affect the orbit, providing an acceleration on the order of 1E-6 on the spacecraft. By analyzing the outgassing jets, it was found that the chance of dust perforation is very low. However it could pose a problem for guidance, navigation, and control.