Investigations into the Relationship Between Surface Activity and the Dynamical State of Asteroids
出版項
2020
說明
1 online resource (263 pages)
文字
text
無媒介
computer
成冊
online resource
附註
Source: Dissertations Abstracts International, Volume: 81-11, Section: B
Advisor: McMahon, Jay W
Thesis (Ph.D.)--University of Colorado at Boulder, 2020
Includes bibliographical references
Asteroids undergo processes that change their orbit, spin state, and structure, and the relationship between these properties. This evolution usually occurs slowly, changing the asteroid's behavior over millennia, reaching an equilibrium between rotational state and shape. But no equilibria lasts forever, and asteroids' states change and are redefined by the relationship between orbit, spin, and structure, sometimes in cascading series of events in short time frames. The work presented in this dissertation derives a model which links asteroid rotation with small scale structural changes on asteroid surfaces. The model allows for boulders placed on asteroid surfaces to move on and off these surfaces in accordance with the geopotential environment and surface material properties. In turn, boulder motion and other surface phenomena affect asteroid rotational states, at times further perturbing the asteroid system. Results are presented for fast rotating asteroids, showing the tendency of boulders to move towards the equator and in doing so reduce asteroid spin rates. However, boulder launches to orbit and variables in surface conditions add chaos to these systems, leading to random walk behavior which affects the system and its relationship with the solar system itself. Small particle events can also affect asteroid states, but in an extent smaller than is detectable with state-of-the-art spacecraft and observation capabilities. Examinations of human induced activity with the model show the extent that human activity such as momentum transfer deflection or material launch to space can have on asteroid rotational states and, in turn, how the shape-spin relationship affects the success of human activity. Mainly, the results demonstrate the importance of understanding an asteroid's shape and rotation prior to planning a deflection mission. Additionally, the dynamics of mass driver deflection derived show that optimized material launch schemes can be found which reduce the side effects on asteroid rotation. Mass launches can be used for deflection in several year time scales through a variety of operational schemes
Electronic reproduction. Ann Arbor, Mich. : ProQuest, 2020
