Orbit manipulation of two closely-passing asteroids using a tether

Q Science (General);QA Mathematics;QC Physics;TL Motor vehicles. Aeronautics. Astronautics

Pandian, Chenthamarai ; Matteo, Ceriotti

University:University of Glasgow

Department:School of Engineering

关键词: Orbit manipulation, tethers, asteroids, momentum exchange, energy exchange, dumbbell system, trajectory.;   

Others  :  http://theses.gla.ac.uk/8953/1/2018PandianMSc%28R%29.pdf

来源: University of Glasgow

【 摘 要 】

Asteroids can be considered both a threat as well as a source of mineral resources. Either way, asteroids have become a point of interest for scientists, space enthusiasts and private industries. Whether it be for protecting Earth from an asteroid strike or to obtain an asteroid for the prospect of mining, it is essential that we understand and identify a method to manipulate the orbital trajectory of an asteroid. There are quite some numbers of proposed methods to achieve a change in the orbital trajectory of an asteroid; some of the notable ones are gravity tractors, low thrust propulsion devices, kinetic impactors, and tethers. In this thesis we will manipulate the orbital trajectory of an asteroid by transferring orbital energy between the asteroid in question and another closely-passing asteroid. The energy and momentum transfer are achieved by connecting the asteroids through a tether at their closest point of approach leading to the formation of a dumbbell system. The formation of the dumbbell system results in the transfer of some of the linear kinetic energy of both asteroids into rotational kinetic energy, which causes the dumbbell system to rotate about its centre of mass with an angular velocity leading to a rotational angular momentum. Disconnecting the tether at a point in time leads to the disruption of the dumbbell system and the asteroids gain or lose angular momentum and orbital energy from the system. The distribution of the orbital energy between the system and the asteroids determines the resulting orbit of the asteroids. A study on how parameters such as the length of the tether, the eccentricity of the asteroids at the time of tether connection and the mass of the asteroid affects the distribution of energy and angular momentum between the asteroids and the system is carried out. A detailed analysis with some selected combination of the above discussed parameters, such as how long to wait before tether disconnection to achieve maximum or minimum deflection from the initial orbit is carried out. This is done by modelling the dynamics of the asteroid-dumbbell system in MATLAB, where in the physics involving the orbital and attitude dynamics of the system are set up. Some of the main results showed that the model specific error in orbital energy reduced with the reduction of the tether length, a gradual change in orbital energy for increase in tether length w.r.t angular displacement can be noticed for the dumbbell system, compared to periodic change for individual asteroids, and that there exists multiple opportunities for orbital change of the asteroids in the dumbbell system for a single heliocentric orbital motion of the centre of mass and a more desired orbit change can be achieved with multiple heliocentric orbits of the centre of mass of the dumbbell system.