Master's degree theses

A board for autonomous spacecraft collision avoidance (COLA) is currently being designed at the u3S laboratory. As part of the COLA process, the spacecraft hosting the board shall be capable of performing a preliminary screening of possible close encounters with the many existent resident space objects (RSO), based on the minimum orbital intersection distance (MOID). Several methods have been proposed in the literature for accomplish this task, with different levels of accuracy and computational burden.

Through the thesis work, the candidate will assess and critically compare some of the existing MOID algorithms, for selecting the one more suitable for an onboard implementation on embedded hardware, trading-off between computational burden and accuracy of the computation. Towards this end, the research project will encompass at least the following steps

• Literature review and pre-selection of candidate algorithms for MOID computation.
• Implementation of a Matlab simulator for creating an orbital scenario including the main spacecraft plus hundreds/thousands of RSO considered as possible collision threats.
• Integration of the pre-selected algorithms in the simulator for computing the MOID between the main spacecraft and each of the RSOs
• Comparison of the algorithms in terms of accuracy and computational speed, and selection of a best one.
• Implementation of the selected algorithm on embedded hardware (e.g. raspberry PI or Arduino).

Number of students required: 

• 1 Student

Requirements:

• Attended and passed ‘Spacecraft Orbital Dynamics and Control’
• Good mathematical and programming skills

In the early stage of the definition of a space mission, it is often desirable to have a fast preliminary estimation of the DV cost of a low-thrust transfer. When the transfer is realised through a long spiral trajectory, a quick estimation of the totalDV and transfer time can avoid lengthy calculations. For this reason, a number of authors have proposed simple control laws for the variation of specific orbital elements and/or analytical equations for the estimation of the DV associated to a given transfer. The usual approach to develop such approximations is that of integrating GPE using as integrand a fast anomaly variable while assuming the slow orbital elements as constants. A recent approach developed in our lab proposes a more accurate analytical framework for integrating the GPE formulated as a system of linear differential equations. The thesis work consists of investigating the use of such a framework to develop analytical formulas for the secular orbital element variations, to be then used for the estimation of the DV associated to a given transfer.