Investigation of different strategies for access to space and positioning of small satellites

The Space Economy is expanding and has shown that space no longer belongs only to governments and its access is increasingly possible even to small private companies. Each will soon play an important role in the space race, leading to increased launches and the possibility of ever-faster industry development. Consequently, each company will manage all the parts concerning a space mission in complete autonomy, from the launch to the positioning of its satellite in the desired orbit. However, a company must still consider the most efficient solution to achieve its goal and this thesis is at the heart of the matter. Initially, an overview on space propulsion is provided, explaining the characteristics and operating principles of main types of engines and the major differences between them, which allows to figure out the best solution based on the mission. It has been studied how access to LEO orbits can take place, through transporter missions or microlaunchers with a particular focus to the transportable payload mass in function of the desired final orbit as suggested from the various launchers manuals. Then, an analysis of various orbital maneuvers is carried out for the correct positioning of one or more satellites in target orbit aiming to the maximum efficiency in terms of times and costs, considering both chemical and electric propulsion. The maneuvers that have been investigated are: Hohmann Transfer, Phasing maneuver, where various ways to perform it are shown, Change inclination maneuver, Right ascension of the ascending node (RAAN) change maneuver. All the cases have been studied considering different specific impulses, to simulate all the possible thrusters and find the optimal configuration according to the mission. Finally, particular attention is paid to the effects of J2 zonal perturbation in order to understand how different parameters vary during maneuvers and to save propellant in some of them.