• telecommunication
• QB50
• space mission
• CubeSat

In this thesis a communication architecture for QB50 space mission is analyzed. This mission will provide the biggest CubeSat network in orbit. A constellation of 50 CubeSats in a ‘string-of-pearls’ configuration will be launched together in January 2016 by a single rocket, into a circular orbit at 350 km altitude. Due to the atmospheric drag the orbit will decay and progressively lower layers of the atmosphere will be explored. Main goals are exploration of the lower thermosphere with multi-point measurements, re-entry research and in-orbit science and technology demonstration. In this analysis of communication functions the ground segment is analyzed, with a global overview of different architectures, the main elements of a ground station, mission and control centers, and the link between them. This study is realized through the development of a tool which computes the number of stations required to recover a certain amount of data generated by a constellation of satellites. This tool ensures the efficiency of the communication system taking into account various design parameters like data rates, limited elevation angles from ground stations, and the effects on the link quality such as orbit perturbations, space and atmospheric losses and Doppler shifts. Particular attention is devoted to frequencies: two different types of systems (UHF/VHF and S-band) are analyzed. In order to optimize the positioning and number of stations, an iterative method is applied to compute the fraction of time when a station is in view of a CubeSat in function of various parameters such as the latitude of the station, its elevation and the altitude of the satellite. AGI-STK software was used to compute the access between satellites in the constellation and ground stations, simulating system operability.