Collision analysis for multiple satellites released from a common dispenser

The number of small spacecraft launched to space has increased dramatically in the past few years, and with the emergence of mega-constellations it is projected to increase even more in the coming decades. Small satellites are usually launched together in rideshare launches and released from a common dispenser when reaching nominal orbit. Due to the lack of available measurement and control capabilities, the release phase is vulnerable to collision risk, as small uncertainties in the initial position can quickly grow causing a high probability of collision. In this paper a framework for analysing the safety of a genric dispenser is proposed and applied to the study of a cylindrical dispenser. Through numerical simulations and linear covariance propagation, the evolution of the spacecraft state is retrieved and used for computing a set of performance metrics, such as the total probability of collision and the number of conjunction events. This method is then applied to a parametric analysis of the dispenser, examining how the performance metrics vary with parameters such as the velocity of release or the time between releases. The results thus obtained will be relevant to the safe design of spacecraft dispensers.