Autonomous Cubesat propulsion for affordable access to space

Miniaturized spacecraft, such as the well-known CubeSats, have become more and more popular in the last decade, allowing for dramatic reductions of the mission costs. However, it is not fully clear at the present moment which access to space option is the most convenient and affordable one for this class of satellites, with micro-launchers still penalized by their intrinsically bad structural efficiency and propulsion performance. It seems to be preferable to use onboard propulsion for the orbital transfer of these small spacecraft after being inserted in Low Earth Orbit as a piggyback payload of a larger launcher. However, in turn, this increased autonomy due to the presence of a propulsion system raises significant issues in terms of safety to the other surrounding spacecraft in orbit. Strict measures are expected to be applied in the future regulations, in scenarios such as a thrust-direction failure in a small spacecraft, with consequent damage to other spacecraft creating debris. This problem becomes even more critical in Low Earth Orbit due to the presence of the International Space Station. This paper presents a general overview of the current access to space options for small satellites, and the existing propulsion technology for their orbital transfer. A preliminary analysis is performed on the design requirements related to potential scenarios and recovery actions related to propulsion system failures for small satellites operating in Low Earth Orbit.