Study on Relay Networks based on Lagrangian Points for Optical-based Mars-to-Earth Communications

Future colonies on Mars will require any kind of support from Earth. This will results in a huge amount of data to be transferred through the long-haul connection established between the two planets. A radio-frequency (RF) direct link is not apparently sufficient to guarantee the required capacity. Free space optics (FSO) can be chosen to outperform RF in terms of bandwidth availability, narrow beam divergence, reduced power consumption and lower mass and size of the implemented transceivers. In this paper, an optical multi-relay network for Mars-to-Earth connection has been proposed and tested by taking advantage of the Lagrangian points. Spacecrafts, parked in such Space equilibrium points, work as decode-and-forward (DF) relay nodes forwarding data to the next relay found in the position assuring the lowest path distance, and, therefore the highest capacity. Simulation results confirms the viability of the proposed solution, assuring quasi-error-free connections at an average data rate of more than 20 Mb/s, clearly outperforming state-of-the-art solutions based on direct optical transmission.