Lunar Communication Services: Feasibility Study on Traffic Prioritization of Quasi-Real Time Communications over DTNs

As more missions aim to explore the Moon, the need for a robust communication infrastructure becomes apparent. Such infrastructure is currently being developed by the European Space Agency (ESA) using Delay and Disruption Tolerant Networks (DTN) with the Bundle Protocol (BP). Nevertheless, these networks are not currently equipped with the necessary means to provide quasi-real time communications over highly stressed communication links as the Earth-Moon one. This paper models this link using a three-state Markov Chain which incorporates realistic data, accounting for long- and short-term losses. Using this model, the benefits of using traffic prioritization are assessed through the delay, and other performance-impacting metrics are analyzed, such as the average length of error bursts. This work proves that traffic prioritization reduces delays for data marked as high-priority, achieving delays below the 2.5s mark for 72% of bundles. Natural phenomena, like solar flares, demonstrate a limited impact on overall delay but shown a larger influence on burst losses, which would be significant for streaming-related applications. These results contribute to the understanding of how to transmit quasi-real time data over DTN BP and help pave the way to an efficient design of future communication systems for lunar missions.