Maintaining Connectivity in Multi-Rover Networks for Lunar Exploration Missions

This work focuses on the wireless connectivity of multi-agent lunar robotic systems and how it can be preserved during large-scale lunar exploration missions. In particular, we consider in this work the connectivity of systems composed of a single lunar module and several micro-rovers performing coordinated area coverage exploration tasks. To this end, we adopted a deterministic model for lunar radio propagation to predict the status of point-to-point communication links for agents operating on the moon. We then used this information to build a communication graph for the lunar micro-rover network. The Fiedler value, a metric derived from algebraic graph theory, was then utilized for evaluating the system's evolving network connectivity as the micro-rovers explore finite regions on the lunar surface. Simulations involving a network consisting of a single fixed lunar module and three mobile micro-rovers were performed to illustrate how the rovers' basic mobility can cause disruptions in network connectivity. Results of the simulations show that the overall connectivity of lunar multi-rover networks can be maintained by imposing constraints on the rovers' motion.