Study on the Optimal Access Orbiter Selection Algorithm in Mars Automatic Relay Communications

In current Mars relay communications, the Consultative Committee for Space Data Systems (CCSDS) Proximity-1 protocol is simple and efficient but it exhibits low flexibility in optimal access orbiter selection. Once connected with the first successful hailing orbiter, the rover would not switch to other better orbiters until the end of that connection, which makes it difficult to provide more convenient and efficient data relay services. The entire system cost is essential for optimal access orbiter selection, which includes both the Proximity-1 links' transmission cost concerned with the data transmission energy consumption and the orbiters' storage cost concerned with the data buffering energy consumption, thus minimizing the system cost on unit data volume could reduce energy consumption and extend the deep space vehicle's life. We employ long-term simulations of the single rover, simultaneously tracking two orbiters utilizing the improved Hotelling oligopoly model, and reveal the potential improvements for the current “first-come first-serve” selection strategy. In this article, a complete solution is proposed to solve the optimal access orbiter selection issues, including the geometric model, orbit design, oligopoly model, storage cost, and optimal selection algorithms. Simulation results show that our new algorithm outperforms current CCSDS Proximity-1 protocols and distance-dependent selection algorithm in the system cost on unit data volume with the selection gains $36.14\%$ and $ 29.59\%$, respectively, which could be used as the rover's optimal access orbiter selection algorithm in Mars automatic relay communications.