Future Architecture of the Interplanetary Internet
Fifty years after the Apollo program, space exploration has recently been regaining popularity thanks to missions with high media coverage. Future space exploration and space station missions will require specific networks to interconnect Earth with other objects and planets in the solar system. The interconnections of these networks form the core of an Interplanetary Internet (IPN). More specifically, we consider the IPN as the combination of physical infrastructure, network architecture, and technologies to provide communication and navigation services for missions and further applications. Compared to the current implementation of the Internet, nodes composing the core of the IPN are highly heterogeneous (base stations on planets, satellites etc.). Moreover, nodes are in constant motion over intersecting elliptical planes, which results in highly variable delays and even temporary unavailability of parts of the network. As such, an IPN has to overcome the challenges of conventional opportunistic networks, with much higher latency and jitter (from a couple of minutes to several days) and the additional constraint of long-term autonomous operations. In this paper, we highlight the challenges of IPN, demonstrate the elements to deploy within the areas of interest, and propose the technologies to handle deep space communication. We provide recommendations for an evolutionary IPN implementation, coherent with specific milestones of space exploration.