System Dynamics and Tradeoffs in Radio Astronomical Data Transport of an Integrated Satellite Communication and Radio Astronomy System

This paper considers an integrated mega-constellation non-geostationary orbit satellite system which provides both communication and radio astronomical observation (RAO) services. We focus on RAO data transport from the RAO-conducting satellites (called source satellites) to the ground gateways where each gateway is directly connected to a certain number of satellites (called destination satellites). We introduce a generalized inter-satellite link (ISL) connection model which extends the existing approach of adjacent-only ISL connections to include non-adjacent ISL connections. This model is implemented with an upper limit on the ISL distance which can be adjusted for performance tradeoffs. Next, we develop analytical expressions to study two impacts of satellite dynamics on the RAO data transport. The first one concerns with the beam misalignment of individual ISL hops. The second one corresponds to whether destination satellites move outside the gateway coverage during the end-to-end delay interval of a data packet transport. Furthermore, we introduce delay, energy, and spectrum usage performance metrics and evaluate them to yield performance tradeoff guidelines. A simplified data transport path model is also presented to facilitate analytical performance evaluation and initial system design settings. Then, we present a new RAO data transport design which incorporates system dynamics and desired performance tradeoffs. Finally, analytical and simulation results and discussions are presented.