Hybrid CubeSat constellation design for observing hurricanes

Abstract

State-of-the-art weather forecasting systems depend on various data collected by airborne, orbiting, and ground sensors. Regional CubeSat constellations have the potential to improve hurricane forecasting by collecting sensor data over data-starved oceanic regions. Even in areas where terrestrial sensor networks exist, constellation sensor data can help reduce forecasting model errors. To this end, we consider the problem of designing a low-Earth orbit CubeSat constellation that meets resolution requirements over a region of interest. Specifically, we envision a novel mission design concept referred to as a regional hybrid constellation in which multiple formation-flying CubeSat clusters are deployed in a traditional multi-plane constellation configuration. To take advantage of the Repeating Ground Track (RGT) orbits within the regional constellation, we present a new optimization-based approach to design an RGT orbit. Using these RGT orbits in the constellation design can reduce the station-keeping cost of the constellation. For the hybrid constellation, we design three novel formation designs that can address the current observation gaps and improve hurricane forecast accuracy. We determine the safe (no collision) relative orbits for each formation design. In addition, we consider a novel optimization framework that utilizes satellite coverage maps to determine the number of satellites and constellation patterns. To facilitate the hybrid constellation design, we determine the CubeSat formation’s coverage map analytically and use it within the optimization framework to determine the optimal hybrid constellation design. Optimizing the hybrid constellation considers minimizing the infrastructure and maintenance cost of the constellation while maximizing the quantity and quality of the hurricane data collection. The hybrid constellation design considers the second-order geo-potential perturbations such that there will be no coverage degradation of the hybrid constellation over the region of interest under these perturbations. Additionally, we develop control strategies for station-keeping and formation-keeping of the hybrid constellation using chemical and electrical propulsion.