Small satellite operations planning for agile disaster response using graph theoretical techniques

Agile, manoeuvrable, satellite constellations have the potential to fundamentally change space mission design by enabling systems that react to real-time events, such as natural disasters. In particular, small satellites with highly efficient, low-thrust, propulsion systems can improve system responsiveness in comparison to traditional architectures, while offsetting the higher risk and shorter mission life associated with manoeuvrable spacecraft. To realise this vision, a holistic view of the concept of operations is introduced that employs graph theoretical techniques to perceive all calculated manoeuvre options as a graph. The manoeuvres are designed using a previously developed analytical methodology that considers multiple targeting options, each with different flyover times, view angles, and propellant requirements. The connections in the graph, representing possible manoeuvres, are rapidly traversed to identify favourable routes. The effect of changes to mission priorities can then be assessed by reweighting the graph, avoiding the need to recalculate the manoeuvre options. The proposed method is used to plan a series of sequential flyovers for a moving target; in this case, a tropical storm. The method can be used to plan flyovers of a moving target using either its actual or predicted path. For the system considered, the possible changes in flyover time for each target location are small, but these adjustments can significantly improve the coverage of the target compared to a non-manoeuvring spacecraft.