| Summary: | The development of remote sensing small satellite constellations has created the potential for high-resolution Earth-observation data to reach end users faster. This work investigates how propulsion and intersatellite links enable constellations to continuously collect and deliver data faster than constellations without these capabilities.
This work has four contributions. The first contribution is a constellation simulation framework that is based on open-source libraries. This simulation framework can propagate satellites and execute propulsive maneuvers. The second contribution is a planning and scheduling algorithm for propulsive maneuvers, target observation times, and optimal data routing paths. The third contribution is the development of high performance constellation designs with respect to constellation cost and the following metrics: age of information, system response time, and total pass time. The cost model is developed from two separate models: the Small Satellite Cost Model (SSCM) and a launch cost model developed in this work. The fourth contribution is a set of cost-estimating relationships (CERs) that models the trade-off between cost and system performance in terms of the aforementioned metrics.
The new simulation framework of contribution 1 is verified against the industry-standard software Systems Tool Kit (STK). The simulation framework is used to run 21 different constellation designs, 3 different satellite models, and 432 distinct ground targets. These scenarios are run during each of the four seasons to eliminate geometric biases for a total of 108,864 individual scenario simulations. A single satellite executing the reconfiguration algorithm produces up to a 125% increase in pass time over seven days when compared to an identical satellite without propulsive capabilities. For an access cone with a nadir half-angle of 20 ,thereconfigurationalgorithm produces a 67% increase in pass time. Comparing the cost of inter-satellite link (ISL) and reconfiguration-capable satellites versus (i) only ISL-capable satellites and (ii) a baseline satellite without ISL or reconfigurable capabilities, a Pareto optimal analysis revealed 29% of designs had both propulsion and intersatellite link capabilities when optimizing for age of information, 7% of designs had both propulsion and intersatellite link capabilities when optimizing for system response time, and 33% of designs had both propulsion and intersatellite link capabilities when optimizing for total pass time. The CERs show that for constellations costing between $150M and $1B (FY24), age of information can be reduced by 32 seconds for every million dollars spent, system response time can be reduced by 35 seconds for every million dollars spent, and total pass time over 3 days can be increased by 2 seconds for every million dollars spent.
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