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Reconfigurability can benefit a wide spectrum of Earth-observation missions where the location of targets is unknown or uncertain a priori, including atmospheric research, disaster monitoring, and reconnaissance. The concept of a reconfigurable constellation (ReCon) is introduced by incorporating reconfigurability into static satellite constellatio...
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... Propulsion module is tasked with computing both the propellant mass (propellant mass) and the dry mass of the propulsion subsystem (prop dry mass) from the propellant type (prop), delta-v (delta v) and the satellite dry mass (sat dry mass). Figure 9 illustrates a satellite mass breakdown, which is broken down into the dry mass (m dry ) and the propellant mass (m p ). First, the dry mass is divided into the bus mass related to the propulsion system and that unrelated to it; the propulsion dry mass (m dry,prop ) contains the tank mass (m tank ) and the thruster/feed mass (m p ); the non-propulsion dry mass (m dry,no prop ) is comprised of the optics mass (m dry,optics )and non-optics mass(m dry,no optics ). the rocket equation, the aforementioned variables are related by m dry,optics +m dry,nooptics +m tank +m p +m p = (m dry,optics +m dry,no optics +m tank +m p )e ∆V gIsp (17) where m dry,optics and m dry,no optics are obtained from the Optics module and the Constellation Properties module, respectively. A Newton solver calculates the propellant mass (m p ) for a given non-propulsion dry mass (m dry ) using this relationship iteratively. ...
Citations
... The delays and inconsistencies reported do not accurately reflect the potential capabilities of satellite constellations. Designing toward responsiveness, through constellation reconfigurability, is a promising solution to this problem [8][9][10]. ...
... Invoking this trade has been the traditional way of thinking for many years. Recent work in the past decade has introduced a new mode of operation, known as reconfigurable satellite constellations (ReCon) [8,10]. ...
With the emerging democratization of space, Earth Observation (EO) imagery is becoming increasingly important to a variety of industries. However, it remains difficult and expensive to build constellations that achieve continuous and high-quality global coverage. Reconfiguring a satellite constellation into different orbital planes to change its observational performance is traditionally a fuel intensive procedure. The concept of a reconfigurable constellation (ReCon) accounts for ��2 perturbation effects when making fuel efficient maneuvers to shift a satellite’s ground track. ReCon reduces the cost of high revisit frequency, high-quality resolution, EO constellations compared to nonreconfigurable constellations by reducing the number of satel- lites required to achieve repeated observations of a given ground event on demand. This paper first explores the sensitivities of ReCon’s performance against uncertainties in reconfigura- tion demand, design costs, and imagery value. The sensitivity analysis reveals that in cases of extremely low demand, ReCon fails to provide a cost-effective solution in terms of events responded to per dollar spent. In cases of high demand ReCon fails to meet demand altogether. A Monte Carlo analysis over a range of demand scenarios shows using a staged deployment for ReCon offers a flexible, cost-effective solution to the uncertainties in the demand of EO imagery. Deferring launch costs to the future, through a staged deployment, not only provides flexibility in constellation design, but also allows the designer to capitalize on the continuation of lowering launch costs and increasing launch opportunities. Staging the deployment of con- stellations also allows for the satellites’ technology to evolve over time, facilitating the capture of higher value imagery and further enhancing the capabilities of ReCon. Implementing the option to deploy additional satellites in stages makes ReCon significantly better equipped to respond to the uncertainty in the demand of space assets.
... The delays and inconsistencies reported do not accurately reflect the potential capabilities of satellite constellations. Designing toward responsiveness, through constellation reconfigurability, is a promising solution to this problem [8][9][10]. ...
... Invoking this trade has been the traditional way of thinking for many years. Recent work in the past decade has introduced a new mode of operation, known as reconfigurable satellite constellations (ReCon) [8,10]. ...
With the emerging democratization of space, Earth Observation (EO) imagery is becoming increasingly important to a variety of industries. However, it remains difficult and expensive to build constellations that achieve continuous and high-quality global coverage. Reconfiguring a satellite constellation into different orbital planes to change its observational performance is traditionally a fuel intensive procedure. The concept of a reconfigurable constellation (ReCon) accounts for J2 perturbation effects when making fuel efficient maneuvers to shift a satellite’s ground track. ReCon reduces the cost of high revisit frequency, high-quality resolution, EO constellations compared to nonreconfigurable constellations by reducing the number of satellites required to achieve repeated observations of a given ground event on demand. This paper first explores the sensitivities of ReCon’s performance against uncertainties in reconfiguration demand, design costs, and imagery value. The sensitivity analysis reveals that in cases of extremely low demand, ReCon fails to provide a cost-effective solution in terms of events responded to per dollar spent. In cases of high demand ReCon fails to meet demand altogether. A Monte Carlo analysis over a range of demand scenarios shows using a staged deployment for ReCon offers a flexible, cost-effective solution to the uncertainties in the demand of EO imagery. Deferring launch costs to the future, through a staged deployment, not only provides flexibility in constellation design, but also allows the designer to capitalize on the continuation of lowering launch costs and increasing launch opportunities. Staging the deployment of constellations also allows for the satellites’ technology to evolve over time, facilitating the capture of higher value imagery and further enhancing the capabilities of ReCon. Implementing the option to deploy additional satellites in stages makes ReCon significantly better equipped to respond to the uncertainty in the demand of space assets.
... Usually, optimization of constellation reconfiguration includes final constellation configuration design and optimal orbital transfer, and the purposes are to minimize the total fuel consumption as well as the reconfiguration time [6,7]. Based on the satellite constellation reconfiguration, the concept of the reconfigurable constellation (ReCon) is proposed [8,9]. Operation of a ReCon comprises the following two modes: global observation mode (GOM) for normal operations and regional observation mode (ROM) for contingent responses, and due to the flexibility of the ReCon, timely and adequate observation for uncertain areas of interest can be achieved [10]. ...
Data collection by satellites during and after a natural disaster is of great significance. In this work, a reconfigurable satellite constellation is designed for disaster monitoring, and satellites in the constellation are made to fly directly overhead of the disaster site through orbital transfer. By analyzing the space geometry relations between satellite orbit and an arbitrary disaster site, a mathematical model for orbital transfer and overhead monitoring is established. Due to the unpredictability of disasters, target sites evenly spaced on the Earth are considered as all possible disaster scenarios, and the optimal reconfigurable constellation is designed with the intention to minimize total velocity increment, maximum and mean reconfiguration time, and standard deviation of reconfiguration times for all target sites. To deal with this multiobjective optimization, a physical programming method together with a genetic algorithm is employed. Numerical results are obtained through the optimization, and different observation modes of the reconfigurable constellation are analyzed by a specific case. Superiority of our design is demonstrated by comparing with the existing literature, and excellent observation performance of the reconfigurable constellation is demonstrated.
... Furthermore, the maximum affordable ∆Vbudget of the satellite for the orbit transfer is taken into account. An application of this framework can be found in the surveillance satellites for monitoring ground targets [3] or exploring a phenomenon near Earth. ...
The study of an unknown region using multiple mobile sensors is considered. The problem involves balancing between the exploration desire \emph{vs.} data refinement desire with either limited or local measurements. The problem raised here may contain several constraints such as the affordable power of the sensors for changing the trajectories and the feasible trajectories, as well. For this purpose, we develop a new framework. Due to the constraints in these types of problems, the proposed framework makes value-laden decisions on selecting the trajectories using Gaussian process modeling and epistemic utility controller.
... The coverage performance of a ReCon improves when the GOM time coverage increases with a higher F 1 value or the ROM revisit time decreases with a lower F 2 value. When formulated as a minimization problem, the sign of a figure-of-merit F 1 should be reversed as shown in Eq. (20) in order to minimize the overall performance objective J 1 . ...
... A faster method for coverage calculation and a more efficient optimization algorithm would be necessary to enhance both quantity and quality of optimal solutions in design space. One solution could be calculating coverage with analytical approaches and optimizing rapidly with a non-dominated sorting genetic algorithm [19,20] Compared to other existing constellations, a ReCon resides 19 somewhere between a monolithic satellite and a swarm of tiny satellites. Table 14 lists a variety of satellite constellations for Earth remote sensing which are already on orbit or in deployment. ...
Remote sensing missions for disaster monitoring or reconnaissance are target-agnostic in that target locations are unknown a priori. Therefore, reconfigurability in satellite orbits can increase responsiveness and quality of imagery data. This paper uses a systems engineering approach to develop an optimization tool for reconfigurable constellations (ReCon). The tool concurrently optimizes the individual satellite design and the constellation geometry. The proposed concept of operations of a ReCon has two operational modes: global observation mode (GOM) and regional observation mode (ROM). Satellites in GOM have drifting ground tracks that provide a global coverage, and ROM features repeating ground tracks (RGT) that increase the access frequency to a particular target. A weighted-sum genetic algorithm (GA) is used to identify non-dominated optimal solutions along a Pareto front in the multi-objective tradespace. In addition to demonstrating the technical feasibility of a ReCon, this paper proposes staged deployment strategies to minimize contingent risks such as launch failures and market uncertainties.
Agile Earth observation can be achieved with responsiveness in satellite launches, sensor pointing, or orbit reconfiguration. This study presents a framework for designing reconfigurable satellite constellations capable of both regular Earth observation and disaster monitoring. These observation modes are termed global observation mode and regional observation mode, constituting a reconfigurable satellite constellation (ReCon). Systems engineering approaches are employed to formulate this multidisciplinary problem of co-optimizing satellite design and orbits. Two heuristic methods, simulated annealing (SA) and genetic algorithm (GA), are widely used for discrete combinatorial problems and therefore used in this study to benchmark against a gradient-based method. Point-based SA performed similar or slightly better than the gradient-based method, whereas population-based GA outperformed the other two. The resultant ReCon satellite design is physically feasible and offers performance-to-cost(mass) superior to static constellations. Ongoing research on observation scheduling and constellation management will extend the ReCon applications to radar imaging and radio occultation beyond visible wavelengths and nearby spectrums.
