1,720,986 research outputs found
Elliptical shape-based model for multi-revolution planeto-centric mission scenarios
Full text linkThe paper presents a novel 3-dimensional shape-based algorithm which extends the domain of analytical solutions to planeto-centric mission scenarios, which classically entail even thousands revolutions to transfer to the final orbit. Thanks to the strong physical meaning the proposed method keeps while shaping the trajectory, the method succeeds in outputting a solution close to the real optimum. The proposed approach allows to easily formalize practical mission constraints, such as maximum thrust threshold and eclipses; free and fixed time of flight is manageable as well. The approach is almost completely analytic, which is beneficial as it significantly decreases the computational load. It is well suited for complex mission scenarios and for fast detection near optimal solutions to support the whole mission design
An Advanced Multi-Orbit Precise Targeting Tool to Rapidly Design Multi-Payload Dispenser Delivery Strategy
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An Analytical 3D Shape-Based Algorithm Based on Orbits Interpolation for Multi-Revolutions Low-Thrust Trajectory Optimization with Eclipses And Perturbations
Full text linkA novel 3-dimensional shape based algorithm is proposed in order to extend the domain of analytical solutions to planeto-centric mission scenarios, in which hundreds or thousands of revolutions are required. Due to the strong physical meaning of the shape the method outputs a trajectory close to the real optimal solution. Practical mission constraints are easily formalized, such as maximum thrust threshold and eclipses; moreover, relevant perturbations effects can be considered; free and fixed time of flight are manageable as well. The approach is almost completely analytic, beneficial to significantly lower the computational load, well suited for complex mission scenarios near optimal solutions fast detection
Relative and absolute on-board optimal formation acquisition and keeping for scientific activities in high-drag low-orbit environment
Full text linkIn this paper, a novel Model Predictive Control (MPC) technique for multi-satellite formation flying geometry acquisition and maintenance in high-drag environment is presented. The proposed MPC relies on a linearized and convexified quasi-nonsingular Relative Orbital Elements (ROE) model based on state transition matrices propagation, allowing to include the effect of perturbations in the prediction to optimize fuel efficiency and tracking accuracy. The formation is controlled with respect to a non-decaying orbiting point to perform absolute and relative station keeping simultaneously. For this purpose, a new dedicated plant matrix to include drag effects on ROE in the propagation is derived and validated with respect to numerical results. In all simulations, the satellites are assumed to be equipped with a single low-thrust propulsion unit, therefore, specific constraints are included in the controller to obtain a feasible solution in a real operational scenario. Moreover, a collision avoidance constraint is added in case of close proximity operations exploiting a linear mapping between the set of ROE and cartesian coordinates expressed in the Local-Vertical-Local-Horizontal (LVLH) reference frame. The controller response is simulated in several realistic mission contexts with a high-fidelity orbital propagator and the results are validated for fuel efficiency by comparing them to similar approaches available in literature and to optimal solutions obtained respectively with a direct single shooting algorithm and with a closed-form impulsive formulation
Cislunar Distributed Architectures for Communication and Navigation Services of Lunar Assets
Full text linkThe last decade saw a renewed interest on the Moon as a well suited training premise in preparation to manned mission to Mars, but also as an interesting target itself, for scientific investigations, technological developments and new markets opportunities. As a result, numerous and very different missions to the Moon are currently being studied and implemented, assuming to have our satellite quite crowded soon. Such a scenario motivates the settling of space infrastructures to offer recurrent services like data relays, communication links and navigation in the cislunar environment which would facilitate and enlighten the single mission's implementation and operation. The paper presents the strategy adopted to address the design of the orbital configuration for a distributed architecture to answer the communication and navigation needs to serve at the best the diversified lunar missions scenario expected for the next decades. First, a set of parameters of merit are identified and explained in their mathematical expression and physical meaning. Then, different regions of interest for possible future missions are identified and mapped to the relevant performances wanted for that specific region. Last a Multi-Objective Optimisation framework is presented, both in the exploited genotype and the different objectives participating to the definition of the cost function, in order to provide a versatile tool. The paper critically discusses the effectiveness of the proposed approach in detecting the best suited distributed orbital architectures for the servicers according to the expected service performance in specific user regions, spread all over the Earth-Moon volume - from Earth vicinity to Lunar surface, considering also robustness aspects. The benefits in the exploitation of the multibody dynamical regime offered by the Earth-Moon system to set up the most promising orbital set with a minimum number of servicing spacecraft are underlined as well
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