Natural configurations for formation flying around triangular libration points for the elliptic and the bicircular problem in the earth-moon system

The concept of Satellite Formation Flying (SFF) means to have two or more satellites in orbit such that their relative positions remain constant or obeying a certain dynamical configuration along the trajectory. This concept involves the control over the coordinated motion of a group of satellites, with the goal of maintaining a specific geometric space configuration between the elements of the cluster. Assume a constellation of satellites is flying close a given nominal trajectory around L 4 or L 5 in the Earth-Moon system, in such a way that, there is some freedom in the selection of the geometry of the constellation. We are interested in avoiding large variations of the mutual distances between spacecraft. In this case, previous studies about triangular libration points have determined the existence of regions of zero and minimum relative radial acceleration with respect to the nominal trajectory that prevent from the expansion or contraction of the constellation. Similarly, these studies have also shown the existence of regions of maximum relative radial acceleration with respect to the nominal trajectory that produce a larger expansion and contraction of the constellation. However, these studies only considered the gravitational force of the Earth and the Moon using as approximation the Circular Restricted Three Body Problem (CRTBP). Although the CRTBP model is a good approximation for the dynamics of spacecraft in the Earth-Moon system, the stability of constellations flying around L4 and L5 is strongly a ff ected when the primary orbit eccentricity and perturbations from the sun (gravity and light pressure) are considered. As consequence, the previous studies show that, using the CRTBP model, the fuel consumption to maintain the geometry of the constellation computed by the residual acceleration is practically zero. In this manner, the goal of this work is the study and analysis of the best regions to place a constellation that is flying close a given nominal trajectory around L 4 or L 5 , involving a linear approximation of the equations of motion relative to the periodic orbits around triangular libration points and taking into account the Moon’s eccentricity and perturbations from the Sun. This model is not only more realistic for practical engineering applications but permits to determine more accurately the fuel consumption to maintain the geometry of the constellationPostprint (published version

Bailout Embeddings, Targeting of KAM Orbits, and the Control of Hamiltonian Chaos

We present a novel technique, which we term bailout embedding, that can be used to target orbits having particular properties out of all orbits in a flow or map. We explicitly construct a bailout embedding for Hamiltonian systems so as to target KAM orbits. We show how the bailout dynamics is able to lock onto extremely small KAM islands in an ergodic sea.Comment: 3 figures, 9 subpanel

Isochronal synchronization in networks and chaos-based TDMA communication

Pairs of delay-coupled chaotic systems were shown to be able to achieve isochronal synchronization under bidirectional coupling and self-feedback. Such identical-in-time behavior was demonstrated to be stable under a set of conditions and to support simultaneous bidirectional communication between pairs of chaotic oscillators coupled with time-delay. More recently, it was shown that isochronal synchronization can emerge in networks with several hundreds of oscillators, which allows its exploitation for communication in distributed systems. In this paper, we introduce a conceptual framework for the application of isochronal synchronization to TDMA communication in networks of delay-coupled chaotic oscillators. On the basis of the stable and identical-in-time behavior of delay-coupled chaotic systems, the chaotic dynamics of distributed oscillators is used to support and sustain coordinate communication among nodes over the network. On the basis of the unique features of chaotic systems in isochronal synchronization, the chaotic signals are used to timestamp clock readings at the physical layer such that logical clock synchronization among the nodes (a prerequisite for TDMA) can be exploited using the same basic structure. The result is a standalone network communication scheme that can be advantageously applied in the context of ad-hoc networks or alike, especially short-ranged ones that yield low values of time-delay. As explored to its depths in practical implementations, this conceptual framework is argued to have potential to provide gain in simplicity, security and efficiency in communication schemes for autonomous/standalone network applications

Adaptive pinning control: A review of the fully decentralized strategy and its extensions

In this work, we review recent developments related to the problem of guiding a complex network of agents toward a synchronized state. Specifically, we focus on adaptive pinning control strategies, expounding those developed by the authors in the context of the existing literature, in which only a small fraction of the network nodes is directly controlled. The methodologies described herein are adaptive in the sense that the control and coupling gains are updated on the basis of the local mismatch with the desired trajectory and between coupled nodes, respectively. A selection of adaptive strategies recently proposed in the literature is reviewed, and the main stability results are expounded. As a numerical validation, the selected approaches are applied to control an ensemble of coupled mobile agents moving in a formation

The zero, minimum and maximum relative radial accelerations along a family of periodic orbits around L4 in the Earth-Moon system

Constellations of satellites, Zero relative radial acceleration, Earth-Moon.Assume a constellations of satellites flighting close a given nominal trajectory around L4 or L5 in the Earth-Moon system in such a way that there is freedom in the selection of the geometry of the constellation. We are interested in to avoid large variations of the mutual distance between the spacecrafts. In this case, the possible existence of regions of zero relative radial acceleration with respect to the nominal trajectory will prevent from the expansion or contraction of the constellation. The goal of this paper is the study of theses regions.Postprint (published version

The zero, minimum and maximum relative radial accelerations along a family of periodic orbits around L4 in the Earth-Moon system

Constellations of satellites, Zero relative radial acceleration, Earth-Moon.Assume a constellations of satellites flighting close a given nominal trajectory around L4 or L5 in the Earth-Moon system in such a way that there is freedom in the selection of the geometry of the constellation. We are interested in to avoid large variations of the mutual distance between the spacecrafts. In this case, the possible existence of regions of zero relative radial acceleration with respect to the nominal trajectory will prevent from the expansion or contraction of the constellation. The goal of this paper is the study of theses regions

A study of intermodulation interference due to non-linearities in metallic structures

SIGLEAvailable from British Library Document Supply Centre- DSC:DX78723 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

The zero, minimum and maximum relative radial accelerations along a family of periodic orbits around L4 in the Earth-Moon system

Constellations of satellites, Zero relative radial acceleration, Earth-Moon.Assume a constellations of satellites flighting close a given nominal trajectory around L4 or L5 in the Earth-Moon system in such a way that there is freedom in the selection of the geometry of the constellation. We are interested in to avoid large variations of the mutual distance between the spacecrafts. In this case, the possible existence of regions of zero relative radial acceleration with respect to the nominal trajectory will prevent from the expansion or contraction of the constellation. The goal of this paper is the study of theses regions

Zero drift regions and control strategies to keep satellite in formation around triangular libration point in the restricted Sun-Earth-Moon scenario

In this work, we are interested in avoiding large variations in the mutual distances among multiple satellites and also in controlling their geometric configuration around an Earth Moon triangular point. Previous studies about triangular libration points have determined the existence of zero drift regions with respect to the nominal trajectory, in which the expansion or contraction of the formation never take place. Our goal is to carry out two different control strategies for a formation near a given nominal trajectory around L-4: a bang-off-bang control and a minimum weighted total AV consumption. A linearization relative to the reference trajectory around the triangular libration point is carried out, and different geometrical possibilities in the zero drift regions are studied. To investigate the influence of the gravitational force of the Sun, the BiCircular Four Body Problem is considered here. According to the results obtained, some meaningful insights to allow a proper design of the geometric configuration of the formation are drawn. (C) 2015 COSPAR. Published by Elsevier Ltd. All rights reserved.Peer Reviewe