Subjects -> AERONAUTICS AND SPACE FLIGHT (Total: 124 journals)
 Showing 1 - 30 of 30 Journals sorted by number of followers AIAA Journal       (Followers: 1003) SpaceNews       (Followers: 779) Journal of Spacecraft and Rockets       (Followers: 702) Journal of Propulsion and Power       (Followers: 570) Aviation Week       (Followers: 412) Aerospace Science and Technology       (Followers: 307) Advances in Space Research       (Followers: 296) IEEE Transactions on Aerospace and Electronic Systems       (Followers: 281) Journal of Aircraft       (Followers: 264) IEEE Aerospace and Electronic Systems Magazine       (Followers: 252) Control Systems       (Followers: 235) Acta Astronautica       (Followers: 220) Gyroscopy and Navigation       (Followers: 178) Journal of Navigation       (Followers: 178) Journal of Guidance, Control, and Dynamics       (Followers: 165) Aircraft Engineering and Aerospace Technology       (Followers: 139) Space Science International       (Followers: 118) Space Science Reviews       (Followers: 92) Propulsion and Power Research       (Followers: 89) International Journal of Aerospace Engineering       (Followers: 86) Progress in Aerospace Sciences       (Followers: 82) Advances in Aerospace Engineering       (Followers: 74) Journal of Aerospace Engineering       (Followers: 66) Aerospace       (Followers: 64) Journal of Aerospace Information Systems       (Followers: 57) Space Safety Magazine       (Followers: 50) International Journal of Aerodynamics       (Followers: 46) IEEE Transactions on Circuits and Systems I: Regular Papers       (Followers: 43) Space Research Today       (Followers: 43) Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering       (Followers: 42) International Journal of Aeroacoustics       (Followers: 37) International Journal of Aerospace Sciences       (Followers: 36) Canadian Aeronautics and Space Journal       (Followers: 31) Space Policy       (Followers: 30) Journal of Space Weather and Space Climate       (Followers: 30) CEAS Aeronautical Journal       (Followers: 30) Journal of Aerodynamics       (Followers: 27) Journal of Aerospace Information Systems       (Followers: 27) Egyptian Journal of Remote Sensing and Space Science       (Followers: 25) Russian Aeronautics (Iz VUZ)       (Followers: 23) International Journal of Aerospace Innovations       (Followers: 23) Aviation Psychology and Applied Human Factors       (Followers: 23) Aerospace Medicine and Human Performance       (Followers: 22) International Journal of Aerospace Psychology       (Followers: 22) Journal of Aerospace Engineering & Technology       (Followers: 22) Journal of Wind Engineering and Industrial Aerodynamics       (Followers: 21) Artificial Satellites       (Followers: 21) Fatigue of Aircraft Structures       (Followers: 21) Research & Reviews : Journal of Space Science & Technology       (Followers: 20) Frontiers in Aerospace Engineering       (Followers: 20) International Journal of Space Structures       (Followers: 19) Nonlinear Dynamics       (Followers: 19) Chinese Journal of Aeronautics       (Followers: 19) Proceedings of the Human Factors and Ergonomics Society Annual Meeting       (Followers: 16) International Journal of Satellite Communications Policy and Management       (Followers: 15) Frontiers in Astronomy and Space Sciences       (Followers: 15) Journal of Aircraft and Spacecraft Technology       (Followers: 15) Advances in Aerospace Science and Technology       (Followers: 14) International Journal of Space Science and Engineering       (Followers: 13) Aviation       (Followers: 12) International Journal of Micro Air Vehicles       (Followers: 11) Journal of Airline and Airport Management       (Followers: 11) Journal of the Astronautical Sciences       (Followers: 11) International Journal of Space Technology Management and Innovation       (Followers: 11) Population Space and Place       (Followers: 10) Journal of Aviation Technology and Engineering       (Followers: 10) Journal of Aeronautical Materials       (Followers: 10) Aerospace Systems       (Followers: 10) International Journal of Crashworthiness       (Followers: 10) Journal of Aerospace Technology and Management       (Followers: 10) Aeronautical Journal, The       (Followers: 9) Journal of the American Helicopter Society       (Followers: 9) International Journal of Aviation, Aeronautics, and Aerospace       (Followers: 9) International Journal of Aviation Technology, Engineering and Management       (Followers: 8) Journal of Space Safety Engineering       (Followers: 8) International Journal of Applied Geospatial Research       (Followers: 7) Transportmetrica A : Transport Science       (Followers: 7) Aerospace technic and technology       (Followers: 7) Aviation in Focus - Journal of Aeronautical Sciences       (Followers: 7) New Space       (Followers: 6) Space and Polity       (Followers: 6) Aerotecnica Missili & Spazio : Journal of Aerospace Science, Technologies & Systems       (Followers: 6) Civil Aviation High Technologies       (Followers: 6) Air Medical Journal       (Followers: 6) REACH - Reviews in Human Space Exploration       (Followers: 5) RocketSTEM       (Followers: 5) International Journal of Sustainable Aviation       (Followers: 5) Journal of Astrobiology & Outreach       (Followers: 5) Life Sciences in Space Research       (Followers: 5) International Journal of Aviation Management       (Followers: 5) Cosmic Research       (Followers: 5) Journal of Spatial Science       (Followers: 4) Journal of KONBiN       (Followers: 4) Astrodynamics       (Followers: 4) International Journal of Aeronautical and Space Sciences       (Followers: 4) Unmanned Systems       (Followers: 4) Transport and Aerospace Engineering       (Followers: 4) Open Aerospace Engineering Journal       (Followers: 4) Problemy Mechatroniki. Uzbrojenie, lotnictwo, inżynieria bezpieczeństwa / Problems of Mechatronics. Armament, Aviation, Safety Engineering       (Followers: 3) Microgravity Science and Technology       (Followers: 3) Journal of the Australasian Society of Aerospace Medicine       (Followers: 3) npj Microgravity       (Followers: 3) ASTRA Proceedings       (Followers: 3) MAD - Magazine of Aviation Development       (Followers: 3) Ciencia y Poder Aéreo       (Followers: 3) Journal of Aviation/Aerospace Education & Research       (Followers: 2) Advances in Astronautics Science and Technology       (Followers: 2) Journal of Engineering and Technological Sciences       (Followers: 2) IEEE Journal on Miniaturization for Air and Space Systems       (Followers: 2) Perspectives of Earth and Space Scientists i       (Followers: 1) Investigación Pecuaria       (Followers: 1) Transactions on Aerospace Research       (Followers: 1) Вісник Національного Авіаційного Університету       (Followers: 1) Science and Education : Scientific Publication of BMSTU       (Followers: 1) Spatial Information Research       (Followers: 1) Xibei Gongye Daxue Xuebao / Journal of Northwestern Polytechnical University Mekanika : Jurnal Teknik Mesin i
Similar Journals
 Journal of the Astronautical SciencesJournal Prestige (SJR): 0.461 Citation Impact (citeScore): 1Number of Followers: 11      Hybrid journal (It can contain Open Access articles) ISSN (Print) 0021-9142 - ISSN (Online) 2195-0571 Published by Springer-Verlag  [2469 journals]
• Angular Velocity and Covariance Estimates for Rigid Bodies in Near
Pure-Spin Using Orientation Measurements

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Abstract: The problem of estimating relative pose and angular velocity for uncooperative space objects has garnered great interest, especially within applications such as asteroid mapping and satellite servicing. This paper provides a batch estimator based on orientation measurements to estimate not only the angular velocity magnitude and spin-axis direction of a target body (either external or oneself) undergoing pure-spin, but also the associated uncertainty bounds for the resulting angular velocity magnitude and spin-axis direction estimates under reasonable assumptions. In addition, this paper derives statistics for the third eigenvalue of the stacked measurement matrix, which enable detection of whether the target body’s spin-axis direction is changing. The statistics of the third eigenvalue are shown to match those of a Monte-Carlo-based Gamma distribution fit. Instead of a recursive filtering methodology, the batch formulation pursued in this paper is well-suited to exploit the geometric properties associated with singular value decomposition techniques and Toeplitz recursion. This batch approach relinquishes the need for an iterative scheme to compute the error bounds upon the estimated spin-axis direction.
PubDate: 2022-05-19

• Consensus Control of Rigid Body Spacecraft in Orbital Relative Motion
using TSE(3) and Exponential Coordinates

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Abstract: In this paper, two consensus control algorithms are proposed for control of multi-agent rigid body spacecraft in orbital relative motion. In the first approach, a proportional-derivative (PD) consensus control method, an extension of the Morse-Lyapunov analysis in the framework of the tangent bundle TSE(3) associated with Lie group SE(3) is used where rotation matrices parameterize the attitude of the rigid bodies. In the second approach, a proportional-integral-derivative (PID) consensus control protocol is introduced where the configurations of the rigid bodies are described in terms of the exponential coordinates associated with the Lie group SE(3). The control objective is to stabilize the relative pose configurations with velocity synchronization of the spacecraft which share their states according to a static communication topology in the presence of gravitational forces and torques. Finally, simulation examples are given to demonstrate the proposed methods.
PubDate: 2022-05-18

• Analytical Radial Adaptive Method for Spherical Harmonic Gravity Models

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Abstract: Accurate orbit propagation for satellites in motion around a massive central body requires the inclusion of a high-fidelity gravity model for that central body. Including such a model significantly increases computational costs as a sufficiently large degree for the spherical harmonic series is required. The higher the degree of a specific series, the higher the decay rate as a function of increasing altitude, and hence the smaller its contribution to the total gravitational acceleration. To maintain a particular accuracy solution for a satellite in a highly elliptic orbit, a high gravity degree is needed near the perigee, and a low degree is sufficient at the apogee. This paper presents an analytic method for automatically selecting the degree of the spherical harmonic series based on the desired solution accuracy specified by the user and the instantaneous radial distance of the satellite from the central body. We present results for several test case orbits around the Earth, the Moon, and Mars that demonstrate a significant speedup when using our analytical radial adaptive model in orbit propagation.
PubDate: 2022-05-06

• Correction to: Analytical Guidance for Mars Aerocapture via Drag
Modulation

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PubDate: 2022-04-29

• Visibility Study in a Chief-Deputy Formation for CMB Polarization Missions

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Abstract: Abstract Scientific instruments on board satellites are becoming increasingly sensitive, making it imperative to submit these instruments to a thorough calibration. In-flight calibration could be largely improved by using an ancillary microsatellite flying in formation with the main satellite and emitting a well-defined and known reference signal. Due to the main satellite attitude motion, the calibration satellite and therefore, its calibration signal, will only enter the instrument FoV (Field of View) at certain instants. It is not intuitive how frequently and during how much time this will happen, or how this depends on the scan strategy. In the present work, the available time for calibration and its characteristics in terms of total, mean, and maximum duration are studied, deriving analytical expressions for these quantities. These expressions are validated numerically and allow us to assess the impact of different scan strategies and to evaluate the most suitable region to locate the calibration satellite. The focal plane of the instrument is also modelled to evaluate the calibration process at detector level, calculating the number of detectors viewed and the direction of the polarized signal that they received. For this last analysis, only numerical methods have been employed. The tools are finally used in a case study in order to show how they can be employed to test, evaluate, and optimize scanning strategies and relative positions. The tools presented in this work can be easily adapted to evaluate more generally the characteristics of the observation of each point in the sky for a given scan strategy and instrument FoV.
PubDate: 2022-04-29

• Parallel Evaluation of Chebyshev Approximations: Applications in
Astrodynamics

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Abstract: Abstract Approximations based on Chebyshev polynomials have several astrodynamic applications. The performance of these approximations can be improved by parallel implementations exploiting parallel architectures, such as OpenMP and CUDA. In this paper, we introduce the parallel implementation to two astrodynamic applications. The first is the gravitational finite element model (FEM): a piecewise Chebyshev approximation that replaces high degree and order gravitational spherical harmonic models (SHMs). Thus, much lower degree, locally valid functions can efficiently model and compute local gravity perturbations in parallel structure for efficient performance. For this model, the total gravity acceleration is split into a reference and disturbance term. The reference includes two-body plus $$J_2$$ , which are relatively cheap to compute. The FEM approximates the higher-order gravity terms. It is developed from a 2D mesh grid covering a sphere of a specified radius, and a family of spherical shells is sampled using a cosine distribution in the radial direction. To reduce the required memory when seeking a specific accuracy, an adaptive version of the gravitational FEM is introduced. In addition, a parallel implementation of the FEM using OpenMP is preseneted. We show the runtime comparison for the 200 degree × 200 order EGM2008 SHM and the serial and parallel equivalent FEM algorithms. The other application is the Chebyshev-Picard method (CPM): a numerical integrator that solves an ordinary differential equation by approximating the integrand using a Chebyshev approximant and iterates over the trajectory via Picard iteration. A parallel CUDA implementation of the CPM method in conjunction with the EGM2008 SHM and the FEM is introduced. We present numerical examples for propagating four Earth-orbiting satellites considering both the $$200\times 200$$ EGM2008 SHM and the equivalent FEM representation to test the algorithm’s performance via parallel and serial computation (i.e., a single CPU thread).
PubDate: 2022-04-26

• Comparison of Deep Space Navigation Using Optical Imaging, Pulsar
Time-of-Arrival Tracking, and/or Radiometric Tracking

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Abstract: Abstract Recent advances with space navigation technologies developed by NASA in space-based atomic clocks and pulsar X-ray navigation, combined with past successes in autonomous navigation using optical imaging, brings to the forefront the need to compare space navigation using optical, radiometric, and pulsar-based measurements using a common set of assumptions and techniques. This review article examines these navigation data types in two different ways. First, a simplified deep space orbit determination problem is posed that captures key features of the dynamics and geometry, and then each data type is characterized for its ability to solve for the orbit. The data types are compared and contrasted using a semi-analytical approach with geometric dilution of precision techniques. The results provide useful parametric insights into the strengths of each data type. In the second part of the paper, a high-fidelity, Monte Carlo simulation of a Mars cruise, approach, and entry navigation problem is studied. The results found complement the semi-analytic results in the first part, and illustrate specific issues such as each data type’s quantitative impact on solution accuracy and their ability to support autonomous delivery to a planet.
PubDate: 2022-04-21

• Characterization of Resident Space object States Using Functional Data
Analysis

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Abstract: Abstract To date, most characterization techniques (e.g., using photometric light curves) take place using time and frequency domain analyses of data samples generally lacking in the complete information content needed for unambiguous characterization of non-resolved Resident Space Objects (RSOs). In this paper, the information content of multiple measurement types is examined using information theoretic and functional data analysis (FDA) approaches which have shown promise in characterizing the physical and dynamic attributes of space objects from non-resolved observations. With limited data and information, it may still be valuable to understand whether the “state” of an RSO is: (a) active (operational), (b) passive (debris), (c) dormant (a potential threat acting passive), or (4) transitionary between any of 2 of the a-c states. Representative use cases are established, and the information content is examined in a probabilistic context for a set of simulated astrometric, photometric, Long Wave Infra-red (LWIR) and Radio Frequency (RF) observations for a diverse set of object shapes, sizes and dynamics representative of states a-d are used to demonstrate the application and value of FDA. The results confirm the value of these approaches by correctly categorizing independent sets of measurements and quantifying the likelihood of a given combination of observation types as being associated with a specific object. The value and information contribution of each observation type to the characterization is assessed by virtue of the Hellinger Distance metric.
PubDate: 2022-04-20

• Impact of Using Analytic Derivatives In Optimization For N-Impulse Orbit
Transfer Problems

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Abstract: Abstract Several formulations are possible for the optimization of N-impulse two-body orbit transfers. One formulation that assumes the first N − 1 impulses are design variables, and implements Lambert’s algorithm in the final leg is considered here. This paper presents a derivation for the analytic expressions of the gradients needed to optimize a transfer using this formulation. The derivations of the analytic gradients, verification tests using complex-step differentiation, as well as numerical case studies for three-impulse orbit transfers are presented. The numerical case studies highlight a significant reduction in the computational cost, measured in terms of the number of objective function evaluations.
PubDate: 2022-04-19

• Analytical Guidance for Mars Aerocapture via Drag Modulation

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Abstract: Abstract Aerocapture is a maneuver where a spacecraft makes a single pass through a planetary atmosphere, thus using aerodynamic drag to deplete enough energy to establish a captured orbit. A new analytical predictor-corrector guidance algorithm has been developed for the Mars aerocapture problem. This paper presents a drag-modulation method where ballistic coefficient is continuously adjusted in order to control the vehicle during the atmospheric flight phase. An analytical function for velocity during aerocapture serves as the basis for the guidance method, and this expression results in a closed-form control law for ballistic coefficient. Guidance periodically updates the velocity profile so that the correct exit conditions are achieved. The ballistic coefficient control law utilizes the ratio of the measured and reference drag accelerations to improve the targeting accuracy of the guidance scheme. Two different apoapsis-targeting scenarios for Mars aerocapture are investigated in this paper. Monte Carlo simulations demonstrate the performance and robustness of the proposed guidance algorithm.
PubDate: 2022-04-07

• Hyper-Spectral Speckle Imaging for Space Situational Awareness

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Abstract: Abstract When observing targets in the near-Earth space environment using ground-based telescopes, the Earth’s turbulent atmosphere and the telescope’s aperture combine to act as a low-resolution spectrometer. The light at disparate wavelengths from a given point in the object lands at different spatial locations in the focal plane. Here we investigate the feasibility of capitalizing on this effect to provide snapshot hyper-spectral imaging of targets in the near-Earth space environment through ultra-broadband speckle imaging. In particular, we focus on the potential for using ultra-broadband speckle images for high-resolution, high-contrast imaging of closely spaced objects with a large contrast in brightness. It was found that this technique is capable of distinguishing closely spaced objects down to 0.14 arc-seconds and providing estimates on the spectra. The primary component of the closely spaced objects had very good recovery, while the secondary’s recovery was dependent on dependent on separation and contrast ratio.
PubDate: 2022-04-01

• Maximum A Posteriori Estimation of Hamiltonian Systems with High Order
Taylor Polynomials

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Abstract: Abstract This paper presents a new approach to Maximum A Posteriori (MAP) estimation for Hamiltonian dynamic systems. By representing probability density functions through Taylor polynomials and using Differential Algebra techniques, this work proposes to derive the MAP estimate directly from high order polynomials. The polynomial representation of the posterior probability density function leads to an accurate approximation of the true a posterior distribution, that describes the uncertainties of the state of the system. The new method is applied to a demonstrative orbit determination problem.
PubDate: 2022-03-23

• Analysis of Angles-Only Hybrid Space-Based/Ground-Based Approach for
Geosynchronous Orbit Catalog Maintenance

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Abstract: Abstract Geosynchronous Equatorial Orbit (GEO) is critical to Earth communications, weather monitoring, and national defense. Orbit estimation of GEO objects is difficult due to physical constraints placed on ground-based tracking devices such as weather, object range, lighting conditions and tracking frequency restrictions. These constraints are commonly mitigated through the use of two-way signaling devices for cooperative GEO satellites. However, determining the position and velocity of uncooperative GEO satellites and/or objects is more challenging. The objective of this paper is to develop an efficient tool to quantify the increased orbit determination accuracy of objects in the GEO catalog when the Air Force Space Command Space Surveillance Network (AFSPC SSN) is augmented with space-based angles-only measurements from a sensor in a unique near-GEO orbit. To accomplish this, a linear covariance tool is developed and validated by Monte Carlo analysis over a range of problem parameters. It is shown that linear covariance analysis is an efficient approach in determining the covariance of the position and velocity estimation errors of an uncooperative GEO object. Additionally, the linear covariance tool is used to perform error budget analysis.
PubDate: 2022-03-21

• Transfers from Geosynchronous Transfer Orbits to Sun-Earth Libration Point
Trajectories

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Abstract: Abstract Rideshares increase launch capabilities and decrease the launch costs. However, the range of orbits available for secondary payloads is dependent on launch constraints for the primary mission. Additionally, communications constraints and limited propellant options must be incorporated in the preliminary mission design strategy for secondary payloads. Ridesharing opportunities are now available for orbit destinations beyond Low Earth Orbit (LEO). In this investigation, transfers from Geosynchronous Transfer Orbits (GTO) to Sun-Earth libration point orbits are constructed by leveraging stable manifold structures and Poincaré maps.
PubDate: 2022-03-09
DOI: 10.1007/s40295-022-00308-0

• Bayesian Shape Reconstruction and Optimal Guidance for Autonomous Landing
on Asteroids

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Abstract: Abstract Construction of the precise shape of an asteroid is critical for spacecraft operations as the gravitational potential is determined by spatial mass distribution. The typical approach to shape determination requires a prolonged “mapping” phase of the mission over which extensive measurements are collected and transmitted for Earth-based processing. This paper presents a set of approaches to explore an unknown asteroid with onboard calculations, and to land on its surface area selected in an optimal fashion. The main motivation is to avoid the extended period of mapping or preliminary ground observations that are commonly required in spacecraft missions around asteroids. First, range measurements from the spacecraft to the surface are used to incrementally correct an initial shape estimate according to the Bayesian framework. Then, an optimal guidance scheme is proposed to control the vantage point of the range sensor to construct a complete 3D model of the asteroid shape. This shape model is then used in a nonlinear controller to track a desired trajectory about the asteroid. Finally, a multi resolution approach is presented to construct a higher fidelity shape representation in a specified location while avoiding the inherent burdens of a uniformly high resolution mesh. This approach enables for an accurate shape determination around a potential landing site. We demonstrate this approach using several radar shape models of asteroids and provide a full dynamical simulation about asteroid 4769 Castalia.
PubDate: 2022-03-09
DOI: 10.1007/s40295-022-00310-6

• Comparison of Four Space Propulsion Methods for Reducing Transfer Times of
Crewed Mars Missions

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Abstract: Abstract We assess the possibility of reducing the travel time of a crewed mission to Mars by examining four different propulsion methods and keeping the mass at departure under 2500 t, for a fixed architecture. We evaluated representative systems of three different state of the art technologies (chemical, nuclear thermal and electric) and one advance technology, the “Pure Electro-Magnetic Thrust” (PEMT) concept (proposed by Rubbia). A mission architecture mostly based on the Design Reference Architecture 5.0 is assumed in order to estimate the mass budget, that influences the performance of the propulsion system. Pareto curves of the duration of the mission and time of flight versus mass of mission are drawn. We conclude that the ion engine technology, combined with the classical chemical engine, yields the shortest mission times for this architecture with the lowest mass and that chemical propulsion alone is the best to minimise travel time. The results obtained using the PEMT suggest that it could be a more suitable solution for farther destinations than Mars.
PubDate: 2022-03-07
DOI: 10.1007/s40295-021-00300-0

• Docking Manoeuvre Control for CubeSats

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Abstract: Abstract Rendezvous and docking missions of small satellites are opening new scenarios to accomplish unprecedented in-obit operations. These missions impose to win the new technical challenges that enable the possibility to successfully perform complex and safety–critical manoeuvres. The disturbance forces and torques due to the hostile space environment, the uncertainties introduced by the onboard technologies and the safety constraints and reliability requirements lead to select advanced control systems. The paper proposes a control strategy based on Model Predictive Control for trajectory control and Sliding Mode Control for attitude control of the chaser in last meters before the docking. The control performances are verified in a dedicated simulation environment in which a non-linear six Degrees of Freedom and coupled dynamics, uncertainties on sensors and actuators responses are included. A set of 300 Monte Carlo Simulation with this Non-Linear system are carried out, demonstrating the capabilities of the proposed control system to achieve the final docking point with the required accuracy.
PubDate: 2022-03-03
DOI: 10.1007/s40295-022-00307-1

• Convolutional Neural Networks for Inference of Space Object Attitude
Status

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Abstract: Abstract Convolutional neural networks (CNNs) are utilized for the task of inferring the attitude status in terms of rotation rate of resident space objects (RSOs) using simulated light curve measurements. Research into the performance of CNNs on synthetic light curve data-sets has shown significant promise that has not yet translated into success when working with empirically collected light curves. This limitation appears to be due to a number of factors including: mixing of bidirectional reflectance distribution function (BRDF) signatures, the effects of sensor noise, and blurring due to atmospheric turbulence. A synthetic data-set of approximately 7500 light curves was generated that takes into account realistic BRDF signatures and environmental parameters. The RSO used in this study was texture mapped with three unique material BRDF signatures: silicon solar panel, glossy paint, and aluminum. A two-step BRDF model inversion of the Beard-Maxwell model was performed using empirically collected data-sets of these materials in order to physically derive the BRDF model parameters. The CNN was trained on light curves resulting from the RSO performing four different maneuvers: tumbling, accelerating in rotational rate, stabilizing, and inactive (or stable in rotation rate). The CNN achieved an overall classification accuracy of 86.2% across the four maneuver classes. A confusion matrix analysis of the different classes of maneuvers suggested that our model performed best when classifying tumbling and accelerating RSOs (94% accuracy) and worst at classifying inactive RSOs (60% accuracy). This performance limitation when classifying inactive RSOs is attributed to (1) back-scatter signatures and specular glints within the synthetic light curves of inactive satellites being mistaken as attitude maneuvers, and (2) low signal-to-noise ratio due to factors such as atmospheric blurring. These results suggest that CNNs have strong potential for aiding in the problem of classifying satellite attitude status from light curves, but that machine learning research must focus on developing training sets and pre-processing techniques that account for these complications.
PubDate: 2022-02-28
DOI: 10.1007/s40295-022-00309-z

• Observability of Light Curve Inversion for Shape and Feature Determination
Exemplified by a Case Analysis

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Abstract: Abstract As the resident space object population continues to grow, Space Situational Awareness becomes most important for reducing the risk of collision among these objects. Obtaining object characteristic information, such as shape or reflectivity properties among other aspects, is essential for precise orbit propagation and object identification. Measurements of object brightness over time, or so-called light curve measurements, have a rich history of use for characterizing astronomical objects. If light curve measurements do not sufficiently capture the geometry of a system, the resulting shape and characteristic estimates from light curve inversion are not guaranteed to be accurate. Previous methods for increasing the likelihood of sufficient sampling involve acquisition of unfeasibly large amounts of light curve data, which binds valuable sensor resources to focus on one object for long periods of time. In this paper, observability is defined for the shape inversion problem from light curve measurements with a diffuse reflection model. This opens the horizon for efficient and effective object characterization on a routine basis within a sensor network, thus making dedicated, several night-long observations of one object for characterization obsolete. A realistic orbit and attitude motion are implemented to determine whether supplied light curve measurements of an Atlas V upper stage are sufficient for light curve inversion.
PubDate: 2022-02-24
DOI: 10.1007/s40295-021-00293-w

• Deep-Space Optical Navigation Exploiting Multiple Beacons

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Abstract: Abstract Ground facilities relying on traditional radiometric tracking are reaching saturation due to the growth of satellites launched into space. As such, autonomous navigation is one of the main enabling technologies for sustainable deep-space missions. This paper tackles the deep-space optical navigation problem exploiting multiple beacons to estimate the observer position independently from ground. The paper derives the least-squares solution and the analytical covariance to the deep-space navigation problem exploiting multiple beacons. The perturbations in the line-of-sight directions as well as in the objects ephemeris are incorporated into the covariance formulation. Then, the geometrical interpretation of the perturbations models, the navigation solution, and the navigation covariance are elaborated. The sensitivity of the navigation accuracy to the number of beacons is assessed by virtue of a test case, showing the correspondence between the numerical and the analytical solutions. Eventually, the paper shows the comparison of the navigation accuracy exploiting multiple beacons against two optimal beacons.
PubDate: 2022-02-23
DOI: 10.1007/s40295-022-00303-5

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