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  Subjects -> AERONAUTICS AND SPACE FLIGHT (Total: 124 journals)
Showing 1 - 30 of 30 Journals sorted alphabetically
Acta Astronautica     Hybrid Journal   (Followers: 220)
Advances in Aerospace Engineering     Open Access   (Followers: 74)
Advances in Aerospace Science and Technology     Open Access   (Followers: 14)
Advances in Astronautics Science and Technology     Hybrid Journal   (Followers: 2)
Advances in Space Research     Hybrid Journal   (Followers: 295)
Aeronautical Journal, The     Hybrid Journal   (Followers: 9)
Aerospace     Open Access   (Followers: 64)
Aerospace Medicine and Human Performance     Full-text available via subscription   (Followers: 22)
Aerospace Science and Technology     Hybrid Journal   (Followers: 305)
Aerospace Systems     Hybrid Journal   (Followers: 10)
Aerospace technic and technology     Open Access   (Followers: 7)
Aerotecnica Missili & Spazio : Journal of Aerospace Science, Technologies & Systems     Hybrid Journal   (Followers: 6)
AIAA Journal     Hybrid Journal   (Followers: 1002)
Air Medical Journal     Hybrid Journal   (Followers: 6)
Aircraft Engineering and Aerospace Technology     Hybrid Journal   (Followers: 139)
Artificial Satellites     Open Access   (Followers: 21)
ASTRA Proceedings     Open Access   (Followers: 3)
Astrodynamics     Hybrid Journal   (Followers: 4)
Aviation     Open Access   (Followers: 12)
Aviation in Focus - Journal of Aeronautical Sciences     Open Access   (Followers: 7)
Aviation Psychology and Applied Human Factors     Hybrid Journal   (Followers: 23)
Aviation Week     Full-text available via subscription   (Followers: 410)
Canadian Aeronautics and Space Journal     Full-text available via subscription   (Followers: 31)
CEAS Aeronautical Journal     Hybrid Journal   (Followers: 30)
Chinese Journal of Aeronautics     Open Access   (Followers: 19)
Ciencia y Poder Aéreo     Open Access   (Followers: 3)
Civil Aviation High Technologies     Open Access   (Followers: 6)
Control Systems     Hybrid Journal   (Followers: 235)
Cosmic Research     Hybrid Journal   (Followers: 5)
Egyptian Journal of Remote Sensing and Space Science     Open Access   (Followers: 25)
Fatigue of Aircraft Structures     Open Access   (Followers: 21)
Frontiers in Aerospace Engineering     Open Access   (Followers: 20)
Frontiers in Astronomy and Space Sciences     Open Access   (Followers: 15)
Gyroscopy and Navigation     Hybrid Journal   (Followers: 177)
IEEE Aerospace and Electronic Systems Magazine     Full-text available via subscription   (Followers: 251)
IEEE Journal on Miniaturization for Air and Space Systems     Hybrid Journal   (Followers: 2)
IEEE Transactions on Aerospace and Electronic Systems     Hybrid Journal   (Followers: 280)
IEEE Transactions on Circuits and Systems I: Regular Papers     Hybrid Journal   (Followers: 43)
International Journal of Aeroacoustics     Hybrid Journal   (Followers: 37)
International Journal of Aerodynamics     Hybrid Journal   (Followers: 46)
International Journal of Aeronautical and Space Sciences     Hybrid Journal   (Followers: 4)
International Journal of Aerospace Engineering     Open Access   (Followers: 86)
International Journal of Aerospace Innovations     Full-text available via subscription   (Followers: 23)
International Journal of Aerospace Psychology     Hybrid Journal   (Followers: 22)
International Journal of Aerospace Sciences     Open Access   (Followers: 36)
International Journal of Applied Geospatial Research     Hybrid Journal   (Followers: 7)
International Journal of Aviation Management     Hybrid Journal   (Followers: 5)
International Journal of Aviation Technology, Engineering and Management     Full-text available via subscription   (Followers: 8)
International Journal of Aviation, Aeronautics, and Aerospace     Open Access   (Followers: 9)
International Journal of Crashworthiness     Hybrid Journal   (Followers: 10)
International Journal of Micro Air Vehicles     Open Access   (Followers: 11)
International Journal of Satellite Communications Policy and Management     Hybrid Journal   (Followers: 15)
International Journal of Space Science and Engineering     Hybrid Journal   (Followers: 13)
International Journal of Space Structures     Full-text available via subscription   (Followers: 19)
International Journal of Space Technology Management and Innovation     Full-text available via subscription   (Followers: 11)
International Journal of Sustainable Aviation     Hybrid Journal   (Followers: 5)
Investigación Pecuaria     Open Access   (Followers: 1)
Journal of Aerodynamics     Open Access   (Followers: 27)
Journal of Aeronautical Materials     Open Access   (Followers: 10)
Journal of Aerospace Engineering     Full-text available via subscription   (Followers: 66)
Journal of Aerospace Engineering & Technology     Full-text available via subscription   (Followers: 22)
Journal of Aerospace Information Systems     Hybrid Journal   (Followers: 27)
Journal of Aerospace Information Systems     Hybrid Journal   (Followers: 57)
Journal of Aerospace Technology and Management     Open Access   (Followers: 10)
Journal of Aircraft     Hybrid Journal   (Followers: 261)
Journal of Aircraft and Spacecraft Technology     Open Access   (Followers: 15)
Journal of Airline and Airport Management     Open Access   (Followers: 11)
Journal of Astrobiology & Outreach     Open Access   (Followers: 5)
Journal of Aviation Technology and Engineering     Open Access   (Followers: 10)
Journal of Aviation/Aerospace Education & Research     Open Access   (Followers: 2)
Journal of Engineering and Technological Sciences     Open Access   (Followers: 2)
Journal of Guidance, Control, and Dynamics     Hybrid Journal   (Followers: 165)
Journal of KONBiN     Open Access   (Followers: 4)
Journal of Navigation     Hybrid Journal   (Followers: 176)
Journal of Propulsion and Power     Hybrid Journal   (Followers: 569)
Journal of Space Safety Engineering     Hybrid Journal   (Followers: 8)
Journal of Space Weather and Space Climate     Open Access   (Followers: 30)
Journal of Spacecraft and Rockets     Hybrid Journal   (Followers: 702)
Journal of Spatial Science     Hybrid Journal   (Followers: 4)
Journal of the American Helicopter Society     Full-text available via subscription   (Followers: 9)
Journal of the Astronautical Sciences     Hybrid Journal   (Followers: 11)
Journal of the Australasian Society of Aerospace Medicine     Open Access   (Followers: 3)
Journal of Wind Engineering and Industrial Aerodynamics     Hybrid Journal   (Followers: 21)
Life Sciences in Space Research     Hybrid Journal   (Followers: 5)
MAD - Magazine of Aviation Development     Open Access   (Followers: 3)
Mekanika : Jurnal Teknik Mesin i     Open Access  
Microgravity Science and Technology     Hybrid Journal   (Followers: 3)
New Space     Hybrid Journal   (Followers: 6)
Nonlinear Dynamics     Hybrid Journal   (Followers: 19)
npj Microgravity     Open Access   (Followers: 3)
Open Aerospace Engineering Journal     Open Access   (Followers: 4)
Perspectives of Earth and Space Scientists i     Open Access   (Followers: 1)
Population Space and Place     Hybrid Journal   (Followers: 10)
Problemy Mechatroniki. Uzbrojenie, lotnictwo, inżynieria bezpieczeństwa / Problems of Mechatronics. Armament, Aviation, Safety Engineering     Open Access   (Followers: 3)
Proceedings of the Human Factors and Ergonomics Society Annual Meeting     Hybrid Journal   (Followers: 16)
Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering     Hybrid Journal   (Followers: 42)
Progress in Aerospace Sciences     Full-text available via subscription   (Followers: 82)
Propulsion and Power Research     Open Access   (Followers: 89)
REACH - Reviews in Human Space Exploration     Full-text available via subscription   (Followers: 5)
Research & Reviews : Journal of Space Science & Technology     Full-text available via subscription   (Followers: 20)
RocketSTEM     Free   (Followers: 5)
Russian Aeronautics (Iz VUZ)     Hybrid Journal   (Followers: 23)
Science and Education : Scientific Publication of BMSTU     Open Access   (Followers: 1)
Space and Polity     Hybrid Journal   (Followers: 6)
Space Policy     Hybrid Journal   (Followers: 30)
Space Research Today     Full-text available via subscription   (Followers: 43)
Space Safety Magazine     Free   (Followers: 50)
Space Science International     Open Access   (Followers: 117)
Space Science Reviews     Hybrid Journal   (Followers: 92)
SpaceNews     Free   (Followers: 778)
Spatial Information Research     Hybrid Journal   (Followers: 1)
Transactions on Aerospace Research     Open Access   (Followers: 1)
Transport and Aerospace Engineering     Open Access   (Followers: 4)
Transportmetrica A : Transport Science     Hybrid Journal   (Followers: 7)
Unmanned Systems     Hybrid Journal   (Followers: 4)
Xibei Gongye Daxue Xuebao / Journal of Northwestern Polytechnical University     Open Access  
Вісник Національного Авіаційного Університету     Open Access   (Followers: 1)

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Journal Cover
Astrodynamics
Number of Followers: 4  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 2522-008X - ISSN (Online) 2522-0098
Published by Springer-Verlag Homepage  [2469 journals]
  • Non-cooperative spacecraft proximity control considering target behavior
           uncertainty

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      Abstract: Abstract The significant characteristics of space non-cooperative targets include the uncertainties of dynamic parameters and behaviors. Herein, a hybrid proximity control strategy adapted to the behavior uncertainty of a non-cooperative target is presented. First, the relative motion dynamics between the chaser and target is established in the geocentric inertial coordinate system and transcribed based on the chaser spacecraft body coordinate system. Subsequently, to facilitate proximity control under uncertain conditions, an extended state observer is designed to estimate and compensate for the total uncertainty in the relative motion dynamics. Finally, an event-triggered sliding mode control law is designed to track the target with behavior uncertainty and realize synchronization. Numerical simulations demonstrate the effectiveness of the proposed proximity control strategy for both tumbling and maneuvering targets.
      PubDate: 2022-05-11
       
  • Geophysical and orbital environments of asteroid 469219 2016 HO3

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      Abstract: Abstract Asteroid 469219 Kamo’oalewa, also named 2016 HO3, is a small-size fast-rotating near-Earth asteroid, which is a potential target for future explorations. Owing to its weak gravity and fast spin rate, the dynamics on the surface or in the vicinity of 2016 HO3 are significantly different from those of planets or other small bodies explored in previous missions. In this study, the geophysical and orbital environments of 2016 HO3 were investigated to facilitate a potential mission design. First, the geometric and geopotential topographies of 2016 HO3 were examined using different shape models. The lift-off and escape conditions on its fast-rotating surface were investigated. Then, the periodic orbits around 2016 HO3 were studied in the asteroid-fixed frame and the Sun—asteroid frame considering the solar radiation pressure. The stable regions of the terminator orbits were discussed using different parameters. Finally, the influence of the nonspherical shape on the terminator orbits was examined. The precise terminator orbits around a real shape model of 2016 HO3 were obtained and verified in the high-fidelity model. This study shows that the polar region of 2016 HO3 is the primary region for landing or sampling, and the terminator orbits are well suited for global mapping and measurements of 2016 HO3. The analysis and methods can also serve as references for the exploration of other small fast-rotating bodies.
      PubDate: 2022-05-04
       
  • Rapid accessibility evaluation for ballistic lunar capture via manifolds:
           A Gaussian process regression application

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      Abstract: Abstract In this study, a supervised machine learning approach called Gaussian process regression (GPR) was applied to approximate optimal bi-impulse rendezvous maneuvers in the cis-lunar space. We demonstrate the use of the GPR approximation of the optimal bi-impulse transfer to patch points associated with various invariant manifolds in the cis-lunar space. The proposed method advances preliminary mission design operations by avoiding the computational costs associated with repeated solutions of the optimal bi-impulsive Lambert transfer because the learned map is computationally efficient. This approach promises to be useful for aiding in preliminary mission design. The use of invariant manifolds as part of the transfer trajectory design offers unique features for reducing propellant consumption while facilitating the solution of trajectory optimization problems. Long ballistic capture coasts are also very attractive for mission guidance, navigation, and control robustness. A multi-input single-output GPR model is presented to represent the fuel costs (in terms of the ΔV magnitude) associated with the class of orbital transfers of interest efficiently. The developed model is also proven to provide efficient approximations. The multi-resolution use of local GPRs over smaller sub-domains and their use for constructing a global GPR model are also demonstrated. One of the unique features of GPRs is that they provide an estimate of the quality of approximations in the form of covariance, which is proven to provide statistical consistency with the optimal trajectories generated through the approximation process. The numerical results demonstrate our basis for optimism for the utility of the proposed method.
      PubDate: 2022-04-19
       
  • Real-time space object tracklet extraction from telescope survey images
           with machine learning

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      Abstract: Abstract In this study, a novel approach based on the U-Net deep neural network for image segmentation is leveraged for real-time extraction of tracklets from optical acquisitions. As in all machine learning (ML) applications, a series of steps is required for a working pipeline: dataset creation, preprocessing, training, testing, and post-processing to refine the trained network output. Online websites usually lack ready-to-use datasets; thus, an in-house application artificially generates 360 labeled images. Particularly, this software tool produces synthetic night-sky shots of transiting objects over a specified location and the corresponding labels: dual-tone pictures with black backgrounds and white tracklets. Second, both images and labels are downscaled in resolution and normalized to accelerate the training phase. To assess the network performance, a set of both synthetic and real images was inputted. After the preprocessing phase, real images were fine-tuned for vignette reduction and background brightness uniformity. Additionally, they are down-converted to eight bits. Once the network outputs labels, post-processing identifies the centroid right ascension and declination of the object. The average processing time per real image is less than 1.2 s; bright tracklets are easily detected with a mean centroid angular error of 0.25 deg in 75% of test cases with a 2 deg field-of-view telescope. These results prove that an ML-based method can be considered a valid choice when dealing with trail reconstruction, leading to acceptable accuracy for a fast image processing pipeline.
      PubDate: 2022-04-13
       
  • A review of space-object collision probability computation methods

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      Abstract: Abstract The collision probability computation of space objects plays an important role in space situational awareness, particularly for conjunction assessment and collision avoidance. Early works mainly relied on Monte Carlo simulations to predict collision probabilities. Although such simulations are accurate when a large number of samples are used, these methods are perceived as computationally intensive, which limits their application in practice. To overcome this limitation, many approximation methods have been developed over the past three decades. This paper presents a comprehensive review of existing space-object collision probability computation methods. The advantages and limitations of different methods are analyzed and a systematic comparison is presented. Advice regarding how to select a suitable method for different short-term encounter scenarios is then provided. Additionally, potential future research avenues are discussed.
      PubDate: 2022-04-05
       
  • Measuring the mechanical properties of small body regolith layers using a
           granular penetrometer

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      Abstract: Abstract Small bodies in the solar system are known to be covered by a layer of loose unconsolidated soil composed of grains ranging from dusty sands to rugged boulders. Various geophysical processes have modified these regolith layers since their origin. Therefore, the landforms on regolith-blanketed surfaces hold vital clues for reconstructing the geological processes occurring on small bodies. However, the mechanical strength of small body regolith remains unclear, which is an important parameter for understanding its dynamic evolution. Furthermore, regolith mechanical properties are key factors for the design and operation of space missions that interact with small body surfaces. The granular penetrometer, which is an instrument that facilitates in situ mechanical characterization of surface/subsurface materials, has attracted significant attention. However, we still do not fully understand the penetration dynamics related to granular regolith, partially because of the experimental difficulties in measuring grain-scale responses under microgravity, particularly on the longer timescales of small body dynamics. In this study, we analyzed the slow intrusion of a locomotor into granular matter through large-scale numerical simulations based on a soft sphere discrete element model. We demonstrated that the resistance force of cohesionless regolith increases abruptly with penetration depth after contact and then transitions to a linear regime. The scale factor of the steady-state component is roughly proportional to the internal friction of the granular materials, which allows us to deduce the shear strength of planetary soils by measuring their force-depth relationships. When cohesion is included, due to the brittle behavior of cohesive materials, the resistance profile is characterized by a stationary state at a large penetration depth. The saturation resistance, which represents the failure threshold of granular materials, increases with the cohesion strength of the regolith. This positive correlation provides a reliable tool for measuring the tensile strength of granular regolith in small body touchdown missions.
      PubDate: 2022-04-02
       
  • Resonant orbit search and stability analysis for elongated asteroids

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      Abstract: Abstract Periodic orbits are crucial in facilitating the understanding of the dynamical behavior of elongated asteroids. As a specific type of periodic orbit, resonant orbits can enrich the orbit design method of deep-space exploration missions. Herein, a dipole segment model for investigating the orbital dynamics of elongated asteroids is briefly introduced. A new numerical algorithm named the modified path searching method for identifying spin-orbit resonant orbits is proposed. Using the modified path searching and pseudo-arclength continuation methods, four spin-orbit resonant families for asteroid 2063 Bacchus are obtained. The distribution of eigenvalues and stability curves for the four resonant families are presented. In particular, some critical points corresponding to period-doubling and tangent bifurcations appear in the stability curves.
      PubDate: 2022-03-29
       
  • Co-orbital transition of 2016 HO3

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      Abstract: Abstract In this paper, we investigate the orbital behavior of the transition between the quasisatellite (QS) and horseshoe (HS) motions of 2016 HO3. Based on the phase space structure in the Sun–Earth circular restricted three-body problem, we find that the surface of 2016 HO3 in the torus space is a compound surface formed by QS and HS portions. Its co-orbital motion is therefore a QS–HS transition. 2016 HO3 is currently located in a QS state, and its locus clings to the QS portion in the isosurface in agreement with the semi-analytical results. We provide a criterion to separate the QS and HS stages in the transition and obtain accurate incoming and outgoing epochs of the QS motion. We then propose an approximate curve to describe the locus of 2016 HO3 in the ω − e projection. Virtual asteroids (VAs) near 2016 HO3 in the isosurface were created to study the influence of the initial state of the QS–HS transition. We find that the duration of the QS state is mainly influenced by the loci in the ω − e projection. The VAs with large QS durations usually have longer loci across the QS region than those with shorter durations. In addition, although some VAs are close to 2016 HO3 in the ω − e projection, their co-orbital behaviors are significantly different from that of the latter. This indicates that the QS–HS transition of 2016 HO3 is sensitive to the (ω, e) position.
      PubDate: 2022-03-08
       
  • Calculating collision probability for long-term satellite encounters
           through the reachable domain method

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      Abstract: Abstract Satellite encounters during close operations, such as rendezvous, formation, and cluster flights, are typical long-term encounters. The collision probability in such an encounter is a primary safety concern. In this study, a parametric method is proposed to compute the long-term collision probability for close satellite operations with initial state uncertainty. Random relative state errors resulting from system uncertainty lead to possible deviated trajectories with respect to the nominal one. To describe such a random event meaningfully, each deviated trajectory sample should be mapped to a unique and time-independent element in a random variable (RV) space. In this study, the RV space was identified as the transformed state space at a fixed initial time. The physical dimensions of both satellites were characterized by a combined hard-body sphere. Transforming the combined hard-body sphere into the RV space yielded a derived ellipsoid, which evolved over time and swept out a derived collision volume. The derived collision volume was solved using the reachable domain method. Finally, the collision probability was computed by integrating a probability density function over the derived collision volume. The results of the proposed method were compared with those of a nonparametric computation-intensive Monte Carlo method. The relative difference between the two results was found to be < 0.6%, verifying the accuracy of the proposed method.
      PubDate: 2022-03-08
       
  • Message from the Guest Editors of the Special Issue on Entry, Descent, and
           Landing of Tianwen-1—China’s First Mission to Mars

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      PubDate: 2022-03-01
      DOI: 10.1007/s42064-021-0129-6
       
  • Tianwen-1 Mars entry vehicle trajectory and atmosphere reconstruction
           preliminary analysis

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      Abstract: Abstract The Tianwen-1 Mars entry vehicle successfully landed on the surface of Mars in southern Utopia Planitia on May 15, 2021, at 7:18 (UTC+8). To acquire valuable Martian flight data, a scientific instrumentation package consisting of a flush air data system and a multilayer temperature-sensing system was installed aboard the entry vehicle. A combined approach was applied in the entry, descent, and landing trajectory reconstruction using all available data obtained by the inertial measurement unit and the flush air data system. An aerodynamic database covering the entire flight regime was generated using computational fluid dynamics methods to assist in the reconstruction process. A preliminary analysis of the trajectory reconstruction result, along with the atmosphere reconstruction and aerodynamic performance, was conducted. The results show that the trajectory agrees closely with the nominal trajectory and the wind-relative attitude. Suspected wind occurred at the end of the trajectory.
      PubDate: 2022-03-01
      DOI: 10.1007/s42064-021-0116-y
       
  • Aerodynamic design, analysis, and validation techniques for the Tianwen-1
           entry module

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      Abstract: Abstract The clear differences between the atmosphere of Mars and the Earth coupled with the lack of a domestic research basis were significant challenges for the aerodynamic prediction and verification of Tianwen-1. In addition, the Mars entry, descent, and landing (EDL) mission led to specific requirements for the accuracy of the aerodynamic deceleration performance, stability, aerothermal heating, and various complex aerodynamic coupling problems of the entry module. This study analyzes the key and difficult aerodynamic and aerothermodynamic problems related to the Mars EDL process. Then, the study process and results of the design and optimization of the entry module configuration are presented along with the calculations and experiments used to obtain the aerodynamic and aerothermodynamic characteristics in the Martian atmosphere. In addition, the simulation and verification of the low-frequency free oscillation characteristics under a large separation flow are described, and some special aerodynamic coupling problems such as the aeroelastic buffeting response of the trim tab are discussed. Finally, the atmospheric parameters and aerodynamic characteristics obtained from the flight data of the Tianwen-1 entry module are compared with the design data. The data obtained from the aerodynamic design, analysis, and verification of the Tianwen-1 entry module all meet the engineering requirements. In particular, the flight data results for the atmospheric parameters, trim angles of attack, and trim axial forces are within the envelopes of the prediction deviation zones.
      PubDate: 2022-03-01
      DOI: 10.1007/s42064-021-0123-z
       
  • Landing site positioning and descent trajectory reconstruction of
           Tianwen-1 on Mars

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      Abstract: Abstract Tianwen-1 (TW-1) is the first Chinese interplanetary mission to have accomplished orbiting, landing, and patrolling in a single exploration of Mars. After safe landing, it is essential to reconstruct the descent trajectory and determine the landing site of the lander. For this purpose, we processed descent images of the TW-1 optical obstacle-avoidance sensor (OOAS) and digital orthophoto map (DOM) of the landing area using our proposed hybrid-matching method, in which the landing process is divided into two parts. In the first, crater matching is used to obtain the geometric transformations between the OOAS images and DOM to calculate the position of the lander. In the second, feature matching is applied to compute the position of the lander. We calculated the landing site of TW-1 to be 109.9259° E, 25.0659° N with a positional accuracy of 1.56 m and reconstructed the landing trajectory with a horizontal root mean squared error of 1.79 m. These results will facilitate the analyses of the obstacle-avoidance system and optimize the control strategy in the follow-up planetary-exploration missions.
      PubDate: 2022-03-01
      DOI: 10.1007/s42064-021-0121-1
       
  • Powered-descent landing GNC system design and flight results for Tianwen-1
           mission

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      Abstract: Abstract The powered-descent landing (PDL) phase of the Tianwen-1 mission began with composite backshell—parachute (CBP) separation and ended with landing-rover touchdown. The main tasks of this phase were to reduce the velocity of the lander, perform the avoidance maneuver, and guarantee a soft touchdown. The PDL phase overcame many challenges: performing the divert maneuver to avoid collision with the CBP while simultaneously avoiding large-scale hazards; slowing the descent from approximately 95 to 0 m/s; performing the precise hazard-avoidance maneuver; and placing the lander gently and safely on the surface of Mars. The architecture and algorithms of the guidance, navigation, and control system for the PDL phase were designed; its execution resulted in Tianwen-1’s successful touchdown in the morning of 15 May 2021. Consequently, the Tianwen-1 mission achieved a historic autonomous landing with simultaneous hazard and CBP avoidance.
      PubDate: 2022-03-01
      DOI: 10.1007/s42064-021-0118-9
       
  • Entry vehicle control system design for the Tianwen-1 mission

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      Abstract: Abstract The entry vehicle for the Tianwen-1 mission successfully landed on the surface of Mars at 7:18 AM BJT on May 15, 2021. This successful landing made China the first country to orbit, land, and release a rover in their first attempt at the Mars exploration. The guidance, navigation, and control (GNC) system plays a crucial role in the entry, descent, and landing (EDL) phases. This study focused on the attitude control component of the GNC system design. The EDL phase can be divided into several sub-phases, namely the angle of attack control phase, lift control phase, parachute descent phase, and powered descent phase. Each sub-phase has unique attitude control requirements and challenges. This paper introduces the key aspects of designing attitude controllers for each phase. Furthermore, flight results are presented and analyzed.
      PubDate: 2022-03-01
      DOI: 10.1007/s42064-021-0124-y
       
  • End-to-end Mars entry, descent, and landing modeling and simulations for
           Tianwen-1 guidance, navigation, and control system

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      Abstract: Abstract On May 15, 2021, the Tianwen-1 lander successfully touched down on the surface of Mars. To ensure the success of the landing mission, an end-to-end Mars entry, descent, and landing (EDL) simulator is developed to assess the guidance, navigation, and control (GNC) system performance, and determine the critical operation and lander parameters. The high-fidelity models of the Mars atmosphere, parachute, and lander system that are incorporated into the simulator are described. Using the developed simulator, simulations of the Tianwen-1 lander EDL are performed. The results indicate that the simulator is valid, and the GNC system of the Tianwen-1 lander exhibits excellent performance.
      PubDate: 2022-03-01
      DOI: 10.1007/s42064-021-0115-z
       
  • Adaptive entry guidance for the Tianwen-1 mission

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      Abstract: Abstract To meet the requirements of the Tianwen-1 mission, adaptive entry guidance for entry vehicles, with low lift-to-drag ratios, limited control authority, and large initial state bias, was presented. Typically, the entry guidance law is divided into four distinct phases: trim angle-of-attack phase, range control phase, heading alignment phase, and trim-wing deployment phase. In the range control phase, the predictor—corrector guidance algorithm is improved by planning an on-board trajectory based on the Mars Science Laboratory (MSL) entry guidance algorithm. The nominal trajectory was designed and described using a combination of the downrange value and other states, such as drag acceleration and altitude rate. For a large initial state bias, the nominal downrange value was modified onboard by weighing the landing accuracy, control authority, and parachute deployment altitude. The biggest advantage of this approach is that it allows the successful correction of altitude errors and the avoidance of control saturation. An overview of the optimal trajectory design process, including a discussion of the design of the initial flight path angle, relevant event trigger, and transition conditions between the four phases, was also presented. Finally, telemetry data analysis and post-flight assessment results were used to illustrate the adaptive guidance law, create good conditions for subsequent parachute reduction and power reduction processes, and gauge the success of the mission.
      PubDate: 2022-03-01
      DOI: 10.1007/s42064-021-0120-2
       
  • Correction to: Missing Declaration of Competing Interest statements in
           previously published articles

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      Abstract: Declaration of Competing Interest statements were not included in the published versions of the mentioned articles that appeared in the previous issues of Astrodynamics.
      PubDate: 2022-02-11
      DOI: 10.1007/s42064-022-0136-2
       
  • PHiFA—A tool for numerical propagation of high-fidelity
           astrodynamics

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      Abstract: Abstract This paper presents a tool for the numerical propagation of high-fidelity astrodynamics, called PHiFA. The coupled orbit—attitude dynamics for space objects are modeled by considering various types of perturbative forces and torques. Two methods have been implemented to calculate the surface forces: the area matrix method and the beam method. The beam method is more precise as it discretizes the source media (e.g., sunlight and aerodynamic wind) and the surface of the target into multiple rays and finite elements, respectively, and then accumulates the effect of each hit. The PHiFA tool was tested and validated using a 3U CubeSat model and the defunct European environment satellite (Envisat) model.
      PubDate: 2022-01-29
      DOI: 10.1007/s42064-021-0113-1
       
  • On the dynamics and control of the Sun-Earth L2 tetrahedral formation

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      Abstract: Abstract The dynamics and control of a tetrahedral spacecraft formation flying in the Sun-Earth L2 region is initiatively studied, based on the circular restricted three-body problem (CR3BP). Driven by the science goal of identifying extra-solar terrestrial planets and the requirement of imaging optics, a conceptional four-spacecraft triangular pyramid configuration has been proposed for the Multiple-spacecraft Exoplanet Aperture sYnthetic INterferometer (MEAYIN) project, China’s first mid-infrared interferometric imaging mission. Although it looked promising from an optical perspective, the configuration has not been verified dynamically. The formation is required to be virtually “rigid”, because its mutual distances and inertial pointing direction must be maintained with very high accuracy during each observation. In this study, the spatial geometrical relationship between the four spacecraft was established by introducing the parameters of lengths, angles, and a reference vector. The first contribution is that a compact set of normalized factors and critical time indices are defined, which can provide a complete description of the drift of the shape and pointing direction of the configuration, caused by the unstable dynamical environment. Five design variables are isolated and analyzed, and their individual impacts on the uncontrolled evolution of the formation are studied. The main results obtained reveal that the dimensions of the rigid configuration allow a free drift for a time period on the order of tens of hours, while the inertial pointing direction will be lost within merely tens of seconds. Therefore, to form a rigid configuration, the control challenge lies in the fact that control efforts are frequently required for each spacecraft in the fleet, owing to the diverging dynamics. As a second contribution, a simple and feasible control algorithm is proposed to maintain the rigidity of the formation configuration. The results indicate that the associated energy cost is merely 0.05 m/s per observation on average.
      PubDate: 2021-11-12
      DOI: 10.1007/s42064-021-0111-3
       
 
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