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  Subjects -> AERONAUTICS AND SPACE FLIGHT (Total: 120 journals)
Showing 1 - 30 of 30 Journals sorted by number of followers
AIAA Journal     Hybrid Journal   (Followers: 1189)
SpaceNews     Free   (Followers: 826)
Journal of Spacecraft and Rockets     Hybrid Journal   (Followers: 771)
Journal of Propulsion and Power     Hybrid Journal   (Followers: 610)
Acta Astronautica     Hybrid Journal   (Followers: 494)
Advances in Space Research     Full-text available via subscription   (Followers: 457)
Aviation Week     Full-text available via subscription   (Followers: 437)
Aerospace Science and Technology     Hybrid Journal   (Followers: 427)
IEEE Transactions on Aerospace and Electronic Systems     Hybrid Journal   (Followers: 383)
Journal of Aircraft     Hybrid Journal   (Followers: 335)
Control Systems     Hybrid Journal   (Followers: 313)
IEEE Aerospace and Electronic Systems Magazine     Full-text available via subscription   (Followers: 279)
Journal of Navigation     Hybrid Journal   (Followers: 277)
Aircraft Engineering and Aerospace Technology     Hybrid Journal   (Followers: 261)
Gyroscopy and Navigation     Hybrid Journal   (Followers: 258)
Journal of Guidance, Control, and Dynamics     Hybrid Journal   (Followers: 204)
Space Science International     Open Access   (Followers: 199)
Space Science Reviews     Hybrid Journal   (Followers: 97)
International Journal of Aerospace Engineering     Open Access   (Followers: 82)
Progress in Aerospace Sciences     Full-text available via subscription   (Followers: 80)
Advances in Aerospace Engineering     Open Access   (Followers: 69)
Journal of Aerospace Engineering     Full-text available via subscription   (Followers: 69)
Propulsion and Power Research     Open Access   (Followers: 68)
Aerospace     Open Access   (Followers: 60)
Space Safety Magazine     Free   (Followers: 51)
Space Research Today     Full-text available via subscription   (Followers: 48)
Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering     Hybrid Journal   (Followers: 46)
International Journal of Aeroacoustics     Hybrid Journal   (Followers: 40)
IEEE Transactions on Circuits and Systems I: Regular Papers     Hybrid Journal   (Followers: 39)
International Journal of Aerodynamics     Hybrid Journal   (Followers: 37)
Canadian Aeronautics and Space Journal     Full-text available via subscription   (Followers: 34)
Journal of Aerospace Information Systems     Hybrid Journal   (Followers: 34)
International Journal of Aerospace Sciences     Open Access   (Followers: 32)
Journal of Aeronautics & Aerospace Engineering     Open Access   (Followers: 31)
Space Policy     Hybrid Journal   (Followers: 30)
CEAS Aeronautical Journal     Hybrid Journal   (Followers: 29)
Journal of Space Weather and Space Climate     Open Access   (Followers: 27)
Aviation Psychology and Applied Human Factors     Hybrid Journal   (Followers: 27)
Russian Aeronautics (Iz VUZ)     Hybrid Journal   (Followers: 24)
Egyptian Journal of Remote Sensing and Space Science     Open Access   (Followers: 24)
Artificial Satellites     Open Access   (Followers: 23)
International Journal of Aerospace Psychology     Hybrid Journal   (Followers: 23)
Journal of Aerospace Information Systems     Hybrid Journal   (Followers: 22)
Annual of Navigation     Open Access   (Followers: 22)
Chinese Journal of Aeronautics     Open Access   (Followers: 21)
Nonlinear Dynamics     Hybrid Journal   (Followers: 20)
Aerospace Medicine and Human Performance     Full-text available via subscription   (Followers: 19)
Journal of Aerospace Engineering & Technology     Full-text available via subscription   (Followers: 18)
Journal of Aerodynamics     Open Access   (Followers: 18)
Aerospace Scientific Journal     Open Access   (Followers: 18)
Journal of Wind Engineering and Industrial Aerodynamics     Hybrid Journal   (Followers: 17)
Aviation     Open Access   (Followers: 17)
International Journal of Space Structures     Full-text available via subscription   (Followers: 17)
Research & Reviews : Journal of Space Science & Technology     Full-text available via subscription   (Followers: 17)
Proceedings of the Human Factors and Ergonomics Society Annual Meeting     Hybrid Journal   (Followers: 16)
Fatigue of Aircraft Structures     Open Access   (Followers: 15)
International Journal of Satellite Communications Policy and Management     Hybrid Journal   (Followers: 13)
Frontiers in Astronomy and Space Sciences     Open Access   (Followers: 12)
Elsevier Astrodynamics Series     Full-text available via subscription   (Followers: 12)
Aeronautical Journal, The     Hybrid Journal   (Followers: 12)
International Journal of Crashworthiness     Hybrid Journal   (Followers: 12)
Journal of Airline and Airport Management     Open Access   (Followers: 12)
International Journal of Micro Air Vehicles     Full-text available via subscription   (Followers: 11)
Journal of Aviation Technology and Engineering     Open Access   (Followers: 11)
International Journal of Space Science and Engineering     Hybrid Journal   (Followers: 11)
Air Force Magazine     Full-text available via subscription   (Followers: 11)
COSPAR Colloquia Series     Full-text available via subscription   (Followers: 11)
International Journal of Space Technology Management and Innovation     Full-text available via subscription   (Followers: 10)
Aviation in Focus - Journal of Aeronautical Sciences     Open Access   (Followers: 10)
Journal of Aircraft and Spacecraft Technology     Open Access   (Followers: 9)
Population Space and Place     Hybrid Journal   (Followers: 9)
Journal of Aeronautical Materials     Open Access   (Followers: 9)
International Journal of Aviation Management     Hybrid Journal   (Followers: 9)
Transportmetrica A : Transport Science     Hybrid Journal   (Followers: 9)
Journal of the Astronautical Sciences     Hybrid Journal   (Followers: 9)
Advances in Aerospace Science and Technology     Open Access   (Followers: 8)
Air Medical Journal     Hybrid Journal   (Followers: 8)
Journal of Space Safety Engineering     Hybrid Journal   (Followers: 8)
International Journal of Aviation Technology, Engineering and Management     Full-text available via subscription   (Followers: 7)
Journal of the American Helicopter Society     Full-text available via subscription   (Followers: 7)
Journal of Aerospace Technology and Management     Open Access   (Followers: 7)
International Journal of Applied Geospatial Research     Hybrid Journal   (Followers: 7)
New Space     Hybrid Journal   (Followers: 6)
Aerospace Systems     Hybrid Journal   (Followers: 6)
International Journal of Turbo and Jet-Engines     Hybrid Journal   (Followers: 6)
RocketSTEM     Free   (Followers: 6)
Civil Aviation High Technologies     Open Access   (Followers: 5)
International Journal of Aviation, Aeronautics, and Aerospace     Open Access   (Followers: 5)
REACH - Reviews in Human Space Exploration     Full-text available via subscription   (Followers: 5)
International Journal of Sustainable Aviation     Hybrid Journal   (Followers: 5)
Aviation Advances & Maintenance     Open Access   (Followers: 5)
Cosmic Research     Hybrid Journal   (Followers: 5)
Unmanned Systems     Hybrid Journal   (Followers: 5)
Space and Polity     Hybrid Journal   (Followers: 4)
Life Sciences in Space Research     Hybrid Journal   (Followers: 4)
Aerotecnica Missili & Spazio : Journal of Aerospace Science, Technologies & Systems     Hybrid Journal   (Followers: 4)
Astrodynamics     Hybrid Journal   (Followers: 4)
Investigación Pecuaria     Open Access   (Followers: 3)
Aerospace technic and technology     Open Access   (Followers: 3)
Journal of Spatial Science     Hybrid Journal   (Followers: 3)
ASTRA Proceedings     Open Access   (Followers: 3)
Journal of KONBiN     Open Access   (Followers: 3)
Problemy Mechatroniki. Uzbrojenie, lotnictwo, inżynieria bezpieczeństwa / Problems of Mechatronics. Armament, Aviation, Safety Engineering     Open Access   (Followers: 3)
npj Microgravity     Open Access   (Followers: 3)
Journal of Astrobiology & Outreach     Open Access   (Followers: 3)
Journal of Aviation/Aerospace Education & Research     Open Access   (Followers: 2)
IEEE Journal on Miniaturization for Air and Space Systems     Hybrid Journal   (Followers: 2)
Microgravity Science and Technology     Hybrid Journal   (Followers: 2)
Вісник Національного Авіаційного Університету     Open Access   (Followers: 2)
International Journal of Aeronautical and Space Sciences     Hybrid Journal   (Followers: 2)
Ciencia y Poder Aéreo     Open Access   (Followers: 2)
MAD - Magazine of Aviation Development     Open Access   (Followers: 2)
Journal of the Australasian Society of Aerospace Medicine     Open Access   (Followers: 1)
Open Aerospace Engineering Journal     Open Access   (Followers: 1)
Advances in Astronautics Science and Technology     Hybrid Journal   (Followers: 1)
Journal of Engineering and Technological Sciences     Open Access   (Followers: 1)
Technical Soaring     Full-text available via subscription   (Followers: 1)
Spatial Information Research     Hybrid Journal   (Followers: 1)
Mekanika : Jurnal Teknik Mesin i     Open Access   (Followers: 1)
Perspectives of Earth and Space Scientists i     Open Access  

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Similar Journals
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  [2653 journals]
  • Jupiter system exploration trajectory design: Summary of the winning
           solution at CTOC10
    • Abstract: This paper presents the methods and results submitted by the winning team from Harbin Institute of Technology of the 10th China Trajectory Optimization Competition (CTOC10). The problem posed by CTOC10 requires exploring the Jupiter system using a combined spacecraft. The exploration mission consists of the detection of Jupiter’s magnetic field and an exploration of the Galilean moons. The mission is completed through three steps: problem analysis, orbital design process, and data processing. The orbital design process is mainly divided into four parts, namely, repeating ground-track orbit design, gravity-assisted orbit design, initial orbit parameter selection, and local optimization adjustment. The designed orbit is then evaluated using a heuristic optimization algorithm applied during the data processing. Finally, six full-coverage observations of Jupiter’s magnetic field are realized under the constraints of fuel and time. The final index of the submitted result is 357.8067.
      PubDate: 2021-03-01
       
  • Dynamical behavior of flexible net spacecraft for landing on asteroid
    • Abstract: A new era of up-close asteroid exploration has been entered in the 21st century. However, the widely rugged terrain and microgravity field of asteroids still pose significant challenges to the stable landing of spacecraft and may even directly lead to the escape of the explorer. Owing to the substantial energy dissipation arising from the interaction among multiple bodies, the flexible net, which is a typical multibody system, may be capable of overcoming the above problems. In this study, a dynamical model was established to analyze the movement of the flexible net spacecraft (FNS) near and on the asteroid comprehensively. First, we investigated the dynamical environment of the target asteroid by combining the polyhedron method and spherical harmonics parametric surface modeling approach. Thereafter, we constructed the multibody dynamics model of the explorer using the linear Kelvin-Voigt method. Subsequently, we studied the collision process between the FNS and asteroid based on the spring-damper contact dynamics model. The trajectory and speed of the FNS could be derived by solving the system dynamic equations in parallel. Finally, we analyzed the deformation, descent, jumping motion, and surface movement process of the FNS during the movement. Consequently, a promising scheme is provided for asteroid exploration missions in the future.
      PubDate: 2021-03-01
       
  • Correction to: Orbit insertion strategy of Hayabusa2’s rover with large
           release uncertainty around the asteroid Ryugu
    • Abstract: The article “Orbit insertion strategy of Hayabusa2’s rover with large release uncertainty around the asteroid Ryugu” written by Yusuke Oki, Kent Yoshikawa, Hiroshi Takeuchi et al., was originally published electronically on the publisher’s internet portal (currently SpringerLink) on 05 November 2020 without open access. After publication in Volume 4, Issue 4, page 309’329, the author(s) decided to opt for Open Choice and to make the article an open access publication. Therefore, the copyright of the article has been changed to © The Author(s) 2020 and the article is forthwith distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits use, duplication, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
      PubDate: 2021-02-10
       
  • Geometrical approach for an optimal inter-satellite visibility
    • Abstract: In the field of satellite constellations, an important requirement is often represented by the possibility to exchange data among the satellites or exploit mutual visibility to carry out measurements on the parameters of the Earth’s atmosphere. Therefore, recursive and routing algorithms are usually implemented to evaluate inter-satellite visibility intervals. However, to design the configuration of the constellation, it is important to consider the orbital conditions that guarantee the mutual visibility between couples of satellites. Thus, in this study, a geometric analysis was performed to identify the optimal inter-satellite visibility conditions, expressed in terms of the difference in the true anomaly between satellites characterized by different orbital configurations. This approach allows a handy constellation design, without performing a numerical analysis. It is particularly useful in the case of a high number of satellites, when numerical techniques require significant computational effort. Therefore, it is possible to considerably simplify the design of a constellation in which the mutual visibility between couples of satellites is always guaranteed. This type of constellation, usually referred to as satellite chain, can be exploited in several network services and remote sensing systems devoted to enhancing the knowledge of atmospheric parameters.
      PubDate: 2021-02-04
       
  • SmallSat swarm gravimetry: Revealing the interior structure of asteroids
           and comets
    • Abstract: A growing interest in small body exploration has motivated research into the rapid characterization of near-Earth objects to meet economic or scientific objectives. Specifically, knowledge of the internal density structure can aid with target selection and enables an understanding of prehistoric planetary formation to be developed. To this end, multi-layer extensions to the polyhedral gravity model are suggested, and an inversion technique is implemented to present their effectiveness. On-orbit gravity gradiometry is simulated and employed in stochastic and deterministic algorithms, with results that imply robustness in both cases.
      PubDate: 2021-02-01
       
  • Trajectory correction for lunar flyby transfers to libration point orbits
           using continuous thrust
    • Abstract: Trajectory corrections for lunar flyby transfers to Sun-Earth/Moon libration point orbits (LPOs) with continuous thrusts are investigated using an ephemeris model. The lunar flyby transfer has special geometrical and dynamical structures; therefore, its trajectory correction strategy is considerably different from that of previous studies and should be specifically designed. In this paper, we first propose a control strategy based on the backstepping technique with a dead-band scheme using an ephemeris model. The initial error caused by the launch time error is considered. Since the perturbed transfers significantly diverge from the reference transfers after the spacecraft passes by the Moon, we adopt two sets of control parameters in two portions before and after the lunar flyby, respectively. Subsequently, practical constraints owing to the navigation and propellant systems are introduced in the dynamical model of the trajectory correction. Using a prograde type 2 orbit as an example, numerical simulations show that our control strategy can efficiently address trajectory corrections for lunar flyby transfers with different practical constraints. In addition, we analyze the effects of the navigation intervals and dead-band scheme on trajectory corrections. Finally, trajectory corrections for different lunar flyby transfers are depicted and compared.
      PubDate: 2021-02-01
       
  • Efficient design techniques for cislunar-space VLBI spacecraft formation
           in GTOC8
    • Abstract: The 8th edition of the Global Trajectory Optimization Competition (GTOC8) presented a novel concept of a space-based very-long-baseline interferometry (VLBI) telescope in cislunar space for observing selected radio sources in cosmos. It requires designing a three-spacecraft triangular formation with changeable sizes and orientations such that observation can be scheduled as efficiently as possible. We first review the problem, and then describe the methods employed by representative teams participating in the competition. Subsequently, we present the design techniques employed by the team from the Chinese Academy of Sciences, which are primarily based on orbital-geometry analysis. Two efficient trajectory patterns are summarized: million-kilometer triangular formations with symmetric circular orbits, and consecutive-lunar-flyby trajectories with Moon-to-Moon transfer orbits. These two trajectory patterns enable establishing and reconfiguring the triangular formation with sufficiently different sizes so that a number of radio sources can be observed, thus maximizing the performance index. Finally, we present a solution with the best currently known score of J = 158 million km.
      PubDate: 2021-01-07
      DOI: 10.1007/s42064-020-0096-3
       
  • Leveraging quasi-periodic orbits for trajectory design in cislunar space
    • Abstract: Incorporating quasi-periodic orbits into the preliminary design process offers a wide range of options to meet mission constraints and address the challenges in a complex trade space. In this investigation, linear stability and quasi-periodic orbit family continuation schemes are examined to meet various types of constraints. Applications in eclipse avoidance and transfer design are examined by leveraging quasi-periodic orbits and their associated hyperbolic manifolds in the lunar region. Solutions are transitioned to an ephemeris model to validate that geometries are maintained in higher-fidelity models. When the natural dynamical structures associated with quasi-periodic orbits are leveraged, novel trajectory solutions can emerge.
      PubDate: 2021-01-07
      DOI: 10.1007/s42064-020-0094-5
       
  • Mars orbit insertion via ballistic capture and aerobraking
    • Abstract: A novel Mars orbit insertion strategy that combines ballistic capture and aerobraking is presented. Mars ballistic capture orbits that neglect the aerodynamics are first generated, and are distilled from properly computed stable and unstable sets by using a pre-established method. A small periapsis maneuver is implemented at the first close encounter to better submit a post-capture orbit to the aerobraking process. An adhoc patching point marks the transition from ballistic capture to aerobraking, from which an exponential model simulating the Martian atmosphere and a box-wing satellite configuration are considered. A series of apoapsis trim maneuvers are then computed by targeting a prescribed pericenter dynamic pressure. The aerobraking duration is then estimated using a simplified two-body model. Yaw angle tuning cancels the inclination deflections owing to out-of-plane perturbation from the Sun. A philosophy combining in-plane and out-of-plane dynamics is proposed to simultaneously achieve the required semi-major axis and inclination. Numerical simulations indicate that the developed method is more efficient in terms of the fuel consumption, insertion safety, and flexibility when compared with other state-of-the-art insertion strategies.
      PubDate: 2021-01-07
      DOI: 10.1007/s42064-020-0095-4
       
  • Integrated constellation design and deployment method for a regional
           augmented navigation satellite system using piggyback launches
    • Abstract: The method proposed in this paper is adopted to solve problem B of the 9th China Trajectory Optimization Competition (CTOC). An accurate and economical constellation design strategy for regional augmented navigation satellite systems (RANSSs) has attracted a substantial amount of research interest owing to the increased demand for navigation services in complex environments. This paper proposes a hybrid method of constellation design and deployment for a RANSS to satisfy the navigation performance requirements and minimize the construction cost. First, the search spaces of the design parameters are determined by analyzing the orbital parameters of piggyback launches. Second, the constellation is designed as a combined Walker constellation and optimized by a differential evolution (DE) algorithm. Finally, optimal strategies for deploying satellites to the desired orbits are obtained using a transfer optimization design. The method was adopted to design a RANSS for servicing the 182 cities in the Asia-Pacific region. The configuration consists of five orbital planes and 80 navigation satellites and achieves a low construction cost with 10 piggyback launches. Furthermore, the constellation can cooperate with an existing navigation satellite system to further improve the navigation accuracy for all cities. The results reveal that the RANSS design and deployment problem can be effectively solved with a low construction cost and high navigation performance.
      PubDate: 2020-12-28
      DOI: 10.1007/s42064-020-0091-8
       
  • Orbit design and mission planning for global observation of Jupiter
    • Abstract: This paper presents the method created by the National University of Defense Technology (NUDT) team in the 10th China Trajectory Optimization Competition, which entails a 3-year observation mission of 180 regions on Jupiter. The proposed method can be divided into three steps. First, a preliminary analysis and evaluation via an analytical method is undertaken to decide whether the third subtask of the mission, i.e., exploring the Galilean moons, should be ignored. Second, a near-optimal orbit for magnetic field observation is designed by solving an analytical equation. Third, a set of observation windows and their sequence are optimized using a customized genetic algorithm. The final index obtained is 354.505, ranking second out of all teams partaking in the competition.
      PubDate: 2020-12-03
      DOI: 10.1007/s42064-020-0090-9
       
  • Spiral trajectories induced by radial thrust with applications to
           generalized sails
    • Abstract: In this study, new analytical solutions to the equations of motion of a propelled spacecraft are investigated using a shape-based approach. There is an assumption that the spacecraft travels a two-dimensional spiral trajectory in which the orbital radius is proportional to an assigned power of the spacecraft angular coordinate. The exact solution to the equations of motion is obtained as a function of time in the case of a purely radial thrust, and the propulsive acceleration magnitude necessary for the spacecraft to track the prescribed spiral trajectory is found in a closed form. The analytical results are then specialized to the case of a generalized sail, that is, a propulsion system capable of providing an outward radial propulsive acceleration, the magnitude of which depends on a given power of the Sun-spacecraft distance. In particular, the conditions for an outward radial thrust and the required sail performance are quantified and thoroughly discussed. It is worth noting that these propulsion systems provide a purely radial thrust when their orientation is Sun-facing. This is an important advantage from an engineering point of view because, depending on the particular propulsion system, a Sun-facing attitude can be stable or obtainable in a passive way. A case study is finally presented, where the generalized sail is assumed to start the spiral trajectory from the Earth’s heliocentric orbit. The main outcome is that the required sail performance is in principle achievable on the basis of many results available in the literature.
      PubDate: 2020-12-02
      DOI: 10.1007/s42064-020-0093-6
       
  • Limits of drag augmentation at spacecraft end-of-mission and a mitigation
           strategy
    • Abstract: An increasing number of objects are being launched into low-Earth orbit. Consequently, to avoid the possibility of future in-orbit collisions space object removal techniques are receiving attention. As one of the most developed techniques, drag augmentation is increasingly being considered as an option for end-of-mission removal of objects from low-Earth orbit. This paper highlights a common misconception around drag augmentation: although it can be used to reduce de-orbit time, when used inappropriately it can increase the volume swept by an object and, thus, increase the occurrence risk of collision with another space object. Knowingly ignoring this increased risk of collisions could leave spacecraft operators, and consequently their responsible state party, open to liability risk. By investigating the volume swept and de-orbit lifetime, a strategy of delayed deployment is proposed as a compromise between reducing volume swept and time to de-orbit. However, this increases system complexity and, likely, cost.
      PubDate: 2020-12-02
      DOI: 10.1007/s42064-020-0092-7
       
  • 10th China Trajectory Optimization Competition: Problem description and
           summary of the results
    • Abstract: From March 20, 2019 to April 30, 2019, the 10th China Trajectory Optimization Competition (CTOC10) was jointly held by the Chinese Society of Theoretical and Applied Mechanics and Nanjing University of Aeronautics and Astronautics. The CTOC10 focused on trajectory optimization for Jovian exploration. The team from Harbin Institute of Technology won the first prize. In this paper, first, the history of the CTOC is presented. Subsequently, the mission of the CTOC10 is introduced, and an account of the final rankings of the competition is given. Finally, trajectory optimization methods are discussed, and suggestions for practical missions are provided.
      PubDate: 2020-11-27
      DOI: 10.1007/s42064-020-0089-2
       
  • Guidance, navigation, and control of Hayabusa2 touchdown operations
    • Abstract: Hayabusa2 is a Japanese sample return mission from the asteroid Ryugu. The Hayabusa2 spacecraft was launched on 3 December 2014 and arrived at Ryugu on 27 June 2018. It stayed there until December 2019 for in situ observation and soil sample collection, and will return to the Earth in November or December 2020. During the stay, the spacecraft performed the first touchdown operation on 22 February 2019 and the second touchdown on 11 July 2019, which were both completed successfully. Because the surface of Ryugu is rough and covered with boulders, it was not easy to find target areas for touchdown. There were several technical challenges to overcome, including demanding guidance, navigation, and control accuracy, to realize the touchdown operation. In this paper, strategies and technical details of the guidance, navigation, and control systems are presented. The flight results prove that the performance of the systems was satisfactory and largely contributed to the success of the operation.
      PubDate: 2020-11-21
      DOI: 10.1007/s42064-020-0086-5
       
  • Ground-based low altitude hovering technique of Hayabusa2
    • Abstract: The asteroid explorer Hayabusa2 carries multiple rovers and separates them to land on an asteroid surface. One of these rovers, called MASCOT, was developed under the international cooperation between the Deutsches Zentrum für Luft- und Raumfahrt and the Centre National d’Etudes Spatiales. This rover was designed to be separated to land and perform several missions on an asteroid surface. To support these missions, the mother ship Hayabusa2 must separate this rover at a low altitude of approximately 50 m and hover at approximately 3 km after separation to achieve are liable communication link with MASCOT. Because the on-board guidance, navigation, and control (GNC) does not have an autonomous hovering function, this hovering operation is performed by ground-based control. This paper introduces the GNC operation scheme for this hovering operation and reports on its flight results.
      PubDate: 2020-11-21
      DOI: 10.1007/s42064-020-0082-9
       
  • Spanning tree trajectory optimization in the galaxy space
    • Abstract: The 10th edition of the Global Trajectory Optimization Competition considered the problem of the galaxy settlement wherein competitors from all over the world were expected to design the trajectories of different settler vessels to maximize the given multi-faceted merit function. The synthesis methods used by the winning team, led jointly by the National University of Defense Technology (NUDT) and Xi’an Satellite Control Center (XSCC), are described along with a greedy search method and the improved solution obtained by University of Jena. Specifically, we presented a layout-first topology-second approach that allows an efficient settlement tree search guided by the pre-specified ideal spatial distribution. We also explained how the problem of constructing settlement trees can be modeled as the widely studied minimum spanning tree problem. Furthermore, University of Jena explored the possibility that a greedy search can generate even better settlement trees, based on the same initial conditions, when compared to that of the winning solution.
      PubDate: 2020-11-13
      DOI: 10.1007/s42064-020-0088-3
       
  • Orbit insertion strategy of Hayabusa2’s rover with large release
           uncertainty around the asteroid Ryugu
    • Abstract: This paper describes the orbit design of the deployable payload Rover 2 of MINERVA-II, installed on the Hayabusa2 spacecraft. Because Rover 2 did not have surface exploration capabilities, the operation team decided to experiment with a new strategy for its deployment to the surface. The rover was ejected at a high altitude and made a semi-hard landing on the surface of the asteroid Ryugu after several orbits. Based on the orbital analysis around Ryugu, the expected collision speed was tolerable for the rover to function post-impact. Because the rover could not control its position, its motion was entirely governed by the initial conditions. Thus, the largest challenge was to insert the rover into a stable orbit (despite its large release uncertainty), and avoid its escape from Ryugu due to an environment strongly perturbed by solar radiation pressure and gravitational irregularities. This study investigates the solution space of the orbit around Ryugu and evaluates the orbit’s robustness by utilizing Monte Carlo simulations to determine the orbit insertion policy. Upon analyzing the flight data of the rover operation, we verified that the rover orbited Ryugu for more than one period and established the possibility of a novel method for estimating the gravity of an asteroid.
      PubDate: 2020-11-05
      DOI: 10.1007/s42064-020-0080-y
       
  • Motion reconstruction of the small carry-on impactor aboard Hayabusa2
    • Abstract: Subsurface exploration is one of the most ambitious scientific objectives of the Hayabusa2 mission. A small device called small carry-on impactor (SCI) was developed to create an artificial crater on the surface of asteroid Ryugu. This enables us to sample subsurface materials, which will provide a window to the past. The physical properties of the resulting crater are also useful for understanding the internal structure of Ryugu. Accurate understanding of the crater and ejecta properties, including the depth of excavation of subsurface materials, requires accurate information on impact conditions. In particular, the impact angle is a critical factor because it greatly influences the size and shape of the crater. On April 5, 2019, the Hayabusa2 spacecraft deployed the SCI at 500 m of altitude above the asteroid surface. The SCI gradually reduced its altitude, and it shot a 2 kg copper projectile into the asteroid 40 min after separation. Estimating the position of the released SCI is essential for determining the impact angle. This study describes the motion reconstruction of the SCI based on the actual operation data. The results indicate that the SCI was released with high accuracy.
      PubDate: 2020-11-02
      DOI: 10.1007/s42064-020-0077-6
       
  • The deep-space multi-object orbit determination system and its application
           to Hayabusa2’s asteroid proximity operations
    • Abstract: The deep-space multi-object orbit determination system (DMOODS) and its application in the asteroid proximity operation of the Hayabusa2 mission are described. DMOODS was developed by the Japan Aerospace Exploration Agency (JAXA) for the primary purpose of determining the trajectory of deep-space spacecraft for JAXA’s planetary missions. The weighted least-squares batch filter is used for the orbit estimator of DMOODS. The orbit estimator supports more than 10 data types, some of which are used for relative trajectory measurements between multiple space objects including natural satellites and small bodies. This system consists of a set of computer programs running on Linux-based consumer PCs on the ground, which are used for orbit determination and the generation of radiometric tracking data, such as delta differential one-way ranging and doppler tracking data. During the asteroid proximity phase of Hayabusa2, this system played an essential role in operations that had very strict navigation requirements or operations in which few optical data were obtained owing to special constraints on the spacecraft attitude or distance from the asteroid. One example is orbit determination during the solar conjunction phase, in which the navigation accuracy is degraded by the effect of the solar corona. The large range bias caused by the solar corona was accurately estimated with DMOODS by combining light detection and ranging (LIDAR) and ranging measurements in the superior solar conjunction phase of Hayabusa2. For the orbiting operations of target markers and the MINERVA-II2 rover, the simultaneous estimation of six trajectories of four artificial objects and a natural object was made by DMOODS. This type of simultaneous orbit determination of multi-artificial objects in deep-space has never been accomplished before.
      PubDate: 2020-10-17
      DOI: 10.1007/s42064-020-0084-7
       
 
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