This paper presents a novel optimal Motion Cueing Algorithm(MCA)to control the rotations of a Human Centrifuge(HC)and achieve the best simulation of a Space Craft(SC)motion.Relations of the specific forces sensed by a...This paper presents a novel optimal Motion Cueing Algorithm(MCA)to control the rotations of a Human Centrifuge(HC)and achieve the best simulation of a Space Craft(SC)motion.Relations of the specific forces sensed by astronauts of the SC and the HC have been derived and linearized.A Linear Quadratic Regulator(LQR)controller is implemented for the problem which tends to minimize the error between the two sensed specific forces as well as control input in a cost function.It results in control inputs of the HC to generate its sensed specific force as close as possible to the one in the SC.The algorithm is implemented for both linearized and nonlinear portions of a US space shuttle mission trajectory as a verification using MATLAB.In longitudinal direction,the proposed MCA,works well when the acceleration is less than 2 g in which the tracking error does not exceed 12%.In lateral direction the tracking is much better even in nonlinear region since the error remains less than 7%for tilting up to 50°.Finally,the effect of weight matrixes in the LQR cost function on overall weight and power of the HC motion system is discussed.展开更多
1 This paper considers Lagrangian finite elements for structural dynamics constructed with cubic displacement shape functions.The method of templates is used to investigate the construction of accurate mass-stiffness ...1 This paper considers Lagrangian finite elements for structural dynamics constructed with cubic displacement shape functions.The method of templates is used to investigate the construction of accurate mass-stiffness pairs.This method introduces free parameters that can be adjusted to customize elements according to accuracy and rank-sufficiency criteria.One-and two-dimensional Lagrangian cubic elements with only translational degrees of freedom(DOF)carry two additional nodes on each side,herein called side nodes or SN.Although usually placed at the third-points,the SN location may be adjusted within geometric limits.The adjustment effect is studied in detail using symbolic computations for a bar element.The best SN location is taken to be that producing accurate approximation to the lowest natural frequencies of the continuum model.Optimality is investigated through Fourier analysis of the propagation of plane waves over a regular infinite lattice of bar elements.Focus is placed on the acoustic branch of the frequency-vs.-wavenumber dispersion diagram.It is found that dispersion results using the fully integrated consistent mass matrix(CMM)are independent of the SN location whereas its lowfrequency accuracy order is O(κ8),whereκis the dimensionless wave number.For the diagonally lumped mass matrix(DLMM)constructed through the HRZ scheme,two optimal SN locations are identified,both away from third-points and of accuracy order O(κ8).That with the smallest error coefficient corresponds to the Lobatto 4-point integration rule.A special linear combination of CMM and DLMM with nodes at the Lobatto points yields an accuracy of O(κ10)without any increase in the computational effort over CMM.The effect of reduced integration(RI)on both mass and stiffness matrices is also studied.It is shown that singular mass matrices can be constructed with 2-and 3-point RI rules that display the same optimal accuracy of the exactly integrated case,at the cost of introducing spurious modes.The optimal SN location in two-dimensional,bicubic,isoparametric plane stress quadrilateral elements is briefly investigated by numerical experiments.The frequency accuracy of flexural modes is found to be fairly insensitive to that position,whereas for bar-like modes it agrees with the one-dimensional results.展开更多
We investigate primal and mixed u−p isogeometric collocation methods for application to nearly-incompressible isotropic elasticity.The primal method employs Navier’s equations in terms of the displacement unknowns,an...We investigate primal and mixed u−p isogeometric collocation methods for application to nearly-incompressible isotropic elasticity.The primal method employs Navier’s equations in terms of the displacement unknowns,and the mixed method employs both displacement and pressure unknowns.As benchmarks for what might be considered acceptable accuracy,we employ constant-pressure Abaqus finite elements that are widely used in engineering applications.As a basis of comparisons,we present results for compressible elasticity.All the methods were completely satisfactory for the compressible case.However,results for low-degree primal methods exhibited displacement locking and in general deteriorated in the nearly-incompressible case.The results for the mixed methods behaved very well for two of the problems we studied,achieving levels of accuracy very similar to those for the compressible case.The third problem,which we consider a“torture test”presented a more complex story for the mixed methods in the nearly-incompressible case.展开更多
Direct numerical simulations (DNS) of non-rotating and rotating turbulent channel flow were conducted. The data base obtained from these DNS simulations was used to investigate the prominent coherent structures involv...Direct numerical simulations (DNS) of non-rotating and rotating turbulent channel flow were conducted. The data base obtained from these DNS simulations was used to investigate the prominent coherent structures involved in the turbulence generation cycle. Predictions from three theoretical models concerning the formation and evolution of sublayer streaks, three-dimensional hairpin vortices and propagating plane waves were validated using visualizations from the present DNS data. Quadrant analysis was used to determine a phase shift between the fluctuating streamwise and wall-normal velocities as a characteristic of turbulence production in the suction region at a low rotation number.展开更多
This paper summarizes a few cases of spacecraft orbital motion around asteroid for which averaging method can be applied, i.e., when central body rotates slowly, fast, and when a spacecraft is near to the resonant orb...This paper summarizes a few cases of spacecraft orbital motion around asteroid for which averaging method can be applied, i.e., when central body rotates slowly, fast, and when a spacecraft is near to the resonant orbits between the spacecraft mean motion and the central body＇s rotation. Averaging conditions for these cases are given. As a major extension, a few classes of near resonant orbits are analyzed by the averaging method. Then some resulted conclusions of these averaging analyses are applied to understand the stabil- ity regions in a numerical experiment. Some stability conclu- sions are obtained. As a typical example, it is shown in detail that near circular 1 ： 2 resonant orbit is always unstable.展开更多
The minimum energy and stable configurations in the spherical,equal mass full 4-body problem are investigated.This problem is defined as the dynamics of finite density spheres which interact gravitationally and throug...The minimum energy and stable configurations in the spherical,equal mass full 4-body problem are investigated.This problem is defined as the dynamics of finite density spheres which interact gravitationally and through surface contact forces.This is a variation of the gravitational n-body problem in which the bodies are not allowed to come arbitrarily close to each other(due to their finite density),enabling the existence of resting configurations in addition to orbital motion.Previous work on this problem has outlined an efficient and simple way in which the stability of configurations in this problem can be defined.This methodology is applied to the 4-body problem,where we find multiple resting equilibrium configurations and outline the stability of a number of these.The study of these configurations is important for understanding the mechanics and morphological properties of small rubble pile asteroids.These results can also be generalized to other configurations of bodies that interact via field potentials and surface contact forces.展开更多
Dear authors and readers,Orbit determination is an old topic in celestial mechanics and astrodynamics.It originates from the need to determine the position and speed of natural or artificial objects in space through g...Dear authors and readers,Orbit determination is an old topic in celestial mechanics and astrodynamics.It originates from the need to determine the position and speed of natural or artificial objects in space through ground-station measurements,along with the need to estimate parameters involved in dynamics and observations.It has been the key to many important space applications.展开更多
Advancements in space technology are enabling more sophisticated spacecraft designs with time-varying spacecraft configurations to account for varying power considerations.For example,articulating solar arrays that ro...Advancements in space technology are enabling more sophisticated spacecraft designs with time-varying spacecraft configurations to account for varying power considerations.For example,articulating solar arrays that rotate about an axis fixed with respect to the hub can track the Sun at all times.Electric thrusters also have become omnipresent in modern spacecraft designs.Because these thrusters operate over long time windows,and the thrust vector must at all times be aligned with a specific inertial orientation,the optimal spacecraft attitude reference needs to accommodate the thruster too.Multiple pointing constraints pose a challenge to the attitude reference generation problem,because the attitude is characterized by three degrees of freedom,whereas the different constraints are often described by overdetermined systems of multiple equations.This paper leverages a range of attitude parameterizations to provide a mathematical description of the solution spaces of the constraints outlined above.When the intersection space is nonzero,it is possible to compute a solution that satisfies multiple constraints simultaneously.Conversely,an ordered list of pointing priorities is required in order to enforce the most important requirements,and reformulate the subsequent ones in terms of constrained optimization problems.The attitude guidance formulation is written in a general manner,which makes it applicable to a broad range of mission configurations.展开更多
Velocity field of China continent constrained by Global Positioning System (GPS) reveals both continuous and block-like styles of deformation. Continuous deformation commonly characterizes actively deforming mountain ...Velocity field of China continent constrained by Global Positioning System (GPS) reveals both continuous and block-like styles of deformation. Continuous deformation commonly characterizes actively deforming mountain ranges such as the Tianshan Mountain, Qilian Mountain, and Tibet. The block-like movement often represents deformation in the tectonically stable regions such as Ordos, South China and Tarim blocks. GPS measurements indicate 5.1±2.5 mm/a left-lateral strike-slip rate along the Altun fault. Eastward convergence along the Longmenshan fault is less than 6.7±3.0 mm/a. South China moves 11-14 mm/a eastward compared with the stable Eurasia. These low slip rates do not imply rapid eastward extrusion of China continent predicted by the model of 'continental extrusion'. It appears that 'crustal thickening' model more properly describes both continuous and block-like styles of deformation in China continent.展开更多
Regularization of the level-set(LS)field is a critical part of LS-based topology optimization(TO)approaches.Traditionally this is achieved by advancing the LS field through the solution of a Hamilton-Jacobi equation c...Regularization of the level-set(LS)field is a critical part of LS-based topology optimization(TO)approaches.Traditionally this is achieved by advancing the LS field through the solution of a Hamilton-Jacobi equation combined with a reinitialization scheme.This approach,however,may limit the maximum step size and introduces discontinuities in the design process.Alternatively,energy functionals and intermediate LS value penalizations have been proposed.This paper introduces a novel LS regularization approach based on a signed distance field(SDF)which is applicable to explicit LSbased TO.The SDF is obtained using the heat method(HM)and is reconstructed for every design in the optimization process.The governing equations of the HM,as well as the ones describing the physical response of the system of interest,are discretized by the extended finite element method(XFEM).Numerical examples for pro?blems modeled by linear elasticity,nonlinear hyperelasticity and the incompressible Navier-Stokes equations in two and three dimensions are presented to show the applicability of the proposed scheme to a broad range of design optimization problems.展开更多
This paper demonstrates how artificial neural networks can be used to alleviate common problems encountered when creating a large database of Poincar´e map responses.A general architecture is developed using a co...This paper demonstrates how artificial neural networks can be used to alleviate common problems encountered when creating a large database of Poincar´e map responses.A general architecture is developed using a combination of regression and classification feedforward neural networks.This allows one to predict the response of the Poincar´e map,as well as to identify anomalies,such as impact or escape.Furthermore,this paper demonstrates how an artificial neural network can be used to predict the error between a more complex and a simpler dynamical system.As an example application,the developed architecture is implemented on the Sun-Mars eccentric Hill system.Error statistics of the entire architecture are computed for both one Poincar´e map and for iterated maps.The neural networks are then applied to study the long-term impact and escape stability of trajectories in this system.展开更多
Comet exploration missions represented by the Comet Interceptor mission have attracted our attention to unravel the origin of our solar system.However,it is difficult to know the details of orbital data about long per...Comet exploration missions represented by the Comet Interceptor mission have attracted our attention to unravel the origin of our solar system.However,it is difficult to know the details of orbital data about long period comets(LPCs)until their approach.Additionally,the amount of fuel consumption by the current intercept approach depends on the intersection points of cometary orbits with the ecliptic plane.To address these challenges,designing low-energy transfer trajectories suitable for the observation of LPCs is necessary.This paper introduces a novel approach bv utilizing invariant manifold structures in the Sun-Earth circular restricted three-body problem for comet missions with multiple probes.As candidates for departure orbits,periodic orbits and quasi-periodic orbits are considered.Based on the optimal control theory,low-thrust trajectories to improve mission efficiency for enlarging the reachable domain of multiple probes are designed by leveraging invariant manifolds.The trajectories guided by invariant manifolds and optimal control theory facilitate formation flying,multi-point observations,and explorations of unknown comets by multiple probes.展开更多
The Hayabusa2 extended mission,named Hayabusa2#(SHARP:Small Hazardous Asteroid Reconnaissance Probe),is planned to rendezvous with the fast-rotating asteroid 1998 KY26 in 2031.Hayabusa2#will be the first ever mission ...The Hayabusa2 extended mission,named Hayabusa2#(SHARP:Small Hazardous Asteroid Reconnaissance Probe),is planned to rendezvous with the fast-rotating asteroid 1998 KY26 in 2031.Hayabusa2#will be the first ever mission to rendezvous with such a rapidly rotating small asteroid,posing significant challenges because of its distinctive dynamical environment.In this paper,we investigate potential target marker(TM)deployment strategies,for both landing and orbiting scenarios,to maximize science acquisition.In particular,we model the surface and orbital environments to identify feasible target market operations and present landing site selection strategies and candidate insertion orbits considering realistic deployment errors.The TM is one of the only two remaining deployable payloads,and therefore,can play a critical role during the extended mission phase.Our results show that surface operations can be extremely challenging whereas orbit operations could help us gain valuable information on the asteroid's gravity field.Overall,this research contributes to the exploration and characterization of extremely small bodies specifically through the use of artificial objects,in this case the target marker.展开更多
文摘This paper presents a novel optimal Motion Cueing Algorithm(MCA)to control the rotations of a Human Centrifuge(HC)and achieve the best simulation of a Space Craft(SC)motion.Relations of the specific forces sensed by astronauts of the SC and the HC have been derived and linearized.A Linear Quadratic Regulator(LQR)controller is implemented for the problem which tends to minimize the error between the two sensed specific forces as well as control input in a cost function.It results in control inputs of the HC to generate its sensed specific force as close as possible to the one in the SC.The algorithm is implemented for both linearized and nonlinear portions of a US space shuttle mission trajectory as a verification using MATLAB.In longitudinal direction,the proposed MCA,works well when the acceleration is less than 2 g in which the tracking error does not exceed 12%.In lateral direction the tracking is much better even in nonlinear region since the error remains less than 7%for tilting up to 50°.Finally,the effect of weight matrixes in the LQR cost function on overall weight and power of the HC motion system is discussed.
基金This paper expands on work conducted during the 2005-2006 summer aca-demic recesses while the author was a visitor at CIMNE(Centro Internacional de Métodos Numéricos en Ingenieria)at Barcelona,SpainThe visits were partly supported by fellowships awarded by the Spanish Ministerio de Educación y Cultura during May-June of those years,and partly by the National Science Foundation under grant High-Fidelity Simulations for Heteroge-neous Civil and Mechanical Systems,CMS-0219422。
文摘1 This paper considers Lagrangian finite elements for structural dynamics constructed with cubic displacement shape functions.The method of templates is used to investigate the construction of accurate mass-stiffness pairs.This method introduces free parameters that can be adjusted to customize elements according to accuracy and rank-sufficiency criteria.One-and two-dimensional Lagrangian cubic elements with only translational degrees of freedom(DOF)carry two additional nodes on each side,herein called side nodes or SN.Although usually placed at the third-points,the SN location may be adjusted within geometric limits.The adjustment effect is studied in detail using symbolic computations for a bar element.The best SN location is taken to be that producing accurate approximation to the lowest natural frequencies of the continuum model.Optimality is investigated through Fourier analysis of the propagation of plane waves over a regular infinite lattice of bar elements.Focus is placed on the acoustic branch of the frequency-vs.-wavenumber dispersion diagram.It is found that dispersion results using the fully integrated consistent mass matrix(CMM)are independent of the SN location whereas its lowfrequency accuracy order is O(κ8),whereκis the dimensionless wave number.For the diagonally lumped mass matrix(DLMM)constructed through the HRZ scheme,two optimal SN locations are identified,both away from third-points and of accuracy order O(κ8).That with the smallest error coefficient corresponds to the Lobatto 4-point integration rule.A special linear combination of CMM and DLMM with nodes at the Lobatto points yields an accuracy of O(κ10)without any increase in the computational effort over CMM.The effect of reduced integration(RI)on both mass and stiffness matrices is also studied.It is shown that singular mass matrices can be constructed with 2-and 3-point RI rules that display the same optimal accuracy of the exactly integrated case,at the cost of introducing spurious modes.The optimal SN location in two-dimensional,bicubic,isoparametric plane stress quadrilateral elements is briefly investigated by numerical experiments.The frequency accuracy of flexural modes is found to be fairly insensitive to that position,whereas for bar-like modes it agrees with the one-dimensional results.
基金FF and LDL gratefully acknowledge the financial support of the German Research Foundation(DFG)within the DFG Priority Program SPP 1748“Reliable Simulation Techniques in Solid Mechanics”.AR has been partially supported by the MIUR-PRIN project XFAST-SIMS(No.20173C478 N).
文摘We investigate primal and mixed u−p isogeometric collocation methods for application to nearly-incompressible isotropic elasticity.The primal method employs Navier’s equations in terms of the displacement unknowns,and the mixed method employs both displacement and pressure unknowns.As benchmarks for what might be considered acceptable accuracy,we employ constant-pressure Abaqus finite elements that are widely used in engineering applications.As a basis of comparisons,we present results for compressible elasticity.All the methods were completely satisfactory for the compressible case.However,results for low-degree primal methods exhibited displacement locking and in general deteriorated in the nearly-incompressible case.The results for the mixed methods behaved very well for two of the problems we studied,achieving levels of accuracy very similar to those for the compressible case.The third problem,which we consider a“torture test”presented a more complex story for the mixed methods in the nearly-incompressible case.
文摘Direct numerical simulations (DNS) of non-rotating and rotating turbulent channel flow were conducted. The data base obtained from these DNS simulations was used to investigate the prominent coherent structures involved in the turbulence generation cycle. Predictions from three theoretical models concerning the formation and evolution of sublayer streaks, three-dimensional hairpin vortices and propagating plane waves were validated using visualizations from the present DNS data. Quadrant analysis was used to determine a phase shift between the fluctuating streamwise and wall-normal velocities as a characteristic of turbulence production in the suction region at a low rotation number.
基金partially supported by an innovation fund from Chinese academy of space technology and a grant from the Jet Propulsion Laboratory
文摘This paper summarizes a few cases of spacecraft orbital motion around asteroid for which averaging method can be applied, i.e., when central body rotates slowly, fast, and when a spacecraft is near to the resonant orbits between the spacecraft mean motion and the central body＇s rotation. Averaging conditions for these cases are given. As a major extension, a few classes of near resonant orbits are analyzed by the averaging method. Then some resulted conclusions of these averaging analyses are applied to understand the stabil- ity regions in a numerical experiment. Some stability conclu- sions are obtained. As a typical example, it is shown in detail that near circular 1 ： 2 resonant orbit is always unstable.
文摘The minimum energy and stable configurations in the spherical,equal mass full 4-body problem are investigated.This problem is defined as the dynamics of finite density spheres which interact gravitationally and through surface contact forces.This is a variation of the gravitational n-body problem in which the bodies are not allowed to come arbitrarily close to each other(due to their finite density),enabling the existence of resting configurations in addition to orbital motion.Previous work on this problem has outlined an efficient and simple way in which the stability of configurations in this problem can be defined.This methodology is applied to the 4-body problem,where we find multiple resting equilibrium configurations and outline the stability of a number of these.The study of these configurations is important for understanding the mechanics and morphological properties of small rubble pile asteroids.These results can also be generalized to other configurations of bodies that interact via field potentials and surface contact forces.
文摘Dear authors and readers,Orbit determination is an old topic in celestial mechanics and astrodynamics.It originates from the need to determine the position and speed of natural or artificial objects in space through ground-station measurements,along with the need to estimate parameters involved in dynamics and observations.It has been the key to many important space applications.
文摘Advancements in space technology are enabling more sophisticated spacecraft designs with time-varying spacecraft configurations to account for varying power considerations.For example,articulating solar arrays that rotate about an axis fixed with respect to the hub can track the Sun at all times.Electric thrusters also have become omnipresent in modern spacecraft designs.Because these thrusters operate over long time windows,and the thrust vector must at all times be aligned with a specific inertial orientation,the optimal spacecraft attitude reference needs to accommodate the thruster too.Multiple pointing constraints pose a challenge to the attitude reference generation problem,because the attitude is characterized by three degrees of freedom,whereas the different constraints are often described by overdetermined systems of multiple equations.This paper leverages a range of attitude parameterizations to provide a mathematical description of the solution spaces of the constraints outlined above.When the intersection space is nonzero,it is possible to compute a solution that satisfies multiple constraints simultaneously.Conversely,an ordered list of pointing priorities is required in order to enforce the most important requirements,and reformulate the subsequent ones in terms of constrained optimization problems.The attitude guidance formulation is written in a general manner,which makes it applicable to a broad range of mission configurations.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 49825104) National Key Basic Research Program (Grant No. 19980407), National Climbing Project and National Major Scientific Infrastructure Program, and National S
文摘Velocity field of China continent constrained by Global Positioning System (GPS) reveals both continuous and block-like styles of deformation. Continuous deformation commonly characterizes actively deforming mountain ranges such as the Tianshan Mountain, Qilian Mountain, and Tibet. The block-like movement often represents deformation in the tectonically stable regions such as Ordos, South China and Tarim blocks. GPS measurements indicate 5.1±2.5 mm/a left-lateral strike-slip rate along the Altun fault. Eastward convergence along the Longmenshan fault is less than 6.7±3.0 mm/a. South China moves 11-14 mm/a eastward compared with the stable Eurasia. These low slip rates do not imply rapid eastward extrusion of China continent predicted by the model of 'continental extrusion'. It appears that 'crustal thickening' model more properly describes both continuous and block-like styles of deformation in China continent.
基金the United States National Science Foundation(CMMI-1463287)The third author acknowledge the support of the SUTD Digital Manufacturing and Design(DManD)Centre supported by the National Research Foundation of Singapore.The fourth author acknowledges the support of the Air Force Office of Scientific Research(Grant No.FA9550-16-1-0169)from the Defense Advanced Research Projects Agency(DARPA)under the TRADES program(agreement HR0011-17-2-0022).
文摘Regularization of the level-set(LS)field is a critical part of LS-based topology optimization(TO)approaches.Traditionally this is achieved by advancing the LS field through the solution of a Hamilton-Jacobi equation combined with a reinitialization scheme.This approach,however,may limit the maximum step size and introduces discontinuities in the design process.Alternatively,energy functionals and intermediate LS value penalizations have been proposed.This paper introduces a novel LS regularization approach based on a signed distance field(SDF)which is applicable to explicit LSbased TO.The SDF is obtained using the heat method(HM)and is reconstructed for every design in the optimization process.The governing equations of the HM,as well as the ones describing the physical response of the system of interest,are discretized by the extended finite element method(XFEM).Numerical examples for pro?blems modeled by linear elasticity,nonlinear hyperelasticity and the incompressible Navier-Stokes equations in two and three dimensions are presented to show the applicability of the proposed scheme to a broad range of design optimization problems.
基金This work utilized the RMACC Summit supercomputer,which is supported by the National Science Foundation(awards ACI-1532235 and ACI-1532236)the University of Colorado Boulder,and Colorado State University.
文摘This paper demonstrates how artificial neural networks can be used to alleviate common problems encountered when creating a large database of Poincar´e map responses.A general architecture is developed using a combination of regression and classification feedforward neural networks.This allows one to predict the response of the Poincar´e map,as well as to identify anomalies,such as impact or escape.Furthermore,this paper demonstrates how an artificial neural network can be used to predict the error between a more complex and a simpler dynamical system.As an example application,the developed architecture is implemented on the Sun-Mars eccentric Hill system.Error statistics of the entire architecture are computed for both one Poincar´e map and for iterated maps.The neural networks are then applied to study the long-term impact and escape stability of trajectories in this system.
基金The work of the second author was supported by JSPS KAKENHI(Grant Number JP 23KJ1692)The work of the third author was partially supported by Japan Science and Technology Agency,Fusion Oriented Research for Disruptive Science and Technology(JST FOREST Program)(Grant Number JPMJFR206M)Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science(Grant Number 22H03663).
文摘Comet exploration missions represented by the Comet Interceptor mission have attracted our attention to unravel the origin of our solar system.However,it is difficult to know the details of orbital data about long period comets(LPCs)until their approach.Additionally,the amount of fuel consumption by the current intercept approach depends on the intersection points of cometary orbits with the ecliptic plane.To address these challenges,designing low-energy transfer trajectories suitable for the observation of LPCs is necessary.This paper introduces a novel approach bv utilizing invariant manifold structures in the Sun-Earth circular restricted three-body problem for comet missions with multiple probes.As candidates for departure orbits,periodic orbits and quasi-periodic orbits are considered.Based on the optimal control theory,low-thrust trajectories to improve mission efficiency for enlarging the reachable domain of multiple probes are designed by leveraging invariant manifolds.The trajectories guided by invariant manifolds and optimal control theory facilitate formation flying,multi-point observations,and explorations of unknown comets by multiple probes.
基金the financial support offered by the la Caixa Foundation(ID 100010434)under agreement LCF/BQ/AA20/11820034 to support the Ph.D.studies of A.P.F.This project has received funding from the European Union's Horizon 2020 research+1 种基金innovation programme under the Marie Sklodowska-Curie grant agreement No.896404-CRADLEThis work was supported by JSPS KAKENHI Grant Number JP22H01687.
文摘The Hayabusa2 extended mission,named Hayabusa2#(SHARP:Small Hazardous Asteroid Reconnaissance Probe),is planned to rendezvous with the fast-rotating asteroid 1998 KY26 in 2031.Hayabusa2#will be the first ever mission to rendezvous with such a rapidly rotating small asteroid,posing significant challenges because of its distinctive dynamical environment.In this paper,we investigate potential target marker(TM)deployment strategies,for both landing and orbiting scenarios,to maximize science acquisition.In particular,we model the surface and orbital environments to identify feasible target market operations and present landing site selection strategies and candidate insertion orbits considering realistic deployment errors.The TM is one of the only two remaining deployable payloads,and therefore,can play a critical role during the extended mission phase.Our results show that surface operations can be extremely challenging whereas orbit operations could help us gain valuable information on the asteroid's gravity field.Overall,this research contributes to the exploration and characterization of extremely small bodies specifically through the use of artificial objects,in this case the target marker.
