Hongru Chen | Chinese Academy of Sciences (original) (raw)

Papers by Hongru Chen

Research paper thumbnail of BIRDY - Planetary Geodesy of Small Bodies _through CubeSats in Autonomous Navigation

42nd COSPAR Scientific Assembly, Jul 1, 2018

Research paper thumbnail of Analysis and Design of Asteroid Retrieval Missions Using Luni-Solar Gravity Assists

41st COSPAR Scientific Assembly, Jul 1, 2016

Research paper thumbnail of Stability analysis of three-dimensional quasi-satellite orbits around phobos

69th International Astronautical Congress: #InvolvingEveryone, IAC 2018, 2018

Research paper thumbnail of Mission Analysis and Orbital Maneuver Experiment for Interplanetary Micro-spacecraft PROCYON

Research paper thumbnail of An Asteroid Flyby Mission Design for HAYABUSA2 Piggy-Back Explore : PROCYON

Research paper thumbnail of Effective Stability of Quasi-Satellite Orbits in the Spatial Problem for Phobos Exploration

Journal of Guidance, Control, and Dynamics, 2020

Research paper thumbnail of Accuracy of meteor positioning from space- and ground-based observations

Astronomy & Astrophysics, 2020

Aims. The knowledge of the orbits and origins derived from meteors is important for the study of ... more Aims. The knowledge of the orbits and origins derived from meteors is important for the study of meteoroids and of the early solar system. With an increase in nano-satellite projects dedicated to Earth observations or directly to meteor observations (e.g., the Meteorix CubeSat), we investigate the stereoscopic measurement of meteor positions using a pair of cameras, one deployed in space and one on the ground, and aim to understand the accuracy and the main driving factors. This study will reveal the requirements for system setups and the geometry favorable for meteor triangulation. Methods. This Letter presents the principle of the stereoscopic measurement from space and the ground, and an error analysis. Specifically, the impacts of the resolutions of the cameras, the attitude and orbit determination accuracy of the satellite, and the geometry formed by the moving target and observers are investigated. Results. To reach a desirable positioning accuracy of 1 km it is necessary to e...

Research paper thumbnail of Phasing Delta-V for transfers from Sun–Earth halo orbits to the Moon

Acta Astronautica, 2016

Abstract Inspired by successful extended missions such as the ISEE-3, an investigation for the ex... more Abstract Inspired by successful extended missions such as the ISEE-3, an investigation for the extended mission that involves a lunar encounter following a Sun-Earth halo orbit mission is considered valuable. Most previous studies present the orbit-to-orbit transfers where the lunar phase is not considered. Intended for extended missions, the present work aims to solve for the minimum phasing ∆V for various initial lunar phases. Due to the solution multiplicity of the two-point boundary value problem, the general constrained optimization algorithm that does not identify multiple feasible solutions is shown to miss minima. A two-step differential corrector with a two-body Lambert solver is developed for identifying multiple solutions. The minimum ∆V associated with the short-way and long-way approaches can be recovered. It is acquired that the required ∆V to cover all initial lunar phases is around 45 m/s for the halo orbit with out-of-plane amplitude Az greater than 3.5×105 km, and 14 m/s for a small halo orbit with Az=1×105 km. In addition, the paper discusses the phasing planning based on the ∆V result and the shift of lunar phase with halo orbit revolution.

Research paper thumbnail of Earth Escape from a Sun-Earth Halo Orbit using Unstable Manifold and Lunar Swingbys

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 2016

Research paper thumbnail of Phasing Trajectories to Deploy a Constellation in a Halo Orbit

Journal of Guidance, Control, and Dynamics, 2017

Research paper thumbnail of Attitude Motion Under Full Orbit Perturbations

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN, 2015

Research paper thumbnail of IDEA: In-situ Debris Environmental Awareness

This paper introduces IDEA the project for in-situ debris environmental awareness. The environmen... more This paper introduces IDEA the project for in-situ debris environmental awareness. The environment of micro debris, whose size is below 1 cm, has not been continuously monitored in any spatial region by common ground-based sensors due to their small dimension. The lack of the environmental awareness also results in the significant difference between the two widely used debris environment models: the one is ORDEM developed by NASA and the other is MASTER developed by ESA. The IDEA project aims to monitor the environment of micro debris at congested orbital altitudes to identify the accuracy of those models, and to provide practical information for the satellites at the same altitude region. This paper introduces and evaluates the concept of proposed monitoring missions. Nomenclature ! : number of detected debris hits, # ! : average value of hits predicted by models ! : estimated mean number of debris hits, # ! : residual of estimation to measurement ! : debris flux, #/m 2 /yr ! : ave...

Research paper thumbnail of Low-Energy Escape from the Sun-Earth L2 Halo Orbit Utilizing Unstable Manifolds and Lunar Gravity Assist

The paper investigates the escape strategy using the unstable manifolds of the Sun-Earth L2 halo ... more The paper investigates the escape strategy using the unstable manifolds of the Sun-Earth L2 halo orbit and lunar gravity assist. There are four cases of intersec- tion of the manifold tubes associated with halo orbits and the orbit of the Moon. The four intersections have different V∞ with respect to the Moon. The corre- sponding lunar gravity assists can result in a range of escape trajectories, grant- ing choices for the extended mission of halo orbits. In order to satisfy the lunar encounter requirements, the strategy and ∆V costs of phasing maneuvers are presented as well.

Research paper thumbnail of Storm-time atmospheric density modeling using neural networks and its application in orbit propagation

Advances in Space Research, 2014

ABSTRACT Upper atmospheric densities during geomagnetic storms are usually poorly estimated due t... more ABSTRACT Upper atmospheric densities during geomagnetic storms are usually poorly estimated due to a lack of clear understanding of coupling mechanisms between the thermosphere and magnetosphere. Consequently, the orbit determination and propagation for low-Earth-orbit objects during geomagnetic storms have large uncertainties. Artificial neural networks are often used to identify nonlinear systems in the absence of rigorous theory. In the present study, an attempt has been made to model the storm-time atmospheric density using neural networks. Considering the debate over the representative of geomagnetic storm effect, i.e. the geomagnetic indices ap and Dst, three neural network models (NNM) are developed with ap, Dst and a combination of ap and Dst respectively. The density data used for training the NNMs are derived from the measurements of the satellites CHAMP and GRACE. The NNMs are evaluated by looking at: (a) the mean residuals and the standard deviations with respect to the density data that are not used in training process, and (b) the accuracy of reconstructing the orbits of selected objects during storms employing each model. This empirical modeling technique and the comparisons with the models NRLMSIS-00 and Jacchia-Bowman 2008 reveal (1) the capability of neural networks to model the relationship between solar and geomagnetic activities, and density variations; and (2) the merits and demerits of ap and Dst when it comes to characterizing density variations during storms.

Research paper thumbnail of Thruster Parameters Estimation for a Micro Deep Space Explorer: PROCYON

This paper presents the results of parameters estimation of a micro deep space explorer. PROCYON ... more This paper presents the results of parameters estimation of a micro deep space explorer. PROCYON (Proximate Object Close flyby with Optical Navigation) is a 50kg-class microspacecraft for deep space exploration, which was launched on December 3, 2014 as a secondary payload by an H-IIA launch vehicle along with the Hayabusa-2 spacecraft . The objectives of PROCYON are to demonstrate the technology of micro spacecraft deep space exploration and proximity flyby to asteroids performing optical measurements. The propulsion system can be one of PROCYON’s features, which is called I-COUPS (Ion Thruster and Cold-gas Thruster Unified Propulsion System) . The I-COUPS is a combined propulsion system of ion thruster and coldgas thrusters by sharing the same xenon gas system. This enables both systems to reduce its sizes and to use these 2 thrusters with different characteristics for efficient low-thrust maneuver and high thrust by the cold-gas system. This system is indispensable for the orbit ...

Research paper thumbnail of BIRDY - Planetary Geodesy of Small Bodies _through CubeSats in Autonomous Navigation

42nd COSPAR Scientific Assembly, Jul 1, 2018

Research paper thumbnail of Analysis and Design of Asteroid Retrieval Missions Using Luni-Solar Gravity Assists

41st COSPAR Scientific Assembly, Jul 1, 2016

Research paper thumbnail of Stability analysis of three-dimensional quasi-satellite orbits around phobos

69th International Astronautical Congress: #InvolvingEveryone, IAC 2018, 2018

Research paper thumbnail of Mission Analysis and Orbital Maneuver Experiment for Interplanetary Micro-spacecraft PROCYON

Research paper thumbnail of An Asteroid Flyby Mission Design for HAYABUSA2 Piggy-Back Explore : PROCYON

Research paper thumbnail of Effective Stability of Quasi-Satellite Orbits in the Spatial Problem for Phobos Exploration

Journal of Guidance, Control, and Dynamics, 2020

Research paper thumbnail of Accuracy of meteor positioning from space- and ground-based observations

Astronomy & Astrophysics, 2020

Aims. The knowledge of the orbits and origins derived from meteors is important for the study of ... more Aims. The knowledge of the orbits and origins derived from meteors is important for the study of meteoroids and of the early solar system. With an increase in nano-satellite projects dedicated to Earth observations or directly to meteor observations (e.g., the Meteorix CubeSat), we investigate the stereoscopic measurement of meteor positions using a pair of cameras, one deployed in space and one on the ground, and aim to understand the accuracy and the main driving factors. This study will reveal the requirements for system setups and the geometry favorable for meteor triangulation. Methods. This Letter presents the principle of the stereoscopic measurement from space and the ground, and an error analysis. Specifically, the impacts of the resolutions of the cameras, the attitude and orbit determination accuracy of the satellite, and the geometry formed by the moving target and observers are investigated. Results. To reach a desirable positioning accuracy of 1 km it is necessary to e...

Research paper thumbnail of Phasing Delta-V for transfers from Sun–Earth halo orbits to the Moon

Acta Astronautica, 2016

Abstract Inspired by successful extended missions such as the ISEE-3, an investigation for the ex... more Abstract Inspired by successful extended missions such as the ISEE-3, an investigation for the extended mission that involves a lunar encounter following a Sun-Earth halo orbit mission is considered valuable. Most previous studies present the orbit-to-orbit transfers where the lunar phase is not considered. Intended for extended missions, the present work aims to solve for the minimum phasing ∆V for various initial lunar phases. Due to the solution multiplicity of the two-point boundary value problem, the general constrained optimization algorithm that does not identify multiple feasible solutions is shown to miss minima. A two-step differential corrector with a two-body Lambert solver is developed for identifying multiple solutions. The minimum ∆V associated with the short-way and long-way approaches can be recovered. It is acquired that the required ∆V to cover all initial lunar phases is around 45 m/s for the halo orbit with out-of-plane amplitude Az greater than 3.5×105 km, and 14 m/s for a small halo orbit with Az=1×105 km. In addition, the paper discusses the phasing planning based on the ∆V result and the shift of lunar phase with halo orbit revolution.

Research paper thumbnail of Earth Escape from a Sun-Earth Halo Orbit using Unstable Manifold and Lunar Swingbys

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 2016

Research paper thumbnail of Phasing Trajectories to Deploy a Constellation in a Halo Orbit

Journal of Guidance, Control, and Dynamics, 2017

Research paper thumbnail of Attitude Motion Under Full Orbit Perturbations

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN, 2015

Research paper thumbnail of IDEA: In-situ Debris Environmental Awareness

This paper introduces IDEA the project for in-situ debris environmental awareness. The environmen... more This paper introduces IDEA the project for in-situ debris environmental awareness. The environment of micro debris, whose size is below 1 cm, has not been continuously monitored in any spatial region by common ground-based sensors due to their small dimension. The lack of the environmental awareness also results in the significant difference between the two widely used debris environment models: the one is ORDEM developed by NASA and the other is MASTER developed by ESA. The IDEA project aims to monitor the environment of micro debris at congested orbital altitudes to identify the accuracy of those models, and to provide practical information for the satellites at the same altitude region. This paper introduces and evaluates the concept of proposed monitoring missions. Nomenclature ! : number of detected debris hits, # ! : average value of hits predicted by models ! : estimated mean number of debris hits, # ! : residual of estimation to measurement ! : debris flux, #/m 2 /yr ! : ave...

Research paper thumbnail of Low-Energy Escape from the Sun-Earth L2 Halo Orbit Utilizing Unstable Manifolds and Lunar Gravity Assist

The paper investigates the escape strategy using the unstable manifolds of the Sun-Earth L2 halo ... more The paper investigates the escape strategy using the unstable manifolds of the Sun-Earth L2 halo orbit and lunar gravity assist. There are four cases of intersec- tion of the manifold tubes associated with halo orbits and the orbit of the Moon. The four intersections have different V∞ with respect to the Moon. The corre- sponding lunar gravity assists can result in a range of escape trajectories, grant- ing choices for the extended mission of halo orbits. In order to satisfy the lunar encounter requirements, the strategy and ∆V costs of phasing maneuvers are presented as well.

Research paper thumbnail of Storm-time atmospheric density modeling using neural networks and its application in orbit propagation

Advances in Space Research, 2014

ABSTRACT Upper atmospheric densities during geomagnetic storms are usually poorly estimated due t... more ABSTRACT Upper atmospheric densities during geomagnetic storms are usually poorly estimated due to a lack of clear understanding of coupling mechanisms between the thermosphere and magnetosphere. Consequently, the orbit determination and propagation for low-Earth-orbit objects during geomagnetic storms have large uncertainties. Artificial neural networks are often used to identify nonlinear systems in the absence of rigorous theory. In the present study, an attempt has been made to model the storm-time atmospheric density using neural networks. Considering the debate over the representative of geomagnetic storm effect, i.e. the geomagnetic indices ap and Dst, three neural network models (NNM) are developed with ap, Dst and a combination of ap and Dst respectively. The density data used for training the NNMs are derived from the measurements of the satellites CHAMP and GRACE. The NNMs are evaluated by looking at: (a) the mean residuals and the standard deviations with respect to the density data that are not used in training process, and (b) the accuracy of reconstructing the orbits of selected objects during storms employing each model. This empirical modeling technique and the comparisons with the models NRLMSIS-00 and Jacchia-Bowman 2008 reveal (1) the capability of neural networks to model the relationship between solar and geomagnetic activities, and density variations; and (2) the merits and demerits of ap and Dst when it comes to characterizing density variations during storms.

Research paper thumbnail of Thruster Parameters Estimation for a Micro Deep Space Explorer: PROCYON

This paper presents the results of parameters estimation of a micro deep space explorer. PROCYON ... more This paper presents the results of parameters estimation of a micro deep space explorer. PROCYON (Proximate Object Close flyby with Optical Navigation) is a 50kg-class microspacecraft for deep space exploration, which was launched on December 3, 2014 as a secondary payload by an H-IIA launch vehicle along with the Hayabusa-2 spacecraft . The objectives of PROCYON are to demonstrate the technology of micro spacecraft deep space exploration and proximity flyby to asteroids performing optical measurements. The propulsion system can be one of PROCYON’s features, which is called I-COUPS (Ion Thruster and Cold-gas Thruster Unified Propulsion System) . The I-COUPS is a combined propulsion system of ion thruster and coldgas thrusters by sharing the same xenon gas system. This enables both systems to reduce its sizes and to use these 2 thrusters with different characteristics for efficient low-thrust maneuver and high thrust by the cold-gas system. This system is indispensable for the orbit ...