Sent out at 1:31am GMT+8 on May 29 by a Long March-3B carrier rocket from the Xichang Satellite Launch Center in Sichuan province,China,Tianwen-2,the second mission of China’s Planetary Exploration Program,correctly ...Sent out at 1:31am GMT+8 on May 29 by a Long March-3B carrier rocket from the Xichang Satellite Launch Center in Sichuan province,China,Tianwen-2,the second mission of China’s Planetary Exploration Program,correctly entered the transfer trajectory toward an asteroid named 2016HO3 after flying for 18 minutes.Its solar wings unfolded properly,signaling a successful start,and primed for the next stage of its mission.展开更多
To examine the environmental characteristics of the microgravity force and the weathered layer on an asteroid surface,a symmetric wheel brush asteroid sampler is proposed for the collection of particles on the asteroi...To examine the environmental characteristics of the microgravity force and the weathered layer on an asteroid surface,a symmetric wheel brush asteroid sampler is proposed for the collection of particles on the asteroid surface.To study the influence of the wheel brush rotation speed on the sampling efficiency and the driving torque required for the wheel brush,the contact dynamics model between particles and sampling wheel brushes is established and a simulation and experimental verification of the sampling process are conducted.The parameter calibration of the sampled particles is studied first,and the calibrated particle parameters are used in the numerical simulation of the sampling process.The sampling results and the particle stream curves are obtained for the working conditions of different rotation speeds,and the effects of different parameter settings on the sampling efficiency are analyzed.In addition,a set of rotating symmetrical sampling wheel brush devices is built for the ground test,and the dynamic torque sensor is used to test the torque change of the wheel brush during the sampling process.The relationship between the speed of the wheel brush and the driving torque of the wheel brush motor is determined by comparing the simulation results with the test results.Results indicate that when the rotating speed of the wheel brush is faster,the sampling efficiency is higher,and the driving torque required for the sampling wheel brush is greater.Moreover,a numerical simulation analysis of the sampling process of the wheel brush sampler in a microgravity environment is conducted to determine the optimal speed condition,and the brushing test of the wheel brush sampler in the microgravity environment is verified with the drop tower method.This research proposes the structural optimization design and motor selection of a wheel brush asteroid sampler,which provides important reference value and engineering significance.展开更多
Scientific interest in asteroids and their physical characteristics is growing.These bodies provide insights into the primordial solar system and represent a valuable source of metals,silicates,and water.Several missi...Scientific interest in asteroids and their physical characteristics is growing.These bodies provide insights into the primordial solar system and represent a valuable source of metals,silicates,and water.Several missions over the past few years have aimed to improve and better identify the main properties of these poorly known celestial bodies.However,these missions relied on touchdown(s)on the target asteroid to gather samples,which is complicated owing to the difficulty of accurately reaching and rendezvousing with the body.This study aims to assess the feasibility of an in-orbit asteroid sample collection mission.Such a strategy could prevent complex operations related to landing and touchdown maneuvers and avoid the dead times present in a mission requiring several landings.The presented collection scenario,which focuses on the asteroid Ryugu,proposes gathering samples using a spacecraft injected into a halo orbit around the second libration point,L2.For this purpose,the orbits in the neck region of the zero velocity curves are analyzed.A novel methodology to characterize bouncing behavior is introduced.An interpolation-based approach was used to recover the appropriate restitution coefficients for each collision occurring at a specific impact angle.This was applied to both the rigid body model and the point mass approximation studied for two different sites on the asteroid.Furthermore,the study enlarged the region of interest from only L2 to its neighboring zones to return a more global and realistic point of view.Considering the solar radiation pressure and asteroid aspherical potential,particles of different sizes ejected from different longitudes and with different ejection angles were classified according to their trajectories to finally build a database.Based on this analysis,an aerogel-based collection strategy inspired by that used in the Stardust-NExT(NASA)mission was investigated to assess its possible applicability to the analyzed scenario.展开更多
FORAY INTO THE SPACE FRONTIER.The Tianwen-2 probe,China's first asteroid sample-return spacecraft,pictured alongside Earth,during its deep-space journey.The image was acquired by a monitoring camera mounted on the...FORAY INTO THE SPACE FRONTIER.The Tianwen-2 probe,China's first asteroid sample-return spacecraft,pictured alongside Earth,during its deep-space journey.The image was acquired by a monitoring camera mounted on the probe's robotic arm and released by the China National Space Administration(CNSA)on October 1.展开更多
文摘Sent out at 1:31am GMT+8 on May 29 by a Long March-3B carrier rocket from the Xichang Satellite Launch Center in Sichuan province,China,Tianwen-2,the second mission of China’s Planetary Exploration Program,correctly entered the transfer trajectory toward an asteroid named 2016HO3 after flying for 18 minutes.Its solar wings unfolded properly,signaling a successful start,and primed for the next stage of its mission.
基金supported by the National Natural Science Foundation of China(Grant No.51975567)the Strategic Priority Research Program on Space Science,CAS(Grant No.XDA1502030505)+4 种基金the independent project of State Key Laboratory of Robotics,China(Grant Nos.2022-Z01 and 2019-Z06)the Liaoning Revitalization Talents Program,China(Grant No.XLYC1907152)the Youth Innovation Promotion Association,CAS(Grant No.2018237)the Natural Science Foundation of Liaoning Province,China(Grant Nos.2020-MS-029 and 2021-MS-029)the Development Fund of Space Automation Technology Laboratory,SIA,CAS.
文摘To examine the environmental characteristics of the microgravity force and the weathered layer on an asteroid surface,a symmetric wheel brush asteroid sampler is proposed for the collection of particles on the asteroid surface.To study the influence of the wheel brush rotation speed on the sampling efficiency and the driving torque required for the wheel brush,the contact dynamics model between particles and sampling wheel brushes is established and a simulation and experimental verification of the sampling process are conducted.The parameter calibration of the sampled particles is studied first,and the calibrated particle parameters are used in the numerical simulation of the sampling process.The sampling results and the particle stream curves are obtained for the working conditions of different rotation speeds,and the effects of different parameter settings on the sampling efficiency are analyzed.In addition,a set of rotating symmetrical sampling wheel brush devices is built for the ground test,and the dynamic torque sensor is used to test the torque change of the wheel brush during the sampling process.The relationship between the speed of the wheel brush and the driving torque of the wheel brush motor is determined by comparing the simulation results with the test results.Results indicate that when the rotating speed of the wheel brush is faster,the sampling efficiency is higher,and the driving torque required for the sampling wheel brush is greater.Moreover,a numerical simulation analysis of the sampling process of the wheel brush sampler in a microgravity environment is conducted to determine the optimal speed condition,and the brushing test of the wheel brush sampler in the microgravity environment is verified with the drop tower method.This research proposes the structural optimization design and motor selection of a wheel brush asteroid sampler,which provides important reference value and engineering significance.
基金the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No.896404-CRADLEthe European Research Council(ERC)under the European Union’s Horizon 2020 Research and Innovation Program(grant agreement No.679086-COMPASS).
文摘Scientific interest in asteroids and their physical characteristics is growing.These bodies provide insights into the primordial solar system and represent a valuable source of metals,silicates,and water.Several missions over the past few years have aimed to improve and better identify the main properties of these poorly known celestial bodies.However,these missions relied on touchdown(s)on the target asteroid to gather samples,which is complicated owing to the difficulty of accurately reaching and rendezvousing with the body.This study aims to assess the feasibility of an in-orbit asteroid sample collection mission.Such a strategy could prevent complex operations related to landing and touchdown maneuvers and avoid the dead times present in a mission requiring several landings.The presented collection scenario,which focuses on the asteroid Ryugu,proposes gathering samples using a spacecraft injected into a halo orbit around the second libration point,L2.For this purpose,the orbits in the neck region of the zero velocity curves are analyzed.A novel methodology to characterize bouncing behavior is introduced.An interpolation-based approach was used to recover the appropriate restitution coefficients for each collision occurring at a specific impact angle.This was applied to both the rigid body model and the point mass approximation studied for two different sites on the asteroid.Furthermore,the study enlarged the region of interest from only L2 to its neighboring zones to return a more global and realistic point of view.Considering the solar radiation pressure and asteroid aspherical potential,particles of different sizes ejected from different longitudes and with different ejection angles were classified according to their trajectories to finally build a database.Based on this analysis,an aerogel-based collection strategy inspired by that used in the Stardust-NExT(NASA)mission was investigated to assess its possible applicability to the analyzed scenario.
文摘FORAY INTO THE SPACE FRONTIER.The Tianwen-2 probe,China's first asteroid sample-return spacecraft,pictured alongside Earth,during its deep-space journey.The image was acquired by a monitoring camera mounted on the probe's robotic arm and released by the China National Space Administration(CNSA)on October 1.
