Deep space is incredibly quiet,but once astronauts leave the station,they must contend with extreme temperatures,fluctuating pressures,and high levels of radiation.Their spacesuits are equipped with life-support syste...Deep space is incredibly quiet,but once astronauts leave the station,they must contend with extreme temperatures,fluctuating pressures,and high levels of radiation.Their spacesuits are equipped with life-support systems,which are essential for a safe“walk in space.”On 15 August,the crew of Shenzhou-20 successfully completed their third spacewalk.For this mission,taikonaut Chen Dong wore the extravehicular spacesuit B,which has now been used in 20 spacewalks.With this achievement,the space station has reached the target of“four years and 20 spacewalks.”展开更多
The early involvement of test and evaluation can significantly reduce the cost of modifying issues and errors found in the later stages of aircraft development and design process.This paper presents a methodology for ...The early involvement of test and evaluation can significantly reduce the cost of modifying issues and errors found in the later stages of aircraft development and design process.This paper presents a methodology for aircraft mission effectiveness evaluation and design space exploration based on Virtual Operational Test(VOT),incorporating Virtual Open Scenario(VOS)and User in Scenarios(UIS)concepts.By employing modeling and simulation technologies in the early stages of aircraft development and design,a virtual environment can be constructed,allowing aircraft users to participate more closely and conveniently in the design process.Virtual tests conducted by users within the mission context provide data on mission effectiveness and critical user feedback.This paper outlines the main components of the virtual operational test process and related conceptual methods,and discusses an open support system framework that supports VOT.The effectiveness and adaptability of the method are demonstrated through two case studies:a beyond-visual-range air combat scenario and a helicopter ground attack scenario.These case studies demonstrate the evaluation of aircraft mission effectiveness and the sensitivity analysis and optimization of design and operational parameters based on VOT.展开更多
The spacecraft for deep space exploration missions will face extreme environments,including cryogenic temperature,intense radiation,wide-range temperature variations and even the combination of conditions mentioned ab...The spacecraft for deep space exploration missions will face extreme environments,including cryogenic temperature,intense radiation,wide-range temperature variations and even the combination of conditions mentioned above.Harsh environments will lead to solder joints degradation or even failure,resulting in damage to onboard electronics.The research activities on high reliability solder joints using in extreme environments can not only reduce the use of onboard protection devices,but effectively improve the overall reliability of spacecraft,which is of great significance to the aviation industry.In this paper,we review the reliability research on SnPb solder alloys,Sn-based lead-free solder alloys and In-based solder alloys in extreme environments,and try to provide some suggestions for the follow-up studies,which focus on solder joint reliability under extreme environments.展开更多
China has carried out four unmanned missions to the Moon since it launched Chang’E-1,the first lunar orbiter in 2007.With the implementation of the Chang’E-5 mission this year,the three phases of the lunar explorati...China has carried out four unmanned missions to the Moon since it launched Chang’E-1,the first lunar orbiter in 2007.With the implementation of the Chang’E-5 mission this year,the three phases of the lunar exploration program,namely orbiting,landing and returning,have been completed.In the plan of follow-up unmanned lunar exploration missions,it is planned to establish an experimental lunar research station at the lunar south pole by 2030 through the implementation of several missions,laying a foundation for the establishment of practical lunar research station in the future.China successfully launched its first Mars probe on 23 July 2020,followed in future by an asteroid mission,second Mars mission,and a mission to explore Jupiter and its moons.展开更多
Four future missions for deep space exploration and future space-based exoplanet surveys on habitable planets by 2030 are scheduled to be launched.Two Mars exploration missions are designed to investigate geological s...Four future missions for deep space exploration and future space-based exoplanet surveys on habitable planets by 2030 are scheduled to be launched.Two Mars exploration missions are designed to investigate geological structure,the material on Martian surface,and retrieve returned samples.The asteroids and main belt comet exploration is expected to explore two objects within 10 years.The small-body mission will aim to land on the asteroid and get samples return to Earth.The basic physical characteristics of the two objects will be obtained through the mission.The exploration of Jupiter system will characterize the environment of Jupiter and the four largest Moons and understand the atmosphere of Jupiter.In addition,we further introduce two space-based exoplanet survey by 2030,Miyin Program and Closeby Habitable Exoplanet Survey(CHES Mission).Miyin program aims to detect habitable exoplanets using interferometry,while CHES mission expects to discover habitable exoplanets orbiting FGK stars within 10 pc through astrometry.The above-mentioned missions are positively to achieve breakthroughs in the field of planetary science.展开更多
The footpad structure of a deep space exploration lander is a critical system that makes the initial contact with the ground,and thereby plays a crucial role in determining the stability and energy absorption characte...The footpad structure of a deep space exploration lander is a critical system that makes the initial contact with the ground,and thereby plays a crucial role in determining the stability and energy absorption characteristics during the impact process.The conventional footpad is typically designed with an aluminum honeycomb structure that dissipates energy through plastic deformation.Nevertheless,its effectiveness in providing cushioning and energy absorption becomes significantly compromised when the structure is crushed,rendering it unusable for reusable landers in the future.This study presents a methodology for designing and evaluating structural energy absorption systems incorporating recoverable strain constraints of shape memory alloys(SMA).The topological configuration of the energy absorbing structure is derived using an equivalent static load method(ESL),and three lightweight footpad designs featuring honeycomb-like Ni-Ti shape memory alloys structures and having variable stiffness skins are proposed.To verify the accuracy of the numerical modelling,a honeycomb-like structure subjected to compression load is modeled and then compared with experimental results.Moreover,the influence of the configurations and thickness distribution of the proposed structures on their energy absorption performance is comprehensively evaluated using finite element simulations.The results demonstrate that the proposed design approach effectively regulates the strain threshold to maintain the SMA within the constraint of maximum recoverable strain,resulting in a structural energy absorption capacity of 362 J/kg with a crushing force efficiency greater than 63%.展开更多
In order to realize the explorer autonomy, the software architecture of autonomous mission management system (AMMS) is given for the deep space explorer, and the autonomous mission planning system, the kernel part of ...In order to realize the explorer autonomy, the software architecture of autonomous mission management system (AMMS) is given for the deep space explorer, and the autonomous mission planning system, the kernel part of this architecture, is designed in detail. In order to describe the parallel activity, the state timeline is introduced to build the formal model of the planning system and based on this model, the temporal constraint satisfaction planning algorithm is proposed to produce the explorer’s activity sequence. With some key subsystems of the deep space explorer as examples, the autonomous mission planning simulation system is designed. The results show that this system can calculate the executable activity sequence with the given mission goals and initial state of the explorer.展开更多
Space environment exploration is a hot topic globally.The scope of space exploration ranges from near-Earth space to the moon,other planets in the solar system,and even the heliosphere and interplanetary space.It is u...Space environment exploration is a hot topic globally.The scope of space exploration ranges from near-Earth space to the moon,other planets in the solar system,and even the heliosphere and interplanetary space.It is used for various crucial applications,including aerospace technology development,space weather research,understanding the origin and evolution of the universe,searching for extraterrestrial life,and finding human livable places.Although China’s space environment exploration started late,its progress has been rapid.China is gradually narrowing the gap with advanced countries and may eventually lead the world in space research.This article briefly reviews the development history of China’s space environmental detectors.展开更多
China has successfully launched six lunar probes so far.From Chang'E-1 to Chang'E-4,they completed the circling,landing and roving exploration,of which Chang'E-4 was the first landing on the far side of th...China has successfully launched six lunar probes so far.From Chang'E-1 to Chang'E-4,they completed the circling,landing and roving exploration,of which Chang'E-4 was the first landing on the far side of the Moon in human history.Chang'E-5 was launched in December 2020,bringing back 1731 g of lunar soil samples.Through the detailed analysis of the samples,the scientists understand the history of late lunar volcanism,specifically extending lunar volcanism by about 800 million to 1 billion years,and proposed possible mechanisms.In addition,there are many new understandings of space weathering such as meteorite impacts and solar wind radiation on the Moon.China's first Mars exploration mission Tianwen-1 was successfully launched in July 2021.Through the study of scientific data,a number of important scientific achievements have been made in the topography,water environment and shallow surface structure of Mars.This paper introduces the main scientific achievements of Chang'E-4,Chang'E-5 and Tianwen-1 in the past two years,excluding technical and engineering contents.Due to the large number of articles involved,this paper only introduces part of the results.展开更多
With the increasing demand of computational power in artificial intelligence(AI)algorithms,dedicated accelerators have become a necessity.However,the complexity of hardware architectures,vast design search space,and c...With the increasing demand of computational power in artificial intelligence(AI)algorithms,dedicated accelerators have become a necessity.However,the complexity of hardware architectures,vast design search space,and complex tasks of accelerators have posed significant challenges.Tra-ditional search methods can become prohibitively slow if the search space continues to be expanded.A design space exploration(DSE)method is proposed based on transfer learning,which reduces the time for repeated training and uses multi-task models for different tasks on the same processor.The proposed method accurately predicts the latency and energy consumption associated with neural net-work accelerator design parameters,enabling faster identification of optimal outcomes compared with traditional methods.And compared with other DSE methods by using multilayer perceptron(MLP),the required training time is shorter.Comparative experiments with other methods demonstrate that the proposed method improves the efficiency of DSE without compromising the accuracy of the re-sults.展开更多
Deep space exploration missions and the construction of planetary research stations impose strict demands on energy self-sufficiency systems.Solar energy,due to its abundant availability and sustainability,has become ...Deep space exploration missions and the construction of planetary research stations impose strict demands on energy self-sufficiency systems.Solar energy,due to its abundant availability and sustainability,has become the preferred solution.However,extreme environmental conditions in space-including drastic temperature fluctuations,vacuum environments,high-energy particles,and intense radiation-pose significant challenges to the performance and lifespan of solar energy systems.Concentration technology,which enhances photoelectric and photothermal conversion efficiency by focusing sunlight,is crucial for space missions.This review examines the primary environmental factors affecting the performance of solar concentrators,including solar irradiance,thermal cycling,vacuum-induced outgassing,radiation effects,and impacts from micrometeoroids and orbital debris.The analysis focuses on three types of high-temperature concentrators:Fresnel lenses,Scheffler concentrators,and parabolic dish concentrators.Fresnel lenses are characterized by low cost and simple structure but are susceptible to optical degradation at high temperatures.Scheffler concentrators utilize geometric optimization to improve uniformity of light distribution,while parabolic dish concentrators achieve high optical efficiency,making them suitable for high-energy applications though requiring precise solar tracking.Performance comparisons in the thermal power range of 0 to 25 kW reveal that parabolic dish concentrators excel in high-power scenarios with greater efficiency and smaller aperture sizes.Conversely,Fresnel lenses and Scheffler concentrators are more effective in medium to low-temperature applications.Based on these findings,this review emphasizes the need to select concentrators according to mission requirements and outlines future research directions.These include the development of advanced materials,optimized optical designs,and improvements in system integration to enhance the adaptability and reliability of solar concentration technologies in deep space missions.展开更多
Unmanned Aerial Vehicle(UAV)plays a prominent role in various fields,and autonomous navigation is a crucial component of UAV intelligence.Deep Reinforcement Learning(DRL)has expanded the research avenues for addressin...Unmanned Aerial Vehicle(UAV)plays a prominent role in various fields,and autonomous navigation is a crucial component of UAV intelligence.Deep Reinforcement Learning(DRL)has expanded the research avenues for addressing challenges in autonomous navigation.Nonetheless,challenges persist,including getting stuck in local optima,consuming excessive computations during action space exploration,and neglecting deterministic experience.This paper proposes a noise-driven enhancement strategy.In accordance with the overall learning phases,a global noise control method is designed,while a differentiated local noise control method is developed by analyzing the exploration demands of four typical situations encountered by UAV during navigation.Both methods are integrated into a dual-model for noise control to regulate action space exploration.Furthermore,noise dual experience replay buffers are designed to optimize the rational utilization of both deterministic and noisy experience.In uncertain environments,based on the Twin Delay Deep Deterministic Policy Gradient(TD3)algorithm with Long Short-Term Memory(LSTM)network and Priority Experience Replay(PER),a Noise-Driven Enhancement Priority Memory TD3(NDE-PMTD3)is developed.We established a simulation environment to compare different algorithms,and the performance of the algorithms is analyzed in various scenarios.The training results indicate that the proposed algorithm accelerates the convergence speed and enhances the convergence stability.In test experiments,the proposed algorithm successfully and efficiently performs autonomous navigation tasks in diverse environments,demonstrating superior generalization results.展开更多
Deep space exploration is the term used for the exploration of the Moon and the celestial bodies or space beyond the Moon, which is an important part of human space activities. Firstly, the development of deep space e...Deep space exploration is the term used for the exploration of the Moon and the celestial bodies or space beyond the Moon, which is an important part of human space activities. Firstly, the development of deep space exploration (not including the Moon) during the last few decades is summarized. Secondly, the development trend of different space countries and regions is analyzed. Then the experience and enlightenment of deep space exploration are briefly discussed. Some suggestions for China's future deep space exploration are given in the end.展开更多
Ecology seeks to explain species coexistence,but experimental tests of mechanisms for coexistence are difficult to conduct.We synthesized an arbuscular mycorrhizal(AM)fungal community with three fungal species that di...Ecology seeks to explain species coexistence,but experimental tests of mechanisms for coexistence are difficult to conduct.We synthesized an arbuscular mycorrhizal(AM)fungal community with three fungal species that differed in their capacity of foraging for orthophosphate(P)due to differences in soil exploration.We tested whether AM fungal species-specific hyphosphere bacterial assemblages recruited by hyphal exudates enabled differentiation among the fungi in the capacity of mobilizing soil organic P(P_(o)).We found that the less efficient space explorer,Gigaspora margarita,obtained less ^(13)C from the plant,whereas it had higher efficiencies in P_(o)mobilization and alkaline phosphatase(Al Pase)production per unit C than the two efficient space explorers,Rhizophagusintraradices and Funneliformis mosseae.Each AM fungus was associated with a distinct alp gene harboring bacterial assemblage,and the alp gene abundance and P_(o)preference of the microbiome associated with the less efficient space explorer were higher than those of the two other species.We conclude that the traits of AM fungal associated bacterial consortia cause niche differentiation.The trade-off between foraging ability and the ability to recruit effective P_(o)mobilizing microbiomes is a mechanism that allows co-existence of AM fungal species in a single plant root and surrounding soil habitat.展开更多
Drug molecule design is a classic research topic.Drug experts traditionally design molecules relying on their experience.Manual drug design is time-consuming and may produce low-efficacy and offtarget molecules.With t...Drug molecule design is a classic research topic.Drug experts traditionally design molecules relying on their experience.Manual drug design is time-consuming and may produce low-efficacy and offtarget molecules.With the popularity of deep learning,drug experts are beginning to use generative models to design drug molecules.A well-trained generative model can learn the distribution of training samples and infinitely generate drug-like molecules similar to the training samples.The automatic process improves design efficiency.However,most existing methods focus on proposing and optimizing generative models.How to discover ideal molecules from massive candidates is still an unresolved challenge.We propose a visualization system to discover ideal drug molecules generated by generative models.In this paper,we investigated the requirements and issues of drug design experts when using generative models,i.e.,generating molecular structures with specific constraints and finding other molecular structures similar to potential drug molecular structures.We formalized the first problem as an optimization problem and proposed using a genetic algorithm to solve it.For the second problem,we proposed using a neighborhood sampling algorithm based on the continuity of the latent space to find solutions.We integrated the proposed algorithms into a visualization tool,and a case study for discovering potential drug molecules to make KOR agonists and experiments demonstrated the utility of our approach.展开更多
Real-time multi-media applications are increasingly mapped on modern embedded systems based on multiprocessor systems-on-chip （MPSoC）. Tasks of the applications need to be mapped on the MPSoC resources efficiently i...Real-time multi-media applications are increasingly mapped on modern embedded systems based on multiprocessor systems-on-chip （MPSoC）. Tasks of the applications need to be mapped on the MPSoC resources efficiently in order to satisity their performance constraints. Exploring all the possible mappings, i.e., tasks to resources combinations exhaustively may take days or weeks. Additionally, the exploration is performed at design-time, which cannot handle dynamism in applications and resources＇ status. A runtime mapping technique can cater for the dynamism but cannot guarantee for strict timing deadlines due to large computations involved at run-time. Thus, an approach performing feasible compute intensive exploration at design-time and using the explored results at run-time is required. This paper presents a solution in the same direction. Communicationaware design space exploration （CADSE） techniques have been proposed to explore different mapping options to be selected at run-time subject to desired performance and available MPSoC resources. Experiments show that the proposed techniques for exploration are faster over an exhaustive exploration and provides almost the same quality of results.展开更多
The Strategic Priority Program(SPP)on Space Science,which is under the leadership of the Chinese Academy of Sciences(CAS),has established China’s space science satellite series from scratch.A number of major scientif...The Strategic Priority Program(SPP)on Space Science,which is under the leadership of the Chinese Academy of Sciences(CAS),has established China’s space science satellite series from scratch.A number of major scientific achievements have been made by the first phase of the Program(SPPⅠ),while SPPⅡhas been currently being implemented.The future development of space science needs urgent top-level planning and advanced layout to clarify the overall goal and investment portfolio from 2025 to 2030.We will briefly introduce the initiative and possible space science missions of SPPⅢ,including the preparatory work which already started in July 2021.Following the effective administrative tradition since SPPⅠ,National Space Science Center(NSSC,CAS)is responsible for the whole procedure,including soliciting,assessment,and implementation of SPPⅢ.Brief information on the 13 candidate missions will be described,including missions in the fields of astronomy&astrophysics,exoplanets,heliophysics and planetary&Earth science,respectively.展开更多
Since 2011,the Chinese Academy of Sciences(CAS)has implemented the Strategic Priority Program on Space Science(SPP).A series of scientific satellites have been developed and launched,such as Dark Matter Particle Explo...Since 2011,the Chinese Academy of Sciences(CAS)has implemented the Strategic Priority Program on Space Science(SPP).A series of scientific satellites have been developed and launched,such as Dark Matter Particle Explorer(DAMPE),Quantum Experiments at Space Scale(QUESS),Advanced Space-based Solar Observatory(ASO-S),Einstein Probe(EP),and significant scientific outcomes have been achieved.In order to plan the future space science missions in China,CAS has organized the Chinese space science community to conduct medium and long-term development strategy studies,and summarized the major scientific frontiers of space science as“One Black,Two Dark,Three Origins and Five Characterizations”.Five main scientific themes have been identified for China’s future breakthroughs,including the Extreme Universe,Space-Time Ripples,the Panoramic View of the Sun and Earth,the Habitable Planets,and Biological&Physical Science in Space.Space science satellite missions to be implemented before 2030 are proposed accordingly.展开更多
To meet the increasing research demand for deep space exploration,especially for the second libration point (L2) conditional periodic orbit (Halo orbit) in the Sun-Earth system,the methods to get analytical Halo orbit...To meet the increasing research demand for deep space exploration,especially for the second libration point (L2) conditional periodic orbit (Halo orbit) in the Sun-Earth system,the methods to get analytical Halo orbit and differential-correction Halo orbit were described firstly,and the corresponding orbits accuracy was analyzed.Then,based on the results of third-order and differential-correction Halo orbits,the formation form was studied.Analysis was carried out to discuss the influence of system amplitude,initial phase,and phase difference on the formation form,as well as that of initial orbit values on form accuracy.Finally,some simulation results demonstrate the validity of the proposed methods.展开更多
First, this paper suggests a hypothetical formula that aims to explain how we are conditioned to think. Finding different ways to think about relevant decisions and problems through multilogical approaches could help ...First, this paper suggests a hypothetical formula that aims to explain how we are conditioned to think. Finding different ways to think about relevant decisions and problems through multilogical approaches could help make the decision-making or problem easier to understand and manage than any conventional one-directional way of thinking (or monological thinking). Secondly, one theory to help understand the quality of how we think is through associating ideas of reality with what we observe. This is helpful through a theory such as Memetics, or the study of memes (and evolutionary replicator points [genes, memes, tremes]), as coined by Richard Dawkins in his 1976 book, <i>The Selfish Gene</i>, and proposed by other authors including Dr. Susan Blackmore (“The meme machine”, 1999). Plenty of indications and evidences seem to show how we are entering the third replicator point (technomemes), consisting in a psycho-sociological process of merging human beings and societies (memeplexes) with technological advancement. Digital and non-digital relationships to our values/ideas/ideologies and beliefs make us think differently and often via manners that can damage our reasoning skills and proper ways to process information (see problematic topics such as “post-truth era”, disinformation, information overload, anti-science and anti-intellectual trends, conspiracies and so on), but we still do not have any educational and/or individual training to understand critically and apply such an understanding in such relationships (through states of mind). This paper intends to explore a theory of Metamemetics and Multilogical Thinking theorized by Diego Fontanive (<a href="https://en.wikipedia.org/wiki/Memetics">https://en.wikipedia.org/wiki/Memetics</a> see: *terminology, see: *Meta-memetic thinking). Lastly, this approach is explored and applied with examples of approaches to problems people hypothetically have. This exploration is put into the context of space exploration and studying the psychology of individuals who are in solitary situations for long periods.展开更多
文摘Deep space is incredibly quiet,but once astronauts leave the station,they must contend with extreme temperatures,fluctuating pressures,and high levels of radiation.Their spacesuits are equipped with life-support systems,which are essential for a safe“walk in space.”On 15 August,the crew of Shenzhou-20 successfully completed their third spacewalk.For this mission,taikonaut Chen Dong wore the extravehicular spacesuit B,which has now been used in 20 spacewalks.With this achievement,the space station has reached the target of“four years and 20 spacewalks.”
文摘The early involvement of test and evaluation can significantly reduce the cost of modifying issues and errors found in the later stages of aircraft development and design process.This paper presents a methodology for aircraft mission effectiveness evaluation and design space exploration based on Virtual Operational Test(VOT),incorporating Virtual Open Scenario(VOS)and User in Scenarios(UIS)concepts.By employing modeling and simulation technologies in the early stages of aircraft development and design,a virtual environment can be constructed,allowing aircraft users to participate more closely and conveniently in the design process.Virtual tests conducted by users within the mission context provide data on mission effectiveness and critical user feedback.This paper outlines the main components of the virtual operational test process and related conceptual methods,and discusses an open support system framework that supports VOT.The effectiveness and adaptability of the method are demonstrated through two case studies:a beyond-visual-range air combat scenario and a helicopter ground attack scenario.These case studies demonstrate the evaluation of aircraft mission effectiveness and the sensitivity analysis and optimization of design and operational parameters based on VOT.
基金Supported by National Natural Science Foundation of China (Grant No.51775141)Heilongjiang Touyan Innovation Team Program。
文摘The spacecraft for deep space exploration missions will face extreme environments,including cryogenic temperature,intense radiation,wide-range temperature variations and even the combination of conditions mentioned above.Harsh environments will lead to solder joints degradation or even failure,resulting in damage to onboard electronics.The research activities on high reliability solder joints using in extreme environments can not only reduce the use of onboard protection devices,but effectively improve the overall reliability of spacecraft,which is of great significance to the aviation industry.In this paper,we review the reliability research on SnPb solder alloys,Sn-based lead-free solder alloys and In-based solder alloys in extreme environments,and try to provide some suggestions for the follow-up studies,which focus on solder joint reliability under extreme environments.
基金Supported by National Key R&D Program of China(2020YFE0202100)Beijing Municipal Science and Technology Commission(Z181100002918003)。
文摘China has carried out four unmanned missions to the Moon since it launched Chang’E-1,the first lunar orbiter in 2007.With the implementation of the Chang’E-5 mission this year,the three phases of the lunar exploration program,namely orbiting,landing and returning,have been completed.In the plan of follow-up unmanned lunar exploration missions,it is planned to establish an experimental lunar research station at the lunar south pole by 2030 through the implementation of several missions,laying a foundation for the establishment of practical lunar research station in the future.China successfully launched its first Mars probe on 23 July 2020,followed in future by an asteroid mission,second Mars mission,and a mission to explore Jupiter and its moons.
基金Supported by the B-type Strategic Priority Program of the Chinese Academy of Sciences(XDB41000000)the National Natural Science Foundation of China(11773081,11573073)CAS Interdisciplinary Innovation Team,Foundation of Minor Planets of the Purple Mountain Observatory and Youth Innovation Promotion Association。
文摘Four future missions for deep space exploration and future space-based exoplanet surveys on habitable planets by 2030 are scheduled to be launched.Two Mars exploration missions are designed to investigate geological structure,the material on Martian surface,and retrieve returned samples.The asteroids and main belt comet exploration is expected to explore two objects within 10 years.The small-body mission will aim to land on the asteroid and get samples return to Earth.The basic physical characteristics of the two objects will be obtained through the mission.The exploration of Jupiter system will characterize the environment of Jupiter and the four largest Moons and understand the atmosphere of Jupiter.In addition,we further introduce two space-based exoplanet survey by 2030,Miyin Program and Closeby Habitable Exoplanet Survey(CHES Mission).Miyin program aims to detect habitable exoplanets using interferometry,while CHES mission expects to discover habitable exoplanets orbiting FGK stars within 10 pc through astrometry.The above-mentioned missions are positively to achieve breakthroughs in the field of planetary science.
基金Supported by Fundamental Research Funds for the Central Universities of China(Grant No.2021JBM021)National Natural Science Foundation of China(Grant Nos.52202431,52172353).
文摘The footpad structure of a deep space exploration lander is a critical system that makes the initial contact with the ground,and thereby plays a crucial role in determining the stability and energy absorption characteristics during the impact process.The conventional footpad is typically designed with an aluminum honeycomb structure that dissipates energy through plastic deformation.Nevertheless,its effectiveness in providing cushioning and energy absorption becomes significantly compromised when the structure is crushed,rendering it unusable for reusable landers in the future.This study presents a methodology for designing and evaluating structural energy absorption systems incorporating recoverable strain constraints of shape memory alloys(SMA).The topological configuration of the energy absorbing structure is derived using an equivalent static load method(ESL),and three lightweight footpad designs featuring honeycomb-like Ni-Ti shape memory alloys structures and having variable stiffness skins are proposed.To verify the accuracy of the numerical modelling,a honeycomb-like structure subjected to compression load is modeled and then compared with experimental results.Moreover,the influence of the configurations and thickness distribution of the proposed structures on their energy absorption performance is comprehensively evaluated using finite element simulations.The results demonstrate that the proposed design approach effectively regulates the strain threshold to maintain the SMA within the constraint of maximum recoverable strain,resulting in a structural energy absorption capacity of 362 J/kg with a crushing force efficiency greater than 63%.
文摘In order to realize the explorer autonomy, the software architecture of autonomous mission management system (AMMS) is given for the deep space explorer, and the autonomous mission planning system, the kernel part of this architecture, is designed in detail. In order to describe the parallel activity, the state timeline is introduced to build the formal model of the planning system and based on this model, the temporal constraint satisfaction planning algorithm is proposed to produce the explorer’s activity sequence. With some key subsystems of the deep space explorer as examples, the autonomous mission planning simulation system is designed. The results show that this system can calculate the executable activity sequence with the given mission goals and initial state of the explorer.
文摘Space environment exploration is a hot topic globally.The scope of space exploration ranges from near-Earth space to the moon,other planets in the solar system,and even the heliosphere and interplanetary space.It is used for various crucial applications,including aerospace technology development,space weather research,understanding the origin and evolution of the universe,searching for extraterrestrial life,and finding human livable places.Although China’s space environment exploration started late,its progress has been rapid.China is gradually narrowing the gap with advanced countries and may eventually lead the world in space research.This article briefly reviews the development history of China’s space environmental detectors.
文摘China has successfully launched six lunar probes so far.From Chang'E-1 to Chang'E-4,they completed the circling,landing and roving exploration,of which Chang'E-4 was the first landing on the far side of the Moon in human history.Chang'E-5 was launched in December 2020,bringing back 1731 g of lunar soil samples.Through the detailed analysis of the samples,the scientists understand the history of late lunar volcanism,specifically extending lunar volcanism by about 800 million to 1 billion years,and proposed possible mechanisms.In addition,there are many new understandings of space weathering such as meteorite impacts and solar wind radiation on the Moon.China's first Mars exploration mission Tianwen-1 was successfully launched in July 2021.Through the study of scientific data,a number of important scientific achievements have been made in the topography,water environment and shallow surface structure of Mars.This paper introduces the main scientific achievements of Chang'E-4,Chang'E-5 and Tianwen-1 in the past two years,excluding technical and engineering contents.Due to the large number of articles involved,this paper only introduces part of the results.
基金the National Key R&D Program of China(No.2018AAA0103300)the National Natural Science Foundation of China(No.61925208,U20A20227,U22A2028)+1 种基金the Chinese Academy of Sciences Project for Young Scientists in Basic Research(No.YSBR-029)the Youth Innovation Promotion Association Chinese Academy of Sciences.
文摘With the increasing demand of computational power in artificial intelligence(AI)algorithms,dedicated accelerators have become a necessity.However,the complexity of hardware architectures,vast design search space,and complex tasks of accelerators have posed significant challenges.Tra-ditional search methods can become prohibitively slow if the search space continues to be expanded.A design space exploration(DSE)method is proposed based on transfer learning,which reduces the time for repeated training and uses multi-task models for different tasks on the same processor.The proposed method accurately predicts the latency and energy consumption associated with neural net-work accelerator design parameters,enabling faster identification of optimal outcomes compared with traditional methods.And compared with other DSE methods by using multilayer perceptron(MLP),the required training time is shorter.Comparative experiments with other methods demonstrate that the proposed method improves the efficiency of DSE without compromising the accuracy of the re-sults.
基金supported in part by the National Natural Science Foundation of China(Grant No.52275241)the Fund for National Key Laboratory of Space Environment and Matter Behaviors(Grant No.2023059).
文摘Deep space exploration missions and the construction of planetary research stations impose strict demands on energy self-sufficiency systems.Solar energy,due to its abundant availability and sustainability,has become the preferred solution.However,extreme environmental conditions in space-including drastic temperature fluctuations,vacuum environments,high-energy particles,and intense radiation-pose significant challenges to the performance and lifespan of solar energy systems.Concentration technology,which enhances photoelectric and photothermal conversion efficiency by focusing sunlight,is crucial for space missions.This review examines the primary environmental factors affecting the performance of solar concentrators,including solar irradiance,thermal cycling,vacuum-induced outgassing,radiation effects,and impacts from micrometeoroids and orbital debris.The analysis focuses on three types of high-temperature concentrators:Fresnel lenses,Scheffler concentrators,and parabolic dish concentrators.Fresnel lenses are characterized by low cost and simple structure but are susceptible to optical degradation at high temperatures.Scheffler concentrators utilize geometric optimization to improve uniformity of light distribution,while parabolic dish concentrators achieve high optical efficiency,making them suitable for high-energy applications though requiring precise solar tracking.Performance comparisons in the thermal power range of 0 to 25 kW reveal that parabolic dish concentrators excel in high-power scenarios with greater efficiency and smaller aperture sizes.Conversely,Fresnel lenses and Scheffler concentrators are more effective in medium to low-temperature applications.Based on these findings,this review emphasizes the need to select concentrators according to mission requirements and outlines future research directions.These include the development of advanced materials,optimized optical designs,and improvements in system integration to enhance the adaptability and reliability of solar concentration technologies in deep space missions.
基金the Collaborative Innovation Project of Shanghai,China for the financial support。
文摘Unmanned Aerial Vehicle(UAV)plays a prominent role in various fields,and autonomous navigation is a crucial component of UAV intelligence.Deep Reinforcement Learning(DRL)has expanded the research avenues for addressing challenges in autonomous navigation.Nonetheless,challenges persist,including getting stuck in local optima,consuming excessive computations during action space exploration,and neglecting deterministic experience.This paper proposes a noise-driven enhancement strategy.In accordance with the overall learning phases,a global noise control method is designed,while a differentiated local noise control method is developed by analyzing the exploration demands of four typical situations encountered by UAV during navigation.Both methods are integrated into a dual-model for noise control to regulate action space exploration.Furthermore,noise dual experience replay buffers are designed to optimize the rational utilization of both deterministic and noisy experience.In uncertain environments,based on the Twin Delay Deep Deterministic Policy Gradient(TD3)algorithm with Long Short-Term Memory(LSTM)network and Priority Experience Replay(PER),a Noise-Driven Enhancement Priority Memory TD3(NDE-PMTD3)is developed.We established a simulation environment to compare different algorithms,and the performance of the algorithms is analyzed in various scenarios.The training results indicate that the proposed algorithm accelerates the convergence speed and enhances the convergence stability.In test experiments,the proposed algorithm successfully and efficiently performs autonomous navigation tasks in diverse environments,demonstrating superior generalization results.
基金supported by the National Science and Technology Major Project on Lunar Exploration Program and the National High Technology Research and Development Program ("863" Program) (Grant Nos. 2010AA122206 and 2010AA7030506C)
文摘Deep space exploration is the term used for the exploration of the Moon and the celestial bodies or space beyond the Moon, which is an important part of human space activities. Firstly, the development of deep space exploration (not including the Moon) during the last few decades is summarized. Secondly, the development trend of different space countries and regions is analyzed. Then the experience and enlightenment of deep space exploration are briefly discussed. Some suggestions for China's future deep space exploration are given in the end.
基金supported by the National Natural Science Foundation of China (32272807,U1703232)the National Key Research and Development Program of China (2017YFD0200200)。
文摘Ecology seeks to explain species coexistence,but experimental tests of mechanisms for coexistence are difficult to conduct.We synthesized an arbuscular mycorrhizal(AM)fungal community with three fungal species that differed in their capacity of foraging for orthophosphate(P)due to differences in soil exploration.We tested whether AM fungal species-specific hyphosphere bacterial assemblages recruited by hyphal exudates enabled differentiation among the fungi in the capacity of mobilizing soil organic P(P_(o)).We found that the less efficient space explorer,Gigaspora margarita,obtained less ^(13)C from the plant,whereas it had higher efficiencies in P_(o)mobilization and alkaline phosphatase(Al Pase)production per unit C than the two efficient space explorers,Rhizophagusintraradices and Funneliformis mosseae.Each AM fungus was associated with a distinct alp gene harboring bacterial assemblage,and the alp gene abundance and P_(o)preference of the microbiome associated with the less efficient space explorer were higher than those of the two other species.We conclude that the traits of AM fungal associated bacterial consortia cause niche differentiation.The trade-off between foraging ability and the ability to recruit effective P_(o)mobilizing microbiomes is a mechanism that allows co-existence of AM fungal species in a single plant root and surrounding soil habitat.
基金supported by the NSFC project(61972278)the NSFC project(62372321).
文摘Drug molecule design is a classic research topic.Drug experts traditionally design molecules relying on their experience.Manual drug design is time-consuming and may produce low-efficacy and offtarget molecules.With the popularity of deep learning,drug experts are beginning to use generative models to design drug molecules.A well-trained generative model can learn the distribution of training samples and infinitely generate drug-like molecules similar to the training samples.The automatic process improves design efficiency.However,most existing methods focus on proposing and optimizing generative models.How to discover ideal molecules from massive candidates is still an unresolved challenge.We propose a visualization system to discover ideal drug molecules generated by generative models.In this paper,we investigated the requirements and issues of drug design experts when using generative models,i.e.,generating molecular structures with specific constraints and finding other molecular structures similar to potential drug molecular structures.We formalized the first problem as an optimization problem and proposed using a genetic algorithm to solve it.For the second problem,we proposed using a neighborhood sampling algorithm based on the continuity of the latent space to find solutions.We integrated the proposed algorithms into a visualization tool,and a case study for discovering potential drug molecules to make KOR agonists and experiments demonstrated the utility of our approach.
基金The authors would like to thank the reviewers for their feedback and suggestions. We also wish to mention that this work is partly supported by Singapore Ministry of Education Academic Research Fund Tier 1 （R-263-000-655-133） and National Natural Science Foundation of China （NSFC） （Grant No. 61173032）.
文摘Real-time multi-media applications are increasingly mapped on modern embedded systems based on multiprocessor systems-on-chip （MPSoC）. Tasks of the applications need to be mapped on the MPSoC resources efficiently in order to satisity their performance constraints. Exploring all the possible mappings, i.e., tasks to resources combinations exhaustively may take days or weeks. Additionally, the exploration is performed at design-time, which cannot handle dynamism in applications and resources＇ status. A runtime mapping technique can cater for the dynamism but cannot guarantee for strict timing deadlines due to large computations involved at run-time. Thus, an approach performing feasible compute intensive exploration at design-time and using the explored results at run-time is required. This paper presents a solution in the same direction. Communicationaware design space exploration （CADSE） techniques have been proposed to explore different mapping options to be selected at run-time subject to desired performance and available MPSoC resources. Experiments show that the proposed techniques for exploration are faster over an exhaustive exploration and provides almost the same quality of results.
基金Supported by Strategic Priority Research Program of the Chinese Academy of Sciences(XDA15060102)。
文摘The Strategic Priority Program(SPP)on Space Science,which is under the leadership of the Chinese Academy of Sciences(CAS),has established China’s space science satellite series from scratch.A number of major scientific achievements have been made by the first phase of the Program(SPPⅠ),while SPPⅡhas been currently being implemented.The future development of space science needs urgent top-level planning and advanced layout to clarify the overall goal and investment portfolio from 2025 to 2030.We will briefly introduce the initiative and possible space science missions of SPPⅢ,including the preparatory work which already started in July 2021.Following the effective administrative tradition since SPPⅠ,National Space Science Center(NSSC,CAS)is responsible for the whole procedure,including soliciting,assessment,and implementation of SPPⅢ.Brief information on the 13 candidate missions will be described,including missions in the fields of astronomy&astrophysics,exoplanets,heliophysics and planetary&Earth science,respectively.
基金Supported by Consultation and Evaluation Program on Academic Divisions of the Chinese Academy of Sciences(2022-DX02-B-007)。
文摘Since 2011,the Chinese Academy of Sciences(CAS)has implemented the Strategic Priority Program on Space Science(SPP).A series of scientific satellites have been developed and launched,such as Dark Matter Particle Explorer(DAMPE),Quantum Experiments at Space Scale(QUESS),Advanced Space-based Solar Observatory(ASO-S),Einstein Probe(EP),and significant scientific outcomes have been achieved.In order to plan the future space science missions in China,CAS has organized the Chinese space science community to conduct medium and long-term development strategy studies,and summarized the major scientific frontiers of space science as“One Black,Two Dark,Three Origins and Five Characterizations”.Five main scientific themes have been identified for China’s future breakthroughs,including the Extreme Universe,Space-Time Ripples,the Panoramic View of the Sun and Earth,the Habitable Planets,and Biological&Physical Science in Space.Space science satellite missions to be implemented before 2030 are proposed accordingly.
文摘To meet the increasing research demand for deep space exploration,especially for the second libration point (L2) conditional periodic orbit (Halo orbit) in the Sun-Earth system,the methods to get analytical Halo orbit and differential-correction Halo orbit were described firstly,and the corresponding orbits accuracy was analyzed.Then,based on the results of third-order and differential-correction Halo orbits,the formation form was studied.Analysis was carried out to discuss the influence of system amplitude,initial phase,and phase difference on the formation form,as well as that of initial orbit values on form accuracy.Finally,some simulation results demonstrate the validity of the proposed methods.
文摘First, this paper suggests a hypothetical formula that aims to explain how we are conditioned to think. Finding different ways to think about relevant decisions and problems through multilogical approaches could help make the decision-making or problem easier to understand and manage than any conventional one-directional way of thinking (or monological thinking). Secondly, one theory to help understand the quality of how we think is through associating ideas of reality with what we observe. This is helpful through a theory such as Memetics, or the study of memes (and evolutionary replicator points [genes, memes, tremes]), as coined by Richard Dawkins in his 1976 book, <i>The Selfish Gene</i>, and proposed by other authors including Dr. Susan Blackmore (“The meme machine”, 1999). Plenty of indications and evidences seem to show how we are entering the third replicator point (technomemes), consisting in a psycho-sociological process of merging human beings and societies (memeplexes) with technological advancement. Digital and non-digital relationships to our values/ideas/ideologies and beliefs make us think differently and often via manners that can damage our reasoning skills and proper ways to process information (see problematic topics such as “post-truth era”, disinformation, information overload, anti-science and anti-intellectual trends, conspiracies and so on), but we still do not have any educational and/or individual training to understand critically and apply such an understanding in such relationships (through states of mind). This paper intends to explore a theory of Metamemetics and Multilogical Thinking theorized by Diego Fontanive (<a href="https://en.wikipedia.org/wiki/Memetics">https://en.wikipedia.org/wiki/Memetics</a> see: *terminology, see: *Meta-memetic thinking). Lastly, this approach is explored and applied with examples of approaches to problems people hypothetically have. This exploration is put into the context of space exploration and studying the psychology of individuals who are in solitary situations for long periods.
