The unique characteristics of the deep space environment,microgravity,cosmic radiation,and extreme temperature fluctuations,are emerging as major driving forces for pharmaceutical innovation.These factors provide new ...The unique characteristics of the deep space environment,microgravity,cosmic radiation,and extreme temperature fluctuations,are emerging as major driving forces for pharmaceutical innovation.These factors provide new avenues for optimizing drug formulations,improving crystal structure quality,and accelerating the discovery of therapeutic targets.Advances in deep space research not only help overcome critical bottlenecks in terrestrial drug development but also promote progress in structure-based drug design and deepen understanding of cellular stress-response mechanisms.Current progress in space-based pharmaceutical research primarily includes the study of disease mechanisms under microgravity,protein crystallization in microgravity,and drug development utilizing deep space radiation and resources.However,the operational complexity,high costs,and limited data reproducibility of space experiments remain key challenges hindering widespread application.Looking ahead,with the integration of automation,artificial intelligence analysis,and on-orbit manufacturing,deep space drug development is expected to achieve greater scalability and precision,opening a new frontier in biopharmaceutical science.展开更多
Satellite mega-constellations(SMCs)encounter significant operational challenges due to various space environmental effects.While the mechanisms underlying some of these effects have been studied from a physical perspe...Satellite mega-constellations(SMCs)encounter significant operational challenges due to various space environmental effects.While the mechanisms underlying some of these effects have been studied from a physical perspective,their precise impact on the network performance of SMCs remains unclear.To elucidate this further,this study investigates the spatiotemporal distribution characteristics of space environmental effects,such as solar radiation,ionizing radiation,and space debris,and the associated failure mechanisms in the nodes and links of SMCs.In addition,the impacts of solar radiation and single-event effects on performance of SMC system,particularly network throughput capacity,are examined.Results reveal that under the effect of the space environment,the throughput capacity degradation of SMC system varies with different parameters such as orbital altitude and inclination.Most importantly,the results bridge the gap between the physical phenomena of space environmental effects and network-level modeling.Finally,future research directions are prospected,regarding network topology control,constellation architecture,network routing techniques,and so on,to help mitigate network performance degradation due to space environmental effects.展开更多
The paper studies the nonlinear dynamics of a flexible tethered satellite system subject to space environments, such as the J2 perturbation, the air drag force, the solar pressure, the heating effect, and the orbital ...The paper studies the nonlinear dynamics of a flexible tethered satellite system subject to space environments, such as the J2 perturbation, the air drag force, the solar pressure, the heating effect, and the orbital eccentricity. The flexible tether is modeled as a series of lumped masses and viscoelastic dampers so that a finite multi- degree-of-freedom nonlinear system is obtained. The stability of equilibrium positions of the nonlinear system is then analyzed via a simplified two-degree-freedom model in an orbital reference frame. In-plane motions of the tethered satellite system are studied numerically, taking the space environments into account. A large number of numerical simulations show that the flexible tethered satellite system displays nonlinear dynamic characteristics, such as bifurcations, quasi-periodic oscillations, and chaotic motions.展开更多
For the purpose of ensuring normal operations of Shenzhou (SZ) series of manned spacecrafts and cosmonauts' safety, Space Environment Monitors (SEM)are mounted on board SZ-2, 3, 4, 5. SEMs aim to detect the high e...For the purpose of ensuring normal operations of Shenzhou (SZ) series of manned spacecrafts and cosmonauts' safety, Space Environment Monitors (SEM)are mounted on board SZ-2, 3, 4, 5. SEMs aim to detect the high energy particles, the low energy particles, charging potential, atmospheric desity and composition. Detection of SEMs enable us to understand better the space environment in the manned spacecraft's orbit, and to provide a good space environment services for the spacecraft and cosmonauts. In addition, by using the data from SEMs, we have achieved some scientific accomplishments, such as the energy spectra of precipitating electrons, the abnormal variety of atmospheric density and composition during geomagnetic disturbances, the electron angle distribution in the low orbit and so on.展开更多
Tianhe Core Module of China Space Station(CSS)equips a set of instruments consisting of a Particle Fluxes and Solar Activity Detector(PFSAD)and two Atmospheric Density Multi-directional Detectors(ADMDs).The PFSAD is t...Tianhe Core Module of China Space Station(CSS)equips a set of instruments consisting of a Particle Fluxes and Solar Activity Detector(PFSAD)and two Atmospheric Density Multi-directional Detectors(ADMDs).The PFSAD is to measure X-rays from the Sun and energetic particles in the low-latitude and low altitude regions,including electrons,protons,and helium ions.The ADMDs are to measure thermospheric atmospheric density.The instruments provide real-time data of the orbital space environment,including solar flares,energetic particle variation and thermospheric density enhancement.All the data contribute to the CSS space weather service for mission control and astronaut’s safety.The paper gives preliminary analyses of the space environment measurements from the PFSAD and the ADMDs.By further analysis,the 1024-channel fine spectra of the solar X-ray can be used to study the mechanism of solar flares and their impacts on the Earth’s atmosphere.Data accumulation will be helpful for analyzing mid-term and long-term variations of the South Atlantic Anomaly and atmosphere density.Furthermore,the data are useful to calibrate previous empirical models and establish new models to study the space environment.展开更多
The planet Earth is an integrated system, in which its multi-spheres are coupled, from the space to the inner core. Whether the space environment in short to long terms has been controlled by the earth's interior ...The planet Earth is an integrated system, in which its multi-spheres are coupled, from the space to the inner core. Whether the space environment in short to long terms has been controlled by the earth's interior process is contentious. In the past several decades,space weather and space climate have been extensively studied based on either observation data measured directly by man-made instruments or ancient data inferred indirectly from some historical medium of past thousands of years. The acquired knowledge greatly helps us to understand the dynamic processes in the space environment of modern Earth, which has a strong magnetic dipole and an oxygen-rich atmosphere. However, no data is available for ancient space weather and climate(>5 ka). Here, we propose to take the advantage of " space-diversity" to build a " generalized planetary space family", to reconcile the ancient space environment evolution of planet Earth from modern observations of other planets in our solar system. Such a method could also in turn give us a valuable insight into other planets' evolution.展开更多
Volume visualization can not only illustrate overall distribution but also inner structure and it is an important approach for space environment research.Space environment simulation can produce several correlated var...Volume visualization can not only illustrate overall distribution but also inner structure and it is an important approach for space environment research.Space environment simulation can produce several correlated variables at the same time.However,existing compressed volume rendering methods only consider reducing the redundant information in a single volume of a specific variable,not dealing with the redundant information among these variables.For space environment volume data with multi-correlated variables,based on the HVQ-1d method we propose a further improved HVQ method by compositing variable-specific levels to reduce the redundant information among these variables.The volume data associated with each variable is divided into disjoint blocks of size 43 initially.The blocks are represented as two levels,a mean level and a detail level.The variable-specific mean levels and detail levels are combined respectively to form a larger global mean level and a larger global detail level.To both global levels,a splitting based on a principal component analysis is applied to compute initial codebooks.Then,LBG algorithm is conducted for codebook refinement and quantization.We further take advantage of progressive rendering based on GPU for real-time interactive visualization.Our method has been tested along with HVQ and HVQ-1d on high-energy proton flux volume data,including>5,>10,>30 and>50 MeV integrated proton flux.The results of our experiments prove that the method proposed in this paper pays the least cost of quality at compression,achieves a higher decompression and rendering speed compared with HVQ and provides satisficed fidelity while ensuring interactive rendering speed.展开更多
The Space Environment Prediction Center (SEPC) of the Center for Space Science and Applied Research of the Chinese Academy of Sciences (CSSAR, CAS)took on the mission of offering the space environment parameters which...The Space Environment Prediction Center (SEPC) of the Center for Space Science and Applied Research of the Chinese Academy of Sciences (CSSAR, CAS)took on the mission of offering the space environment parameters which may be of use to the safety of manned spacecraft. In order to complete the space environment safety guarantee mission for SZ-4 and SZ-5, SEPC improved the space environment monitoring system, database system, prediction result display system, prediction implementation system, etc. For guaranteeing the safety of the airship and cosmonaut in the first manned SZ-5, flying experiment mission,SEPC developed the software for analyzing radiation dose and early-warning software for large debris collision with SZ-5. Three months before the flights of SZ-4 and SZ-5, SEPC began to predict the safe launch period in view of the space environment, and offered timely and valid reference opinions for selecting the safety period. Especially during the mission of SZ-5, SEPC analyzed the space high-energy environment in a pre-arranged orbit and abnormal orbit andevaluated the radiation dose which cosmonauts may encounter in space. The evaluation offered an important reference for cosmonaut safety and decisionmaking in the SZ-5 mission. The calculation of the distribution of large debris and the collision risk assessment at different orbit entry times for SZ-5 provided an important base for the superior department to make flight decisions.展开更多
In the mid July, 2011, the GVU-600 space environment simulator developed by Bei-jing Institute of Spacecraft Environment Engineering of China Academy of Space Technology (CAST) under China
3D printing technology can realize the rapid fabrication of complicated structures with short production chain,which just meet the requirements for space manufacturing in the future.This Special Issue features the cut...3D printing technology can realize the rapid fabrication of complicated structures with short production chain,which just meet the requirements for space manufacturing in the future.This Special Issue features the cutting-edge 3D printing technologies considering the space environment,focusing on the experimental validation and simulation on the 3D printing process and structural technologies,including whole process chain from raw materials,structural design,process,equipment,as well as functional verification.展开更多
Polyimide(PI)is widely used in aerospace applications due to its excellent electrical insulation and thermal stability.However,prolonged exposure to high-temperature vacuum conditions in space can significantly compro...Polyimide(PI)is widely used in aerospace applications due to its excellent electrical insulation and thermal stability.However,prolonged exposure to high-temperature vacuum conditions in space can significantly compromise its structural integrity and reliability.To gain deeper insight into the pyrolysis behaviour and structural evolution of PI,this study employs molecular dynamics(MD)simulations to conduct full-scale dynamic tracking of the heating process from 300 K to 3800 K.The evolution of bond breakage,gas-phase product formation,and system free volume is monitored in real time.The results indicate that PI pyrolysis proceeds in three distinct stages:an initial induction phase,a rapid decomposition phase,and a prolonged evolution phase.Product analysis reveals that CO accounts for 47.3%of gaseous species,primarily originating from the cleavage of carbonyl groups in the imide ring;H_(2)O makes up 18.4%,closely related to hydroxyl radical recombination;and C_(5)-C_(10) hydrocarbon fragments constitute 15.6%,reflecting deep fragmentation and molecular rearrangement.As temperature increases from 300 K to 800 K,the free volume fraction rises from 16.9%to 27.7%,indicating significant structural relaxation and diffusion pathway expansion.This work elucidates the multi-stage cooperative mechanism of PI pyrolysis at the atomic level and provides a theoretical basis for improving thermal stability and evaluating service life in aerospace environments.展开更多
Space solar power stations(SSPS)present a promising solution for addressing global energy challenges.However,the in-orbit operation of SSPS will be subjected to harsh space environments.The space environments and thei...Space solar power stations(SSPS)present a promising solution for addressing global energy challenges.However,the in-orbit operation of SSPS will be subjected to harsh space environments.The space environments and their effects on the SSPS are analyzed firstly in this paper,followed by a discussion of the unique characteristics and requirements of SSPS,including ultra-large-area structures,ultra-high-power electrical systems,ultra-long distance wireless energy transmission,ultra-high-power electronic devices,and ultra-long service life.And then the key technical issues related to the space environmental adaptability of SSPS are systematically investigated,and a corresponding framework of countermeasures and engineering solutions are proposed.展开更多
The space environment monitor(SEM)aboard FY-2 satellite consists of the high energy particle detector(HEPD)and the solar X-ray flux detector(SXFD).The SEM can provide real-time monitoring of flare and solar proton eve...The space environment monitor(SEM)aboard FY-2 satellite consists of the high energy particle detector(HEPD)and the solar X-ray flux detector(SXFD).The SEM can provide real-time monitoring of flare and solar proton event for its operation at geostationary orbit and is also the first Chinese space system for monitoring and alerting solar proton event.During the 23rd solar maximum cycle,almost all the solar proton events that took place in this period are monitored and some of them are predicted successfully by analyzing the characteristics of X-ray flare monitored by the SEM.Some basic variation characteristics of particle at geostationary orbit are found such as day-night periodic variation of particle flux,the electron flux with energy>1.4 MeV in the scope from 10 to 200/cm^(2).s-sr and the proton flux with energy>1.1 MeV in the scope from 600 to 8000/cm^(2)-s.sr during the time with no magnetic storm and solar eruption.展开更多
To further study the characteristics of changes on the molecular level of rice mutants induced in space environment, we analyzed proteins in leaves and seeds of four rice mutants （two high-tillering and two low-tille...To further study the characteristics of changes on the molecular level of rice mutants induced in space environment, we analyzed proteins in leaves and seeds of four rice mutants （two high-tillering and two low-tillering） in the 8th and 9th generations after a 15-day spaceflight, and compared with their ground controls by two-dimentional polyacrylamide gel electrophoresis and reverse phase liquid chromatography （RPLC）. In addition, the albumin, globulin, prolamine, glutelin, and amylose of the mutant seeds were analyzed by RPLC and ultra-violet spectrometry. The results showed that the low-abundance proteins of leaves in the peak tillering stage are more likely to he induced compared with their corresponding controls. The albumin, globulin, and prolamine of the mutant seeds revealed changes when compared with their controls, and the characteristics of changes in different mu- tants were stably inherited in the 8th and 9th generations, suggesting that they can be used as biomarkers to identity the mutants induced by spaceflight. Moreover, two proteins （SSP9111 and SSP6302） were found to be expressed with high intensity （two-fold change） in different mutants, which were both correlated with photosystem according to mass spectrometry and database searching.展开更多
A considerable portion of space mechanism failures are related to space tribological problems.Cold welding in high vacuum;surface erosion and collision damage caused by various radiations,high temperature oxidation un...A considerable portion of space mechanism failures are related to space tribological problems.Cold welding in high vacuum;surface erosion and collision damage caused by various radiations,high temperature oxidation under atomic oxygen(AO)bombardment;and thermal stress caused by temperature alternation all alter the physical,chemical,and friction properties of materials.In particular,the space vibration caused by alternating temperatures and microgravity environments can alter the motion of the contact body,further affecting its friction properties.Improving the friction properties of contact surfaces in the space environment is an important way to extend the service life of spacecraft.Traditional lubricants can no longer meet the lubrication requirements of the space environment.This study describes the characteristics of the space environment and the applications of solid lubricants.The friction properties of MoS_(2),a solid lubricant widely used in space,are discussed.The synergistic lubrication of MoS_(2)with surface textures or metals is presented.Advances in research on the friction properties of collision sliding contacts in the space environment are reviewed.The combination of MoS_(2)and soft metals with surface textures is introduced to reduce the effects of vibration environments on the friction properties of moving parts in space mechanisms.Finally,the challenges and future research interests of MoS_(2)films in space tribology are presented.展开更多
Space solar power station(SSPS)are important space infrastructure for humans to efficiently utilize solar energy and can effectively reduce the pollution of fossil fuels to the earth’s natural environment.As the ener...Space solar power station(SSPS)are important space infrastructure for humans to efficiently utilize solar energy and can effectively reduce the pollution of fossil fuels to the earth’s natural environment.As the energy conversion system of SSPS,solar array is an important unit for the successful service of SSPS.Today,solar arrays represent the standard technology for providing energy for spacecraft,thanks to their high conversion efficiency and reliability/stability in orbit.With the development of solar arrays,many new materials,new photovoltaic devices and new control systems have emerged.Solar arrays are directly exposed to the space environment,and harsh environmental factors can degrade the performance.To ensure the long-term safe inorbit service of SSPS as well as its ultra-large solar array,these new materials,devices,and control systems must operate certification and evaluation that can be used in space applications.In this review,the development history and research progress of SSPS and the corresponding space solar arrays are summarized and discussed,and the space environmental effects of solar arrays are analyzed at multiple levels(materials,devices,and systems).Finally,in response to the current space environmental effects of the ultra-large solar array used in the SSPS,future development trends and challenges are proposed.展开更多
This paper systematically investigated the impact mechanisms of proton irradiation,atomic oxygen irradiation and space debris collision,both individually and in combination,on the laser damage threshold and damage evo...This paper systematically investigated the impact mechanisms of proton irradiation,atomic oxygen irradiation and space debris collision,both individually and in combination,on the laser damage threshold and damage evolution characteristics of HfO_(2)/SiO_(2) triple-band high-reflection films and fused silica substrates using a simulated near-Earth space radiation experimental system.For the high-reflection film samples,the damage thresholds decreased by 15.38%,13.12% and 46.80% after proton,atomic oxygen and simulated space debris(penetration) irradiation,respectively.The coupling irradiation of the first two factors resulted in a decrease of 26.93%,while the combined effect of all the three factors led to a reduction of 63.19%.Similarly,the fused silica substrates exhibited the same pattern of laser damage performance degradation.Notably,the study employed high-precision fixed-point in situ measurement techniques to track in detail the microstructural changes,surface roughness and optical-thermal absorption intensity before and after proton and atomic oxygen irradiation at the same location,thus providing a more accurate and comprehensive analysis of the damage mechanisms.In addition,simulations were conducted to quantitatively analyze the transmission trajectories and concentration distribution lines of protons and atomic oxygen incident at specific angles into the target material.The research findings contribute to elucidating the laser damage performance degradation mechanism of transmissive elements in near-Earth space environments and provide technical support for the development of high-damage-threshold optical components resistant to space radiation.展开更多
To solve the problem of stray interference to star point target identification while a star sensor imaging to the sky, a study on space luminous environment adaptability of missile-borne star sensor was carried out. B...To solve the problem of stray interference to star point target identification while a star sensor imaging to the sky, a study on space luminous environment adaptability of missile-borne star sensor was carried out. By Plank blackbody radiation law and some astronomic knowledge, irradiancies of the stray at the star sensor working height were estimated. By relative astrophysical and mathematics knowledge, included angles between the star sensor optical axis point and the stray at any moment were calculated. The calculation correctness was verified with the star map software of Stellarium. By combining the upper analysis with the baffle suppression effect, a real-time model for space luminous environment of missile-borne star sensor was proposed. By signal-noise rate （SNR） criterion, the adaptability of missile-borne star sensor to space luminous environment was studied. As an example, a certain type of star sensor was considered when imaging to the starry sky on June 22, 2011 （the Summer Solstice） and September 20, 2011 （August 23 of the lunar year, last quarter moon） in Beijing. The space luminous environment and the adaptability to it were simulated and analyzed at the star sensor working height. In each period of time, the stray suppression of the baffle is analyzed by comparing the calculated included angle between the star sensor optical axis point and the stray with the shielded provided by system index. When the included angle is larger than the shielded angle and less than 90~, the stray is restrained by the baffle. The stray effect on star point target identification is analyzed by comparing the irradiancy of 6 magnitude star with that of the stray on star sensor sensitization surface. When the irradiancy of 6 magnitude star is 5 times more than that of the stray, there is no effect on the star point target identification. The simulation results are identicat with the actual situation. The space luminous environment of the missile-borne star sensor can be estimated real-timely by this model. The adaptability of the star sensor to space luminous environment can be analyzed conveniently. A basis for determining the relative star sensor indexes, the navigation star chosen strategy and the missile launch window can be provided.展开更多
It is known that ion channel can effectively limit the radial expansion of an artificial electron beam during its longrange propagation in the space plasma environment.Most prior studies discussed the focusing charact...It is known that ion channel can effectively limit the radial expansion of an artificial electron beam during its longrange propagation in the space plasma environment.Most prior studies discussed the focusing characteristics of the beam in the ion channel,but the establishment process and transient properties of the ion channel itself,which also plays a crucial role during the propagation of the relativistic electron beam in the plasma environment,were commonly neglected.In this study,a series of two-dimensional(2D)particle-in-cell simulations is performed and an analytical model of ion channel oscillation is constructed according to the single-particle motion.The results showed that when the beam density is higher than the density of plasma environment,ion channel can be established and always continues to oscillate periodically over the entire propagation.Multiple factors,including the beam electron density,initial beam radius,and the plasma density can affect the oscillation properties of ion channel.Axial velocity of the beam oscillates synchronously with the ion channel and this phenomenon will finally develop into a two-stream instability which can seriously affect the effective transport for relativistic electron beam.Choosing appropriate beam parameters based on various plasma environments may contribute to the improvement of the stability of ion channel.Additionally,radial expansion of the beam can be limited by ion channel and a stable long-range propagation in terrestrial atmosphere may be achieved.展开更多
基金supported by the National Natural Science Foundation of China(82272067).
文摘The unique characteristics of the deep space environment,microgravity,cosmic radiation,and extreme temperature fluctuations,are emerging as major driving forces for pharmaceutical innovation.These factors provide new avenues for optimizing drug formulations,improving crystal structure quality,and accelerating the discovery of therapeutic targets.Advances in deep space research not only help overcome critical bottlenecks in terrestrial drug development but also promote progress in structure-based drug design and deepen understanding of cellular stress-response mechanisms.Current progress in space-based pharmaceutical research primarily includes the study of disease mechanisms under microgravity,protein crystallization in microgravity,and drug development utilizing deep space radiation and resources.However,the operational complexity,high costs,and limited data reproducibility of space experiments remain key challenges hindering widespread application.Looking ahead,with the integration of automation,artificial intelligence analysis,and on-orbit manufacturing,deep space drug development is expected to achieve greater scalability and precision,opening a new frontier in biopharmaceutical science.
基金supported in part by the National Natural Science Foundation of China(62495022,62495020,62422114,62461160329,62121001,and 62371360)the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(CAST2022QNRC001).
文摘Satellite mega-constellations(SMCs)encounter significant operational challenges due to various space environmental effects.While the mechanisms underlying some of these effects have been studied from a physical perspective,their precise impact on the network performance of SMCs remains unclear.To elucidate this further,this study investigates the spatiotemporal distribution characteristics of space environmental effects,such as solar radiation,ionizing radiation,and space debris,and the associated failure mechanisms in the nodes and links of SMCs.In addition,the impacts of solar radiation and single-event effects on performance of SMC system,particularly network throughput capacity,are examined.Results reveal that under the effect of the space environment,the throughput capacity degradation of SMC system varies with different parameters such as orbital altitude and inclination.Most importantly,the results bridge the gap between the physical phenomena of space environmental effects and network-level modeling.Finally,future research directions are prospected,regarding network topology control,constellation architecture,network routing techniques,and so on,to help mitigate network performance degradation due to space environmental effects.
基金supported by the National Natural Science Foundation of China(Nos.11002068 and11202094)the Research Fund of State Key Laboratory of Mechanics and Control of Mechanical Structures(No.0113Y01)the Priority Academic Program of Jiangsu Higher Education Institutions
文摘The paper studies the nonlinear dynamics of a flexible tethered satellite system subject to space environments, such as the J2 perturbation, the air drag force, the solar pressure, the heating effect, and the orbital eccentricity. The flexible tether is modeled as a series of lumped masses and viscoelastic dampers so that a finite multi- degree-of-freedom nonlinear system is obtained. The stability of equilibrium positions of the nonlinear system is then analyzed via a simplified two-degree-freedom model in an orbital reference frame. In-plane motions of the tethered satellite system are studied numerically, taking the space environments into account. A large number of numerical simulations show that the flexible tethered satellite system displays nonlinear dynamic characteristics, such as bifurcations, quasi-periodic oscillations, and chaotic motions.
文摘For the purpose of ensuring normal operations of Shenzhou (SZ) series of manned spacecrafts and cosmonauts' safety, Space Environment Monitors (SEM)are mounted on board SZ-2, 3, 4, 5. SEMs aim to detect the high energy particles, the low energy particles, charging potential, atmospheric desity and composition. Detection of SEMs enable us to understand better the space environment in the manned spacecraft's orbit, and to provide a good space environment services for the spacecraft and cosmonauts. In addition, by using the data from SEMs, we have achieved some scientific accomplishments, such as the energy spectra of precipitating electrons, the abnormal variety of atmospheric density and composition during geomagnetic disturbances, the electron angle distribution in the low orbit and so on.
文摘Tianhe Core Module of China Space Station(CSS)equips a set of instruments consisting of a Particle Fluxes and Solar Activity Detector(PFSAD)and two Atmospheric Density Multi-directional Detectors(ADMDs).The PFSAD is to measure X-rays from the Sun and energetic particles in the low-latitude and low altitude regions,including electrons,protons,and helium ions.The ADMDs are to measure thermospheric atmospheric density.The instruments provide real-time data of the orbital space environment,including solar flares,energetic particle variation and thermospheric density enhancement.All the data contribute to the CSS space weather service for mission control and astronaut’s safety.The paper gives preliminary analyses of the space environment measurements from the PFSAD and the ADMDs.By further analysis,the 1024-channel fine spectra of the solar X-ray can be used to study the mechanism of solar flares and their impacts on the Earth’s atmosphere.Data accumulation will be helpful for analyzing mid-term and long-term variations of the South Atlantic Anomaly and atmosphere density.Furthermore,the data are useful to calibrate previous empirical models and establish new models to study the space environment.
基金supported by the National Science Foundation of China (41525016,41474155,41661164034,41621004)Macao FDCT grant 001/2016/AFJsupported by the Thousand Young Talents Program of China
文摘The planet Earth is an integrated system, in which its multi-spheres are coupled, from the space to the inner core. Whether the space environment in short to long terms has been controlled by the earth's interior process is contentious. In the past several decades,space weather and space climate have been extensively studied based on either observation data measured directly by man-made instruments or ancient data inferred indirectly from some historical medium of past thousands of years. The acquired knowledge greatly helps us to understand the dynamic processes in the space environment of modern Earth, which has a strong magnetic dipole and an oxygen-rich atmosphere. However, no data is available for ancient space weather and climate(>5 ka). Here, we propose to take the advantage of " space-diversity" to build a " generalized planetary space family", to reconcile the ancient space environment evolution of planet Earth from modern observations of other planets in our solar system. Such a method could also in turn give us a valuable insight into other planets' evolution.
基金the Key Research Program of the Chinese Academy of Sciences(ZDRE-KT-2021-3)。
文摘Volume visualization can not only illustrate overall distribution but also inner structure and it is an important approach for space environment research.Space environment simulation can produce several correlated variables at the same time.However,existing compressed volume rendering methods only consider reducing the redundant information in a single volume of a specific variable,not dealing with the redundant information among these variables.For space environment volume data with multi-correlated variables,based on the HVQ-1d method we propose a further improved HVQ method by compositing variable-specific levels to reduce the redundant information among these variables.The volume data associated with each variable is divided into disjoint blocks of size 43 initially.The blocks are represented as two levels,a mean level and a detail level.The variable-specific mean levels and detail levels are combined respectively to form a larger global mean level and a larger global detail level.To both global levels,a splitting based on a principal component analysis is applied to compute initial codebooks.Then,LBG algorithm is conducted for codebook refinement and quantization.We further take advantage of progressive rendering based on GPU for real-time interactive visualization.Our method has been tested along with HVQ and HVQ-1d on high-energy proton flux volume data,including>5,>10,>30 and>50 MeV integrated proton flux.The results of our experiments prove that the method proposed in this paper pays the least cost of quality at compression,achieves a higher decompression and rendering speed compared with HVQ and provides satisficed fidelity while ensuring interactive rendering speed.
文摘The Space Environment Prediction Center (SEPC) of the Center for Space Science and Applied Research of the Chinese Academy of Sciences (CSSAR, CAS)took on the mission of offering the space environment parameters which may be of use to the safety of manned spacecraft. In order to complete the space environment safety guarantee mission for SZ-4 and SZ-5, SEPC improved the space environment monitoring system, database system, prediction result display system, prediction implementation system, etc. For guaranteeing the safety of the airship and cosmonaut in the first manned SZ-5, flying experiment mission,SEPC developed the software for analyzing radiation dose and early-warning software for large debris collision with SZ-5. Three months before the flights of SZ-4 and SZ-5, SEPC began to predict the safe launch period in view of the space environment, and offered timely and valid reference opinions for selecting the safety period. Especially during the mission of SZ-5, SEPC analyzed the space high-energy environment in a pre-arranged orbit and abnormal orbit andevaluated the radiation dose which cosmonauts may encounter in space. The evaluation offered an important reference for cosmonaut safety and decisionmaking in the SZ-5 mission. The calculation of the distribution of large debris and the collision risk assessment at different orbit entry times for SZ-5 provided an important base for the superior department to make flight decisions.
文摘In the mid July, 2011, the GVU-600 space environment simulator developed by Bei-jing Institute of Spacecraft Environment Engineering of China Academy of Space Technology (CAST) under China
文摘3D printing technology can realize the rapid fabrication of complicated structures with short production chain,which just meet the requirements for space manufacturing in the future.This Special Issue features the cutting-edge 3D printing technologies considering the space environment,focusing on the experimental validation and simulation on the 3D printing process and structural technologies,including whole process chain from raw materials,structural design,process,equipment,as well as functional verification.
基金supported by the National Natural Science Founda-tion of China(52477145).
文摘Polyimide(PI)is widely used in aerospace applications due to its excellent electrical insulation and thermal stability.However,prolonged exposure to high-temperature vacuum conditions in space can significantly compromise its structural integrity and reliability.To gain deeper insight into the pyrolysis behaviour and structural evolution of PI,this study employs molecular dynamics(MD)simulations to conduct full-scale dynamic tracking of the heating process from 300 K to 3800 K.The evolution of bond breakage,gas-phase product formation,and system free volume is monitored in real time.The results indicate that PI pyrolysis proceeds in three distinct stages:an initial induction phase,a rapid decomposition phase,and a prolonged evolution phase.Product analysis reveals that CO accounts for 47.3%of gaseous species,primarily originating from the cleavage of carbonyl groups in the imide ring;H_(2)O makes up 18.4%,closely related to hydroxyl radical recombination;and C_(5)-C_(10) hydrocarbon fragments constitute 15.6%,reflecting deep fragmentation and molecular rearrangement.As temperature increases from 300 K to 800 K,the free volume fraction rises from 16.9%to 27.7%,indicating significant structural relaxation and diffusion pathway expansion.This work elucidates the multi-stage cooperative mechanism of PI pyrolysis at the atomic level and provides a theoretical basis for improving thermal stability and evaluating service life in aerospace environments.
文摘Space solar power stations(SSPS)present a promising solution for addressing global energy challenges.However,the in-orbit operation of SSPS will be subjected to harsh space environments.The space environments and their effects on the SSPS are analyzed firstly in this paper,followed by a discussion of the unique characteristics and requirements of SSPS,including ultra-large-area structures,ultra-high-power electrical systems,ultra-long distance wireless energy transmission,ultra-high-power electronic devices,and ultra-long service life.And then the key technical issues related to the space environmental adaptability of SSPS are systematically investigated,and a corresponding framework of countermeasures and engineering solutions are proposed.
文摘The space environment monitor(SEM)aboard FY-2 satellite consists of the high energy particle detector(HEPD)and the solar X-ray flux detector(SXFD).The SEM can provide real-time monitoring of flare and solar proton event for its operation at geostationary orbit and is also the first Chinese space system for monitoring and alerting solar proton event.During the 23rd solar maximum cycle,almost all the solar proton events that took place in this period are monitored and some of them are predicted successfully by analyzing the characteristics of X-ray flare monitored by the SEM.Some basic variation characteristics of particle at geostationary orbit are found such as day-night periodic variation of particle flux,the electron flux with energy>1.4 MeV in the scope from 10 to 200/cm^(2).s-sr and the proton flux with energy>1.1 MeV in the scope from 600 to 8000/cm^(2)-s.sr during the time with no magnetic storm and solar eruption.
文摘To further study the characteristics of changes on the molecular level of rice mutants induced in space environment, we analyzed proteins in leaves and seeds of four rice mutants （two high-tillering and two low-tillering） in the 8th and 9th generations after a 15-day spaceflight, and compared with their ground controls by two-dimentional polyacrylamide gel electrophoresis and reverse phase liquid chromatography （RPLC）. In addition, the albumin, globulin, prolamine, glutelin, and amylose of the mutant seeds were analyzed by RPLC and ultra-violet spectrometry. The results showed that the low-abundance proteins of leaves in the peak tillering stage are more likely to he induced compared with their corresponding controls. The albumin, globulin, and prolamine of the mutant seeds revealed changes when compared with their controls, and the characteristics of changes in different mu- tants were stably inherited in the 8th and 9th generations, suggesting that they can be used as biomarkers to identity the mutants induced by spaceflight. Moreover, two proteins （SSP9111 and SSP6302） were found to be expressed with high intensity （two-fold change） in different mutants, which were both correlated with photosystem according to mass spectrometry and database searching.
基金supported by the National Natural Science Foundation of China(Grant No.52075444)the National Key R&D Program of China(Grant No.2022YFB3402800).
文摘A considerable portion of space mechanism failures are related to space tribological problems.Cold welding in high vacuum;surface erosion and collision damage caused by various radiations,high temperature oxidation under atomic oxygen(AO)bombardment;and thermal stress caused by temperature alternation all alter the physical,chemical,and friction properties of materials.In particular,the space vibration caused by alternating temperatures and microgravity environments can alter the motion of the contact body,further affecting its friction properties.Improving the friction properties of contact surfaces in the space environment is an important way to extend the service life of spacecraft.Traditional lubricants can no longer meet the lubrication requirements of the space environment.This study describes the characteristics of the space environment and the applications of solid lubricants.The friction properties of MoS_(2),a solid lubricant widely used in space,are discussed.The synergistic lubrication of MoS_(2)with surface textures or metals is presented.Advances in research on the friction properties of collision sliding contacts in the space environment are reviewed.The combination of MoS_(2)and soft metals with surface textures is introduced to reduce the effects of vibration environments on the friction properties of moving parts in space mechanisms.Finally,the challenges and future research interests of MoS_(2)films in space tribology are presented.
基金acknowledge financial support provided by the National Key Research and Development Program of China(2022YFF0503600).
文摘Space solar power station(SSPS)are important space infrastructure for humans to efficiently utilize solar energy and can effectively reduce the pollution of fossil fuels to the earth’s natural environment.As the energy conversion system of SSPS,solar array is an important unit for the successful service of SSPS.Today,solar arrays represent the standard technology for providing energy for spacecraft,thanks to their high conversion efficiency and reliability/stability in orbit.With the development of solar arrays,many new materials,new photovoltaic devices and new control systems have emerged.Solar arrays are directly exposed to the space environment,and harsh environmental factors can degrade the performance.To ensure the long-term safe inorbit service of SSPS as well as its ultra-large solar array,these new materials,devices,and control systems must operate certification and evaluation that can be used in space applications.In this review,the development history and research progress of SSPS and the corresponding space solar arrays are summarized and discussed,and the space environmental effects of solar arrays are analyzed at multiple levels(materials,devices,and systems).Finally,in response to the current space environmental effects of the ultra-large solar array used in the SSPS,future development trends and challenges are proposed.
基金supported by the National Natural Science Foundation of China(No.61975153)。
文摘This paper systematically investigated the impact mechanisms of proton irradiation,atomic oxygen irradiation and space debris collision,both individually and in combination,on the laser damage threshold and damage evolution characteristics of HfO_(2)/SiO_(2) triple-band high-reflection films and fused silica substrates using a simulated near-Earth space radiation experimental system.For the high-reflection film samples,the damage thresholds decreased by 15.38%,13.12% and 46.80% after proton,atomic oxygen and simulated space debris(penetration) irradiation,respectively.The coupling irradiation of the first two factors resulted in a decrease of 26.93%,while the combined effect of all the three factors led to a reduction of 63.19%.Similarly,the fused silica substrates exhibited the same pattern of laser damage performance degradation.Notably,the study employed high-precision fixed-point in situ measurement techniques to track in detail the microstructural changes,surface roughness and optical-thermal absorption intensity before and after proton and atomic oxygen irradiation at the same location,thus providing a more accurate and comprehensive analysis of the damage mechanisms.In addition,simulations were conducted to quantitatively analyze the transmission trajectories and concentration distribution lines of protons and atomic oxygen incident at specific angles into the target material.The research findings contribute to elucidating the laser damage performance degradation mechanism of transmissive elements in near-Earth space environments and provide technical support for the development of high-damage-threshold optical components resistant to space radiation.
文摘To solve the problem of stray interference to star point target identification while a star sensor imaging to the sky, a study on space luminous environment adaptability of missile-borne star sensor was carried out. By Plank blackbody radiation law and some astronomic knowledge, irradiancies of the stray at the star sensor working height were estimated. By relative astrophysical and mathematics knowledge, included angles between the star sensor optical axis point and the stray at any moment were calculated. The calculation correctness was verified with the star map software of Stellarium. By combining the upper analysis with the baffle suppression effect, a real-time model for space luminous environment of missile-borne star sensor was proposed. By signal-noise rate （SNR） criterion, the adaptability of missile-borne star sensor to space luminous environment was studied. As an example, a certain type of star sensor was considered when imaging to the starry sky on June 22, 2011 （the Summer Solstice） and September 20, 2011 （August 23 of the lunar year, last quarter moon） in Beijing. The space luminous environment and the adaptability to it were simulated and analyzed at the star sensor working height. In each period of time, the stray suppression of the baffle is analyzed by comparing the calculated included angle between the star sensor optical axis point and the stray with the shielded provided by system index. When the included angle is larger than the shielded angle and less than 90~, the stray is restrained by the baffle. The stray effect on star point target identification is analyzed by comparing the irradiancy of 6 magnitude star with that of the stray on star sensor sensitization surface. When the irradiancy of 6 magnitude star is 5 times more than that of the stray, there is no effect on the star point target identification. The simulation results are identicat with the actual situation. The space luminous environment of the missile-borne star sensor can be estimated real-timely by this model. The adaptability of the star sensor to space luminous environment can be analyzed conveniently. A basis for determining the relative star sensor indexes, the navigation star chosen strategy and the missile launch window can be provided.
基金supported by the Joint Funds of the National Natural Science Foundation of China(Grant Nos.61372050 and U1730247).
文摘It is known that ion channel can effectively limit the radial expansion of an artificial electron beam during its longrange propagation in the space plasma environment.Most prior studies discussed the focusing characteristics of the beam in the ion channel,but the establishment process and transient properties of the ion channel itself,which also plays a crucial role during the propagation of the relativistic electron beam in the plasma environment,were commonly neglected.In this study,a series of two-dimensional(2D)particle-in-cell simulations is performed and an analytical model of ion channel oscillation is constructed according to the single-particle motion.The results showed that when the beam density is higher than the density of plasma environment,ion channel can be established and always continues to oscillate periodically over the entire propagation.Multiple factors,including the beam electron density,initial beam radius,and the plasma density can affect the oscillation properties of ion channel.Axial velocity of the beam oscillates synchronously with the ion channel and this phenomenon will finally develop into a two-stream instability which can seriously affect the effective transport for relativistic electron beam.Choosing appropriate beam parameters based on various plasma environments may contribute to the improvement of the stability of ion channel.Additionally,radial expansion of the beam can be limited by ion channel and a stable long-range propagation in terrestrial atmosphere may be achieved.
