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    Development status and prospect of satellite-based surveying
    YANG Yuanxi, WANG Jianrong, LOU Liangsheng, SUN Zhongmiao, XIAO Yun, MIAO Yuzhe
    Chinese Space Science and Technology    2022, 42 (3): 1-9.   DOI: 10.16708/j.cnki.1000-758X.2022.0031
    Abstract729)      PDF(pc) (918KB)(659)      
    Satellite-based surveying is the main platform of global fundamental surveying, including satellite topographic survey, satellite gravimetry, satellite magnetic measuring, satellite altimetry, etc. The developments of satellite-based measuring projects have experienced “return type measuring satellite project”, “transmission type measuring satellite project” and some of “loads integration measuring satellite project”. This paper firstly reviews the development history and current situation of international satellite-based surveying projects, then analyzes the roles of China′s satellite-based surveying projects in various stages, including some existing problems. Finally, the ideas for the future development of satellite-based surveying are put forward.
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    Space robotic manipulation: a multi-task learning perspective
    LI Linfeng, XIE Yongchun
    Chinese Space Science and Technology    2022, 42 (3): 10-24.   DOI: 10.16708/j.cnki.1000-758X.2022.0032
    Abstract406)      PDF(pc) (3443KB)(327)      
    It is a technological development trend in recent years to apply space robot in place of spaceman to perform on-orbit service tasks. Using deep neural network controller, the learning-based space robotic manipulation has shown good potential in adaptability to the unstructured space environments and applicability in fileds such as high earth orbit, extraterrestrial planet exploration, etc. At present, a large number of studies focus on single task robotic manipulation learning problems, for either onground robots or in-space robots. From a new perspective of multi-task learning, a thorough literature review on multi-task robot learning was made, including algorithms and robotic applications therein. To further apply the state-of-the-art multi-task robot learning algorthms, main technical challenges were analyzed and suggestions on key technology development were given. The breakthrough of the above challenges will increase the overall autonomy and robustness level of the space robot system, which is expected to further facilitate the development of China′s on-orbit service towards completely unmanned autonomy.
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    Research of thrust measurement for space electric propulsion
    ZHANG Lupeng, YANG Xin, CHANG Lei, XU Qian, ZHOU Haishan, LUO Guangnan
    Chinese Space Science and Technology    2022, 42 (3): 25-38.   DOI: 10.16708/j.cnki.1000-758X.2022.0033
    Abstract406)      PDF(pc) (8286KB)(774)      
     Accurate measurement of thrust is very important in the development and planning of space electric propulsion.In recent years,with the increasing of complexity and task difficulty for electric propulsion,higher requirements are put forward for the evaluation techniques and methods of thrust performance.In response to this demand,a review of the thrust measurement for space electric propulsion was presented.Measurement methods and the underlying mechanisms,technical features and applications were covered.The methods of thrust measurement can be divided into direct measurement and indirect measurement.The former mainly includes balance structure,torsional pendulum,suspension and inverted pendulum,while the latter mainly includes target and cantilever beam.The advantages and disadvantages of these measurement methods were summarized and compared,which provided a reference for developers to design the thrust measuring system.The key problems in the five segments including system design,system calibration,system response,system response measurement and calculation of thrust during the process of thrust measurement were described in detail,and the corresponding improvement methods were proposed.To serve as a reference for future thrust measurement research,suggestions were also provided by considering the development trend of electric propulsion and its demand of thrust measurement.
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    Analysis of the first stage deployment of Starlink constellation based on TLE
    XUE Wen, HU Min, RUAN Yongjing, YUN Chaoming, SUN Tianyu
    Chinese Space Science and Technology    2022, 42 (5): 24-33.   DOI: 10.16708/j.cnki.1000-758X.2022.0064
    Abstract381)      PDF(pc) (7069KB)(457)      
     In recent years,with the rapid development of satellite technology and the increasing demand for low earth orbit(LEO)satellite broadband internet construction,the development of LEO large-scale constellations is changing rapidly.Aiming at the initial deployment of Starlink constellation,firstly,the current status of the Starlink constellation was discussed,and the altitude changes of orbiting satellites were analysed.Then,the deployment of the Starlink constellation was briefly analyzed from two aspects by utilizing the public two-line element(TLE),including satellite being launched into orbit and orbital plane distribution,and the changing rule of ascending node was given.At the same time,the ground coverage performance of the Starlink constellation was simulated and analyzed.Finally,the constellation orbital planes and phase distribution,handling of the faulty satellites,and the number of visible satellites were obtained.The results of the analysis are expected to provide reference for China′s future deployment of large-scale LEO constellations.
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    Cloud detection methods for remote sensing images:a survey
    LIU Zili, YANG Jiajun, WANG Wenjing, SHI Zhenwei
    Chinese Space Science and Technology    2023, 43 (1): 1-17.   DOI: 10.16708/j.cnki.1000-758X.2023.0001
    Abstract355)      PDF(pc) (3043KB)(495)      
     The cloud cover in the optical remote sensing images will obscure the ground information in different degrees,which causes the blurring and missing of the surface observation information and greatly affects the imaging quality of remote sensing images.Therefore,the detection and evaluation of cloud cover in remote sensing images are the basis and key to further analyze and utilize remote sensing image information.Through sufficient investigation and summary,the development trend and representative work of cloud detection methods based on remote sensing images at home and abroad since the 1990s were combed.Cloud detection methods based on remote sensing images were divided into three categories:methods based on band threshold,methods based on classical machine learning and methods based on deep learning.Besides,the public datasets at home and abroad used in the related research on cloud detection were summarized,and the accuracy of some representative cloud detection methods was compared.In addition to the vanilla cloud detection method,the cloud/fog(haze)detection,cloud/snow detection,cloud shadow detection and cloud removal methods related to cloud detection were also briefly combed.Based on the review and summary of cloud detection work above,the existing problems and future development trends of cloud detection were analyzed and prospected.
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    Research progress and prospect of spacecraft reconfiguration technology
    PENG Qibo, WU Xinfeng, WANG Beichao, LI Shuang
    Chinese Space Science and Technology    2023, 43 (2): 16-31.   DOI: 10.16708/j.cnki.1000-758X.2023.0017
    Abstract320)      PDF(pc) (6523KB)(441)      
     Spacecraft reconfiguration technology is the key technology that must be broken through for the in-orbit service of spacecraft and other major space missions,having a profound effect on the design,research and development of new spacecraft systems.Firstly,the connotation and classification of the spacecraft reconfiguration were presented.Then,the domestic and overseas research status of the technology was systematically concluded and discussed based on main structure reconfiguration and other typical technologies.Next,the system of the spacecraft reconfiguration technology was proposed based on the methods such as standardized modular design,and then application prospects were summarized in the aspects such as supporting fault elimination of spacecraft.Finally,overall research progress of the reconfiguration technology was concluded,and future development was also expected.
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    Progress and prospect of solar exploration in space
    YANG Mengfei, DAI Shuwu, WANG Ying, ZHU Chenglin, YANG Shangbin, ZHANG Yechi
    Chinese Space Science and Technology    2022, 42 (5): 1-10.   DOI: 10.16708/j.cnki.1000-758X.2022.0062
    Abstract316)      PDF(pc) (2853KB)(354)      
     In order to explore the development direction of solar space exploration activities,ten typical probes were selected taking into account their implementation era,orbital design,exploration elements,technical characteristics and each mission′s result based on extensive research on solar probe missions.Scientific objectives,payloads,satellite platform characteristics and scientific achievements of the ten typical probes were analyzed.Solar space exploration progress and development trend were summarized.In general,the orbit of solar detectors has been gradually diversified,detection elements of payload have become more abundant,and the detection accuracy and resolution have been significantly improved.However,there are still a lot of problems to be solved.On the basis of analyzing the current achievements and pending problems,the development outlook of solar space exploration was proposed,pointing out that all round and multielement exploration is a feasible way to break the bottleneck of solar physics and space weather forecast.
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    Intelligent program synthesis framework and key scientific problems for embedded software
    YANGMengfei, GUBin, DUANZhenhua, JINZhi, ZHANNaijun, DONGYunwei, TIANCong, LIGe, DONG Xiaogang , LIXiaofeng
    Chinese Space Science and Technology    0, (): 1-7.   DOI: 10.16708/j.cnki.1000-758X.2022.0046
    Abstract303)      PDF(pc) (2052KB)(239)      
    Program synthesis is an effective way to improve the efficiency of software development and the quality of software,and it is one of the most challenging problems in computer science.Firstly,the research status and existing problems of program synthesis methods were reviewed.Secondly,the concept of software IP(intellectual property)and an embedded software intelligent synthesis development method based on software IP(IP based embedded software intelligent synthesis,IPESIS)with its framework were proposed.Finally,the key scientific problems and main research contents that IPESIS needs to solve were discussed.IPESIS describes software requirement at a higher level of abstraction by defining the domain requirement description language,reduces the program search space with software IP as the granularity,and uses machine learning and other artificial intelligence technologies to automatically synthesize programs.It is expected to break through the limitations of existing methods,and then realize the transition of embedded software development from manual programming to software IP research and development plus intelligent synthesis based on software IP.
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    Ion beam characteristics of iodine RF ion thruster optical system
    ZHANG Yuanzhe, HAN Xianwei, YANG Zhenyu, LU Haifeng, TAN Chang
    Chinese Space Science and Technology    2022, 42 (6): 115-124.   DOI: 10.16708/j.cnki.1000-758X.2022.0090
    Abstract252)      PDF(pc) (5836KB)(169)      
    Based on the particlein cell(PIC)method,a numerical simulation on iodine RF ion thruster optics system was carried out to analyze characteristics of ion beam.Besides substantial I+,ionization products of iodine contain a little multivalent ions including I2+,I2+,I3+.Comparison of ion beam characteristics′ simulation results with and without addition of multivalent ions obtained spatial distribution of ions,potential distribution,phase space distribution,beam current and divergence angle.The results show that the program can simulate the motion of ions in optics system properly.With addition of multivalent ions,plasma potential increases and saddle point potential declines,though the variation range of the whole potential distribution is limited.The charge-to-mass ratio of the ion group increases slightly with addition of multivalent ions,therefore beam current increases and divergence angle declines a little.Both thrust and specific impulse increase slightly through theoretical analysis.When the plasma density in discharge chamber increases to about 2.4×1017m-3,the optics system reaches the limit of beam extraction,and extracted beam current decreases instead of increasing with proceeding increase of plasma density.The simulation results can provide a reference for design of RF ion thruster optics system.
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    Life prediction of 30cm ion thruster for deep space exploration
    GENG Hai, LI Xingda, JIA Lianjun, JIA Yanhui, WU Chenchen, SUN Mingming, SUN Xinfeng
    Chinese Space Science and Technology    2022, 42 (6): 107-114.   DOI: 10.16708/j.cnki.1000-758X.2022.0089
    Abstract242)      PDF(pc) (7619KB)(161)      
     In order to evaluate the lifetime of 30cm ion thruster,the thruster lifetime prediction method based on finite life test and simulation model was proposed.The grid hole sputtering erosion model was established by PIC-MCC method.The lifetime prediction research of 30cm ion thruster was carried out.The grid hole etching rate,electric field and ion extraction characteristics were analyzed,and the lifetime prediction value was given.The simulation results are in good agreement with measured values,and the error is less than 20%,which shows the modification of the model based on the measured values of grid holes in each life test section is effective.According to the simulation results,the deceleration grid is the first to fail after the 10000h life test.The estimated lifetime of 30cm ion thruster under the maximum(3kW)condition is 36000h,which can meet the long-lifetime requirements of the electric propulsion system for the small celestial body exploration mission.
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    Domain control strategy for the large-scale satellite cluster
    LI Ning, YUE Chengfei, GUO Haibo, QIU Shi, CAO Xibin
    Chinese Space Science and Technology    2023, 43 (1): 18-28.   DOI: 10.16708/j.cnki.1000-758X.2023.0002
    Abstract237)      PDF(pc) (6485KB)(336)      
    In large-scale satellite constellations,single node management and control will lead to poor system connectivity and high dependence on ground resources.A distributed domain control strategy for satellite constellations with hierarchical management,intradomain autonomy and dynamic maintenance was proposed.Firstly,both the static index and dynamic index to measure the governability were defined.According to the newly-defined indexes,a multi-factor weighted cluster head selection method was proposed.Then,based on the selected cluster head node,a cascading optimal initialization algorithm of the cluster was established.Aiming at dynamic maintaining of the established cluster control structure,an event-triggered dynamic time slice domain control method was proposed.Finally,control simulation result of the proposed method in the case of LEO large-scale satellite constellation verifies the effectiveness of cluster head selection,cluster initialization and long-time maintaining.The number of satellites which were managed through ground station was reduced to 14%.High dependence on ground resources was resolved.
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    Research progress and prospect of on-orbit additive manufacturing technology
    LIU Jie, SHI Yun, CUI Yutao, HOU Juan, ZHANG Kai, HUANG Aijun
    Chinese Space Science and Technology    2022, 42 (6): 23-34.   DOI: 10.16708/j.cnki.1000-758X.2022.0080
    Abstract230)      PDF(pc) (5450KB)(318)      
    In-space additive manufacturing technology is a “space 3D” printing technology,which has attracted major attention due to its application in on-orbit manufacturing and space base additive manufacturing.The basic concepts were introduced and the progress of space on-orbit additive manufacturing technology in the world was summarized.With the requirement of space stations and on-orbit spacecraft,the significant challenge of in-space additive manufacturing was the raw materials,printing technology and equipment.This was attributed to the unique feature of the space environment,including microgravity and high vacuum,etc. Finally,based on the current development status,requirements,and possible implementation paths of in-space onorbit manufacturing technology,the development direction of in-space additive manufacturing was pointed out.
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    Review of the research on spacecraft end-of-life de-orbit technology
    KANG Huifeng, MEI Tianyu, XIA Guangqing, WANG Xiaoyang, FAN Yipeng, LU Chang
    Chinese Space Science and Technology    2022, 42 (5): 11-23.   DOI: 10.16708/j.cnki.1000-758X.2022.0063
    Abstract213)      PDF(pc) (2258KB)(272)      
    To purify the space environment,the existing spacecraft de-orbit technologies were analyzed for the spacecraft de-orbit problem at the lifetime end.The research status of spacecraft end-of-life de-orbit technologies was introduced.The characteristics and applicability of various de-orbit methods were summarized.Then the development trends and key technologies of various de-orbit methods were analyzed,and the development suggestions for the de-orbit technologies at the lifetime end of the spacecraft were put forward.The results show that the spacecraft end-of-life de-orbit technologies can de-orbit spacecraft within 25 years,but the reliability of de-orbit device,the stability of deorbit,the deorbit time of spacecraft and the aftertreatment can still be greatly improved.
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    Multi-satellite responsive inspection mission planning with multiple constraints
    PENG Chenyuan, ZHANG Jin, YAN Bing, ZHOU Hongxi, LUO Yazhong
    Chinese Space Science and Technology    2022, 42 (3): 39-48.   DOI: 10.16708/j.cnki.1000-758X.2022.0034
    Abstract209)      PDF(pc) (4964KB)(225)      
    Multi-satellite responsive inspection mission refers to the fact that multiple target satellites appear unknown, and the inspection service platform carries out orbit transfer within a short period of time, and carries a number of sub spacecraft to perform overflight inspection on the targets. For mission planning of this kind of problem, the platform phasing strategy based on coplanar maneuver was firstly presented and a screening calculation model of inspection window satisfying the constraints of illumination and maneuvering ability was established. Secondly, a greedy search and multiround planning method was proposed to determine the task assignment scheme and inspection order. Finally, this method’s effectiveness was tested under high precision orbit model and it was compared with hybrid en-coding genetic algorithm. In the example, the optimization effect of this method is slightly better than that of hybrid en-coding genetic algorithm and the efficiency is about 227 times of the latter, which indicates that greedy search algorithm and multiround planning method are more suitable for solving this problem efficiently.
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    Retro-directive microwave power beam steering technology for space solar power station
    DONG Shiwei, HOU Xinbin, WANG Xin
    Chinese Space Science and Technology    2022, 42 (5): 91-102.   DOI: 10.16708/j.cnki.1000-758X.2022.0070
    Abstract205)      PDF(pc) (11662KB)(180)      
    Microwave power transmission(MPT)design and demonstration are key jobs in development of space solar power station(SSPS)in China,while retro-directive microwave power beam steering is a primary part of MPT.Research on retro-directive microwave power beam steering was conducted under the prerequisite that the power transmitting array was with an ideal profile.The position and attitude errors of structural modules had seldom been considered of the power transmitting array in space environment.With respect to the four-phased missions of SSPS development in China,the influence of position and attitude errors on power density at the rectifying array and beam steering error was investigated.After the software retro-directive microwave power beam steering was preliminarily demonstrated,software retro-directive beam steering based on phase compensation was proposed,aimed at correcting the position and attitude errors of array modules.The correction effect was simulated and analyzed.The proposed software retrodirective beam steering based on phase compensation has remarkable correction ability for the position and attitude errors of array modules.This article presents guidelines for MPT system design and assembly.
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    Application and development of high-precision Hall electric propulsion technology
    LIU Qi, MAO Wei, HU Peng, WEI Yanming, HU Yanlin, LI Yong, BIAN Bingxiu, LIU Xuhui
    Chinese Space Science and Technology    2023, 43 (2): 1-15.   DOI: 10.16708/j.cnki.1000-758X.2023.0016
    Abstract196)      PDF(pc) (8062KB)(258)      
    Under the application background of modern global communication and navigation,the abilities of precise orbit prediction and real-time orbit control of satellite platforms request better performances such as thrust accuracy and resolution ratio,so it is significant to construct high-precision electric propulsion system.According to the survey of the space application demand and the research status of electric propulsion technology,it is demonstrated that the output accuracy of thrust under current technology can not satisfy requirements of missions such as the high-precision continuous navigation,the real-time drag compensation of super low orbit satellites and imaging during the movement of high-resolution remote sensing satellites.Taking the Hall effect propulsion system as the research object and focusing on the technical difficulties of high-precision electric propulsion system,the research status at home and abroad was depicted,the development trends and the research routes of the key techniques were analyzed and discussed from the aspects of electric thruster technology,mass flow control technology,power supply and control technology as well as testing technology.The future focal directions of research and development were suggested for high-precision electric propulsion technology.
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    Design and verification of thermal control system for Tianwen-1 Mars entry capsule
    ZHENG Kai, XIANG Yanchao, RAO Wei, ZHANG Bingqiang, XUE Shuyan, DAI Chenghao, ZHANG Dong, WANG Yuying
    Chinese Space Science and Technology    2022, 42 (5): 108-116.   DOI: 10.16708/j.cnki.1000-758X.2022.0072
    Abstract188)      PDF(pc) (2550KB)(169)      
    Tianwen-1 Mars entry capsule took Zhurong Mars rover to accomplish the entry,descent and landing process.Its thermal control system met lots of technical challenges,including wide variations of external heat fluxes during the flight from Earth to Mars,high temperature of entry capsule surface caused by aerodynamic ablation during the Mars entry process,and ultra-high temperature caused by the landing engine during the descent and landing process.Accordingly,comprehensive methods consisting of thermal isolation,thermal transmission and temperature compensation were applied.New thermal control coating SAL-2 was applied to overcome the changes of external heat fluxes.To insulate the ultra-high temperature from the landing engine,a new aerogel-based thermal protector was developed.With these measures,the efficient and reliable thermal control system for Tianwen-1 Mars entry capsule was completely constructed.The in-orbit telemetric data shows that working equipments of Tianwen-1 Mars entry capsule all have suitable temperature ranging from 5.0℃ to 40.3℃ during EDL process,and power consumption for temperature compensation does not exceed 43W,which verifies the effectiveness of this thermal control system.
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    Design of a reflector antenna for Zhu-Rong Mars rover
    LIU Zhijia, DUAN Jiangnian, HOU Qinfang, SUN Dayuan, ZHUANG Jianlou, LU Fan, LI Fan
    Chinese Space Science and Technology    2022, 42 (5): 117-124.   DOI: 10.16708/j.cnki.1000-758X.2022.0073
    Abstract188)      PDF(pc) (6542KB)(202)      
    Considering the requirement of TianWen-1 Zhu-Rong Mars rover′s communication,an X band compact broadband circular polarization reflector antenna was introduced.The novel integrated compact feed technology with length and aperture reduced by 20% was adopted in this reflector.This new feed technology can improve the aperture efficiency of the reflector antenna,and resist the impact of Martian dust.The X-band reflector was optimized,fabricated,and measured.The measured results show that the antenna can reach 62.3% aperture efficiency from 7.1GHz to 8.4GHz frequency band as well as obtain better performance in terms of the gain,the VSWR(voltage standing wave ratio),and the circular polarization in the operating frequency band of the deep space exploration.This novel reflector antenna has been successfully applied to Zhu-Rong Mars rover.
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    Study on braking mechanism of planetary probe based on plasma magnetic shell
    DONG Yicheng, WANG Weizong, ZHANG Jinrui, QI Yue, YAN Jiaqi
    Chinese Space Science and Technology    2022, 42 (6): 35-45.   DOI: 10.16708/j.cnki.1000-758X.2022.0081
    Abstract177)      PDF(pc) (4177KB)(126)      
    Plasma magnetic shell braking technology is a new braking method for planetary probes.It has the advantages of adjustable braking resistance,high reliability and light structure mass.In this paper,a numerical simulation on the generation mode and working mechanism of plasma magnetic shell brake was carried out.Firstly,taking the braking of a Martian spacecraft as the background,the plasma magnetic shell was simplified to a cylindrical configuration,and the macroscopic model of the plasma magnetic shell was established.From the model,the relationship of braking resistance,effective capture area and spacecraft velocity changing with the orbital height was obtained.Then,the interaction between ions,electrons and secondary neutral particles in the plasma magnetic shell was studied,the microscopic model of the plasma magnetic shell was established,the rule of the plasma particle number density and temperature changing with time was obtained.The braking resistance calculated by the microscopic model is consistent with that of the macroscopic model,which verifies the validity of the two models.
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    Perspective of extraterrestrial carbon dioxide conversion and utilization technologies
    LIU Shiyuan, Zhang Ce, YIN Zhao, YANG Jinlu, YAO Wei, YANG Mengfei
    Chinese Space Science and Technology    2022, 42 (6): 1-11.   DOI: 10.16708/j.cnki.1000-758X.2022.0078
    Abstract175)      PDF(pc) (8245KB)(148)      
    The development of more efficient extraterrestrial CO2 conversion and utilization technologies is an urgent need for improving the oxygen recovery rate and energy conversion efficiency,and solving insufficient mass supplement of future long-term manned extraterrestrial survival.The current development of the recent extraterrestrial CO2 utilization and representative researches were reviewed.It is necessary to opt for the appropriate technology with full consideration of extraterrestrial environmental constraints in the space application for the large differences among different technologies.The Sabatier device and the MOXIE device have been tested for CO2 conversion and O2 production on International Space Station and on Mars,respectively.What′s more,extraterrestrial artificial photosynthesis,as the representative of ambient CO2 conversion and utilization technology,provides a new route for ECLSS,which can not only realize extraterrestrial O2 supply,but also obtain a variety of fuels or biological raw material such as formic acid,ethylene and methane.With the development of basic researches,it is expected to realize highly efficient CO2 conversion and the production of high value-added organic matter like sugar.The development of extraterrestrial carbon dioxide conversion technology will solve the waste resource utilization and mass recycle in the confined environment of extraterrestrial space,and reduce the mass supply demand.It will also provide innovative ideas for ISRU on the Mars to support future affordable and sustainable extraterrestrial survival missions.
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