地基雷达探测中的空间碎片微弱信号检测技术概况

空间碎片的日益增多。已对航天活动构成严峻威胁。空间碎片的精确监测是对航天员和飞行器实施安全防护的重要前提,也对空间微小碎片探测能力提出了更高要求。文章对国外地基雷达探测空间碎片现状,以及对在雷达微弱信号检测技术方面比较常用的以信号处理为基础的长时间积累检测技术和基于时频分析的雷达微弱信号检测技术研究现状进行了综述。     

空间碎片偏振光谱成像探测技术研究

随着太空探索活动的逐年增多,人类对空间碎片的探测显得越发重要。文章首先介绍了探测空间碎片的意义及其常规的光电探测方法,并分析了探测空间碎片的主要难点;在此基础上,结合空间碎片的具体特征,提出一种对空间碎片进行探测与识别的新方法,即将成像、光谱、偏振三个光学基本量同时使用,通过多元特征融合等识别技术,实现对空间暗、弱、小碎片的高效探测,并对新方法中的关键技术进行了分解和可行性分析。     

空间碎片环境工程模式参数分析

为了评估空间碎片对航天器造成的危害 ,必须建立空间碎片环境工程模式。文章介绍了空间碎片环境的特点及其工程模式表征方法 ,并比较、分析了几种主要空间碎片环境工程模式的参数 ;从数学建模及风险评估应用的需求出发 ,提出了空间碎片环境工程模式参数的建议方案     

空间碎片的空间密度算法研究

由于空间碎片的影响, 空间环境日益恶劣,有必要建立空间碎片环境工程模型对空间碎片撞击航天器进行风险评估.本文研究了空间碎片环境模型中的重要环节, 即碎片的空间密度问题,在统计理论与椭圆轨道理论基础上,分析及推导了空间碎片在空间中的分布状况及空间密度,并得出了碎片空间密度的空间坐标函数解析表达式.同时对引入假设条件的合理性进行了讨论,并利用双行元数据对结论进行了验证, 利用本文方法得出的结果与双行元数据吻合.      

空间飞行器碎片防护结构的简化设计

给出一种基于实验和理论分析的航天器碎片防护结构简化设计方法 ,该方法可用于进行大型空间飞行器碎片防护结构的方案选择和初步结构设计。利用空间碎片的工程环境模型和防护结构几何经验公式 ,采用“设计碎片”的概念 ,对防护结构进行几何结构设计和质量估算 ,并采用改进的防护性能验证算法进行空间碎片的风险评估。通过对惠式防护结构的计算 ,得到的计算结果基本符合实际要求。     

天基激光清除空间碎片方案设想

随着空间碎片数量的不断增长,对人类航天事业的发展构成巨大威胁,清除空间碎片已经迫在眉睫。使用激光清除太空垃圾是一种低成本、高效、安全的清除技术。本文介绍了空间碎片的现状和现有清除方法,针对地基清除空间碎片技术存在的局限性,提出了一种天基激光清除空间碎片方案设想。     

航天器空间碎片防护方案的评价方法

在综述国际上已采用和研究的航天器防护空间碎片超高速撞击防护方案评价方法的基础上,对航天器防护方案的评价方法进行了分析与探讨,给出了各种防护方案的撞击极限曲线和撞击极限方程。     

一种基于TOF×E方法的空间中能离子探测器设计与仿真

对空间中几十keV到几MeV的中能离子进行成分、能谱和角分布进行测量，具有重要的科学价值和应用意义。中国在载人登月等深空探测计划中明确提出了对中能离子的探测需求，但当前尚未掌握中能离子测量技术。本文提出了一种基于SEE TOF×E方法的中能离子探测器方案，方案包括复合材料二次电子薄膜、电极、位置灵敏MCP探测器和SSD等核心部件的设计，可同时实现对5个方向的中能离子和4个方向的中能电子的测量。结合目前空间粒子探测载荷可实现的硬件时间分辨率、能量分辨率和仿真计算结果，可以发现，该设计可以在40 keV～5 MeV能量范围实现中能离子能谱测量；并能够对40 keV～5 MeV的H离子，45 keV～5MeV的He离子，130 keV～5 MeV的O离子和240 keV～5 MeV的Fe离子进行离子成分分辨；同时可实现对20～500 keV的电子进行能谱测量。     

空间碎片消旋柔性冲击末端设计与分析

根据机械冲击式主动消旋方法的特点,设计了变压力柔性冲击末端.考虑到变压力柔性末端的流固耦合作用,通过分析内部气体压力对末端刚度的影响,确定了压力阈值并展开优化设计.对柔性冲击末端与空间碎片之间的碰撞力进行了理论分析与实验研究,建立了柔性末端与空间碎片碰撞的接触模型,设计了冲击与测量实验系统,修正了摩擦模型,通过冲击实验验证模型与实验结果吻合较好,法向碰撞力和切向摩擦力模型计算误差分别小于6.7%和6.9%.研究表明变压力柔性末端设计合理有效,满足空间碎片消旋要求,对发展空间碎片捕获方法具有重要指导意义.     

对一种利用人造粉尘清除空间碎片新方法的理论分析

近地轨道的空间碎片污染日益严重,目前碎片数量已达到历史最高值并可能引发一系列连锁反应.进行主动碎片清除十分必要.利用粉尘主动清除近地轨道空间碎片是一种主动碎片清除的新方法.本文基于此方法的基本原理进行分析研究,建立了单颗碎片与人造粉尘作用的基本假设和机理模型,并对其作用进行定量计算分析;结合碎片的空间密度分布,对该方法的作用效果进行了定量估算,得出一些基本分析结论,有助于对新方法的客观认识.      

新一代空间交会对接光学成像敏感器

摘要： 为满足中国未来空间交会对接任务对光学成像敏感器工作能力尤其是杂光抑制能力的更高需求,研制新一代空间交会对接光学成像敏感器.该产品多项指标优于其上一代产品神舟八号CCD光学成像敏感器,测量距离由原来的150~2 m范围提升为250~0.9 m范围;目标捕获时间由10 s缩短为0.32 s;抗杂光干扰能力大幅提升,实现准全天候工作.该产品已在中国神舟十一号载人飞船、天舟一号货运飞船与天宫二号的交会对接任务中成功验证,可在后续更好地服务中国空间站、探月三期等工程的交会对接任务.介绍该产品的测量原理、系统组成、地面试验和在轨工作表现等情况,并给出相应结论.     

深空探测推进技术发展趋势

推进技术是制约深空探测能力的重要因素,由于深空探测航天器自身特点和任务需求的多样性,对推进系统类型的要求也不尽相同,需要在推力、比冲、功率、重量等关键指标选择方面进行综合衡量。对当前和未来适用于深空探测任务需求的几种典型空间推进技术的发展情况进行了阐述,包括混合模式推进技术、太阳能电推进技术、空间核电推进技术、帆类推进技术等,介绍了这些技术的研究进展和应用情况,并对后续应用进行了展望,为我国深空探测推进技术发展提供参考。     

临近空间太阳紫外辐射环境模拟与地区差异

太阳紫外辐射是临近空间能量输入的主要来源之一,对其在中层大气的辐射特性进行研究,是研究临近空间大气成分与密度变化、光化学反应以及动力学过程的重要基础。依托“鸿鹄”临近空间探测专项计划,利用MODTRAN5辐射传输模型及卫星实测数据,模拟并对比中国11个主要地形区上空临近空间（20~50 km）紫外辐射（200~400 nm）垂直分布和季节演变的异同,计算了臭氧含量、太阳天顶角和日地距离等关键因素对辐射强度的影响。结果表明,各地形区的辐射流量垂直分布廓线和年较差垂直分布廓线较为一致,在地理位置上毗邻的地区辐射特性及季节演变较为接近,但在太阳紫外的不同波段之间区别较大。研究成果为临近空间探测实验提供了数据支撑,为大气反演等相关领域提供参考。      

谈风险管理在航天器研制中的应用

风险管理是航天计划/项目管理的重要组成部分。在航天型号研制中，国际上都十分重视风险的管理，在型号研制工作中都制定风险管理计划，并已有一套系统的做法。文章介绍了在航天项目中风险管理的内容、要求和过程，并介绍了一些国际上应用的情况。     

Operations of a spaceflight experiment to investigate plant tropisms

Plants will be an important component in bioregenerative systems for long-term missions to the Moon and Mars. Since gravity is reduced both on the Moon and Mars, studies that identify the basic mechanisms of plant growth and development in altered gravity are required to ensure successful plant production on these space colonization missions. To address these issues, we have developed a project on the International Space Station (ISS) to study the interaction between gravitropism and phototropism in Arabidopsis thaliana. These experiments were termed TROPI (for tropisms) and were performed on the European Modular Cultivation System (EMCS) in 2006. In this paper, we provide an operational summary of TROPI and preliminary results on studies of tropistic curvature of seedlings grown in space. Seed germination in TROPI was lower compared to previous space experiments, and this was likely due to extended storage in hardware for up to 8 months. Video downlinks provided an important quality check on the automated experimental time line that also was monitored with telemetry. Good quality images of seedlings were obtained, but the use of analog video tapes resulted in delays in image processing and analysis procedures. Seedlings that germinated exhibited robust phototropic curvature. Frozen plant samples were returned on three space shuttle missions, and improvements in cold stowage and handing procedures in the second and third missions resulted in quality RNA extracted from the seedlings that was used in subsequent microarray analyses. While the TROPI experiment had technical and logistical difficulties, most of the procedures worked well due to refinement during the project.     

AstroNewt: early development of newt in space.

AstroNewt experiment explores the effects of earth gravity on the early development of Japanese red-bellied newt, Cynops pyrrhogaster. Since female newts keep spermatophore in cloaca, fertilized eggs could be obtained without mating. Fertilization of newt's egg occurs just prior to spawning, so that gonadotrophic cues applied to females in orbit leads to laying eggs fertilized just in space. A property of newt being kept in hibernation at low temperature may be of great help for the space experiment carried out with much limited resources. A general outline of the AstroNewt project is shown here in addition to some technical advances for the development of the project. Experimental schemes of two space experiments (IML-2 in summer 1994 and unmanned SFU at the beginning of 1995) are also shown.     

Effects of heavy ions on visual function and electrophysiology of rodents: the ALTEA-MICE project.

ALTEA-MICE will supplement the ALTEA project on astronauts and provide information on the functional visual impairment possibly induced by heavy ions during prolonged operations in microgravity. Goals of ALTEA-MICE are: (1) to investigate the effects of heavy ions on the visual system of normal and mutant mice with retinal defects; (2) to define reliable experimental conditions for space research; and (3) to develop animal models to study the physiological consequences of space travels on humans. Remotely controlled mouse setup, applied electrophysiological recording methods, remote particle monitoring, and experimental procedures were developed and tested. The project has proved feasible under laboratory-controlled conditions comparable in important aspects to those of astronauts' exposure to particle in space. Experiments are performed at the Brookhaven National Laboratories [BNL] (Upton, NY, USA) and the Gesellschaft für Schwerionenforschung mbH [GSI]/Biophysik (Darmstadt, FRG) to identify possible electrophysiological changes and/or activation of protective mechanisms in response to pulsed radiation. Offline data analyses are in progress and observations are still anecdotal. Electrophysiological changes after pulsed radiation are within the limits of spontaneous variability under anesthesia, with only indirect evidence of possible retinal/cortical responses. Immunostaining showed changes (e.g. increased expression of FGF2 protein in the outer nuclear layer) suggesting a retinal stress reaction to high-energy particles of potential relevance in space.     

Space Materials Science in China: II. Ground-based Researches and Academic Activities

Activities of space materials science research in China have been continuously supported by two main national programs. One is the China Space Station (CSS) program since 1992, and the other is the Strategic Priority Program (SPP) on Space Science since 2011. In CSS plan in 2019, eleven space materials science experimental projects were officially approved for execution during the construction of the space station. In the SPP Phase II launched in 2018, seven pre-research projects are deployed as the first batch in 2018, and one concept study project in 2019. These pre-research projects will be cultivated as candidates for future selection as space experiment projects on the recovery of scientific experimental satellites in the future. A new apparatus of electrostatic levitation system for ground-based research of space materials science and rapid solidification research has been developed under the support of the National Natural Science Foundation of China. In order to promote domestic academic activities and to enhance the advancement of space materials science in China, the Space Materials Science and Technology Division belong to the Chinese Materials Research Society was established in 2019. We also organized scientists to write five review papers on space materials science as a special topic published in the journal Scientia Sinica to provide valuable scientific and technical references for Chinese researchers.      

质谱计在行星系统与小天体探测中的应用

质谱计多次应用于行星系统和小天体的大气层与土壤吸附气体或挥发组分及其同位素含量探索,是太阳系行星系统和小天体探测计划中的首选载荷之一。大气和土壤元素及其同位素组分探测对资源勘探、行星系统的宜居性、天体演化、起源及其重要事件的精准时间坐标研究等具有重要意义。质谱计已多次成功应用于火星、土星系、木星系、彗星等探测任务中开展大气环境探测。质谱计的探测对象主要包括太阳系行星、行星卫星如月球、木星伽利略卫星、土卫,以及地外小行星和彗星。四极杆质谱计在当前的深空空间环境探测活动中应用最为广泛。利用四极杆质谱计除可用于探测稀薄天体大气与土壤析出气体外,如增加抽真空能力的前端设计,则具备探测稠密大气成分的能力。中科院空间中心研发的星载质谱计已多次成功应用于地球行星大气成分和密度探测。     

Science Research and Utilization Planning of China's Space Station in Operation Period 2022-2032

The core module of China's Space Station (CSS) is scheduled to be launched around the end of 2020, and the experimental module I and II will be launched in the next two years. After on-orbit constructions, CSS will be transferred into an operation period over 10 years (2022-2032 and beyond) to continuously implement space science missions. At present, based on the project selection and research work in the ground development period of CSS, China is systematically making a utilization mission planning for the operation period, which focuses on the fields of aerospace medicine and human research, space life science and biotechnology, microgravity fluid physics, combustion science, materials science, fundamental physics, space astronomy and astrophysics, Earth science, space physics and space environment, space application technology, etc. In combination with the latest development trend of space science and technology, China will continue to update planning for science research and technology development, carry out project cultivation, payload R&D, and upgrade onboard and ground experiment supporting systems to achieve greater comprehensive benefits in science, technology, economy, and society.