空间太阳望远镜热光学环境试验技术

空间太阳望远镜在轨期间,空间环境温度变化会严重影响望远镜成像质量,降低分辨率,因此空间太阳望远镜在模拟空间环境下的热光学试验是其研制过程中的关键技术之一。文章介绍了国外部分空间望远镜的热光学试验及低温光学试验设备,并针对国内空间太阳望远镜的研制和试验研究,提出了一些建设性的意见。     

深空通信文件传输协议的交织技术研究

引入喷泉编码技术应用于深空通信,对CCSDS文件传输协议进行改进,提出了一种针对深空环境长时延、高误码率、丢包率大和链路易中断等特点的基于数据包交织的文件传输协议。根据深空通信文件传输的业务需要设计了两种不同的级别概率分布,接收端只需要接收到一定数量的数据包,就能够恢复出整个原始信息,无需或需要很少反馈确认信息。仿真验证交织技术能够简化传输协议,减少文件传输时延,增大系统的吞吐量并保证通信的有效性。
     

定义于Hilbert空间中星形集上的非扩张映像

假设H是一个实Hilbert空间，C是H的一个非空弱闭星形子集，T：C→C为非扩张映像。研究了T的不动点的存在性及其迭代算法的收敛性，本文结果推广了关于非扩张映像的已有相关结果。     

Using cross correlation to estimate Doppler frequency

Doppler frequency estimation with high accuracy is very important for precise orbit determination and scientific studies in deep space exploration. In this paper, we propose a new method which implements cross correlation of only received signals from one single station to estimate Doppler frequency. The algorithm is relatively simple and it can achieve high accuracy even when signal to noise ratio (SNR) is very low. Moreover, the accuracy can be further improved by implementing frequency compensation, especially when the frequency dynamic range is high. Simulations were performed and results proved the validity of this method. X-band observations on MEX (Mars Express) and Juno were performed by a 13 m telescope of Wuhan University, which was equipped by two back ends, i.e. CDAS (Chinese Data Acquisition System) and RSR (Radio Science Receiver). Raw data recorded by the CDAS were processed by using the proposed method, and the estimated frequencies were in good agreement with the real time frequency estimation values by the RSR. What’s more, the accuracy by using cross correlation was higher than the one of RSR.     

微波无源遥感有效载荷现状与发展

针对微波无源遥感有效载荷这一卫星有效载荷中发展最早、最成熟的子领域,对从20世纪60年代至今,世界范围内在轨与在研共17个具有代表性的载荷产品进行了研究。综合分析了微波无源遥感载荷在气象、海洋、陆地、大气环境及深空微波遥感等应用领域的发展现状,归纳出无源微波遥感有效载荷向定量应用、功能复合、主被动一体、体制混合、太赫兹探测等方向的发展趋势。总结了我国与欧美发达国家在系统应用水平、反演处理能力、关键部组件性能、研发条件等方面存在的差距,提出了后续发展静止轨道毫米波亚毫米波探测仪、一体化微波成像探测仪、太赫兹冰云探测仪、L波段土壤湿度微波探测仪、亚毫米波临边探测仪、行星探测仪等载荷的设想。     

Overview of current capabilities and research and technology developments for planetary protection

The pace of scientific exploration of our solar system provides ever-increasing insights into potentially habitable environments, and associated concerns for their contamination by Earth organisms. Biological and organic-chemical contamination has been extensively considered by the COSPAR Panel on Planetary Protection (PPP) and has resulted in the internationally recognized regulations to which spacefaring nations adhere, and which have been in place for 40 years. The only successful Mars lander missions with system-level “sterilization” were the Viking landers in the 1970s. Since then different cleanliness requirements have been applied to spacecraft based on their destination, mission type, and scientific objectives. The Planetary Protection Subcommittee of the NASA Advisory Council has noted that a strategic Research & Technology Development (R&TD) roadmap would be very beneficial to encourage the timely availability of effective tools and methodologies to implement planetary protection requirements. New research avenues in planetary protection for ambitious future exploration missions can best be served by developing an over-arching program that integrates capability-driven developments with mission-driven implementation efforts. This paper analyzes the current status concerning microbial reduction and cleaning methods, recontamination control and bio-barriers, operational analysis methods, and addresses concepts for human exploration. Crosscutting research and support activities are discussed and a rationale for a Strategic Planetary Protection R&TD Roadmap is outlined. Such a roadmap for planetary protection provides a forum for strategic planning and will help to enable the next phases of solar system exploration.     

星用非金属材料出气物成分及污染光学测试分析

文章利用新研制的分子污染出气物成分检测分析设备,对空间辐射致冷器用的几种星用非金属材料的出气污染物进行测试,分析鉴定材料出气物的成分,确定材料在真空烘烤过程中观察到的各种物质源。利用试验获得的材料出气污染物对光学参数的影响数据,并结合光学效应试验研究结果,进一步得到材料出气引起透镜光学参数变化的结果,为型号设计师提供直接的污染控制依据。     

“嫦娥二号”卫星CCD立体相机的关键技术

文章介绍了中国两次绕月探测中 CCD 立体相机所采用的技术与创新,并与国际同类相机所获取的图像进行了比较;在此基础上详细介绍了“嫦娥二号”(CE-2)卫星CCD立体相机的综合创新集成技术--“单镜头两视角同轨立体成像、时间延迟积分图像传感器（TDICCD）推扫、速高比补偿”,并从工程目标与科学目标出发进行探测灵敏度及成像动态范围的需求分析;根据需求分析确定了总体技术方案,包括光、机、电的优化设计以及对月探测中首次采用TDICCD的技术困难与对策;特别讨论了速高比补偿的方案及实施途径,并进行了在轨试验验证。文章最后分别给出了虹湾地区成像分辨率为1.3m以及全月面分辨率为7m 的代表性图像,图像清晰、层次丰富,显示出中国在对月立体成像技术上取得了显著进步。     

美国小行星俘获任务及其启示

小行星俘获(ACR)任务是美国Keck空间研究中心发起的一项深空探测任务。该任务计划选定一颗近地小行星,通过口袋式抓捕系统对其实施抓捕,并于2025年左右将其带回近月空间。文章介绍了ACR任务的内容和系统设计,具体包括:航天器总体构型、抓捕分系统、探测识别分系统和控制与推进分系统;对小行星抓捕的目标探测与识别、旋转匹配、抓捕、消旋、轨道转移等核心操作。基于ACR任务,提出了空间目标俘获技术的需求与应用、抓捕航天器系统设计的启示;基于我国目前的技术研究情况,总结分析了发展空间目标俘获任务所需的关键技术,如大功率柔性太阳翼、长时间大范围轨道机动、目标探测与识别、快速机动、目标抓捕与消旋。     

碳纳米管气体传感器在空间站在轨检漏中的应用

空间站在轨检漏技术对维护空间站安全起着至关重要的作用。未来空间站检漏技术要求能更加快速、准确地确定微小泄漏点的位置。碳纳米管表面积大,对气体吸附反应灵敏,利用碳纳米管制备的气体传感器具有灵敏度高、响应快、重量轻、体积小、功耗低等特点,可以用于微量气体检测。据此,文章提出可以将碳纳米管气体传感器技术用于空间站的在轨检漏,并探讨了该技术在空间站检漏应用中面临的关键问题和解决方案。碳纳米管气体传感器技术的研究和发展有望提高空间站在轨检漏技术水平,为空间站的安全可靠运行提供保障。