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981.
This paper briefly introduces the history of China's Manned Space Flight Program and concludes the experiments done since 2008, namely, a small satellite and a material science experiment. An outlook of future Chinese Space Station is also described at the end. 相似文献
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983.
In the past two years, most of the works on magnetospheric physics were made by using the data of Double Star Program and Cluster missions. However some works were still conducted by computer simulation or using the data from other space missions and ground geomagnetic observations. This paper briefly review these previous works based on papers selected from the 28 publications from April 2008 to April 2010. The subjects covered various sub-branches of magnetospheric physics, including geomagnetic storm, magnetospheric substorm and etc. 相似文献
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987.
基于激光干涉星间测距原理的下一代月球卫星重力测量计划需求论证 总被引:4,自引:0,他引:4
月球卫星重力测量是21世纪国际开展深空探测的发展趋势和追逐热点。月球重力场的精密测量是国际探月计划的重要组成部分,它决定着月球探测器的轨道优化设计和载人登月飞船月面理想着陆点的合适选取。本文首先介绍未来国际GRAIL(Gravity Recovery and Interior Laboratory)月球重力场探测双星计划的总体概述、关键载荷以及科学目标和研究方向。其次,重点阐述月球卫星观测模式可行性论证、月球卫星关键载荷的优化选取、卫星轨道参数的优化设计、仿真模拟研究的先期开展等我国将来月球卫星重力测量计划的实施建议。第一,由于高低/低低卫星跟踪卫星结合多普勒和甚长基线干涉系统观测模式(SST-HL/LL-Doppler-VLBI)对中长波月球重力场的探测精度较高,技术要求相对较低,月球重力场测定速度快、代价低和效益高,可借鉴地球重力卫星GRACE(Gravity Recovery and Climate Experiment)系统的成功经验,对定轨精度的要求较低,而且可有效探测远月面区域的月球重力场信号,因此我国将来首期月球卫星重力测量计划采用SST-HL/LL-Doppler-VLBI观测模式较优。第二,我国应先期开展高精度的月球重力卫星关键载荷(激光干涉星间测距仪、非保守力补偿系统等)和地面Doppler\|VLBI系统的研制工作。第三,月球卫星轨道高度(50~100 km)和星间距离(100±50 km)的优化设计是成功实施将来我国月球卫星重力测量计划的重要保证。第四,建议我国将仿真技术应用于月球重力卫星的方案论证、系统设计、部件研制、产品检验、实际应用、故障分析等研制和运行的全过程。本文的研究不仅对我国将来首期月球卫星重力测量计划的成功实施具有重要的参考价值,同时对未来国际太阳系行星重力探测的发展方向具有广泛的指导意义。
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988.
989.
《Aerospace Science and Technology》2002,6(5):355-366
Infrared thermography (IRT) is used at Onera in large facilities for boundary layer visualization and for heat flux assessment. Modern IR cameras and insulating paints enable efficient visualization of the laminar/turbulent transition region. This technique is now applied in large transonic test facilities. Heat flux assessment is one of the main purposes of hypersonic tests. It is done mainly with IRT and dedicated softwares, while sensors as thermocouples are used to check the reliability of IRT. A 1D data reduction method has been developed to provide the heat flux through temperature measurements. It takes into account thickness and curvature effects. The method has been recently improved to be used with steel models covered with an insulating paint, which provides a high emissivity. The temperature film is converted into a heat flux film, which is be used to extract the useful information. This requires image processing tools that relate every pixel to a point on the model. A new application of IRT is going on in the Onera's high enthalpy hypersonic wind tunnel F4. The camera is used in single-line scan mode because of the short duration of the run. The main difficulty comes from the flow, which is not transparent. The first trial to cope with this kind of optical pollution is encouraging. 相似文献
990.
《Aerospace Science and Technology》2002,6(1):3-17
The prediction of the performances of supersonic inlets heavily depends on the ability to model Shock-Wave/Turbulent-Boundary-Layer Interactions (SWBLI). A joint experimental and computational study is carried out to identify the flow regimes occurring at Mach 4 between two sharp fins mounted on a flat plate. Three configurations are examined (7°×7°, 7°×11°, 15°×15°) to cover a representative range of interaction strengths. The evolution of the flow regimes with the interaction strength is described. The distributions of pressure and heat-transfer coefficient are related to the identified flow regimes. Experiments and computations agree on the primary features of the flow, while they diverge about the secondary features and the level of the heat transfer in these regions, where it may be over-predicted by a factor of 2−2.5. The SWBLI heat transfer issue is related to specific flow regimes, for which turbulence modeling deficiencies are pointed out. 相似文献