On the assurance of the design accuracy of the space radio telescope RadioAstron

The results are given of the theoretical calculations and the results of measurements of the shape of the reflecting surface of the space telescope conducted during the manufacture of individual elements and assembly of the product as a whole.     

Determination of the Turbulent Diffusion Coefficient in the Plasma Sheet Using the Project INTERBALL Data

The results of an analysis of velocity fluctuations in the plasma sheet of the Earth's magnetotail measured onboard INTERBALL Tail Probe satellite are presented. The hodographs of the velocity in directions (Y, Z) and correlation functions are presented for a number of passages when the satellite was in the plasma sheet for a long time. The turbulent diffusion coefficients are calculated. A comparison of the obtained diffusion coefficients with those predicted theoretically in [1] is carried out. It is shown that the results of observations confirm theoretical predictions.     

正交解调中频误差对脉间变频雷达成像结果的影响

针对采用固定中频正交解调方法的脉间变频雷达可能存在的中频误差进行分析,得到在中频上进行正交解调不会对成像造成影响的结论。推导存在中频频率误差条件下的成像公式,分析误差影响的主要表现。通过仿真对比不同中频频率误差对二维成像结果的影响,得出成像结果随频率误差变化的规律,给出可以忽略此误差的条件。     

固体火箭发动机喷管模态分析

针对某固体发动机喷管结构，建立计算模型，给出了用大型特征值问题求解的子空间迭代法，并对某喷管整体结构进行了自由振动和模态分析，获得了该喷管模型的多阶自振频率和模态。分析结果与实测值吻合较好。     

发动机喷流对飞行器底部流动影响数值模拟

针对发动机燃气喷流对底部流动的影响开展研究。建立冷喷与热喷计算方法，与经典的高压空气尾喷管喷流试验数据进行了对比，验证了本文建立的三维喷流方法的可靠性。对本文选用的飞行器外形采用冷喷与热喷方法开展了对比计算并与飞行试验值进行比较，分析了两种方法结果的差异。采用热喷方法对来流马赫数 2.5 ，不同飞行高度及喷管进口总压开展计算，研究飞行高度及喷管进口总压对发动机喷流及底部流场的影响。结果表明，保持飞行高度、来流马赫数不变，喷管进口总压增加，底部压力系数逐渐提高。燃气质量浓度最大值位于底部空腔的壁面处，且保持一个恒定值。保持喷管进口总压、来流马赫数不变，飞行高度增加，喷流高速区向后移动且中心区最大马赫数增加。在一定飞行高度下，底部压力系数由负转正，即飞行器底部会出现正推力，这对飞行器的射程会产生重要影响，需要提前评估。     

Perturbation effect of the Coulomb drag on the orbital elements of the earth satellite moving in the ionosphere

The perturbation effects of the Coulomb drag on the orbital elements of the earth satellite moving in the ionosphere are studied. The theoretical results show that the Coulomb drag results in both the secular and periodic variation in the semi-major axis and eccentricity. However, the argument of the perigee exhibits no secular variation, but only periodic variation. The inclination and the ascending node remain no variation. As an example, the secular effects of the Coulomb drag on the semi-major axis and the eccentricity of an ionosphere satellite Alouette (S-27) are calculated in the ionosphere with the mean height 1000 km. It can be shown that the semi-major axis contracts and the eccentricity decreases for the case of the Coulomb drag under the interaction of the ions with the electric field of an earth satellite.     

A status report on the characterization of the microgravity environment of the International Space Station

A primary objective of the International Space Station is to provide a long-term quiescent environment for the conduct of scientific research for a variety of microgravity science disciplines. Since continuous human presence on the space station began in November 2000 through the end of Increment-6, over 1260 hours of crew time have been allocated to research. However, far more research time has been accumulated by experiments controlled on the ground. By the end of the time period covered by this paper (end of Increment-6), the total experiment hours performed on the station are well over 100,000 hours (Expedition 6 Press Kit: Station Begins Third Year of Human Occupation, Boeing/USA/NASA, October 25, 2002). This paper presents the results of the on-going effort by the Principal Investigator Microgravity Services project, at NASA Glenn Research Center, in Cleveland, Ohio, to characterize the microgravity environment of the International Space Station in order to keep the microgravity scientific community apprised of the reduced gravity environment provided by the station for the performance of space experiments. This paper focuses on the station microgravity environment for Increments 5 and 6. During that period over 580 Gbytes of acceleration data were collected, out of which over 34,790 hours were analyzed. The results presented in this paper are divided into two sections: quasi-steady and vibratory. For the quasi-steady analysis, over 7794 hours of acceleration data were analyzed, while over 27,000 hours were analyzed for the vibratory analysis. The results of the data analysis are presented in this paper in the form of a grand summary for the period under consideration. For the quasi-steady acceleration response, results are presented in the form of a 95% confidence interval for the station during "normal microgravity mode operations" for the following three attitudes: local vertical local horizontal, X-axis perpendicular to the orbit plane and the Russian torque equilibrium attitude. The same analysis was performed for the station during "non-microgravity mode operations" to assess the station quasi-steady acceleration environment over a long period of time. The same type of analysis was performed for the vibratory, but a 95th percentile benchmark was used, which shows the overall acceleration magnitude during Increments 5 and 6. The results, for both quasi-steady and vibratory acceleration response, show that the station is not yet meeting the microgravity requirements during the microgravity mode operations. However, it should be stressed that the requirements apply only at assembly complete, whereas the results presented below apply up to the station's configuration at the end of Increment-6.     

推力器真空羽流热效应计算模型修正及误差分析

开展羽流热效应计算模型精确评估是合理进行热控设计的前提和条件。文章采用数值求解N-S方程和基于工程经验的点源法相结合的方法得到羽流内外流场;而后采用理论经验公式对羽流热效应计算模型中的关键参数(壁面热适应系数)进行分析,并讨论它们的取值范围;最后利用MBB 10 N推力器的地面试验数据,对羽流热效应关键参数的取值范围进行了精确评估,使得羽流热效应计算误差减小到工程允许的范围内,确认了修正后计算模型的正确性和可信度。     

复燃对液体火箭返回阶段底部热环境的影响

为了研究垂直起降液体火箭在返回阶段发动机反向喷流及复燃对箭体着陆支腿和底部热环境的影响,建立了尾焰复燃、流场及光谱辐射计算模型。在国内率先对垂直起降液体火箭在返回阶段的箭体底部热环境进行了数值计算,流场计算采用商业软件,复燃反应使用有限速率化学反应模型;采用HITRAN数据库获得喷流气体组分的光谱吸收系数、正反光线踪迹法求解辐射传递方程。利用文献实验结果,对计算进行了验证并考察了复燃对底部热环境的影响。结果表明:复燃反应对包括箭体底面、侧壁面及着陆支腿的对流和辐射热流密度均会明显升高,最高可达80%以上。因此,研究成果适用于液体火箭返回阶段底部精细化热设计,且在设计过程中有必要考虑复燃的影响。     

Evaluation of the spectrometric and dose characteristics of neutron fields inside the Russian segment of the ISS by fission detectors

The results of measuring the dose and the energy spectrum of neutrons inside the Russian segment of the International Space Station (ISS) from March 21 until November 10, 2002 are presented. Statistically reliable results of measurement are obtained by using thorium- and uranium-based fission detectors with cadmium and boron filters. The kits of the detectors with filters have been arranged in three compartments within assembled passive detectors in the BRADOS space experiment. The ambient dose rate H* = 139 μSv day and an energy spectrum of neutrons in the range of 10^–2–10⁴ MeV is obtained as average for the ISS compartments and is compared with the measurements carried out inside the compartments of the MIR space station. Recommendations on how to improve the procedure for using the fission detectors to measure the characteristics of neutron fields inside the compartments of space stations are formulated.     

固体火箭发动机接头组合件三维弹塑性有限元分析

对固体发动机复合材料壳体接头组合件在内压作用下的应力变形进行了三雏有限元分析。分析了两种不同厚度的水压堵盖对结构变形的影响，考虑了螺栓、堵盖、接头等金属材料的塑性性质，复合材料按正交各向异性体处理。结果说明，在内压作用下，较厚的堵盖(40mm)和接头在外缘发生分离，使得接头肩部变形略大；而较薄的堵盖(28mm)与接头内缘发生分离，对密封结构不利。在内压作用下，复合材料和接头侧面也发生分离。该分析方法和结果可供接头及其密封设计提供参考。     

Absorbed doses in October–November 2003 onboard the Russian segment of the International Space Station according to the data of radiation control system

The results of radiation control onboard the Service Module of the International Space Station are considered for the period of increased radiation background from 28 to 30 October, 2003. The values of additional irradiation dose caused by strong solar proton events on October 28 and 29, 2003 are obtained. A comparison is made with similar data obtained in the periods of disturbed radiation conditions of fall 2001. The results of estimating the dependence of the absorbed dose on the shield thickness, based on the onboard measurements, are presented. It is established that the daily-averaged dose power onboard the International Space Station increased after the solar proton events of October 2003.     

复合材料壳体在水压和地面热试验状态下的大变形有限元分析

用等效正交异性轴对称八节点等参元对固体火箭发动机壳体进行了大变形有限元分析。首先计算了壳体承受内压作用下的应力与变形,并与其水压试验结果进行了比较,然后计算壳体在热试验状态下的应力与变形,也与其水压试验的计算结果进行了比较。     

丁羟推进剂伸长率主曲线形状的研究

给出了丁羟推进主要曲线的典型结果，针对其中的一些现象，提出了描述基拉焦形行煌双模量模型和描述其拉伸破坏行为规律的韧性断过程模型。     

PSK转换法产生直序扩频MSK信号研究

通过 PSK转换法产生 MSK信号的数学模型的进一步推导和计算机仿真 ,研究了不同长度的扩频码对延时相干解调扩频 MSK信号的影响。然后进行了 PSK转换法产生扩频 MSK信号的系统实验     

速率积分陀螺的数学模型和常值漂移的在轨标定

介绍了东方红三号卫星的速率积分陀螺的基本工作原理和性能指标, 描述了速率积分陀螺的数学模型。分析了东方红三号卫星陀螺在轨飞行四十天中的常值漂移标定和补偿的结果, 证明了BICE生产的速率积分陀螺的可用性和两种标定方法的正确性     

热力学排气系统对液氮贮箱控压特性的影响分析

为研究热力学排气系统(TVS)对低温推进剂贮箱控压特性的影响，搭建了液氮热力学排气技术控压试验平台，开展了混合模式和并行模式下的低温贮箱控压试验，研究了不同控压区间气枕压力及液相温度的变化规律，对并行模式过程中节流特性以及节流制冷量的输入对液相温度变化的影响进行了分析。试验结果表明，在混合模式中由于外部漏热和气枕压力的影响，液相温度呈波浪式上升趋势;在并行模式中，在节流制冷量输入和外部漏热的共同作用下，液相温度停止上升转而下降；在两种模式运行中，液相温度在较高的控压区间比较低的区间变化率大；理论模型能够较好反映试验测试结果，模拟分析得到的液相温度变化率与试验结果基本一致。     

Investigation of Thermal Convection and Low-Frequency Microgravity by the DACON Sensor aboard the MirOrbital Complex

The DACON instrument for studying the convection caused by low frequency microaccelerations aboard spacecraft is described. The convection sensor serves as a measuring element of this instrument. This is a cylindrical cavity filled with air, where two crossed differential thermocouples are located. The thermocouple junctions lay on two mutually perpendicular lines parallel to the bases of the cylinder and crossing at its axis. The distances from the junctions to this axis are equal. The lateral surface of the cylinder is thermally insulated, the difference of temperatures on its bases being kept constant. One of the tasks for the sensor is to prepare the data for checking the adequacy of mathematical models of fluid convection under weightlessness conditions and for obtaining quantitative characteristics of the microgravitational medium. The results of ground-based tests of the DACON instrument and the results of experiments with it aboard the Mirstation are presented.     

铰接桁架结构动力学问题研究

以铰接桁架结构为对象,采用谱元法研究铰对桁架结构动力学行为的影响,拓展了谱元法的应用领域。在频域下将铰结构考虑为一个谱单元,分别建立铰、杆和梁单元的动力学刚度矩阵,并加以整合得到整体结构的动力学刚度阵,进而建立整体结构的动力学方程。通过求解整体结构的动力学方程,获得结构的固有频率、频响曲线和时间响应历程曲线,并将谱元法的计算结果同有限元法的相应结果进行了比较。分析结果表明,谱元法在求解铰接桁架结构的动力学问题上具有较高的精确性,并且铰的存在对桁架结构动力学行为具有显著影响。     

中国上空过渡流区大气月平均状态的模拟结果

利用美国海军研究实验室在MSIS系列模型基础上发展的大气模型NRLMSISE-00, 模拟研究了2001年—2013年中国上空过渡流区80～140 km高度的大气状态。对于中国东部和中部过渡流区, 基于模拟数据得到的月平均结果显示大气密度和温度呈现一致的变化趋势, 还表现出与太阳活动的显著关联。谱分析的结果显示, 在90 km高度以上大气密度呈现半年周期变化, 在90～110 km高度范围这种半年变化的幅度随纬度增大。在100 km高度, 上半年出现的半年周期过程中密度的最大、最小值分别出现在3月和6月, 明显超前中、高热层的半年周期过程。