极坐标系连续常值推力机动分析

连续常值推力是空间飞行常用的轨道机动方式，在空间交会与星际航行使命中具有重要的应用价值。其中，小推力适合于地球轨道航天器交会机动，而切向或周向推力以及较大的正径向推力可用于脱离地球引力场的逃逸飞行，执行星际交会使命。应用常推力作用下的极坐标系质心运动方程，对机动推力的量值没有限制；在航天器交会应用中，对相对距离也无要求。这种方法可直接获得向径与速度等轨道参数随时间或极角（绕地心的转动角）的变化，便于分析轨道转移与逃逸运动，有助于飞行使命与运动轨迹的设计。特别是，若机动转移的初轨为圆轨道，在推力较小、飞行时间不长的情况下，应用无量纲形式运动方程，可获得具有工程应用价值的近似解。文章给出一些有关的结果与应用案例。     

实线性赋范空间中算子的Fermat定理

本文给出并证明了文中的定理１，该定理是经典分析中的Ｆｅｒｍａｔ定理在现代分析学中的合理推广。据此又给出了一个中值公式在抽象分析中成立的充分条件。最后，指出了经典分析中的中值定理在抽象分析中不成立。文中各项内容相结合，较深刻地说明了中值定理在抽象分析学中不成立的原因。     

3种气动弹性状态空间建模方法的对比

研究气动弹性状态空间建模的3种常用方法:最小二乘(LS)法、最小状态(MS)法和拟合状态空间(MA)法.用2个算例从颤振和频响特性角度分析和总结了它们的建模特点.在气动力有理函数拟合建模方法(LS法、MS法)研究中,着重分析滞后根的影响;在MA法的研究中,讨论了建模的特点.最后,系统对比了3种建模方法的建模效果及使用原则,为这些方法的工程应用提供参考.仿真计算结果表明,MS法建立的模型阶数低、精度适中且使用方便,是比较好的方法,而MA法建立的模型频响特性与参考结果最为接近.     

Viability of barley seeds after long-term exposure to outer side of international space station

Barley seeds were exposed to outer space for 13 months in a vented metal container without a climate control system to assess the risk of physiological and genetic mutation during long-term storage in space. The space-stored seeds (S0 generation), with an 82% germination rate in 50 seeds, lost about 20% of their weight after the exposure. The germinated seeds showed normal growth, heading, and ripening. The harvested seeds (S1 generation) also germinated and reproduced (S2 generation) as did the ground-stored seeds. The culm length, ear length, number of seed, grain weight, and fertility of the plants from the space-stored seeds were not significantly different from those of the ground-stored seeds in each of the S0 and S1 generation. Furthermore, the S1 and S2 space-stored seeds respectively showed similar β-glucan content to those of the ground-stored seeds. Amplified fragment length polymorphism analysis with 16 primer combinations showed no specific fragment that appears or disappears significantly in the DNA isolated from the barley grown from the space-stored seeds. Though these data are derived from nine S0 space-stored seeds in a single exposure experiment, the results demonstrate the preservation of barley seeds in outer space for 13 months without phenotypic or genotypic changes and with healthy and vigorous growth in space.     

Estimation of Galactic Cosmic Ray exposure inside and outside the Earth’s magnetosphere during the recent solar minimum between solar cycles 23 and 24

The evidently low solar activity observed between solar cycles 23 and 24 during the years 2008–2010 led to a substantial increase in the Galactic Cosmic Ray (GCR) intensity in comparison with preceding solar minima. As the GCRs consist of highly-ionizing charged particles having the potential to cause biological damage, they are a subject of concern for manned missions to space. With the enhanced particle fluxes observed between 2008 and 2010, it is reasonable to assume that the radiation exposure from GCR must have also increased to unusually high levels. In this paper, the GCR exposure outside and inside the Earth’s magnetosphere is numerically calculated for time periods starting from 1970 to the end of 2011 in order to investigate the increase in dose levels during the years 2008–2010 in comparison with the last three solar minima. The dose rates were calculated in a water sphere, used as a surrogate for the human body, either unshielded or surrounded by aluminium shielding of 0.3, 10 or 40 g/cm².     

一种异型零件空间交点尺寸的测量方法

将被测要素转换成现有三坐标可识别的几何要素，即用小平面代替不规则曲面，用与Ф3.175mm小斜孔相配合的圆器轴线代替该孔的中心线，这样就可以用现有三坐标测量软件编制测量程序，解决测量异型零件不规则曲面空间交点尺寸的技术问题。     

A Detailed Analysis of the Operational Orbit of the Hipparcos Satellite

An analysis of the orbital evolution of the ESA's Hipparcos satellite is presented. Hipparcos operated between August 1989 and March 1993 in a highly elliptical orbit: a geostationary transfer orbit with increased perigee height. The requirements of the scientific mission included high accuracy knowledge of the position and velocity vectors of the spacecraft as a function of time. Through a study of the variations in the total orbital energy, the loss of energy during the mission as a result of non-conservative forces is recovered. These are explained as largely due to atmospheric drag during perigee passages. Apparent variations in the drag coefficient are in agreement with orientation variations of the satellite during those perigee passages. Two different models used for calculating the atmospheric drag give significantly different results, confirming earlier findings by other users of those models. This revised version was published online in August 2006 with corrections to the Cover Date.     

航迹规划中雷达探测空间的生成

从飞机突防习行任务规划出发，综合考虑地球曲率、陆地（或海洋）的反射和杂波干扰、大气折射和吸收损耗等因素的影响，采用临界散射截面法生成了对空警戒雷达在不同地貌、发现概率下，对不同雷达散射截面的目标的探测空间。计算并分析了飞行高度、目标雷达散射截面、发现概率和地貌等因素对雷达探测空间的影响，以便选择低探测概率的飞行走廓，这对制定和实施安全突防飞行策略有实际意义。     

Deep Impact Mission Design

The Deep Impact mission is designed to provide the first opportunity to probe below the surface of a comet nucleus by a high-speed impact. This requires finding a suitable comet with launch and encounter conditions that allow a meaningful scientific experiment. The overall design requires the consideration of many factors ranging from environmental characteristics of the comet (nucleus size, dust levels, etc.), to launch dates fitting within the NASA Discovery program opportunities, to launch vehicle capability for a large impactor, to the observational conditions for the two approaching spacecraft and for telescopes on Earth.     

Deep Impact: A Large-Scale Active Experiment on a Cometary Nucleus

The Deep Impact mission will provide the first data on the interior of a cometary nucleus and a comparison of those data with data on the surface. Two spacecraft, an impactor and a flyby spacecraft, will arrive at comet 9P/Tempel 1 on 4 July 2005 to create and observe the formation and final properties of a large crater that is predicted to be approximately 30-m deep with the dimensions of a football stadium. The flyby and impactor instruments will yield images and near infrared spectra (1–5 μm) of the surface at unprecedented spatial resolutions both before and after the impact of a 350-kg spacecraft at 10.2 km/s. These data will provide unique information on the structure of the nucleus near the surface and its chemical composition. They will also used to interpret the evolutionary effects on remote sensing data and will indicate how those data can be used to better constrain conditions in the early solar system.