空间大型可展开天线展开末瞬时速度控制研究

本文对可展开天线的展开末瞬时的速度控制进行了研究，在可开展天线的动力学建模、动力分析、系统辩识和控制系统设计等方面做了有益的尝试，给出了可开展天线展开末瞬时速度控制的一种智能控制方法。计算机数字仿真结果表明：该控制系统能够满足控制要求，且具有良好的准确性、灵活性、适应性等。该方法也适于其他多柔性系统的末瞬时的速度控制。     

空间可展开天线结构研究进展

扼要综述了空间可展开天线结构的发展及目前的国际动态,叙述了空间可展开天线结构、设计及分析中的主要研究课题及其目前的进展。指出“把多体动力学与有限元法相结合的综合动力学建模法”、“辩识模型后,用预测控制和优化的思想进行展开过程控制”、“用多约束优化法调整网状天线反射面形状精度”等是适合我国目前状况的较好方法。     

基于刚体转动四元数模型的航天器再定向方案

介绍了一种新的刚体转动的四元数模型。这些模型可以提高再定向控制的对边界条件的适应能力，在此基础上还介绍了这些模型的一些实际应用。     

目标天体极轨道卫星的轨道寿命

星际探测器轨道的特征与探测目的密切相关，对目标天体两级地区进行探测显然采用的是极轨道（或接近极轨道）。对于这类卫星（或称轨道器），如果轨道半长径较大，则会因第三体报骚动国导致轨道偏心率增大，使其近星距减小到等于目标天体的赤道半径而落到该天体上，结束其运动寿命，即使目标天体不存在大气（如月球等）亦会如此。     

我国小卫星、微小卫星有效载荷的发展

文章简要介绍了国内外小卫星、微小卫星的发展历史,分析了适用于小卫星、微小卫星的有效载荷的发展趋势,简单介绍了我国光学有效载荷的研究现状,通过归纳分析,就有效栽荷实现体积小型化、功能单一化、接口标准化提出了解决方法。     

空空导弹弹体典型焊接缺陷及其控制技术

介绍了空空导弹弹体的结构特点、焊接技术要求、所用材料及常用的焊接方法,分析了圆周焊缝典型的焊接缺陷、危害及产生原因等,并就如何防止和消除焊接缺陷进行了深入的探讨,同时介绍了几种控制焊接缺陷的工艺方法。     

Satellite orbits in Levi-Civita space

In this paper we consider satellite orbits in central force field with quadratic drag using two formalisms. The first using polar coordinates in which the satellite angular momentum plays a dominant role. The second is in Levi-Civita coordinates in which the energy plays a central role. We then merge these two formalisms by introducing polar coordinates in Levi-Civita space and derive a new equation for satellite orbits which unifies these two paradigms. In this equation energy and angular momentum appear on equal footing and thus characterize the orbit by its two invariants. Using this formalism we show that equatorial orbits around oblate spheroids can be expressed analytically in terms of Elliptic functions. In the second part of the paper we derive in Levi-Civita coordinates a linearized equation for the relative motion of two spacecrafts whose trajectories are in the same plane. We carry out also a numerical verification of these equations.     

Utilization of CAM,CAF, MAX,and FAX for space radiation analyses using HZETRN

To estimate astronaut health risk due to space radiation, one must have the ability to calculate various exposure-related quantities that are averaged over specific organs and tissue types. Such calculations require computational models of the ambient space radiation environment, particle transport, nuclear and atomic physics, and the human body. While significant efforts have been made to verify, validate, and quantify the uncertainties associated with many of these models and tools, relatively little work has focused on the uncertainties associated with the representation and utilization of the human phantoms. In this study, we first examine the anatomical properties of the Computerized Anatomical Man (CAM), Computerized Anatomical Female (CAF), Male Adult voXel (MAX), and Female Adult voXel (FAX) models by comparing the masses of various model tissues used to calculate effective dose to the reference values specified by the International Commission on Radiological Protection (ICRP). The MAX and FAX tissue masses are found to be in good agreement with the reference data, while major discrepancies are found between the CAM and CAF tissue masses and the reference data for almost all of the effective dose tissues. We next examine the distribution of target points used with the deterministic transport code HZETRN (High charge (Z) and Energy TRaNsport) to compute mass averaged exposure quantities. A numerical algorithm is presented and used to generate multiple point distributions of varying fidelity for many of the effective dose tissues identified in CAM, CAF, MAX, and FAX. The point distributions are used to compute mass averaged dose equivalent values under both a galactic cosmic ray (GCR) and solar particle event (SPE) environment impinging isotropically on three spherical aluminum shells with areal densities of 0.4 g/cm², 2.0 g/cm², and 10.0 g/cm². The dose equivalent values are examined to identify a recommended set of target points for each of the tissues and to further assess the differences between CAM, CAF, MAX, and FAX. It is concluded that the previously published CAM and CAF point distributions were significantly under-sampled and that the set of point distributions presented here should be adequate for future studies involving CAM, CAF, MAX, or FAX. It is also found that the errors associated with the mass and location of certain tissues in CAM and CAF have a significant impact on the mass averaged dose equivalent values, and it is concluded that MAX and FAX are more accurate than CAM and CAF for space radiation analyses.     

老子深邃的贵身思想

老子关注人的一项重要内容就是要确定身与物谁贵谁轻。他主张贵身，反对以物役身；人是目的，物为手段；人以身为贵，依道贵身；贵身有道。     

Asteroid and comet hazard: Identification problem of observed space objects with the parental bodies

This article focuses on the genetic identification of observed small cosmic bodies with alleged parental bodies; namely, comets, asteroids and meteoroid swarms. There is a problem of the upper D-value limit as a measure of proximity between the orbits of the bodies in the five-dimensional phase space (Southworth and Hawkins, 1963). In the study of genetic relationships of the comet and meteor complexes, the D value is usually taken as equal to 0.2 for all meteor showers. However, the upper D limit should be investigated for each meteoroid complex. For example, such investigation was performed for the Taurid meteor complex (Porub?an et al., 2006). In this paper, the upper D-criterion limit value was investigated for the Perseid meteor shower. The 1862 III Swift–Tuttle comet is its parental comet.