Effects of eccentricity of the reference orbit on multi-tethered satellite formations

The paper discusses the relevance of eccentric reference orbits on the dynamics of a tethered formation, when a massive cable model is included in the analysis of a multi-tethered satellite formation. The formations examined in this study are hub-and-spoke (HAS) and closed-hub-and-spoke (CHAS) configurations for in-plane and Earth-facing spin planes. Stability of the formations is studied by means of numerical simulation, together with the evaluation of the effects of eccentricity on tether elongation, agents relative position, and formation orientation and shape.     

卫星编队飞行相对轨道的摄动研究综述

卫星在编队飞行过程中总受到各种摄动力的作用，由于轨道摄动直接影响卫星的寿命，研究卫星编队飞行相对轨道的摄动问题具有重要的意义。本文综述了国内外有关编队飞行卫星相对轨道摄动问题的研究方法以及进展，最后针对目前相对轨道摄动的研究现状，指出了进一步的研究方向。     

一种卫星在轨自由边界条件模拟方法

随着观测精度的提高,卫星观测设备对微振动愈加敏感,需要在地面开展卫星在轨微振动环境模拟试验及测试验证,而卫星在轨自由边界条件的模拟对于提高地面试验的有效性至关重要。文章提出了一种低频弹性支撑方法,用于模拟卫星在轨飞行时的自由边界条件;并基于该方法,设计和研制了一套模拟试验装置,通过模态和频率响应分析以及型号的整星微振动模拟试验,评估了模拟自由边界条件对卫星动力学特性的影响,也证明了低频弹性支撑模拟方法的有效性。     

“天基红外系统”高轨卫星构型分析与启示

“天基红外系统”（SBIRS）是美国空军为取代“国防支援计划”（DSP）预警卫星而设计部署的后续新型导弹预警卫星系统,用于支持导弹预警、导弹防御和作战空间感知等领域,是美国战略战术作战与防御系统的重要组成部分,对国防军事领域具有关键支撑作用。文章根据公开资料,在对SBIRS GEO-3卫星的任务、技术指标和总体能力进行分析的基础上,对其构型设计与特点以及应用的新技术等进行分析和总结,以期为我国的高轨遥感卫星构型设计提供启示。     

低轨低倾角卫星总体适应性方案研究

针对低轨低倾角卫星的复杂光照特性开展了深入分析,并论述了其对卫星总体设计的具体影响.基于轨道面光照角大动态周期变化规律,系统地提出了四种典型的卫星总体适应性方案并比对分析了各方案特点,最后结合载荷、任务等约束条件给出了方案选择建议.可作为低轨低倾角卫星的总体设计参考.     

Optimization of passive orbit with the use of gravity maneuver

A high-precision method of calculating gravitational interactions is applied in order to determine optimal trajectories. A number of problems, necessary for determination of optimal parameters at a launch of a spacecraft and during its flyby near celestial bodies, are considered. The spacecraft trajectory was determined by numerical integration of the equations of passive motion of the spacecraft and of the equations of motion for planets, the Sun, and the Moon. The optimal trajectory of the spacecraft approaching the Sun is determined by fitting its initial conditions.     

某平台卫星发射及在轨力学环境测量与分析

为获取航天器准确的发射及在轨力学环境数据,设计了一套具有数据采集、存储和传输功能的星载测量系统。利用该系统对某大型平台卫星发射飞行过程进行了测量,获取了星箭界面及卫星结构典型位置在发射主动段的正弦振动响应、随机振动响应、冲击响应及在轨微振动的环境数据。将测量数据与星箭载荷耦合分析结果、地面力学试验结果进行了详细对比,结果表明:星箭载荷耦合分析的结果在星箭界面处横向相对准确,而纵向在有限频段准确,其他频段及星上分析结果均大于测量结果,即存在极大裕度;地面试验结果大于测量结果,意味着有较大的裁剪设计空间。测量数据对后续卫星模型修正、试验条件设计、相似平台卫星抗力学环境优化、部组件设计等均具有重要的参考价值。     

轨道转移推进系统及其发展趋势

根据轨道转移系统的应用分类（包括上面级类、空天飞机类、卫星类、飞船类和新概念类）,对各类型典型飞行器的推进系统进行了综合评述,分别总结了相关的技术方案和应用特点,并针对当前的研究热点,简要论述了未来的发展趋势,最后给出了几点结论.     

A study of evolution of spin-up mode of a satellite in the plane of its orbit

We investigate the mode of spinning up a low-orbit satellite in the plane of its orbit. In this mode the satellite rotates around its principal central axis of the minimum moment of inertia which executes small oscillations with respect to the normal to the orbit plane; the angular velocity of the rotation around this axis several times exceeds the mean orbital motion. Gravitational and restoring aerodynamic moments are taken into account in the satellite’s equations of motion. A small parameter characterizing deviation of the satellite from a dynamically symmetric shape is introduced into the equations. A two-dimensional integral surface of the equations of motion, describing quasi-steady-state rotations of the satellite close to cylindrical precession of the corresponding symmetrical satellite in a gravitational field, has been studied by the method of small parameter and numerically. Such quasi-steady-state rotations are suggested to be considered as unperturbed motions of the satellite in the spin-up mode. Investigation of the integral surface is reduced to numerical solution of a periodic boundary value problem of a certain auxiliary system of differential equations and to calculation of quasi-steady-state rotations by the two-cycle method. A possibility is demonstrated to construct quasi-steady rotations by way of minimization of a special quadratic functional.     

Trends in the design of future communications satellite systems

This paper presents a review of the trends in communication satellite technology. In the near term the development of moderate size, dedicated satellites is to be expected. In the long term international coordination of orbit and spectrum allocations, introduction of higher-frequency bands, spectrum conserving techniques and the concept of large communication platforms deserve particular attention. Means to improve the cost effectiveness of satellite communications system and technology aspects are considered. Finally some German contributions to these developments are presented, mainly concerning high-power TWTs in the 12 and 20 GHz range.     

Analysis of satellite systems for the periodic survey of the Earth

Satellite systems for the periodic survey of a given range of the Earth’s latitudes have been analyzed. As a rule, the efficiency of the satellite systems is estimated based on the maximum interruption, i.e., the maximum time interval that appears when surveying. However, this performance cannot serve as a full criterion for the quality of the survey, since it does not reflect all survey interruptions with their frequencies. To adequately analyze the operation of the satellite system, it is necessary to use the frequency distribution function of the survey interruptions; its determination is a complex problem and has not yet been solved in the general case. In this paper, we propose a method for calculating the set of all interruptions and frequencies suitable for any multisatellite systems with an arbitrary structure. The method is based on the vector model of the Earth’s survey. To estimate the efficiency of the satellite system operation, a complex criterion has been recommended that takes into account all survey interruptions and their frequencies. Two examples of the application of the developed method have been presented.     

提高趋势预报发布率的方法分析

引言2009年民航局空管局开展航空气象服务年活动,并制定趋势预报发布率统计办法,统一评比2009年各月的趋势预报发布率。本文收集了2009年3～11月汕头外砂机场趋势预报发布资料,在分析研究2009年3～11月汕头机场趋势     

Stability of resonance rotation of a satellite with respect to its center of mass in the orbit plane

The stability of resonance oscillations and rotations of a satellite in the plane of its orbit in the case when the difference of the moments of inertia with respect to the principal axes lying in the orbit plane is small is determined at a given rotation number m by the sign of function Φ_m(e), introduced by F.L. Chernous’ko in 1963. In this paper, convenient analytical representations of functions Φ_m(e) are described in the form of integrals and series of Bessel functions regular at e → 1^?. Values of Φ_m(1) are calculated in explicit form. A theorem about the double asymptotic form of functions Φ_m(e) at m → ∞ and e → 1^? is proved by the saddlepoint method.     

Economic effect of satellite communications based on the Great East Japan Earthquake

On 11 March 2011, an undersea earthquake of magnitude 9.0, the largest ever recorded in Japan, occurred off the Oshika Peninsula on the Pacific coast of the Tohoku region. The hypocentral region extended for 500 km in the north–south direction from Iwate Prefecture to Ibaraki Prefecture, and for 200 km in east–west direction. The earthquake generated a tsunami with a height of more than 10 m and a run-up height of up to 40.0 m in certain places, which inflicted devastating damage on the coastal areas of the Tohoku and Kanto regions. In addition to the tsunami, the earthquake caused shaking, liquefaction, subsidence, and the collapse of dams, causing major damage to vast areas in the Tohoku and Kanto regions and disrupting various types of infrastructure, including communication. In light of this unprecedented damage, satellite communications were important from various perspectives while terrestrial communications systems were damaged, and an objective evaluation of the role played by satellite communications is relevant to its future installation, adoption and use as a standalone or backup system. Furthermore, satellite communications can help reduce the extent of damage, particularly damage to communications systems, inflicted by strong earthquakes in the future. Accordingly, we report a preliminary quantitative evaluation of the role of satellite communications in the Great East Japan Earthquake, of the role of satellite communications if it becomes widespread, and of its expected role in future large-scale earthquakes in terms of the economic effect converted into cost.     

Lunar oxygen: Economic benefit for transportation systems and in situ production by fluorination

The use of oxygen produced on the Moon—called “MOONLOX”—is considered as a propellant component for a reusable Earth-Moon transportation system consisting of an aeroassisted orbital transfer vehicle and a lunar bus for lunar descent/ascent. Conditions for economic benefit are discussed and the processing concept of a lunar oxygen plant based on fluorination is presented. It is shown that the necessary mass of supply from Earth for MOONLOX-production is an important parameter, which may not be neglected due to its strong influence on the economy. In the ideal case where no supplies from Earth are required a reduction of up to 50% in masses to be launched into low Earth orbit can be obtained for a typical lunar mission with use of MOONLOX compared to a reference scenario with Earth-derived propellant. Mass-saving decreases, however, significantly with increasing supply from Earth until a critical supply-rate is reached—measured in percentage of MOONLOX-mass produced and consumed—beyond which mass-saving and thus economically promising lunar oxygen production is no longer possible. This critical supply-rate depends on the scenario for MOONLOX-utilization and is much larger in the case of in situ use of MOONLOX on the lunar surface, e.g. as ascent propellant for the lunar bus, than in the case of export for complete refuelling of both space vehicles. The latter scenario therefore requires significantly more autonomy for MOONLOX-production. The reduction of masses to be transported into low Earth orbit and corresponding MOONLOX-consumption define for given specific Earth-to-LEO transportation costs an upper limit on MOONLOX-production costs beyond which economic benefit is not possible. Depending on the MOONLOX-utilization strategy this upper limit varies between 3000 and 55000 $/kg for current Earth-to-LEO transportation costs.     

提高技术资料标准化审查质量的途径与方法

从开展型号研制的标准化大纲、标准化综合要求的编制工作,建立完整的产品标准体系或标准选用范围,编制常用标准标注示例,规范技术文件中引用标准、字体、线型、符号、格式,开展标准的宣贯工作以及建立兼职标准化员队伍等方面,较为系统地阐述了提高技术资料标准化审查质量的途径与方法,并对其做法和工作内容作了说明.     

Robust algorithm of control for a maneuver in the Martian atmosphere to insert a spacecraft into the planet’s satellite orbit

When inserting a satellite into an orbit around Mars with the use of aerodynamic drag, it is required to apply a robust algorithm which is capable of being adapted to the actual conditions of the planet’s atmosphere. We suggest a method of adaptation taking into account the specific features of the maneuver including descending and ascending legs of the trajectory. It is demonstrated that the algorithm is efficient when disturbances of the density of the Martian atmosphere increase by a factor of 2–3.