地球空间双星探测计划的进展

扼要介绍了地球空间双星探测计划的提出和目标、地球空间双星探测工程系统的组成和特点、双星轨道飞行试验的情况     

利用校准卫星进行USB外场试验的方法

探讨一种USB外场试验的方法,即利用在轨卫星对USB进行外场试验,检验设备的跟踪性能,并对测量精度进行评估。阐述在USB设备研制过程中,利用卫星对USB进行外场试验的必要性和可行性。     

既快又省发展战术侦察卫星的新尝试

“战术卫星”(TacSat)1是美国防部正在实施的“实战响应空间实验(ORSE)”创新计划的首次实验。该实验计划从概念到技术,从计划管理到实战应用,处处都充满着创新精神。该计划的最终目标是在危机或战争前夕,按战场指挥官的实战需求,在几周或几个月内,快速组装、发射一颗能够直接向战场用户传送侦察图像的卫星,使空间资产成为美军联合特遣部队装备的重要组成部分。其特点是充分利用高度自主的微小卫星平台、模块化的有效载荷、共同的接口界面以及通过国防部保密的TCP/IP路由网直接向卫星发送指令和分发卫星图像等创新概念与技术,构建快速响应的航天科研生产管理机制与发射模式,获得战术应用的实战响应能力。     

Optimum Number of Stages in a Staged Vehicle

The problem of optimum partitioning of a staged vehicle (SV) and determination of the minimal number of stages to provide for a maximum velocity in the vertical SV motion in a homogeneous gravity field is considered at a given value of payload mass.     

Application of Meteorological Satellites to Rainstorm Research and Forecast in China

The rainstorm is a kind of main natural disasters in China.In recent years the Chinese meteorological scholars have used the meteorological satellite data to study it and have obtained good results.This paper describes the application of six kinds of meteorological satellite data including satellite cloud image,water vapor map,sea surface temperature (SST),outgoing longwave radiation (OLR),cloud cover and brightness temperature to the rain storm research and forecast in China.     

Attitude Determination for Satellites in the INTERBALL Project from a Limited Set of Measurements

The determination of the orientation of satellites in the INTERBALL project from a limited set of measurements is discussed. It is shown that the full set of attitude parameters can be obtained by processing only the solar sensor data. The accuracy of corresponding parameters is estimated from alternative measurements.     

Public school teachers in the U.S. evaluate the educational impact of student space experiments launched by expendable vehicles, aboard Skylab, and aboard Space Shuttle

Space education is a discipline that has evolved at an unprecedented rate over the past 25 years. Although program proceedings, research literature, and historical documentation have captured fragmented pieces of information about student space experiments, the field lacks a valid comprehensive study that measures the educational impact of sounding rockets, Skylab, Ariane, AMSAT, and Space Shuttle. The lack of this information is a problem for space educators worldwide which led to a national study with classroom teachers. Student flown experiments continue to offer a unique experiential approach to teach students thinking and reasoning skills that are imperative in the current international competitive environment in which they live and will work. Understanding the history as well as the current status and educational spin-offs of these experimental programs strengthens the teaching capacity of educators throughout the world to develop problem solving skills and various higher mental processes in the schools. These skills and processes enable students to use their knowledge more effectively and efficiently long after they leave the classroom. This paper focuses on student space experiments as a means of motivating students to meet this educational goal successfully.     

宽马赫数范围高超声速进气道伸缩唇口式变几何方案

针对二元高超声速进气道Ma=4～7的宽马赫数范围工作要求,探索了一种伸缩唇口式简单变几何方案,利用一维流理论对其设计方法进行了讨论,给出了一种具体的实现方案,并利用数值仿真手段对其接力点下的自起动性能及其它不同工作马赫数下的性能进行了研究。结果表明:(1)所设计的伸缩唇口式变几何方案解决了宽马赫数工作范围内定几何进气道难以协调的设计矛盾,该方案能使进气道工作范围进一步拓宽至Ma=4～8(9);(2)变几何进气道能使马赫4接力点下的流量系数保持在0.7以上,这为飞行器宽马赫数范围加速提供了强有力保障;(3)与定几何进气道相比,变几何进气道高低马赫数下的总体性能均得到大幅度提高;(4)研究发现,附面层排移及排移位置对改善进气道接力点下的自起动性能有重要影响。     

2007年商业通信卫星与发射服务市场综述

商业通信卫星市场主要由美国四家卫星公司(劳拉、波音、洛马和轨道科学公司)与欧洲两家卫星公司(泰勒斯·阿列尼亚和阿斯特里姆公司)相互竞争,共同瓜分.在商业发射服务市场,过去一直由欧、美、俄"三足鼎立"的局面在2007年略有变化.     

Statistical Correlation of the Rate of Failures on Geosynchronous Satellites with Fluxes of Energetic Electrons and Protons

A statistical comparison of failures on geosynchronous satellites in the maximum and during the decline of the 22nd solar cycle (1989–1994) with space weather parameters is carried out. A positive correlation of the rate of failures with the flux of relativistic electrons on the geosynchronous orbit and with the proton flux measured before the bow shock front is revealed. The significant positive correlation of the electron flux with the rate of failures is observed during the entire considered interval. The correlation coefficient varies in the solar activity cycle in coordination with the electron flux, and the maxima of the correlation coefficient are observed on the phase of decline of the cycle. A statistically significant positive correlation between the flux of protons with energy of more than 1 MeV and the rate of failures is revealed in the maximum of the solar cycle.__________Translated from Kosmicheskie Issledovaniya, Vol. 43, No. 3, 2005, pp. 186–193.Original Russian Text Copyright © 2005 by Romanova, Pilipenko, Yagova, Belov.     

低轨卫星编队飞行的地面覆盖及轨道调整

通过施加冲量的方法消除J2项摄动和大气阻力摄动对编队飞行的影响,在编队的相对构型和整体绝对位置得到控制后,研究了低轨卫星编队飞行的地面覆盖问题,最后通过算例给出了卫星编队在南北纬86°之间全球覆盖所需的时间、周期、圈数和覆盖角。计算结果表明,对于偏心率较小的低轨编队飞行,根据本文所推导公式计算出的结果是比较可靠的。     

星箭弹船屡创辉煌——中国航天科技集团公司第八研究院在发展中壮大

上海,在国际上是一个著名的大都市;上海,航天的地位和影响也与日俱增。中国航天科技集团公司第八研究院,又称上海航天技术研究院、上海航天局,创建于1961年8月。经过40多年来的艰苦创业和勇于拼搏,上海航天一次次地抓住良好的历史机遇,在发展中不断壮大自己,目前已成为中国航天     

Mass transfer interaction of moving particles in a reactive dispersive system

Mass transfer from a system of particles moving linearly in a viscous fluid is considered. A chemical reaction on the particle surfaces is taken into account. The analysis is based on the investigation of concentration and velocity fields in a particle wake and of the distortion of these fields due to particles interaction. The values of both local and average Sherwood numbers are calculated.The results obtained are applied to the system of drops and solid spherical particles moving in line along the axis of uniform Stokes flow. It is shown, that if the distance 1 between the particles satisfies the condition (a is the sphere radius and P is the Peclet number) then the total diffusion flux to the surface of kth sphere is as follows

Full-size image (1K)

. Here k is the particle number along the stream (for the leading particle k = 1), I₁ is the diffusion flux to the leading particle: n = 1 for drops, n = 2 for solid particles.     

Mass determination of a small body in solar system by using a test-mass during a fly-by

The mass estimation of small bodies in the solar system—such as comets or minor planets—with an accuracy sufficient to get scientific information is difficult. The ground-based range-rate measurements are not practicable for bodies smaller than 100 km diameter.A proof mass, ejected from the spacecraft before the flyby and whose relative trajectory is determined with onboard measurements can give very good results even for small bodies. This paper presents the expected accuracy of mass determination depending on ballistic conditions (relative velocity and closest approach), type and accuracy of measurements (range, optical).     

Variations of Protons and Doubly Ionized Helium Ions in the Solar Wind

Cosmic Research - We investigated variations on scales of 104–105 km and local spatial inhomogeneities in the density of protons Np, doubly ionized helium ions (α-particles) Nα, and...     

Experiments and numerical simulations of an electrodynamic tether deployment from a spool-type reel using thrusters

The amount of space debris is ever increasing, and pollution of the space environment has become a serious problem that can no longer be ignored. Consequently, the active removal of large space debris from crowded economically useful orbits should begin as soon as possible. The Japan Aerospace Exploration Agency has been investigating an active debris removal system that employs highly efficient electrodynamic tether (EDT) technology for orbital transfer. This study investigates the tether deployment from a spool-type reel using thrusters by means of numerical simulations of an EDT system. The thrusters are used in order to ensure the deployment of a tether with the length of several kilometers. In the simulations using a multiple mass tether model, the key parameters are estimated from various on-ground experiments. By means of the numerical simulations, the dynamics of tether deployment is studied and requirements of thruster needed for the deployment, such as the thrust forces and the periods of thruster activation, are clarified.     

Resonance Effects when Moving a Small Spacecraft around the Center of Mass in a Deployable Tether System

Cosmic Research - The resonance motions of a small spacecraft relative to the center of mass when deploying a tether system are analyzed. The tether system is deployed from a base spacecraft moving...     

Empirical Modeling of the Statistical Structure of Radio Signals from Satellites Moving over Mid- and High-Latitude Trajectories in the Southern Hemisphere

The results of developing the empirical model of parameters of radio signals propagating in the inhomogeneous ionosphere at middle and high latitudes are presented. As the initial data we took the homogeneous data obtained as a result of observations carried out at the Antarctic Molodezhnaya station by the method of continuous transmission probing of the ionosphere by signals of the satellite radionavigation Transit system at coherent frequencies of 150 and 400 MHz. The data relate to the summer season period in the Southern hemisphere of the Earth in 1988–1989 during high (F > 160) activity of the Sun. The behavior of the following statistical characteristics of radio signal parameters was analyzed: (a) the interval of correlation of fluctuations of amplitudes at a frequency of 150 MHz ( _kA ); (b) the interval of correlation of fluctuations of the difference phase ( _k); and (c) the parameter characterizing frequency spectra of amplitude (P _A) and phase (P ) fluctuations. A third-degree polynomial was used for modeling of propagation parameters. For all above indicated propagation parameters, the coefficients of the third-degree polynomial were calculated as a function of local time and magnetic activity. The results of calculations are tabulated.     

宽马赫赫数固冲二元进气道设计与研究

针对宽马赫数固体火箭冲压发动机用二元进气道设计开展研究,提出了一种从低维到高维的逐步优化设计方法,即首先经过若于合理假设建立一维计算模型,利用遗传算法得到一个以总压恢复系数最大为目标的一维优化结果;在二维和三维设计中,选取关键影响因素进行详细分析以不断改善一维优化结果.最终给出一套完整、高效的亚燃冲压二元进气道设计方法.设计过程验证了一维计算模型和关键影响因素选取的合理性,给出了进气道性能随这些关键影响因素的变化规律.