返回式卫星上的微重力水平估算

导出了近地卫星上任意部位微重力水平的表达式,分析和近似估算了利用我国返回式卫星进行首次空间材料加工试验时的微重力水平,表明是在按轨道周期变化的优于1×10~(-5)g_0的准稳态加速度上,迭加了幅度不超过2×10~(-4)g_0的随机加速度脉冲干扰。我国在1987年8月5日发射的返回式卫星上,首次搭载了一台空间晶体生长炉,在空间微重力条件下进行了以砷化镓为主的十项材料加工试验。为了对所得结果进行科学的分析,就必须知道晶体生长期间的微重力水平。本文结合卫星的实际运行参数给予了估算。     

悉数实践-10卫星的"第一"头衔

1 我国第一颗专门的微重力科学实验卫星 实践-10返回式科学实验卫星是为开展多项"微重力科学和空间生命科学"空间实验而专门量身定做的返回式卫星.卫星的承载能力、微重力水平、实验载荷服务支持能力等较以往返回式卫星均有进一步提升,是我国新一代具有安全回收、适应中长期在轨试验、应用灵活和成本低廉的空间科学实验平台.在结构布局上,它充分继承了以往返回式卫星的结构特点,外形是一个圆柱圆锥组合体,内部则是由4个舱段构成的仪器舱及返回舱.根据任务要求,实践-10卫星在轨道设计上也进行了调整,由以往返回式卫星的椭圆轨道变为圆轨道,这一改变,大大提高了微重力水平,为更好地开展微重力环境下的科学实验提供了有力的支撑.     

美欲发射第2枚星火火箭

美国空间服务公司计划在今年11月发射第2枚星火火箭,进行商业性亚轨道微重力试验任务。第一枚星火火箭是在3月29日发射的。空间服务公司现经营三种型号的星火探空火箭,并计划再增加两种或更多型号的火箭。星火-1火箭可载454公斤有效载荷,微重力时间为5分钟;它若载90公斤有效载荷,微重力时间可达9分钟。有效载荷用降落伞回收。星火-1型为两级火箭,第一级用的是莫顿·锡奥科尔公司的TX664发动     

美国航天飞机第51次飞行

美国哥伦比亚号航天飞机于1992年10月22日美国东部标准时间12时9分(格林尼治时间17时9分)从肯尼迪空间中心发射升空。这是美国航天飞机的第61次飞行及哥伦比亚号航天飞机的第13次飞行。飞行任务代号为STS-52。因卡纳维拉尔角地区的大风天气,发射推迟了两小时。这次飞行的主要任务是施放意大利制造的激光地球动力学卫星-2(Lageos-2),进行美国微重力有效载荷实验(USMP-1),一些为未来空间站建造做准备的试验,及一些物理学、医学与生物学实验。造价为400万美元的Lageos-2卫星及     

联邦德国托帕斯返回式卫星计划

为了适应日益增长的空间微重力实验的迫切需求,同时还预计在近七年内,这样的实验在美国航天飞机上排不上号,联邦德国的OHB系统公司前不久推出了一项托帕斯(TOPAS)返回式卫星计划,其主要用于空间微重力实验。托帕斯卫星打算充分利用现有成熟的技术和设备,争取在1988年底/1989年初投入使用,其参数如下: 有效载荷质量——100～120公斤。卫星外形——与美国发现者号卫星相同。     

日本研制可执行侦察任务的返回式卫星

据日本电气公司黑田隆二去年底发表的“日本主要空间开发计划”一文介绍,日本正在积极研制一颗可提供空间微重力环境,用于尖端技术产业开发、不载人、可回收的空间实验装置,即返回式卫星。这颗卫星将于1993年用宇宙科学研究所的M-3SⅡ火箭发射到高度为250公里的圆轨道上,工作约一周时间后按预定计划回收(回收舱重800公斤),在日本本土上实现软着路。西德参加了这颗星的部分研究工作。可回收有效载荷舱由热防护罩、观测仪器安装平台、各种有效载荷     

2007年世界航天活动计划

1月 □□1月10日,印度"极轨卫星运载火箭"将4个有效载荷成功发射到了太阳同步轨道.它们分别为:印度本国的制图卫星-2(CARTOSAT-2)、太空舱返回实验-1(SRE-1),以及印度尼西亚的LAPAN-Tubsat和阿根廷的PehuenSat-1卫星.其中,SRE-1是印度第1个返回式可重复使用航天器,质量为550kg,用于进行微重力试验,它已在1月22日成功返回地面.这次发射也是2007年的世界首次发射.     

西德将用我国返回式卫星进行微重力实验

西德研究部和中国不久前签署了一项协定:西德将在1988年和1989年用中国返回式卫星进行两项微重力研究实验。第一项实验是由“印托空间”(Intospace)组织准备的有关微重力蛋白结晶生长(采用西德药品研究所提供的一百多个样品)。西德将放置15公斤的有效载荷,在空间飞行8天后予以回收,支付100万美元。这将是国外第二次使用中国的返回式卫星。     

落塔微重力水平激光干涉测量方法中的干扰因素分析

落塔是获得微重力环境的重要设施,落塔微重力水平的测量对微重力科学实验的研究至关重要. 激光干涉是测量落塔微重力水平的一种新方法,这种方法的基本原理是让一个参考落体在落舱中自由下落,落舱由于受到服外空气阻力的作用将与自由落体运动略有差异,1 11. 肫内的参考落体则更接近理想的自由落体运动,这就使得落舱与参考落体之间存在着加速度差,这种加速度差便反映了落服的微重力水平,其所导致的相对运动则可通过激光干涉的方法测量出来. 本文对落塔微重力水平的激光干涉测量方法中将会遇到的一些主要干扰因素进行了分析,计算结果表明,这些干扰网素所造成的总误差约为 1.2 x 10-7g,低于微重力水平的预测值 10-4~lO-6 g,因此该方法是一种比较可行的测量方法.      

典型弱浮力环境下导线绝缘层的着火先期特性

根据实践十号（SJ-10）科学卫星导线特性箱有效载荷的地面低压模拟实验,通过搭建低压微重力模拟实验台,研究了典型低压弱浮力（3kPa）环境下不同绝缘层种类、厚度和过载电流对导线绝缘层着火先期特性的影响.实验获得了导线绝缘层着火先期的温升特性和烟气析出特性,并根据对比常压（1atm）下绝缘层着火先期特性的结果,初步预测了微重力条件下卫星在轨飞行绝缘层的着火先期特性,低压实验结果为SJ-10卫星空间实验工况优选提供了重要依据.      

Scaling analysis and model estimation of solar corona index

A monthly average solar green coronal index time series for the period from January 1939 to December 2008 collected from NOAA (The National Oceanic and Atmospheric Administration) has been analysed in this paper in perspective of scaling analysis and modelling. Smoothed and de-noising have been done using suitable mother wavelet as a pre-requisite. The Finite Variance Scaling Method (FVSM), Higuchi method, rescaled range (R/S) and a generalized method have been applied to calculate the scaling exponents and fractal dimensions of the time series. Autocorrelation function (ACF) is used to find autoregressive (AR) process and Partial autocorrelation function (PACF) has been used to get the order of AR model. Finally a best fit model has been proposed using Yule-Walker Method with supporting results of goodness of fit and wavelet spectrum. The results reveal an anti-persistent, Short Range Dependent (SRD), self-similar property with signatures of non-causality, non-stationarity and nonlinearity in the data series. The model shows the best fit to the data under observation.     

Stochastic particle acceleration by the forced interaction of relativistic current sheets

We address the problem of interacting relativistic current sheets in self-consistent kinetic plasma simulations within the framework of the Particle-In-Cell model. The interaction is enforced in head-on collisions of up to 10 current sheets at relativistic bulk speeds. The simulations are motivated by the general problem of Poynting flux dissipation in ‘striped wind’ configurations presumably governing the relativistic outflows pervasive in pulsar winds and gamma-ray bursts. We identify the generation of non-thermal particles and formation of a stable power-law shape in the particle energy distributions f(γ) dγ ∝ γ^−s dγ. In 1D, a spectral index s ∼ 2 is observed and attributed to a stochastic Fermi-type acceleration mechanism. In 2D, the generic index of s ∼ 3–4 is retained as in previous simulations of individual current sheets. Whereas in 2D the high energy cut-off is constrained by the limited dissipation of magnetic energy, in 1D the process converts the bulk motion of current sheets towards directed particle momentum of an exclusive class of non-thermal particles.     

Development of a gas chromatography compatible Sample Processing System (SPS) for the in-situ analysis of refractory organic matter in martian soil: preliminary results

In the frame of the 2009 Mars Science Laboratory (MSL) mission a new sample preparation system (SPS) compatible with gas chromatography–mass spectrometry (GC–MS) has been developed for the in situ analysis of complex organic molecules in the Martian soil. The goal is to detect, if they exist, some of the key compounds that play an important role in life on Earth including carboxylic acids, amino acids and nucleobases.     

基于LuGre模型的电液加载系统摩擦补偿

为了提高电液加载系统控制精度,针对摩擦问题提出了基于LuGre摩擦模型的前馈补偿方法.建立了用于摩擦仿真分析和补偿器设计的电液加载系统数学模型;通过实验获取并分析了相关的摩擦数据;基于实验数据进行LuGre模型参数辨识,把LuGre模型和辨识结果引入电液加载系统数学模型,并进行仿真结果与实际摩擦数据的对照,证明了LuGre摩擦模型的准确性.设计前馈补偿器,进行了实验对比,实验结果表明前馈补偿器可将摩擦产生的控制误差有效地降至未补偿时的30%左右.      

Concept options for the aerial survey of Titan

Various aerial platforms intended for long endurance survey of the Titan surface are presented. A few novel concepts are introduced, including a heated methane balloon and a balloon with a tethered wind turbine. All the concept options are predicted to have lower scientific payload fractions than the Huygens probe. It is concluded that the selection of the best aerial platform option depends on more accurate mass estimates and a clear decision on whether, or not, in situ surface composition measurements are required in conjunction with aerial remote sensing.     

Heterogeneous solid/gas chemistry of organic compounds related to comets,meteorites, Titan,and Mars: Laboratory and in lower Earth orbit experiments

To understand the evolution of organic molecules involved in extraterrestrial environments and with exobiological implications, many experimental programs in the laboratory are devoted to photochemical studies in the gaseous phase as well as in the solid state. The validity of such studies and their applications to extraterrestrial environments can be questioned as long as experiments conducted in space conditions, with the full solar spectrum, especially in the short wavelength domain, have not been implemented. The experiments that are described here will be carried out on a FOTON capsule, using the BIOPAN facility, and on the International Space Station, using the EXPOSE facility. Vented and sealed exposition cells will be used, which will allow us to study the chemical evolution in the gaseous phase as well as heterogeneous processes, such as the degradation of solid compounds and the release of gaseous fragments.     

CoRoT and Kepler results: Solar-like oscillators

The space-borne observatories CoRoT (Convection Rotation and planetary Transits) and Kepler have provided photometric time series data of unprecedented precision for large numbers of stars. These data have revolutionized the fields of transiting exoplanets and asteroseismology. In this review some important asteroseismic results obtained using data from the CoRoT and Kepler space missions concerning stars that show solar-like oscillations are discussed. These results comprise, among others, measurements of the location of the base of the convection zone and helium second-ionization zone in main-sequence stars, the presence (or not) of core-helium burning in red-giant stars, as well as differential rotation in these stars.     

Return to Europa: Overview of the Jupiter Europa orbiter mission

Missions to explore Europa have been imagined ever since the Voyager mission first suggested that Europa was geologically very young. Subsequently, the Galileo spacecraft supplied fascinating new insights into this satellite of Jupiter. Now, an international team is proposing a return to the Jupiter system and Europa with the Europa Jupiter System Mission (EJSM). Currently, NASA and ESA are designing two orbiters that would explore the Jovian system and then each would settle into orbit around one of Jupiter’s icy satellites, Europa and Ganymede. In addition, the Japanese Aerospace eXploration Agency (JAXA) is considering a Jupiter magnetospheric orbiter and the Russian Space Agency is investigating a Europa lander.     

HELIO: The Heliophysics Integrated Observatory

Heliophysics is a new research field that explores the Sun–Solar System Connection; it requires the joint exploitation of solar, heliospheric, magnetospheric and ionospheric observations.     

Radioactivity of the Moon and planets

In this report the main results of the study of radioactivity of the solar sistem bodies are considered. The radioactivity of the Moon and planets was measured by means of vehicles in situ. The radioactivity of the lunar samples, brought to the Earth was studied with laboratory equipment.