Astrophysics in 2006

The fastest pulsar and the slowest nova; the oldest galaxies and the youngest stars; the weirdest life forms and the commonest dwarfs; the highest energy particles and the lowest energy photons. These were some of the extremes of Astrophysics 2006. We attempt also to bring you updates on things of which there is currently only one (habitable planets, the Sun, and the Universe) and others of which there are always many, like meteors and molecules, black holes and binaries.     

Emergence of a Habitable Planet

We address the first several hundred million years of Earth’s history. The Moon-forming impact left Earth enveloped in a hot silicate atmosphere that cooled and condensed over ∼1,000 yrs. As it cooled the Earth degassed its volatiles into the atmosphere. It took another ∼2 Myrs for the magma ocean to freeze at the surface. The cooling rate was determined by atmospheric thermal blanketing. Tidal heating by the new Moon was a major energy source to the magma ocean. After the mantle solidified geothermal heat became climatologically insignificant, which allowed the steam atmosphere to condense, and left behind a ∼100 bar, ∼500 K CO₂ atmosphere. Thereafter cooling was governed by how quickly CO₂ was removed from the atmosphere. If subduction were efficient this could have taken as little as 10 million years. In this case the faint young Sun suggests that a lifeless Earth should have been cold and its oceans white with ice. But if carbonate subduction were inefficient the CO₂ would have mostly stayed in the atmosphere, which would have kept the surface near ∼500 K for many tens of millions of years. Hydrous minerals are harder to subduct than carbonates and there is a good chance that the Hadean mantle was dry. Hadean heat flow was locally high enough to ensure that any ice cover would have been thin (<5 m) in places. Moreover hundreds or thousands of asteroid impacts would have been big enough to melt the ice triggering brief impact summers. We suggest that plate tectonics as it works now was inadequate to handle typical Hadean heat flows of 0.2–0.5 W/m². In its place we hypothesize a convecting mantle capped by a ∼100 km deep basaltic mush that was relatively permeable to heat flow. Recycling and distillation of hydrous basalts produced granitic rocks very early, which is consistent with preserved >4 Ga detrital zircons. If carbonates in oceanic crust subducted as quickly as they formed, Earth could have been habitable as early as 10–20 Myrs after the Moon-forming impact.     

摆动扫描地球敏感器数学模型及飞行试验结果

描述了东方红三号卫星(DFH-3)控制系统设计和数学仿真中采用的摆动扫描地球敏感器IRES-01的数学模型，东方红三号卫星近三年飞行试验结果与数学仿真结果基本一致，证明数学模型是正确的。     

国外航天侦察相机和测绘相机发展概况

航天侦察和测绘是战略武装必不可少的组成部分,航天侦察和测绘相机是对地观测卫星的有效载荷。 该文将简要介绍国外航天侦察和测绘相机发展概况、水平和发展趋势。     

FY-2气象卫星在轨管理工程测控关键技术(上)

介绍了风云二号(FY—2)地球静止轨道自旋气象卫星工程测控的关键技术。分析了位置保持、姿态确定、星蚀和日凌的原理，给出了位置保持、姿态控制策略和地影、月影、日凌预报算法。并提出了一种检验定姿结果正确性的方法，提供了相应的工程计算参数。这些策略都已成功地用于FY—2卫星的在轨管理工程测控。     

CBERS-1卫星CCD相机图像预处理

文章简要阐述了资源卫星的发展与现状 ,概括了资源卫星的主要应用领域和将会带来的巨大经济、社会效益。介绍了CBERS_1卫星CCD相机辐射定标技术 ,分析了CBERS_1卫星CCD相机辐射定标和图像预处理过程 ,展示了经过处理的多光谱图像     

中巴地球资源卫星与应用

中巴地球资源卫星是以中国为主研制的第一代传输型地球资源卫星。文章简要介绍了它的发展历程 ,全面介绍了星上的有效载荷、采用的先进技术和应用成果     

温室控制系统设计--用LCD实现控制参数设置与测量参数显示

说明了利用LCD显示模块,实现温室被测数据显示及控制参数的设定输入,其特点是显示数据的汉字名称与测量数据动态变化,系统连接线少,安装,测试,维修简单.     

获取自由飞模型气动导数的综合飞行试验研究

过去已进行过多个机种的自由飞模型大迎角特性试验，但均为单一项目的试验，现介绍了将获取放宽静稳定度特性和气动导数两个项目综合于一个自由飞模型飞行试验项目中的情况，用脉冲升降舵激发起模型的纵向短周期运动，用参数辩识方法获取气动导数，试验结果表明这种方法是可行的，为从事本专业及相关专业的科研人员提供了参考。