TanSat Mission Achievements: from Scientific Driving to Preliminary Observations

The Chinese global carbon dioxide monitoring satellite (TanSat) was successfully launched in December 2016 and has completed its on-orbit tests and calibration. TanSat aims to measure the atmospheric Carbon Dioxide column-averaged dry air mole fractions (X_CO2) with a precision of 4 ppm at the regional scale, and further to derive the CO₂ global and regional fluxes. Progress toward these objectives is reviewed and the first scientific results from TanSat measurements are presented. During the design phase, Observation System Simulation Experiments (OSSE) on TanSat measurements performed prior to launch measurements using a nadir and a glint alternative mode when considering the balance of stable measurements and reduces the flux uncertainty (64%). The constellation measurements of two satellites indicate an extra 10% improvement in flux inversion if the satellite measurements have no bias and similar precision. The TanSat on-orbit test indicates that the instrument is stable and beginning to produce X_CO2 products. The preliminary TanSat measurements have been validated with Total Carbon Column Observing Network (TCCON) measurements and have inter-compared with OCO-2 measurements in an overlap measurement.      

Advances in Researches on the Middle and Upper Atmosphere in 2008-2010

This paper summarizes the results of the researches on the middle and upper atmosphere obtained by Chinese scientists in 2008-2010. The focuses are specifically placed on the researches being associated with ground-based observation capability development, dynamical processes, the property of atmospheric circulation and the chemistry-climate coupling of the middle atmospheric layers.     

Raman spectroscopic analysis of a desert cyanobacterium Nostoc sp. in response to UVB radiation

Cyanobacteria are capable of tolerating environmental extremes. To survive in extreme environments, cyanobacteria have developed the capability to adapt to a variety of stresses. For example, cyanobacteria have adopted a number of strategies with which to survive UV stress, including expression of UV-screening pigments and antioxidant systems. We have previously shown that several antioxidants are significantly expressed in Nostoc sp. by UVB irradiation. We report here that the content of UV-responsive biomarkers such as β-carotene and scytonemin can be easily detected by Fourier transform Raman spectroscopy with use of a small sample size and that the content of β-carotene is dependant on the UVB intensity and exposure time. Our results indicate that Raman spectroscopy may be a helpful tool to analyze UV-protective molecules of cyanobacterium in astrobiological studies without access to large sample sizes and complicated extractions, which are needed by other analytical techniques such as high-performance liquid chromatography and mass spectrometry.     

Near Earth Vortices Driving of Field Aligned Currents Based on Magnetosphere Multiscale and Swarm Observations

A long-standing mystery in the study of Field-Aligned Currents (FACs) has been that:how the currents are generated and why they appear to be much stronger at high altitudes than in the ionosphere.Here we present two events of magnetotail FACs observed by the Magnetospheric Multiscale Spacecraft (MMS) on 1st July and 14th July 2016,to show how the Substorm Current Wedges (SCW) were formed.The results show that particles were transferred heading towards the Earth during the expansion phase of substorms. The azimuthal flow formed clockwise (counter-clockwise) vortex-like motion,and then generated downward (upward) FACs on the tailward/poleward side of the distorted field with opposite vorticity on their Earthward/equatorward side.We also analyzed the Region 1 FACs observed by the Earth Explorer Swarm spacecraft on 1st July 2016 and found that they were associated with FACs observed by MMS,although differing by a factor of 10.This difference suggests that either there was the closure of the currents at altitudes above 500 km or the currents were not strictly parallel to B and closed at longitudes away from where they were generated.      

东方红三号卫星的机械太阳阵和通信天线

介绍了中德合作研制、生产东方红三号机械太阳阵和通信天线的有关技术和项目的进展情况。机械太阳阵的设计是在经过自行验证的技术基础上进行的,有了这些经验,加上计算机设计优化,能够满足苛刻的质量和刚度要求。通信天线的主要特点是收发共用和全极化复用。它是通过两套7喇叭馈源阵照射极化敏感反射器实现的。天线电性能和结构性能均满足技术要求。     

美国防务工业的新合并浪潮

美国两家大型公司,洛克希德、马丁·马丽埃塔公司的合并将使之变成为当今世界上一家最大的航空航天/防务公司。然而,这样的合并究竟能维持多久呢?     

用热塑性塑料代替现在的先进复合材料

飞行动力学实验室与材料实验室协作,正在共同研究用石墨/热塑性塑料结构件代替石墨/环氧构件的可能性问题。其办法是首先将热塑性塑料/石墨材料固化成平板状板材,随后热压成型,利用这种办法可以成型各种复杂外形的构件,而所用的劳动工时及     

航天发动机高空模拟试验新设施

本文介绍了 BPD 公司的 ISA2 高空模拟试验新设施,其性能大大超过本公司原有的 ISA 1航天发动机试验设施。本文介绍了该设施特有的蒸气发生设备、专用试车架、冷却系统和控制系统。同时还谈到了设施的某些特点,如在蒸气发生器内采用饱和水和用机械泵来实现初步真空。分析了设施性能以及它与预测值的一致性,并报导了在真空度大约为0.6千帕(约4.5毫米汞柱)情况下的某些测试结果。     

自动液氮加注系统

大量的光谱学的实验和其它物理测量必须在持续一段时间的液氮温度中进行。从最简单的杜瓦瓶到精心制做的自动冷却剂流体