Searching for biosignatures using electron paramagnetic resonance (EPR) analysis of manganese oxides

Manganese oxide (Mn oxide) minerals from bacterial sources produce electron paramagnetic resonance (EPR) spectral signatures that are mostly distinct from those of synthetic simulants and abiogenic mineral Mn oxides. Biogenic Mn oxides exhibit only narrow EPR spectral linewidths (～500 G), whereas abiogenic Mn oxides produce spectral linewidths that are 2-6 times broader and range from 1200 to 3000 G. This distinction is consistent with X-ray structural observations that biogenic Mn oxides have abundant layer site vacancies and edge terminations and are mostly of single ionic species [i.e., Mn(IV)], all of which favor narrow EPR linewidths. In contrast, abiogenic Mn oxides have fewer lattice vacancies, larger particle sizes, and mixed ionic species [Mn(III) and Mn(IV)], which lead to the broader linewidths. These properties could be utilized in the search for extraterrestrial physicochemical biosignatures, for example, on Mars missions that include a miniature version of an EPR spectrometer.     

2008年国际空间站好戏连台（下）

灵活能干看巧手 3月11日与实验后勤舱一增压段一起升空的还有加拿大研发的巧手双臂机器人,是由加拿大专门为空间站制造的,耗资2.74亿美元.它臂长约3.4米,肩宽约2.4米,高约3.7米,装5台摄像机、2只抓手和全套工具,可算是太空中最复杂的机器人,需通过三次太空行走来安装.     

全球探测战略:协调框架(三)

第三章描绘空间探测路线空间探测遵循着一系列顺理成章的发展步骤,从基础知识起步,而如人所愿的终极目标则是人类在太空中的持久存在。要实现这一历程,需要开展各式各样的无人探测,也需     

Search for the OH (X(2)Pi) Meinel band emission in meteors as a tracer of mineral water in comets: detection of N(2)(+) (A-X)

We report the discovery of the N(2)(+) A-X Meinel band in the 780-840 nm meteor emission from two Leonid meteoroids that were ejected less than 1000 years ago by comet 55P/Tempel-Tuttle. Our analysis indicates that the N(2)(+) molecule is at least an order of magnitude less abundant than expected, possibly as a result of charge transfer reactions with meteoric metal atoms. This new band was found while searching for rovibrational transitions in the X(2)Pi electronic ground state of OH (the OH Meinel band), a potential tracer of water bound to minerals in cometary matter. The electronic A-X transition of OH has been identified in other Leonid meteors. We did not detect this OH Meinel band, which implies that the excited A state is not populated by thermal excitation but by a mechanism that directly produces OH in low vibrational levels of the excited A(2)Sigma state. Ultraviolet dissociation of atmospheric or meteoric water vapor is such a mechanism, as is the possible combustion of meteoric organics.     

Manned exploration and exploitation of solar system: Passive and active shielding for protecting astronauts from ionizing radiation—A short overview

In deep space manned missions for the exploration and exploitation of celestial bodies of Solar System astronauts are not shielded by the terrestrial magnetic field and must be protected against the action of Solar Cosmic Rays (SCRs) and Galactic Cosmic Rays (GCRs). SCRs are sporadically emitted, and in very rare but possible events, their fluence can be so high to be lethal to a unprotected crew. Their relatively low energy allows us to conceive fully passive shields, also if active systems can somewhat reduce the needed mass penalty. GCRs continuously flow without intensity peaks, and are dangerous to the health and operability of the crew in long duration (>1year) missions. Their very high energy excludes the possible use of passive systems, so that recourse must be made to electromagnetic fields for preventing ionizing particles to reach the habitat where astronauts spend most of their living and working time. A short overview is presented of the many ideas developed in last decades of last century; ideas are mainly based on very intense electrostatic shields, flowing plasma bubbles, or enormous superconducting coil systems for producing high magnetic fields. In the first decade of this century the problem began to be afforded in more realistic scenarios, taking into account the present and foreseeable possibilities of launchers (payload mass, diameter and length of the shroud of the rocket, etc.) and of assembling and/or inflating structures in space. Driving parameters are the volume of the habitat to be protected and the level of mitigation of the radiation dose to be guaranteed to the crew. Superconducting magnet systems based on multi-solenoid complexes or on one huge magnetic torus surrounding the habitat are being evaluated for defining the needed parameters: masses, mechanical structures for supporting the huge magnetic forces, needed equipments and safety systems. Technological tests are in preparation or planned for improving density of the current, lightness and stability, to increase working temperature of superconducting cables, and for finding light supporting structures and suitable safety architectures, delineating a possible development program for affording this difficult problem.     

Planning, implementation and optimization of future space missions using an immersive visualization environment (IVE) machine

Beginning in 1995, a team of 3-D engineering visualization experts assembled at the Lockheed Martin Space Systems Company and began to develop innovative virtual prototyping simulation tools for performing ground processing and real-time visualization of design and planning of aerospace missions. At the University of Colorado, a team of 3-D visualization experts also began developing the science of 3-D visualization and immersive visualization at the newly founded British Petroleum (BP) Center for visualization, which began operations in October, 2001. BP acquired ARCO in the year 2000 and awarded the 3-D flexible IVE developed by ARCO (beginning in 1990) to the University of Colorado, CU, the winner in a competition among 6 Universities. CU then hired Dr. G. Dorn, the leader of the ARCO team as Center Director, and the other experts to apply 3-D immersive visualization to aerospace and to other University Research fields, while continuing research on surface interpretation of seismic data and 3-D volumes. This paper recounts further progress and outlines plans in Aerospace applications at Lockheed Martin and CU.     

在轨跟踪与数据中继卫星测控关键技术(上)

根据卫星轨道根数，研究了跟踪与数据中继卫星（TDRS）对用户星的精确跟踪规律，并据此分析了TDRS对卫星平台姿态和天线运动范围的要求。介绍了TDRS测控中的关键技术，如螺旋扫描算法在TDRS搜索用户星时的应用、TDRS对近地卫星的覆盖率、TDRS跟踪多用户星的资源分配准则、星蚀和日凌计算，以及轨道位置保持控制策略等。相关控制策略的正确性已在我国地球同步轨道卫星的在轨测控应用中得到了证实，可用于未来TDRS的工程测控和业务应用。     

A bacterial enrichment study and overview of the extractable lipids from paleosols in the Dry Valleys, Antarctica: implications for future Mars reconnaissance

The Dry Valleys of Antarctica are one of the coldest and driest environments on Earth with paleosols in selected areas that date to the emplacement of tills by warm-based ice during the Early Miocene. Cited as an analogue to the martian surface, the ability of the Antarctic environment to support microbial life-forms is a matter of special interest, particularly with the upcoming NASA/ESA 2018 ExoMars mission. Lipid biomarkers were extracted and analyzed by gas chromatography--mass spectrometry to assess sources of organic carbon and evaluate the contribution of microbial species to the organic matter of the paleosols. Paleosol samples from the ice-free Dry Valleys were also subsampled and cultivated in a growth medium from which DNA was extracted with the explicit purpose of the positive identification of bacteria. Several species of bacteria were grown in solution and the genus identified. A similar match of the data to sequenced DNA showed that Alphaproteobacteria, Gammaproteobacteria, Bacteriodetes, and Actinobacteridae species were cultivated. The results confirm the presence of bacteria within some paleosols, but no assumptions have been made with regard to in situ activity at present. These results underscore the need not only to further investigate Dry Valley cryosols but also to develop reconnaissance strategies to determine whether such likely Earth-like environments on the Red Planet also contain life.     

Application Advantages of Staring Area Imaging Technology(SAIT) for Microsatellites

The Staring Area Imaging Technology(SAIT) satellite continuously images the target over a certain time range, and can realize continuous imaging and multi-angle imaging of the area of interest. It has the characteristics of flexible imaging parameter setting and fast image preprocessing speed, enabling dynamic target detection and tracking, super-resolution, surface 3 D model construction, night-time imaging and many other application tasks. Based on the technical characteristics of the SAIT satellite, this paper analyzes the challenges in satellite development and data processing, focuses on the quasi-realtime application of SAIT satellite data, and looks at the development trend of the SAIT satellite.     

The Mawrth Vallis region of Mars: A potential landing site for the Mars Science Laboratory (MSL) mission

The primary objective of NASA's Mars Science Laboratory (MSL) mission, which will launch in 2011, is to characterize the habitability of a site on Mars through detailed analyses of the composition and geological context of surface materials. Within the framework of established mission goals, we have evaluated the value of a possible landing site in the Mawrth Vallis region of Mars that is targeted directly on some of the most geologically and astrobiologically enticing materials in the Solar System. The area around Mawrth Vallis contains a vast (>1?×?10? km2) deposit of phyllosilicate-rich, ancient, layered rocks. A thick (>150?m) stratigraphic section that exhibits spectral evidence for nontronite, montmorillonite, amorphous silica, kaolinite, saponite, other smectite clay minerals, ferrous mica, and sulfate minerals indicates a rich geological history that may have included multiple aqueous environments. Because phyllosilicates are strong indicators of ancient aqueous activity, and the preservation potential of biosignatures within sedimentary clay deposits is high, martian phyllosilicate deposits are desirable astrobiological targets. The proposed MSL landing site at Mawrth Vallis is located directly on the largest and most phyllosilicate-rich deposit on Mars and is therefore an excellent place to explore for evidence of life or habitability.     

从企业战略管理理论认识航天型号成本工程的必要性(上)

中国航天科技集团公司(以下简称“集团公司”)在2004年正式启动了全员、全过程、全要素航天型号成本管理与控制工程(以下简称“成本工程”)。这是以强化型号成本管理与控制为突破口,旨在建立组织落实、制度健全、权责明晰、奖惩有效的全员、全过程、全要素成本管理体系与机制,基本实现成本管理各个环节的事前、事中、事后有效管理,加快集团公司集约型发展,提高集团公司经济运行质量,增强竞争优势,提升核心竞争能力的重大基础工程,是集团公司的一项重大战略举措。随着战略思想的引入及市场竞争态势的变化,企业战略管理的重心也在不断转移:逐步从注重企业生存的外部环境发展到注重企业的内部条件,再转向内外相结合的资源依赖学派与超越单一企业的联盟及群理论;从关注生产企业转向关注需求方;从关注并超越竞争对手的所作所为转向为买方创新价值,并开创新的市场空间。企业战略管理思想和管理重心的变化,对于我们深入、全面地认识实施航天型号成本工程的必要性,提供了一个很好的分析问题的思路。本文重点从集团公司宏观和微观外部环境的变化、集团公司竞争优势的增强和核心竞争能力的提高以及企业战略联盟和实施“蓝海战略”等方面,对实施航天型号成本工程的必要性做一分析。""""""""""""""""""""""""""""""""""""""""""""""""""""""     

蜡模自动成型新材料(3F)的SLS烧结工艺研究

从实际生产应用出发,对新的蜡模自动成型专用材料(3F)进行了SLS烧结工艺参数试验,研究了温度控制和激光功率对烧结工件成型质量的影响。最后,获得了3F材料常用的0.15mm片层厚度的表面温度和加工激光功率。     

CBERS-1卫星红外多光谱扫描仪图像预处理方法

文章介绍了中国和巴西联合研制的资源一号卫星 (CBERS_1)上的有效载荷之一 - -红外多光谱扫描仪 (IRMSS)图像数据的处理 ,包括错位校正、相对辐射校正和去除噪声等处理过程。     

Calcification and silicification: fossilization potential of cyanobacteria from stromatolites of Niuafo'ou's Caldera Lakes (Tonga) and implications for the early fossil record

Calcification and silicification processes of cyanobacterial mats that form stromatolites in two caldera lakes of Niuafo'ou Island (Vai Lahi and Vai Si'i) were evaluated, and their importance as analogues for interpreting the early fossil record are discussed. It has been shown that the potential for morphological preservation of Niuafo'ou cyanobacteria is highly dependent on the timing and type of mineral phase involved in the fossilization process. Four main modes of mineralization of cyanobacteria organic parts have been recognized: (i) primary early postmortem calcification by aragonite nanograins that transform quickly into larger needle-like crystals and almost totally destroy the cellular structures, (ii) primary early postmortem silicification of almost intact cyanobacterial cells that leave a record of spectacularly well-preserved cellular structures, (iii) replacement by silica of primary aragonite that has already recrystallized and obliterated the cellular structures, (iv) occasional replacement of primary aragonite precipitated in the mucopolysaccharide sheaths and extracellular polymeric substances by Al-Mg-Fe silicates. These observations suggest that the extremely scarce earliest fossil record may, in part, be the result of (a) secondary replacement by silica of primary carbonate minerals (aragonite, calcite, siderite), which, due to recrystallization, had already annihilated the cellular morphology of the mineralized microbiota or (b) relatively late primary silicification of already highly degraded and no longer morphologically identifiable microbial remains.     

近空间飞行器成为各国近期研究的热点(下)

2.美国空军2005年攀登者裸机飞行试验未能达到预期目的。     

国际航行通告正文(E项)内容解读技巧探讨

随着我国改革开放的深入和经济的增长,民航业也得以飞速发展,对外开放的机场逐年增多,机场的国际航班大量增加,航行情报服务任务日渐繁重,作为航行情报服务最基本也是最重要内容之一的航行通告（NOTAM）不仅接收量增大,而且涉及的国家／地区也更加广泛。目前,中南空管局（广州）运行中心航行通告室每天都会收到上百个国家／地区上千份的国际航行通告,     

近空间飞行器成为各国近期研究的热点(上)

近空间（Nearspace）通常是指20～lOOkm的高空，其下面的空域（20km以下）是传统航空器的主要运行空间，其上面的空域（100km以上）是航天器的运行空间。近空间飞行器是指运行在近空间范围的飞行器。由于技术和认识上的原因，近空间的战略价值直到最近才引起各国的重视。因此。近空间飞行器成为各国近期研究的热点。美国、俄罗斯、欧洲、韩国、英国、     

The neutron,gamma-ray,X-ray spectrometer (NGXS): A compact instrument for making combined measurements of neutrons,gamma-rays,and X-rays

The Neutron, Gamma ray, and X-ray Spectrometer (NGXS) is a compact instrument designed to detect neutrons, gamma-rays, and hard X-rays. The original goal of NGXS was to detect and characterize neutrons, gamma-rays, and X-rays from the Sun as part of the Solar Probe Plus mission in order to provide direct insight into particle acceleration, magnetic reconnection, and cross-field transport processes that take place near the Sun. Based on high-energy neutron detections from prompt solar flares, it is estimated that the NGXS would detect neutrons from 15 to 24 impulsive flares. The NGXS sensitivity to 2.2 MeV gamma rays would enable a detection of ∼50–60 impulsive flares. The NGXS is estimated to measure ∼120 counts/s for a GOES C1-type flare at 0.1 AU, which allows for a large dynamic range to detect both small and large flares.     

Space weather forecast: Principles of the construction and boundaries of the implementation (experience of three cycles)

All significant short-term disturbances of the near-Earth space are caused exclusively by solar flare events and regions in the solar corona with the magnetic field open into the interplanetary space (coronal holes). Flare processes occur as a consequence of the interactions of new emerging magnetic fluxes within (flares) and outside (filament ejections) the active regions with already existing magnetic fields. The observation of emerging new magnetic fluxes and the estimate of their magnitude and the emerging rate allow one to forecast solar flares and filament ejections and estimate their degree of geoeffectiveness. The main agents that visualize the propagation of disturbance from solar flares and filaments in the solar corona and the interplanetary space are coronal mass ejections, the characteristics of which ideally allow one to estimate the possible disturbance of the geomagnetic field, the possible growth of high-energy charged particle fluxes in the near-Earth space. For successful forecast of geoeffective active phenomena on the Sun and their consequences in the near-Earth space, it is necessary to know the situation on the Sun for the last 3 days taking into account the development and characteristics of the current cycle and the epoch of solar activity.