The future of earth observations in Central and Eastern Europe

The Central and Eastern Europe are characterized by a high theoretical and scientific level in space research and technology, including remote sensing, but inexperience in practical applications. The emerging private sector lacks management experience and needs appropriate training. Other constraints are inadequate administrative structures, a lack of coordination, and an outdated technology in general. In his report on the results of a study carried out for the European Commission, consultant and emeritus professor of the International Institute for Aerospace Survey and Earth Sciences, Caesar Voûte, outlines the new forms of European and regional cooperation being promoted. Agriculture, yield prediction and agricultural statistics, land use studies, environmental monitoring and environmental management are identified as future high priority operational applications of remote sensing and geographical information systems (GIS). Hazard management and marine observations also need to be developed.     

Earth as an extrasolar planet: Earth model validation using EPOXI earth observations

The EPOXI Discovery Mission of Opportunity reused the Deep Impact flyby spacecraft to obtain spatially and temporally resolved visible photometric and moderate resolution near-infrared (NIR) spectroscopic observations of Earth. These remote observations provide a rigorous validation of whole-disk Earth model simulations used to better understand remotely detectable extrasolar planet characteristics. We have used these data to upgrade, correct, and validate the NASA Astrobiology Institute's Virtual Planetary Laboratory three-dimensional line-by-line, multiple-scattering spectral Earth model. This comprehensive model now includes specular reflectance from the ocean and explicitly includes atmospheric effects such as Rayleigh scattering, gas absorption, and temperature structure. We have used this model to generate spatially and temporally resolved synthetic spectra and images of Earth for the dates of EPOXI observation. Model parameters were varied to yield an optimum fit to the data. We found that a minimum spatial resolution of ～100 pixels on the visible disk, and four categories of water clouds, which were defined by using observed cloud positions and optical thicknesses, were needed to yield acceptable fits. The validated model provides a simultaneous fit to Earth's lightcurve, absolute brightness, and spectral data, with a root-mean-square (RMS) error of typically less than 3% for the multiwavelength lightcurves and residuals of ～10% for the absolute brightness throughout the visible and NIR spectral range. We have extended our validation into the mid-infrared by comparing the model to high spectral resolution observations of Earth from the Atmospheric Infrared Sounder, obtaining a fit with residuals of ～7% and brightness temperature errors of less than 1?K in the atmospheric window. For the purpose of understanding the observable characteristics of the distant Earth at arbitrary viewing geometry and observing cadence, our validated forward model can be used to simulate Earth's time-dependent brightness and spectral properties for wavelengths from the far ultraviolet to the far infrared. Key Words: Astrobiology-Extrasolar terrestrial planets-Habitability-Planetary science-Radiative transfer. Astrobiology 11, 393-408.     

The value of information: Measuring the contribution of space-derived earth science data to resource management

Governments around the world, as well as private industry, invest heavily in remote sensing spacecraft to obtain data about natural and environmental resources, climate change, and the relationship of earth science to human health and quality of life. Numerous studies have been undertaken to describe and measure the value of the data from these spacecraft in order to justify further investments. The studies use a wide variety of methods and generally find a large range of benefits, from quite small to very large, in part because of differences in methodologies. This article offers a general framework for measuring the value of information. The framework serves two purposes. One is provision of a comprehensive and common basis by which to conduct and evaluate studies of the value of earth science. The second is to better inform decision makers about the value of data. Decision makers comprise three communities: consumers and producers of information, public officials whose job is to invest in data acquisition and information development (including sensors and other hardware, algorithm design and software tools, and a trained labor force), and the public at large.     

工作项目执行管理工具在基础管理中的应用

引言如何能够使一项工作从计划的制订开始就处于一个可控的、持续改进的环境中,从而取得理想的执行效果是我们一直探讨的问题。西北空管局网络中心针对工作计划从制订到最后的执行反馈过程中的一系列问题,从一个新的角度通过自主研发的软件平台对其进行了统一的、无间断的实时管理,取得了较好的效果。     

The Aster project: Flight to a near-Earth asteroid

The information on the project being developed in Brazil for a flight to binary or triple near-Earth asteroid is presented. The project plans to launch a spacecraft into an orbit around the asteroid and to study the asteroid and its satellite within six months. Main attention is concentrated on the analysis of trajectories of flight to asteroids with both impulsive and low thrust in the period 2013-2020. For comparison, the characteristics of flights to the (45) Eugenia triple asteroid of the Main Belt are also given.     

项目群风险链管理技术研究

分析了项目群中风险链形成的原因和过程,针对不同类型的风险链给出了应对策略,在此基础上,给出了项目群风险链的协同控制过程模型,从而为复杂系统工程项目的风险管理提供了解决思路.     

浅析空管设备保障的风险评估管理

近几年．江西空管分局把“风险管理”的理念应用到设备保障中,通过设备、人员风险评估等方法．及时发现设备保障运行中的潜在风险．进而对相关设备或系统进行完善、对技术人才结构进行优化．对于提高空管保障能力起到了较好的作用。这也是落实持续安全理念的重要实践。     

风险管理在管制岗位培训中的初步应用

在民航高速发展的今天,空管系统人力资源的培训和管理已经成为各项建设中举足轻重的一环。新员工所占比例迅速增加,各种针对性培训紧锣密鼓地进行,可以说,知识、技术、经验的传承及安全意识的培养,已在日常运行中占据相当的比重。空中交通管制作为特殊行业,其岗位培训存在周期长、知识量大、易懂难精、安全意识培养困难等特点,培     

我和你——航天人与灾区孩子同行记录：我和你之重建校园：为了孩子的读书梦

推开2009年的门窗,春光明媚,和风迎面而来,新的生活淡定而甜美。 新的开始,不代表对过去的忘却。大悲的2008年5月是那么的刻骨铭心。大灾后的大悲,大悲后的大爱,中华民族面对死亡与困难表现出的勇气、信心和力量让世界侧目和动容。     

A symbiotic approach to SETI observations: use of maps from the Westerbork Synthesis Radio Telescope

High spatial resolution continuum radio maps produced by the Westerbork Synthesis Radio Telescope (WSRT) of The Netherlands at frequencies near the 21 cm HI line have been examined for anomalous sources of emmission coincident with the locations of nearby bright stars. From a total of 542 stellar positions investigated, no candidates for radio stars or ETI signals were discovered to formal limits on the minimum detectable signal ranging from 7.7 x 10(-22) W/m2 to 6.4 x 10(-24) W/m2. This preliminary study has verified that data collected by radio astronomers at large synthesis arrays can profitably be analysed for SETI signals (in a non-interfering manner) provided only that the data are available in the form of a more or less standard two dimensional map format.     

用于对地观测定位的编队飞行卫星群轨道构形设计

编队飞行卫星群是一组小卫星,它们具有短的相对距离、相等的轨道半长轴和微小差别的其它轨道要素,它们形成相互伴随运动,并且具有一定的构形。提出将编队飞行卫星群的轨道设计技术应用于对地观测定位卫星系统中。根据设想的要求,针对由四颗伴随卫星围绕基准卫星(或一个虚拟的中心)飞行的轨道设计案例,初步分析了编队飞行卫星群的构形保持,地球引力和大气阻力的摄动影响等问题。     

数字化技术在高分三号卫星总装设计中的应用

针对高分三号(GF-3)卫星大型相控阵天线精准总装技术、大型相控阵天线质量特性精确计算技术、星罩对接后星表插头操作空间的人机工程模拟技术和天线随整星一体化运输设计技术4项设计问题,通过数字化技术,分别应用数学建模、Pro/E质量特性计算、CATIA人机工程模拟和有限元分析等方法,对上述设计问题进行了分析,体现了数字化技术在卫星总装设计与实施过程中的应用,结果表明:试验数据满足且优于指标要求,实践效果良好。对于大型有效载荷卫星的总装设计技术具有一定的借鉴意义。     

WL_Net在导弹飞行控制软件安全性分析中的应用

提出了应用工作流逻辑网(WL_Net)进行软件安全性分析的新方法。介绍了运用WL_Net对导弹飞行控制软件进行安全性分析的步骤并分析了其优缺点和未来的发展方向。首先,综合考虑可能引起危险和风险的条件和环境构建WL_Net结构模型;然后使用可达树或关联矩阵对模型的合理性以及危险或风险出现的可能性进行分析,以确定该飞行控制软件是否安全。WL_Net能较好的完成对系统的建模和对软件安全性的分析,从一定程度上解决模型可读性和网结构爆炸的问题。     

Human exploration of near earth asteroids: Mission analysis for chemical and electric propulsion

This paper presents a mission analysis comparison of human missions to asteroids using two distinct architectures. The objective is to determine if either architecture can reduce launch mass with respect to the other, while not sacrificing other performance metrics such as mission duration. One architecture relies on chemical propulsion, the traditional workhorse of space exploration. The second combines chemical and electric propulsion into a hybrid architecture that attempts to utilize the strengths of each, namely the short flight times of chemical propulsion and the propellant efficiency of electric propulsion. The architectures are thoroughly detailed, and accessibility of the known asteroid population is determined for both. The most accessible asteroids are discussed in detail. Aspects such as mission abort scenarios and vehicle reusability are also discussed. Ultimately, it is determined that launch mass can be greatly reduced with the hybrid architecture, without a notable increase in mission duration. This demonstrates that significant performance improvements can be introduced to the next step of human space exploration with realistic electric propulsion system capabilities. This leads to immediate cost savings for human exploration and simultaneously opens a path of technology development that leads to technologies enabling access to even further destinations in the future.     

Applications of tuned mass dampers to improve performance of large space mirrors

In order for future imaging spacecraft to meet higher resolution imaging capability, it will be necessary to build large space telescopes with primary mirror diameters that range from 10 m to 20 m and do so with nanometer surface accuracy. Due to launch vehicle mass and volume constraints, these mirrors have to be deployable and lightweight, such as segmented mirrors using active optics to correct mirror surfaces with closed loop control. As a part of this work, system identification tests revealed that dynamic disturbances inherent in a laboratory environment are significant enough to degrade the optical performance of the telescope. Research was performed at the Naval Postgraduate School to identify the vibration modes most affecting the optical performance and evaluate different techniques to increase damping of those modes. Based on this work, tuned mass dampers (TMDs) were selected because of their simplicity in implementation and effectiveness in targeting specific modes. The selected damping mechanism was an eddy current damper where the damping and frequency of the damper could be easily changed. System identification of segments was performed to derive TMD specifications. Several configurations of the damper were evaluated, including the number and placement of TMDs, damping constant, and targeted structural modes. The final configuration consisted of two dampers located at the edge of each segment and resulted in 80% reduction in vibrations. The WFE for the system without dampers was 1.5 waves, with one TMD the WFE was 0.9 waves, and with two TMDs the WFE was 0.25 waves. This paper provides details of some of the work done in this area and includes theoretical predictions for optimum damping which were experimentally verified on a large aperture segmented system.     

Detectability of planetary characteristics in disk-averaged spectra II: synthetic spectra and light-curves of earth

Spatially and spectrally resolved models were used to explore the observational sensitivity to changes in atmospheric and surface properties and the detectability of surface biosignatures in the globally averaged spectra and light-curves of the Earth. Compared with previous efforts to characterize the Earth using disk-averaged models, a more comprehensive and realistic treatment of the surface and atmosphere was taken into account here. Our results are presented as a function of viewing geometry and phases at both visible/near-infrared (0.5-1.7 microm) and mid-infrared (5-25 microm) wavelength ranges, applicable to the proposed NASA-Terrestrial Planet Finder visible coronagraph and mid-infrared interferometer and to the ESADarwin mission architectures. Clouds can change the thermal emission by as much as 50% compared with the cloud-free case and increase the visible albedo by up to 500% for completely overcast cases at the dichotomy phase. Depending on the observed phase and their distribution and type, clouds can also significantly alter the spectral shape. Moreover, clouds impact the detectability of surface biosignatures in the visible wavelength range. Modeling the disk-averaged sensitivity to the "red-edge," a distinctive spectral signature of vegetation, showed that Earth's land vegetation could be seen in disk-averaged spectra, even with cloud cover, when the signal was averaged over the daily time scale. We found that vegetation is more readily discriminated from clouds at dichotomy (50% illumination) rather than at full phase. The detectability of phytoplankton was also explored, but was found to be more difficult to detect in the disk-average than land vegetation.     

From GMES to NOE: a European network for the management of the environment

Space techniques are highly appropriate for collecting the information needed to address the problems of environment and security and Europe has been considering establishing its own autonomous system for this purpose. Two years since the first meeting in Baveno, the consensus has grown that, beyond the numerous positive aspects of the committed approach, the GMES initiative has been hampered, on one hand, by a scientific knowledge deficit of the issues at stake and, on the other hand, by the difficulties for potential stakeholders and consumers of reaping all the benefits of space systems of Earth observation. In order to solve these problems a networking approach involving space and in situ observatories, research centres and stakeholders is proposed.     

The formation of sulfate and elemental sulfur aerosols under varying laboratory conditions: implications for early earth

The presence of sulfur mass-independent fractionation (S-MIF) in sediments more than 2.45?×?10(9) years old is thought to be evidence for an early anoxic atmosphere. Photolysis of sulfur dioxide (SO(2)) by UV light with λ?相似文献   

Space nuclear power: technology, policy, and risk considerations in human missions to Mars

There is a large discrepancy between potential needs for nuclear propulsion and power systems for the human exploration of Mars and the current status of R&D funding, public opinion, and governmental support for these technologies. Mission planners and spacecraft designers, energized by the recent claims of possible discovery of life on Mars and responding to increased public interest in the human exploration of Mars, frequently propose nuclear reactors and radioisotope thermoelectric generators (RTGs) for interplanetary spacecraft propulsion and for power supply on the surface of Mars. These plans and designs typically assume that reactors will be available "on-the-shelf," and do not take the extensive R&D costs required to develop such reactors into consideration. However, it is likely that current U.S. policies, if unchanged, will prohibit the launch of nuclear reactors and large RTGs in response to a perceived risk by the public.     

RATAN-600 microwave observations of powerful active regions from October 23 to November 5, 2003

Application of the mode of azimuthal observations on RATAN-600 has made it possible to realize multiple daily observations [1]. The results of multiwavelength observations of the Sun in this mode point to the existence of sharp spectral irregularities in the polarized radiation of flare-productive active regions (FPARs) producing especially powerful flares [2]. These phenomena occur in a broad range of radio-emission fluxes (0.05–200 s.f.u.), in a rather narrow wavelength band (2–5 cm), and they are recorded during the time interval from several hours to several days before a powerful flare, as well as during the flare. Frequently, such events indicate an eruption of powerful coronal mass ejections and high-energy particle (proton) fluxes, which, when reaching the Earth’s magnetosphere, trigger its disturbances. Here, we analyze events in the microwave band connected with the strongest flares which took place on October 28 and November 4, 2003.