国外侦察卫星那些事儿

<正>7月2日,美国国防部宣布,将在2017年发射"作战响应空间"-5小型侦察卫星,以作为从当前的"天基太空监视卫星"到未来小型太空监视三星星座之间的过渡。此前的6月9日,美国空军宣布,其第5、6颗"天基红外系统"导弹预警卫星将采用升级版的A2100卫星平台,以此作为"天基红外系统"项目技术更新工作的一部分。目前,军民两用成像卫星发展迅     

美国“一箭三星”发射同步轨道空间态势感知卫星

2014年7月28日,美国空军从卡纳维拉尔角发射场,用德尔他-4M＋火箭以＂一箭三星＂方式成功将3颗高轨态势感知卫星送入近地球同步轨道,即2颗业务型高轨巡视卫星＂地球同步轨道空间态势感知计划＂（GSSAP）卫星和1颗技术试验卫星＂评估局部空间自主守卫纳卫星＂（ANGELS）。此次发射任务的成功标志着美国高轨空间监视技术走向成熟,高轨目标探测、跟踪和侦察能力快速提升,引起航天界高度关注。     

历尽艰难 终现曙光——从新闻报道看美国天基红外系统的发展历程

美国当地时间2011年5月7日下午2点10分,美国空军第45太空联队从卡纳维拉尔角的第41发射台成功发射一枚"宇宙神5"型运载火箭,将"天基红外系统"(SBIRS)"静地轨道"1(GEO-1)卫星送入轨道。美国的天基红外系统是新一代导弹预警卫星系统,与原有的国防支持计划(DSP)预警卫星相比,SBIRS预警卫星不仅能比DSP卫星更出色地完成战略     

北斗“双胞胎”入网很关键

随着第12、13颗北斗卫星成功入轨,北斗卫星首次"落户"中圆轨道(MEO轨道),我国的北斗区域卫星导航系统日趋成型。在此次双星发射之前,太空中已有5颗地球静止轨道(GEO轨道)北斗卫星和5颗倾斜地球同步轨道(IGSO轨道)北斗卫星,按照"5+5+4"的组网计划,会有4颗MEO轨道卫星上天。而此次发射     

我国成功发射第5颗“北斗”导航卫星

2010年8月1日05:30,我国在西昌卫星发射中心用长征-3A运载火箭,将第5颗"北斗"导航卫星成功送入太空预定转移轨道,8月5日进入最终的倾斜地球同步轨道。这是我国今年连续发射的第3颗"北斗"导航系统组网卫星,也是首颗运行在倾斜地球同步轨道的"北斗"导航卫星,它对整个"北斗"卫星导航系统的建设具有重要意义。     

美“太空篱笆”被下令关闭

据媒体报道,美国空军将在9月1日关闭其卫星和轨道碎片跟踪网络的一个关键组成部分——"空间监视系统"(即"太空篱笆"),并腾空所有场站。"太空篱笆"由分布在美国南部的一系列甚高频雷达组成,其一个升级换代项目眼下已被搁置,正等待涉及整个国防部的一次评审的结果。甚高频"太空篱笆"部署于上世纪60年代,现包括3座发射机场站和6座接收站,承担着美空军"空间监视网"约     

美国第二颗GPS-2F服役 加速导航卫星的更新换代

2011年8月22日,美国波音公司宣布,2011年7月16日由德尔他-4火箭发射的第2颗GPS-2F卫星已经开始在轨服役,被命名为SVN-63,并正式转交给空军第50太空联队和第2太空运行中队。GPS卫星星座现有31颗卫星。波音公司还将建造10颗GPS-2F卫星。美国空军拟     

美国"太空快速响应"计划

1 引言 为保障在未来战争中能及时地补充和维修失效的军用卫星,以便保持太空优势,2003年3月1日,美国空军航天司令部开始实施"作战响应航天运输"(ORS)的"选择分析"(AOA)计划,其目的是寻找有效载荷的快速发射、机动、服务和回收的最优方案,以提高军事效能.     

中国“北斗”跃上新高度

<正>2010年,对于中国北斗卫星导航系统的建设者,特别是北斗导航卫星的研制者而言,是个不一般的年份。这一年,中国北斗卫星导航系统将有多颗卫星连续跃上太空,在属于它们的轨道上安家。经过这一密集发射组网阶段,中国的新一代卫星导航系统将在太空中初     

“北斗”卫星导航系统发展报告

20世纪80年代初,中国开始积极探索适合国情的卫星导航系统。2000年,初步建成"北斗"卫星导航试验系统,标志着中国成为继美、俄之后世界上第3个拥有自主卫星导航系统的国家。目前,中国正在稳步推进"北斗"卫星导航系统的建设,截至2012年2月已成功发射了11颗"北斗"导航卫星。     

2005年全球反恐特警队赛记

2005年3月30日到4月2日为期4天，在美国拉斯维加斯举行的全球特警挑战赛（Original World SWAT Challenge,OWSC）中，总计有18支队伍参赛。[编者按]     

Indirect search for Dark Matter with H.E.S.S.

Observations of the Galactic center region with the H.E.S.S. telescopes have established the existence of a steady, extended source of gamma-ray emission coinciding with the position of the super massive black hole Sgr A^*. This is a remarkable finding given the expected presence of dense self-annihilating Dark Matter in the Galactic center region. The self-annihilation process is giving rise to gamma-ray production through hadronization including the production of neutral pions which decay into gamma-rays but also through (loop-suppressed) annihilation into final states of almost mono-energetic photons. We study the observed gamma-ray signal (spectrum and shape) from the Galactic center in the context of Dark Matter annihilation and indicate the prospects for further indirect Dark Matter searches with H.E.S.S.     

The Comet Halley flyby I.R. sounder “I.K.S.”

An infrared sounder is being developed in France to observe in 1986 Comet Halley from the Soviet “VEGA” flyby probes. The instrument, called “I.K.S.”, has three measuring channels. Two of these channels will provide the spectrum of the comet emission in the spectral intervals 2.5–5.0 μ and 6–12 μ, at a constant resolution λ/Δλ = 50.The third channel analyzes the comet I.R. image at a spatial frequency of about 1 arc minute^?1; two I.R. colours are used in this channel: 7–10 μ and 10–14 μ. From the results expected, it is hoped that (1) most primary simple molecules emitted by the nucleus will be identified; (2) the chemical composition and perhaps crystalline structure of the dust grains and ices released by the comet will be derived; and (3) the diameter of the nucleus and its brightness temperatures will be measured.     

The C.E.B.A.S.-Minimodule: behaviour of an artificial aquatic ecological system during spaceflight.

The C.E.B.A.S.-Minimodule, a closed aquatic ecosystem integrated into a middeck locker and consisting of a Zoological (animal tanks), a Botanical (plant bioreactor), a Microbial (bacteria filter) and an Electronic Component (data acquisition/control system) was flown on the STS-89 spaceshuttle mission in January 1998 for 9 days. Preflight the plant bioreactor was loaded with 53 g of Ceratophyllum demersum (coontail) and the animal tanks with 4 adult pregnant females of the fish, Xiphophorus helleri (sword-tails), 200 juveniles of the same species less than 1 week of age, 38 large and 30 juvenile Biomphalaria glabrata water snails. The filter compartment was filled with 200 g of lava grain inoculated with laboratory strains of ammonia-oxidizing bacteria. A ground reference was undertaken with the same biological setup with a delay of 4 d. After an adaptation period of 5 d the system was closed and integrated into the spaceshuttle one day before launch. Video recordings of the animals were automatically taken for 10 minutes in 2-hour periods; the tapes were changed daily by the astronauts. The chemical and physical data for the aquatic system were within the expected range and were closely comparable in comparison to the ground reference. After 9 d under space conditions, the plant biomass increased to 117 g. The plants were all found in very good condition. All 4 adult female fish were retrieved in a good physiological condition. The juvenile fishes had a survival rate of about 33%. Almost 97% of the snails had survived and produced more than 250 neonates and 40 spawning packs. All samples were distributed according to a defined schedule and satisfied all scientific needs of the involved 12 principal investigators. This was the first successful spaceflight of an artificial aquatic ecosystem containing vertebrates, invertebrates, higher plants and microorganisms self-sustained by its inhabitants only. C.E.B.A.S. in a modified form and biological setup is a promising candidate for the early space station utilization as a first midterm experiment.     

Mechanisms underlying cellular radiosensitivity and R.B.E.: introductory remarks.

A general outline of the symposium titled "Mechanisms underlying cellular radiosensitivity and R.B.E." will be given in the introduction. The essential topics of molecular radiation biology are described with respect to the damage, repair and mutagenesis caused by high-LET irradiation to cellular DNA. The importance of clustered DNA lesions (locally multiply damaged sites) formed in vivo is discussed. This symposium is devoted to the mechanisms of the biological effects of radiation with high LET, especially with regard to the effects of heavy ions and neutrons which may cause possible risks in space flight, (e.g. carcinogenesis and mutagenesis). Detailed understanding of these risks, however, demands knowledge of the molecular mechanisms involved in the biological effects of high-LET radiations. Thus, it was the organizers' idea to hold a symposium dealing with primary physical and chemical events caused in cellular deoxyribonucleoproteins by densely-ionizing radiations and to relate them to track structures and energy transfer processes. The mechanisms of DNA damage were regarded from different points of view including those considering DNA repair and mutagenesis. Problems associated with cell survival and radiation protection were discussed as well. Our knowledge of the molecular mechanisms of high-LET radiation actions, however, is limited compared to what we know about low-LET radiation effects (e.g. from gamma-rays or X-rays). To emphasize this statement, I would like to summarize briefly the open questions in molecular radiation biology, what we know already about low-LET effects and what is lacking describing the effect of high-LET radiation.     

The "C.E.B.A.S. MINI-MODULE": a self-sustaining closed aquatic ecosystem for spaceflight experimentation.

The C.E.B.A.S. MINI-MODULE is the miniaturized space flight version of the Closed Equilibrated Biological Aquatic System (C.E.B.A.S.). It fits into a large middeck locker tray and is scheduled to be flown in the STS 85 and in the NEUROLAB missions. Its volume is about 9 liters and it consists of two animal tanks, a plant cultivator, and a bacteria filter in a monolithic design. An external sensor unit is connected to a data acquisition/control unit. The system integrates its own biological life support. The CO2 exhaled by the consumers (fishes, snails, microorganisms) is assimilated by water plants (Ceratophyllum demersum) which provide them with oxygen. The products of biomass degradation and excretion (mainly ammonia ions) are converted by bacteria into nitrite and nitrate. The latter is taken up by the plants as a nitrogen source together with other ions like phosphate. The plants convert light energy into chemical energy and their illumination is regulated via the oxygen concentration in the water by the control unit. In ground laboratory tests the system exhibited biological stability up to three month. The buffer capacity of the biological filter system is high enough to eliminate the degradation products of about one half of the dead animal biomass as shown in a "crash test". A test series using the laboratory model of the flight hardware demonstrated the biological stability and technical reliability with mission-identical loading and test duration. A comprehensive biological research program is established for the C.E.B.A.S. MINI-MODULE in which five German and three U.S.-American universities as well as the Russian Academy of Sciences are involved.     

C.E.B.A.S. MINI MODULE: test results of an artificial (man-made) aquatic ecosystem.

The original Closed Equilibrated Biological Aquatic System (C.E.B.A.S.) is a long-term multi-generation research facility for experiments with aquatic animals and plants in a space station the development of which is surrounded by a large international scientific program. In addition, a miniaturized laboratory prototype, the C.E.B.A.S. MINI MODULE, with a total volume of about 10-12 liters for a Spacelab middeck locker was developed and a first version was tested successfully for two weeks with a population of fishes (Xiphophorus helleri) in the animal tank and a Ceratophyllum spec. in the illuminated higher plant growth chamber. The water recycling system consisted of a bacteria filter and a mechanical filter and the silastic tubing gas exchanger was separated by valves for the utilization in emergency cases only. Data were collected with the acquisition module of the original C.E.B.A.S. process control system. In addition, an optimized version was tested for 7 weeks with fishes and plants and thereafter with fish and with plants only for 2 and 1 weeks, resp.. The paper presents the relevant water parameters (e.g., pH, pressure, temperature, oxygen saturation, flow rate, ion concentrations) during the test period as well as morphological and physiological data of the enclosed animals and plants. On the basis of the given results the possible role of the C.E.B.A.S. system as a scientific tool in artificial ecosystem research and for the development of a combined animal-plant intensive aquaculture system and its utilization in bioregenerative life support is discussed.     

Aquatic modules for bioregenerative life support systems: developmental aspects based on the space flight results of the C.E.B.A.S. MIN-MODULE.

The Closed Equilibrated Biological Aquatic System (C.E.B.A.S.) is an artificial aquatic ecosystem which contains teleost fishes, water snails, ammonia oxidizing bacteria and edible non-gravitropic water plants. It serves as a model for aquatic food production modules which are not seriously affected by microgravity and other space conditions. Its space flight version, the so-called C.E.B.A.S. MINI-MODULE was already successfully tested in the STS-89 and STS-90 (NEUROLAB) missions. It will be flown a third time in space with the STS-107 mission in January 2003. All results obtained so far in space indicate that the basic concept of the system is more than suitable to drive forward its development. The C.E.B.A.S. MINI-MODULE is located within a middeck locker with limited space for additional components. These technical limitations allow only some modifications which lead to a maximum experiment time span of 120 days which is not long enough for scientifically essential multi-generation-experiments. The first necessary step is the development of "harvesting devices" for the different organisms. In the limited space of the plant bioreactor a high biomass production leads to self-shadowing effects which results in an uncontrolled degradation and increased oxygen consumption by microorganisms which will endanger the fishes and snails. It was shown already that the latter reproduce excellently in space and that the reproductive functions of the fish species are not affected. Although the parent-offspring-cannibalism of the ovoviviparous fish species (Xiphophorus helleri) serves as a regulating factor in population dynamics an uncontrolled snail reproduction will also induce an increased oxygen consumption per se and a high ammonia concentration in the water. If harvesting locks can be handled by astronauts in, e. g., 4-week intervals their construction is not very difficult and basic technical solutions are already developed. The second problem is the feeding of the animals. Although C.E.B.A.S.-based aquaculture modules are designed to be closed food loop systems (edible herbivorous fish species and edible water plants) which are already verified on Earth this will not be possible in space without devices in which the animals are fed from a food storage. This has to be done at least once daily which would waste too much crew time when done by astronauts. So, the development of a reliable automated food dispenser has highest priority. Also in this case basic technical solutions are already elaborated. The paper gives a comprehensive overview of the proposed further C.E.B.A.S.-based development of longer-term duration aquatic food production modules.     

V.L.A. observations of flare build-up in coronal loops

Very Large Array (V.L.A.) measurements at 20 cm wavelength map emission from coronal loops with second-of-arc angular resolution at time intervals as short as 3.3 seconds. The total intensity of the 20 cm emission describes the evolution and structure of the hot plasma that is detected by satellite X-ray observations of coronal loops. The circular polarization of the 20 cm emission describes the evolution, strength and structure of the coronal magnetic field. Preburst heating and magnetic changes that precede burst emission on time scales of between 1 and 30 minutes are discussed. Simultaneous 20 cm and soft X-ray observations indicate an electron temperature $\text{T}{}_{\mathrm{e}}\textcolor{red}{}\text{2.5 × 10}{}^7\text{K}$ and electron density $\text{N}{}_{\mathrm{e}}\textcolor{red}{}\text{10}{}^{10}\text{cm}{}^{\mathrm{?3}}$ during preburst heating in a coronal loop that was also associated with twisting of the entire loop in space. We also discuss the successive triggering of bursts from adjacent coronal loops; highly polarized emission from the legs of loops with large intensity changes over a 32 MHz change in observing frequency; and apparent motions of hot plasma within coronal loops at velocities V > 2,000 kilometerspersecond.     

Pigment composition and concentrations within the plant (Ceratophyllum demersum L.) component of the STS-89 C.E.B.A.S. Mini-Module spaceflight experiment.

The Closed Equilibrated Biological Aquatic System (C.E.B.A.S.) Mini-Module, a Space Shuttle middeck locker payload which supports a variety of aquatic inhabitants (fish, snails, plants and bacteria) in an enclosed 8.6 L chamber, was tested for its biological stability in microgravity. The aquatic plant, Ceratophyllum demersum L., was critical for the vitality and functioning of this artificial mini-ecosystem. Its photosynthetic pigment concentrations were of interest due to their light harvesting and protective functions. "Post-flight" chlorophyll and carotenoid concentrations within Ceratophyllum apical segments were directly related to the quantities of light received in the experiments, with microgravity exposure (STS-89) failing to account for any significant deviation from ground control studies.