美国军用卫星遥感技术(上)

１　冷战结束后美国军事空间政策□□自１９５７年１０月由前苏联发射了第一颗卫星Ｓｐｕｔｎｉｋ后，不到３个月，美国于１９５８年１月也发射了Ｅｘｐｌｏｒｅｒ卫星，此后世界两强开始了军事空间竞赛。在３０多年冷战期间，美苏两国各自发射了大量间谍卫星，相互监视对方的一举一动。冷战结束后，美国国防部（ＤＯＤ）重新制订了军事空间政策，并于１９９６年９月由克林顿总统批准实行。其主要内容如下：·通过人或机器人勘查，以增进对地球、太阳系和宇宙的了解；·加强和维护美国国家安全；·增强美国经济竞争和科学技术能力；·鼓励国…     

美国重返月球计划为何胎死腹中

<正>正当众媒体高调称颂:"美国重返月球计划意义堪比探索南极",没几天的功夫,这个伟大的计划却"胎死腹中"。2月1日,美国总统奥巴马向国会     

美国人强占月球计划揭秘

美国科学家凯伊·戴维森曾披露美军曾打算在月球上引爆一颗原子弹。接着，曼哈顿科学家爱德华·泰勒又在最近出版的《原子能科学家》杂志上披露了更大的内幕：美国空军和陆军早在２０世纪５０年代末就打算在月球上建立一个永久性的军事基地，并且欲宣布月球归美国所有，不允许其他任何国家染指。结合美国军方现在的举动，相信媒体曝光的不仅仅是历史。１９６１年５月２５日，美国前总统肯尼迪在一次国会演讲中提出了“把人类送上月球，又能让他安全返回地球”的目标。８年后的１９６９年７月２０日，美国宇航员阿姆斯特朗和艾尔德林把人类的…     

美国的行星探测热潮（续）

本刊第二期刊登了美国已经发射的行星探测器及其探测成果的报导。本期向读者介绍美国在90年代将要发射的行星探测器及其探测任务。一项是彗星会合小行星飞越(CRAF)任务;一项是探测土星和土卫六的卡西尼(Cassini)任务;一项是火星观测者任务;一项是登上火星的漫游者任务。     

“宁静”号的命名纷争

斯蒂芬&#183;科尔伯特是美国著名电视脱口秀主持人。不过，他在美国以外知名度不高。2009年年初，美国航宇局在网上举办的征名活动给科尔伯特带来扬名机会。     

美国陆军的杀手锏“长矛“地对地战术导弹

乱世出“长矛” 五六十年代,美国和苏联在紧张激烈的核军备竞赛中,各种战略核武器与战术核武器匆匆登场,装备部队。就地对地战术核导弹、核火箭而言,美国发展和装备了“中士”导弹和“诚实约翰”战术火箭;苏联发展装备了“飞毛腿”-A导弹和“蛙”式系列战术火箭。然而,充当这场核军备竞赛急先锋之一的第一代     

报复制裁 俄罗斯拟在2020年将美国踢出空间站

<正>据外媒报道,俄罗斯5月13日宣布2020年起将不再允许美国航宇局(NASA)的航天员进入国际空间站,此举被解读为俄罗斯对美国因其入侵克里米亚进行制裁做出的回击。美国和俄罗斯都是空间站的拥有者,在这种情况下,俄罗斯如何做到禁止美国航天员入内呢?答案其实很简单,NASA目前依赖俄罗斯的"联盟"号飞船将本国航天员送上空间站,一次单程运输的船票费用高达7070万美元。如果俄罗斯不再提供这项服务,     

形形色色的月球基地

2004年，美国总统布什宣布：在2020年前让美国航天员重返月球，然后在月球上建立基地。2006年12月，美国航宇局公布了“月球基地计划”的初步构想——计划在2024年建立月球基地，保障4名航天员在月球基地上连续居住180天。     

美国的航天飞机—C

运货不载人的美国航天飞机-C(Shu-ttle-C)是载人航天飞机的一种派生型号。它作为美航宇局近期大推力运输器的备选方案,正在得到越来越多的支持。这种运输器可以使美空间站的发射变得简便。Shuttle-C成为备选方案的原因是:技术评议处对它的评价较好;固体推进剂本身存在的缺点;人们对空间站的发射和组装问题日益担心。这种新式运输器有可能增强美国的发射能力,同时减少对载人航天飞机的依赖性。对Shuttle-C感兴趣的另一原因是:美     

美国火箭连续失败的原因

今年4月以来,美国的火箭似乎每况愈下,火箭发射时发生爆炸或发动机提前关机导致卫星丢失的比例令人震惊。如果我们追溯到去年8月份,美国火箭已发生6次重大失误,发生失误的既有通常可靠的老式火箭,也有新设计的火箭;造成损失总计超过35亿美元。     

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.     

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.-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.     

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.     

美国的战斧巡航导弹

3月19日,美英法三国开始对利比亚实行军事打击。在当天进行的空袭行动中,部署在地中海的美军和英军军舰与潜艇就向利比亚首都的黎波里郊区和东部城市米苏拉塔等地发射了110多枚战斧巡航导弹,袭击了20多处防空设施和民事目标。在随后的几天里,每天又都发射了一批这种导弹。截止到4月1日,美军共发射了221枚、英军共发射了7枚战斧巡航导弹。那么,战斧巡航导弹究竞