利用卫星实现与飞行中巡航导弹的通信

本文讨论了与飞行中远程巡航导弹通信的需求以及卫星作为中继平台的潜力。国防卫星通信系统Ⅲ(DSCSⅢ)和舰队卫星通信(FLTSATCOM)星至少能够同时为70枚巡航导弹向水面舰只和陆基指挥中心传送200bit的状态信息。DSCSⅢ还可以同时为至少70枚巡航导弹提供准实时有人末制导支持(只要巡航导弹装有共形天线阵)。FLTSATCOM可以为2枚装有全向天线阵的巡航导弹提供相同的能力。这种能力包括传输末段敏感器图象数据,该图象数据的速率为每枚每秒40kbits,取决于可实现的图象数据压缩比。本文还论述了指挥员利用这些系统重新瞄准新目标,允许一枚巡航导弹向地面传送一路末段敏感器图象。     

复合固体推进剂浇入发动机时的流变学

浇铸时未固化的复合固体推进剂的流动特性是十分重要的,因为它直接关系到发动机装药的完整性。增加推进剂的固体含量,可以提高能量特性,却导致药浆的流动性变坏。固体含量高的推进剂呈现非牛顿假塑性流动特性,即表观粘度依赖于剪切应力,以及随着未固化推进剂存放时间的增长,假塑性也增加。本文介绍了在 NASA 主办下进行浇铸研究的一些情况。对浇铸过程中剪切应力的三个明显不同区域和每一区域中推进剂的流动特性,进行了讨论。叙述了推进剂组分和工艺条件的变化对表观粘度的影响和浇铸过程中形成药柱缺陷的有关流变性能的实验结果。     

靶场标准化及自动化计划第二阶段

一、靶场背景 美国主要的航天发射场,包括东靶场(位于弗罗里达州卡纳维拉尔角)和西靶场(位于加利福尼亚州范登堡空军基地)起源于50年代,在随后的几十年内进行了逐步扩展和改进。直到前不久移交给空军空间司令部时,这些靶场才更多地用作研究和开发单位,而不只是操作运行单位。逐步改造使它们具备了支持发射新型航天器、弹道导弹以及逐步发展起来的     

The dynamics of blood biochemical parameters in cosmonauts during long-term space flights

Most of the previously obtained data on cosmonauts' metabolic state concerned certain stages of the postflight period. In this connection, all conclusions, as to metabolism peculiarities during the space flight, were to a large extent probabilistic. The purpose of this work was study of metabolism characteristics in cosmonauts directly during long-term space flights. In the capillary blood samples taken from a finger, by "Reflotron IV" biochemical analyzer, "Boehringer Mannheim" GmbH, Germany, adapted to weightlessness environments, the activity of GOT, GPT, CK, gamma-GT, total and pancreatic amylase, as well as concentration of hemoglobin, glucose, total bilirubin, uric acid, urea, creatinine, total, HDL- and LDL cholesterol, triglycerides had been determined. HDL/LDL-cholesterol ratio also was computed. The crewmembers of 6 main missions to the "Mir" orbital station, a total of 17 cosmonauts, were examined. Biochemical tests were carried out 30-60 days before launch, and in the flights different stages between the 25-th and the 423-rd days of flights. In cosmonauts during space flight had been found tendency to increase, in compare with basal level, GOT, GPT, total amylase activity, glucose and total cholesterol concentration, and tendency to decrease of CK activity, hemoglobin, HDL-cholesterol concentration, and HDL/LDL - cholesterol ratio. Some definite trends in variations of other determined biochemical parameters had not been found. The same trends of mentioned biochemical parameters alterations observed in majority of tested cosmonauts, allows to suppose existence of connection between noted metabolic alterations with influence of space flight conditions upon cosmonaut's body. Variations of other studied blood biochemical parameters depends on, probably, pure individual causes.     

ESA再入探测器的某些空气热动力问题

给出了两种不同的再入飞行器:充气的再入和下滑演示器(IRDT)和Huygens.两者的任务都涉及在靠近轨道的条件下再入并均已于2005年完成.概述了IRDT的使命和具体设计问题,综述了IRDT最近飞行的初步结果和ESTEC估计Huygens受到的辐射通量采用的方法.     

Experimentally tracing the key steps in the origin of life: The aromatic world

Life is generally believed to emerge on Earth, to be at least functionally similar to life as we know it today, and to be much simpler than modern life. Although minimal life is notoriously difficult to define, a molecular system can be considered alive if it turns resources into building blocks, replicates, and evolves. Primitive life may have consisted of a compartmentalized genetic system coupled with an energy-harvesting mechanism. How prebiotic building blocks self-assemble and transform themselves into a minimal living system can be broken into two questions: (1) How can prebiotic building blocks form containers, metabolic networks, and informational polymers? (2) How can these three components cooperatively organize to form a protocell that satisfies the minimal requirements for a living system? The functional integration of these components is a difficult puzzle that requires cooperation among all the aspects of protocell assembly: starting material, reaction mechanisms, thermodynamics, and the integration of the inheritance, metabolism, and container functionalities. Protocells may have been self-assembled from components different from those used in modern biochemistry. We propose that assemblies based on aromatic hydrocarbons may have been the most abundant flexible and stable organic materials on the primitive Earth and discuss their possible integration into a minimal life form. In this paper we attempt to combine current knowledge of the composition of prebiotic organic material of extraterrestrial and terrestrial origin, and put these in the context of possible prebiotic scenarios. We also describe laboratory experiments that might help clarify the transition from nonliving to living matter using aromatic material. This paper presents an interdisciplinary approach to interface state of the art knowledge in astrochemistry, prebiotic chemistry, and artificial life research.     

直接数字式频率合成

直接数字式频率合成采用一种数字码控制的相位累加器。该累加器对包含有所需波形的只读存贮器(ROM)寻址。ROM 依次向数模变换器提供指令,以变换成量化的模拟信号。这种方法由于器件加工工艺(特别是 ROM 和数模变换器)的限制而被列入音频和低频射频信号的合成范围。大规模集成(LSI)器件工艺的迅速发展以及直接数字式电路与间接合成电路的结合将导致兼有两种技术优点的混合电路的设计。本文介绍基本的直接数字式合成器的设计及其与间接锁相环相比较的优缺点。还介绍将两者加以组合来实现兼有两种技术优点的可能方法。     

玻璃碳断裂性能的一些研究

本文简要介绍用“声共振法”测材料的杨氏模量,用“控制裂纹法”测材料的断裂韧性以及材料的极限应变能释放率的计算。对三种玻璃碳的室温-1023°K的杨氏模量和断裂韧性进行了测定,用电子扫描显微镜对玻璃碳的断裂、氧化和加工表面进行研究观察,分析了玻璃碳的极限应变能释放率并与多晶石墨及碳-碳复合材料进行比较。     

利用弹道试验发动机确定弹道性能

本文研究了燃速参数之间的关系。象确定速度系数和速度指数关系那样,确定了温度和压力敏感系数之间的麦克斯韦关系。按一般条件,导出了发动机和速度敏感系数之间的关系。同时由Geckler和Sprenger根据一般经验公式导出了数据相容性关系。