“兰花”(Orchidee)——制定中的战场监视系统研究计划

“兰花”是一种战场监视系统,法国陆军准备在九十年代使用它。 在制定该项研究计划时,采用了用于该系统空中部分的飞行验证飞机和地面部分的数字仿真技术。 本文叙述利用了这些设施后所进行的一些主要试验项目,以及得到的主要试验结果。     

结构可靠性设计中的判定理论

在宇航结构可靠性分析方法的基础上,本文引入了试验方案选择概念,并根据统计判定理论推出了一套判定法。应用这个方法对给定结构部件可决定最佳成本效应设计的因子和试验方案。最后以土星V和航天机的几个结构组件为例,算出了结果。由此结果可以看出:设计费用与重量对最优判据有显著影响。     

用液体喷射作为固体推进剂火箭的推力方向控制

简介液体二次喷射推力方向控制是用液体喷入喷管的排气锥使火箭的喷气偏转,来实现控制的。最好选择浓而又可反应的液体以便增加超音速排气的质量、能量和在超音速排气中产生的冲波。这种特性使受影响的喷气增加推力,不仅产生了用于控制的侧向力,而且增加了轴向推力。这篇论文介绍了现有液体喷射推力方向控制技术的简况,包括设计的程序、研制、     

Spatially resolved genomic, stable isotopic, and lipid analyses of a modern freshwater microbialite from cuatro ciénegas, Mexico

Abstract Microbialites are biologically mediated carbonate deposits found in diverse environments worldwide. To explore the organisms and processes involved in microbialite formation, this study integrated genomic, lipid, and both organic and inorganic stable isotopic analyses to examine five discrete depth horizons spanning the surface 25?mm of a modern freshwater microbialite from Cuatro Ciénegas, Mexico. Distinct bacterial communities and geochemical signatures were observed in each microbialite layer. Photoautotrophic organisms accounted for approximately 65% of the sequences in the surface community and produced biomass with distinctive lipid biomarker and isotopic (δ(13)C) signatures. This photoautotrophic biomass was efficiently degraded in the deeper layers by heterotrophic organisms, primarily sulfate-reducing proteobacteria. Two spatially distinct zones of carbonate precipitation were observed within the microbialite, with the first zone corresponding to the phototroph-dominated portion of the microbialite and the second zone associated with the presence of sulfate-reducing heterotrophs. The coupling of photoautotrophic production, heterotrophic decomposition, and remineralization of organic matter led to the incorporation of a characteristic biogenic signature into the inorganic CaCO(3) matrix. Overall, spatially resolved multidisciplinary analyses of the microbialite enabled correlations to be made between the distribution of specific organisms, precipitation of carbonate, and preservation of unique lipid and isotopic geochemical signatures. These findings are critical for understanding the formation of modern microbialites and have implications for the interpretation of ancient microbialite records. Key Words: Microbial ecology-Microbe-mineral interactions-Microbial mats-Stromatolites-Genomics. Astrobiology 12, 685-698.     

The role of cross-cultural factors in long-duration international space missions: lessons from the SFINCSS-99 study

The role of cross-cultural factors in long-duration international space missions was examined during an isolation study that simulated many of the conditions aboard the International Space Station. Methods: Interactions involving two heterogeneous crews and one homogeneous crew staying in isolation from 110 to 240 days were studied. Data consisted of post-isolation interviews with crewmembers, ground support personnel and management, observational data, and public statements by crewmembers. Data was analyzed using the techniques of linguistic anthropology and ethnography. Results: Sub-cultural (organizational and professional) differences played a larger role than national differences in causing misunderstandings in this study. Conversely, some misunderstandings and conflicts were escalated by participants falsely assuming cultural differences or similarities. Comparison between the two heterogeneous crews showed the importance of training, personality factors, and commander and language skills in preventing and alleviating cultural misunderstandings. Conclusion: The study revealed a number of ways that cultural differences, real as well as assumed, can play a role and interact with other, non-cultural, factors in causing and/or precipitating conflict situations. It is postulated that such difficulties can be avoided by selecting culturally adaptive crewmembers and by cross-cultural and language training. Also the crew composition and role of commander were found to be important in mitigating conflict situations.     

光控宽带阵列天线

介绍了一种使用遥控用光纤链路和宽瞬时带宽用光学时移网络的光控阵列天线。综述了为机载监视雷达设计的宽带共形阵天线的研制情况。介绍了L波段96阵元光控阵列的系统设计和性能。讨论了光学元器件和阵列孔径的封装技术。重点介绍了系统的宽带性能。为了验证用于目标识别(ID)和目标成像的50％瞬时带宽(550MHz，距离分辨率为30cm)，测量了纳秒脉冲响应。应用基于时域脉冲测量的机内信号输入技术用于校准时移波束形成网络中的宽带元器件。     

Effect of Variable Selection on Multidisciplinary Design Optimization： a Flight Vehicle Example

Different multidisciplinary design optimization (MDO) problems are formulated and compared. Two MDO formulations are applied to a sounding rocket in order to optimize the performance of the rocket. In the MDO of the referred vehicle, three disciplines have been considered,which are trajectory, propulsion and aerodynamics. A special design structure matrix is developed to assist data exchange between disciplines. This design process uses response surface method (RSM) for multidisciplinary optimization of the rocket. The RSM is applied to the design in two categories: the propulsion model and the system level. In the propulsion model, RSM deter-mines an approximate mathematical model of the engine output parameters as a function of design variables. In the system level, RSM fits a surface of objective function versus design variables. In the first MDO problem formulation, two design variables are selected to form propulsion discipline. In the second one, three new design variables from geometry are added and finally, an optimization method is applied to the response surface in the system level in order to find the best result. Application of the first developed multidisciplinary design optimization procedure increased accessible altitude (performance index) of the referred sounding rocket by twenty five percents and the second one twenty nine.     

Space motion sickness medications: interference with biomedical parameters

The possibility that drugs administered to Skylab 3 (SL-3) and 4 (SL-4) crewmen for space motion sickness may have interfered with their biomedical evaluation in space was investigated. Healthy volunteers received combinations of Scopolamine/Dexedrine for four days in regimens similar to those used in these missions. Urine samples, heart rate, body temperature, mood and performance were analyzed for drug-related changes. Twenty-four hour urine samples were analyzed by the same procedures as those used to analyze the flight samples. Hormone concentrations determined included cortisol, epinephrine, norepinephrine, aldosterone and antidiuretic hormone (ADH). In addition, volume, specific gravity, osmolarity, sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), chloride (Cl), inorganic phosphate, uric acid and creatinine were measured. Performance was not affected by the Scopolamine/Dexedrine. The drug combination increased daily mean heart rate (HR) significantly in all the subjects and daily mean rectal temperature (RT) in some of the subjects. A 2-4 hr phase shift in the HR circadian rhythm was also observed which indicates that internal circadian synchrony was disturbed by the drugs. Psychological and subjective evaluation indicated that the subjects could usually identify which days they were given the drugs by an increase in tension and anxiety, decreased patience, restlessness, decreased appetite, difficulty in sleeping and feelings of increased heart rate and body temperature. Urinary electrolytes were not changed significantly by the drug, but marked and significant changes occurred in urine volume and hormone excretion patterns. Scopolamine/Dexedrine caused consistent elevations in urinary cortisol and epinephrine and a transient elevation in ADH. Norepinephrine excretion was decreased, but there was no significant change in aldosterone excretion or in 24 hr urine volume. A comparison of these findings with the first four days of inflight data from the SL-3 and SL-4 missions leads to the conclusion that the dramatic increases in aldosterone excretion during the first three days of spaceflight probably can be directly attributed to weightlessness, whereas the antimotion sickness medication could have substantially contributed to the early increased excretion of epinephrine and cortisol during these missions.     

Resistance of bacterial endospores to outer space for planetary protection purposes--experiment PROTECT of the EXPOSE-E mission

Spore-forming bacteria are of particular concern in the context of planetary protection because their tough endospores may withstand certain sterilization procedures as well as the harsh environments of outer space or planetary surfaces. To test their hardiness on a hypothetical mission to Mars, spores of Bacillus subtilis 168 and Bacillus pumilus SAFR-032 were exposed for 1.5 years to selected parameters of space in the experiment PROTECT during the EXPOSE-E mission on board the International Space Station. Mounted as dry layers on spacecraft-qualified aluminum coupons, the "trip to Mars" spores experienced space vacuum, cosmic and extraterrestrial solar radiation, and temperature fluctuations, whereas the "stay on Mars" spores were subjected to a simulated martian environment that included atmospheric pressure and composition, and UV and cosmic radiation. The survival of spores from both assays was determined after retrieval. It was clearly shown that solar extraterrestrial UV radiation (λ≥110?nm) as well as the martian UV spectrum (λ≥200?nm) was the most deleterious factor applied; in some samples only a few survivors were recovered from spores exposed in monolayers. Spores in multilayers survived better by several orders of magnitude. All other environmental parameters encountered by the "trip to Mars" or "stay on Mars" spores did little harm to the spores, which showed about 50% survival or more. The data demonstrate the high chance of survival of spores on a Mars mission, if protected against solar irradiation. These results will have implications for planetary protection considerations.