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1.
This article reports about the results of the latest computer runs of a lunar base simulation model. The lunar base consists of 20 facilities for lunar mining, processing and fabrication. The infrastructure includes solar and nuclear power plants, a central workshop, habitat and farm. Lunar products can be used for construction of solar power systems (SPS) or other spacecraft at several space locations. The simulation model evaluates the mass, energy and manpower flows between the elements of the system as well as system cost and cost of products on an annual basis for a given operational period. The 1983 standard model run over a fifty-years life cycle (beginning about the year 2000) was accomplished for a mean annual production volume of 78 180 Mg of hardware products for export resulting in average specific manufacturing cost of 8.4 $/kg and total annual cost of 1.25 billion dollars during the life cycle. The reference space transportation system uses LOX/LH2 propulsion for which at the average 210 500 Mg LOX per year is produced on the moon. The sensitivity analysis indicates the importance of bootstrapping as well as the influence of market size, space transportation cost and specific resources demand on the mean lunar manufacturing cost. The option using lunar resources turns out to be quite attractive from the economical viewpoint. Systems analysis by this lunar base model and further trade-offs will be a useful tool to confirm this.  相似文献   

2.
Oró J  Lazcano A 《Acta Astronautica》1992,26(3-4):157-158
This paper discusses the already 60 year old ideas of Oparin and Haldane, who suggested that the first forms of life were anaerobic, heterotrophic bacteria coming from chemical abiotic synthesis of organic compounds.  相似文献   

3.
卫星通信网络与地面移动通信网络融合,可提供低时延、广覆盖的泛在接入服务。相控阵天线作为星地传输端到端信息获取的射频前端,具有剖面低、波束成形灵活、多维参数捷变等优点,但也面临降低成本及功耗、增加宽带传输能力、提高宽角扫描性能等方面的挑战。与现有相关综述关注相控阵天线设计流程及制造工艺不同,对相控阵天线在星地融合网络中的应用研究进行综述。首先,阐述相控阵天线的不同架构和特点。其次,总结应对挑战的若干关键技术,包括波束凝视、高精度波束指向、低成本、多波束等。最后,展望在分布式星群组网、高频段演进和通信感知融合等场景中的发展趋势和研究方向。  相似文献   

4.
航天器质量特性测试技术新进展   总被引:2,自引:2,他引:2  
航天器质量特性测试提供航天器轨道控制和姿态控制所需的质量特性参数,同时验证航天器结构和布局设计的合理性,为持续改进提供依据,在航天器的研制中占有重要地位.文章在对国内和欧美等航天发达国家航天器质量特性测试技术深入调研的基础上,阐述了国内外航天器质量特性技术的进展情况,重点分析了NASA哥达德空间飞行中心和欧空局下属法国...  相似文献   

5.
Pozzo T  Berthoz A  Popov C 《Acta Astronautica》1995,36(8-12):727-732
Here are reported preliminary results of the “Synergy” experiment performed aboard the Russian orbital station “MIR” in July 1993 (Altaïr Mission). The experiment was carried out before, during, and after the space flight of two astronauts (S1 and S2). The duration of the flight was 21 days for S1 and 6 month for S2. The subjects were tested during preflight, inflight and postflight. The astronaut subjects were fixed on the ground by the feet. They were asked to pick up a box in front of them on the ground. Two velocities of movement and two distances of the target to be reached were tested. The movement of several small markers placed on the body was recorded on video tape.

Results show that the shape of head and hand trajectories in the sagittal plane remains roughly the same during the flight in spite of the modification of mechanical constraints. Trajectory invariance does not result in joint angular displacement invariance. These data indicate that the planning of the movement takes place in terms of head and hand trajectories rather than joint rotations as it was previously suggested for simple arm reaching movement.  相似文献   


6.
The effect on the organism of a 12-day stay in a water immersion medium (head on the water surface) was studied on 10 subjects. The condition of the metabolic processes in the subjects was judged from the investigation of the parameters of protein and carbohydrate metabolism, acid-base equilibrium, the activity of a number of enzymes and steroid hormones. The venous blood and diurnal urine served as the material for conducting the corresponding biochemical determinations. The stay in an immersion medium is accompanied by a significant increase in the content of residual nitrogen in the blood, by a reduction of the creatinine content in the blood and by an increase of the creatine content of the blood with the simultaneous increase of the excretion of creatinine and creatine with the urine, by a significant increase of the glucose and lactate content in the blood, by the development of acidosis of a respiratory and metabolic character, as well as by a significant increase of the activity of creatine phosphokinase and the isoenzyme fraction of lactate dehydrogenase3. In all the subjects, an expressed intensification of the glucocorticoid and androgenic functions of the adrenal cortex is noted during the experimental period.  相似文献   

7.
国外含能材料研究的新进展   总被引:1,自引:0,他引:1  
介绍当前国外含能材料及固体推进剂研究的一些新进展。支化的缩水甘油叠氮聚醚(B-GAP),含能热塑性弹性体及硝酸酯乙基硝胺类化合物(NENA)的研究正受到关注。卡托辛和巴得辛之类二茂铁衍生物是固体推进剂的高效燃速催化剂,氢化端羟基聚戊二烯能改善推进剂的储存性能,热稳定性和易损性。  相似文献   

8.
Periodic episodes of increased sunspot activity (solar electromagnetic storms) occur with 10-11 and 5-6 year periodicities and may be associated with measurable biological events. We investigated whether this sunspot periodicity characterized the incidence of Pap smear-determined cervical epithelial histopathologies and human physiologic functions. From January 1983 through December 2003, monthly averages were obtained for solar flux and sunspot numbers; six infectious, premalignant and malignant changes in the cervical epithelium from 1,182,421 consecutive, serially independent, screening Pap smears (59°9″N, 4°29″E); and six human physiologic functions of a healthy man (oral temperature, pulse, systolic and diastolic blood pressure, respiration, and peak expiratory flow), which were measured ~5 times daily during ~34,500 self-measurement sessions (44°56″N, 93°8″W). After determining that sunspot numbers and solar flux, which were not annually rhythmic, occurred with a prominent 10-year and a less-prominent 5.75-year periodicity during this 21-year study span, each biological data set was analyzed with the same curve-fitting procedures. All six annually rhythmic Pap smear-detected infectious, premalignant and malignant cervical epithelial pathologies showed strong 10-year and weaker 5.75-year cycles, as did all six self-measured, annually rhythmic, physiologic functions. The phases (maxima) for the six histopathologic findings and five of six physiologic measurements were very near, or within, the first two quarters following the 10-year solar maxima. These findings add to the growing evidence that solar magnetic storm periodicities are mirrored by cyclic phase-locked rhythms of similar period length or lengths in human physiology and pathophysiology.  相似文献   

9.
We consider transfers with low thrust in an arbitrary field of forces. The modified method of transporting trajectory [1–4] is used for optimization of the transfers. The complexity of finding the transporting trajectory of a preset type can be the main obstacle to application of this method. This challenge is solved for the three-body problem in the Hill motion model. Numerical analysis of the method is performed using an example of the transfers to halo-orbits around the solar-terrestrial libration points.  相似文献   

10.
王文俊 《火箭推进》2003,29(2):38-43
根据近年来德国ICT国际会议的报告及其它有关文献报道,对国外高能推进剂研究的最新进展,按照CL-20推进剂、ADN推进剂、HNF推进剂、PGN推进剂等分别进行了较详细地介绍和述评,对新一代高能推进剂的能量特性等做了分析比较.  相似文献   

11.
12.
The volume shift of 2000 cm3 from the lower to the upper part of the human body during weightlessness gave rise to theoretical and practical questions which are addressed in this communication. The analysis revealed that the mobilized fluid reduced the interstitial fluid of the lower extremities by 40%. Applying the current ideas in the field of interstitial tissue physiology to these problems, one must conclude that the fluid displacement can only be brought about by a change of the interstitial tissue compliance. Based on the observations made by the astronauts and on our working hypothesis, a method was proposed to follow the fluid migration and to measure the tissue compliance in man. Results are reported from experiments under terrestrial conditions. They show that the tissue compliance indeed can be modulated. Applying the method in space can eventually help to clarify several concepts in terrestrial physiology.  相似文献   

13.
In the first part the state of the art of the most advanced micrometeoroid simulation techniques is reviewed. Then a new accelerator is described, which was developed jointly by the Technische Universität München and the N.A.S.A. George C. Marshall Space Flight Center. Finally the use of this new technique is indicated for basic research in fields other than astronautics.  相似文献   

14.
GNSS全球导航卫星系统的新发展   总被引:4,自引:0,他引:4  
GNSS全球导航卫星系统是20世纪90年代中期欧盟提出的一种综合星座系统,而不是一个单一星座系统。GNSS主要包括GPS、GLONASS、Galileo、Compass和IRNSS及它们的星基增强系统,例如,WAAS、EGNOS和GDGPS等。文中主要分析了GPS、GLONASS、Galileo的新发展及Compass和IRNSS的建设进展。  相似文献   

15.
介绍了军品电路与整机故障排除的几种常用方法。提出了电子设备的智能化故障诊断系统方案。首先,研制的军品电路与整机自动故障诊断系统应遵循通用化、模块化、系列化的原则,运用先进的自动测试设备与新的故障判断理论,可解决电路板故障诊断测试,测试的范围可以包括数字、模拟以及数模混合电路板,故障自动定位到元器件,达到快速维修的目地。  相似文献   

16.
W Lork 《Acta Astronautica》1988,17(2):271-275
Light is a very essential parameter in a plant's life. Changing the quality and/or quantity of illumination will not only determine the further development (photomorphogenesis), but also effect spontaneous responses like curvatures (phototropism). But there are several still unknown links in the signal transduction chain from the perception of the light signals to the terminal response. It is known from ground-based experiments, that part of this signal transduction path is congruous with that of gravitational signals. Biosample is a technology development programme, which enables sophisticated experiments with whole plants in a microgravity environment. It allows complex sequences of gravitational- and light-stimuli with simultaneous recording of the plant's response (e.g. curvature of the stem) by video. This facility in union with new genetic mutants, which are less- or insensitive to light, gravity or both, are convenient tools for progress in plant physiology research.  相似文献   

17.
The development of big segmented solid rocket motors during the nineties has been supported by an important progress in science and computational tools.

This progress is largely related to the solution of various technical problems in the design and processing of the propellant grains and their effect on the motor operation. It has been possible because of the enormous increase in the available computing power.

After a review of the main problems encountered (grain-flow coupling, motor trace shape prediction, pressure oscillations, slag deposit etc...) recent developments in modeling are described in two areas related to the analysis and prediction of motors operation. The first development couples the propellant surface burnback and pressure field computations during the whole operation of the motor: real tune geometry, pressure field and local burning rates are calculated in order to achieve a much more precise prediction of the motor trace. Pressure oscillations and instabilities are also predicted.

The second development is related to the influence of the process, through the rheology of the propellant on the combustion of the propellant. Rheology and particle segregation under shear may explain such effects as the so-called hump and knitlines effects. Experimental and modeling work in the field are described.  相似文献   


18.
Despite some setbacks – notably an indigenous launch failure – progress is being made in South Korea's space program and its public image has been boosted by the first flight of a Korean astronaut to the ISS. This report provides an update on recent and forthcoming space activities in the country and on its current cooperative arrangements.  相似文献   

19.
Pellis NR  North RM 《Acta Astronautica》2004,55(3-9):589-598
The activation of the US Laboratory Module "Destiny" on the International Space Station (ISS) in February 2001 launched a new era in microgravity research. Destiny provides the environment to conduct long-term microgravity research utilizing human intervention to assess, report, and modify experiments real time. As the only available pressurized space platform, ISS maximizes today's scientific resources and substantially increases the opportunity to obtain much longed-for answers on the effects of microgravity and long-term exposure to space. In addition, it evokes unexpected questions and results while experiments are still being conducted, affording time for changes and further investigation. While building and outfitting the ISS is the main priority during the current ISS assembly phase, seven different space station crews have already spent more than 2000 crew hours on approximately 80 scientific investigations, technology development activities, and educational demonstrations.  相似文献   

20.
吴家彤 《火箭推进》2004,30(2):48-53
根据与NASA签订的协议,CIAM和NASA在CIAM的高超声速飞行实验室“Kholod“上联合进行了第四次双模式超燃冲压发动机飞行试验.此次试验旨在进行6.5马赫飞行,并在哈萨克斯坦中部Sary Shagan试验场成功完成.此次地面发射的火箭是一枚改进型俄罗斯SA5型导弹,该重新设计的超燃冲压发动机加速后达到高于6.4马赫的一个新的最高飞行速度.此次发射是在真实飞行条件下的完超燃模式下进行的,这项计划的主要目的是获取飞行与地面测量数据间的相互关系,分析和风洞试验在俄罗斯或(也可能在)在美国做.本文阐述了该计划的方案设计及其目的,以及为了达到6.5马赫目标试验条件而采用的超燃冲压发动机和SA5型导弹重新设计的技术细节.概述了此次发射的操作过程.最后,对初步飞行试验结果做了介绍和讨论.  相似文献   

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