具有反应及粒子尺寸改变的喷管的气体——粒子流

本文介绍了含有粒子尺寸效应及相变效应的一维气体——粒子混合物流动的控制方程组。除考虑粒子的速度与温度滞后以外,还考虑了如下几种效应:粒子的熔化、液滴的破裂、液滴的凝聚、辐射、粒子密度随温度的变化、蒸发、化学反应、凝结及凝固。本文讨论了一些数值解法及其解,还讨论了这些效应对喷管性能的影响,并将这些综合的效应同几种固体火箭发动机实测的比冲效率作了比较。     

自动功率计校准系统

校准微波功率计所需要的仪器已重新设计成可用计算器控制,并且能在0.5至11毫瓦的11个功率电平上提供0.01到18千兆赫的校准。用这些仪器组成的系统(系统II)可以以每点1.5秒的速度确定校准因子,几乎不需要操作者看管。高度对称的电阻功率分配器用来在整个频率范围内给被测器件和校准用标准提供接近于相等的入射功率。利用校准用标准和射频功率电平控制器,使送入功分器的功率保持在所选择的电平上。被测器件的输出用热敏电阻座或镇流电阻座Hogelarsen双电动势(Two-E.M.F)电桥和数字电压表进行测量。从电压表或被测功率计的IEEE488接口母线的输出可用计算器读出。要使辐射热测量座长期稳定,就需要进行温度控制。利用一对电桥和具有电阻功分器的温度控制器可以对两个辐射热测量座进行交替比较。本文介绍一种自动校准微波功率计、辐射热测量座和其他功率传感器的计算机辅助测量系统,提出了用功分器校准辐射热测量座的理论,讨论了该系统的使用方法。     

推力向量控制技术的论证

大西洋研究公司(ARC)与法国欧洲推进公司(SEP)共同进行先进向量控制方案的设计和论证试验。方案之一是超声速分离线喷管,该推力向量控制试验系由曾在标准(轴向)试车台进行过试验的基本型弹道发动机在ARC的多分力试车台上完成的。超声速分离线喷管是在60年代研制的一种很有希望的方案,由于受当时材料的限制而放弃了;随着喷管材料的新发展,证明该方案有进一步开发的必要,因为它可提供较大的偏转角。SEP制造的一种先进的轻型耐高温复合材料NOVEL-TEX,已被选用为ARC试验的喷管喉衬和出口维。本文叙述了发动机和推力向量控制系统的设计、试验装置和试验结果。     

协助监视任务控制中心软件状态的一种专家系统的开发

这种专家系统的功能是协助监视航天指控中心(MCC)的软件状态。目前,这项工作是由打印机操作手完成的,他密切注视联机打印机,打印机会打印出各种状态和差错信息,他把某些信息报告给指控中心的各位操作手,首先是计算机管理人员。这种专家系统能分辨哪些状态信息很重要、它们意味着什么,它们对准更重要,并能报告相应的状态信息。     

惯性顶级固体发动机的研制现状

惯性顶级(IUS)全尺寸发动机研制计划包括三级发动机的设计、研制和飞行鉴定。这些发动机按不同方法组合起来,可以用来满足给定的有效载荷的能量要求。推进系统的设计已经完成,当前的主要精力集中在完成鉴定阶段前的研制阶段试验上。到目前为止,所有的静止试车都是成功的。本文首先介绍一下惯性顶级飞行器,接着描述每级固体发动机的设计特点,最后总结了迄今为止所作的发动机各部件和整机的试验结果。在必要的地方,文中深入地分析了每项试验中哪些方面是重要的,为什么重要,以及怎样满足了惯性顶级的这些要求。     

Ethological analysis of a polar team in the French Antarctic station Dumont d'Urville as simulation of space teams for future interplanetary missions

This new ethological study focuses on the co-adaptation of the crew's spatial behavior to social isolation in a polar base thus simulating long-term living and working of a space team. The method consisted in drawing the subjects' position (n=13) on an observation map at the midday and evening meals at the Dumont d'Urville French station in Antarctica, daily during the summer campaigns and weekly during the winter-over of the TA46 mission. Quantitative data are presented in geocentric (positions), allocentric (distances) and egocentric (orientations) analyses with an emphasis on three adaptative periods (first 3 months, intermediary 2 months and last 3 months of isolation). Results show a large space occupancy during the first week after arrival and the last week before departure from the polar base, and a team-members' grouping during the winter-over. On the over-all time, the inter-individual distances increase. The social orientations are higher at the beginning than at the end of the mission. Discussion underlies the pertinent use of such ethological indicators collected from polar stations as predictors of well-being and optimal-working of the future orbital and planetary stations users.     

A culture-independent survey of the bacterial community in a radon hot spring

Paralana is an active, radon-containing hot spring situated in a region of South Australia's Flinders Ranges with a long history of hydrothermal activity. Our aim was to determine the bacterial composition of Paralana using a culture-independent, 16S rRNA-based technique. The presence of a diverse bacterial community was strongly suggested by the large number (approximately 180) of different ribotypes obtained upon analysis of nine hot spring samples. DNA sequencing of Paralana 16S rRNA genes corroborated this observation, identifying representatives of seven confirmed and two candidate divisions of the domain Bacteria. These included Cyanobacteria, Proteobacteria (both beta and delta subdivisions), the Cytophaga-Flexibacter-Bacteroides group, Low G + C Gram-positives, Nitrospira, green non-sulfur bacteria, green sulfur bacteria, OP8, and OP12. No known ionizing radiation-resistant Bacteria were identified. Only one Paralana 16S rRNA sequence type (recombinant B5D) was homologous to a sequence previously identified from a radioactive environment.     

固体推进剂裂缝弹道结构分析

本文采用一种计算机程序来预测燃烧时固体推进剂药柱裂缝内的弹道压力相互作用效应及压力引起的裂缝增长问题。本分析系统成功地将断裂力学有限元程序与弹道和裂缝燃烧计算程序结合起来,通过计算机程序,求出燃烧过程中每一时刻的变形和燃烧分布图。本法考虑了药柱表面和裂缝内侧面由燃烧引起的压力载荷,相应地提出了推进剂药柱因燃烧引起的断裂问题。本程序的设计区别了裂缝的燃完和裂缝的失控扩展。本程序业已改进,可用来处理由于点火器的变化和火焰传播效应引起的点火瞬变现象。     

Challenges of assuring crew safety in space shuttle missions with international cargoes

The top priority in America's manned space flight program is the assurance of crew and vehicle safety. This priority gained greater focus during and after the Space Shuttle return-to-flight mission (STS-26). One of the interesting challenges has been to assure crew safety and adequate protection of the Space Shuttle, as a national resource, from increasingly diverse cargoes and operations. The control of hazards associated with the deployment of complex payloads and cargoes has involved many international participants. These challenges are examined in some detail along with examples of how crew safety has evolved in the manned space program and how the international partners have addressed various scenarios involving control and mitigation of potential hazards to crew and vehicle safety.