低温推进剂空间管理技术研究进展与展望

本文介绍了低温推进剂的性能优势与空间管理挑战,梳理了低温流体空间管理(CFM)技术特征及其研究现状,建议按照重力依赖型与重力无关型分类开展技术成熟度提升研究。调研了美国逾半个世纪的CFM技术搭载实验研究历程,分析了各类平台的工作特性与性能优势。基于我国航天发展现状与未来需求,探析了我国开展CFM技术攻关、飞行搭载实验的可行方案。建议在我国载人空间站规划舱内低温技术实验柜与舱外暴露平台实验模块,加速我国CFM技术向工程应用的转化。     

Can identification of a fourth domain of life be made from sequence data alone, and could it be done on Mars?

A central question in astrobiology is whether life exists elsewhere in the universe. If so, is it related to Earth life? Technologies exist that enable identification of DNA- or RNA-based microbial life directly from environmental samples here on Earth. Such technologies could, in principle, be applied to the search for life elsewhere; indeed, efforts are underway to initiate such a search. However, surveying for nucleic acid-based life on other planets, if attempted, must be carried out with caution, owing to the risk of contamination by Earth-based life. Here we argue that the null hypothesis must be that any DNA discovered and sequenced from samples taken elsewhere in the universe are Earth-based contaminants. Experience from studies of low-biomass ancient DNA demonstrates that some results, by their very nature, will not enable complete rejection of the null hypothesis. In terms of eliminating contamination as an explanation of the data, there may be value in identification of sequences that lie outside the known diversity of the three domains of life. We therefore have examined whether a fourth domain could be readily identified from environmental DNA sequence data alone. We concluded that, even on Earth, this would be far from trivial, and we illustrate this point by way of examples drawn from the literature. Overall, our conclusions do not bode well for planned PCR-based surveys for life on Mars, and we argue that other independent biosignatures will be essential in corroborating any claims for the presence of life based on nucleic acid sequences.     

The benefits and harm of transmitting into space

Deliberate and unintentional radio transmissions from Earth propagate into space. These transmissions could be detected by extraterrestrial watchers over interstellar distances. This article analyzes the harm and benefits of deliberate and unintentional transmissions relevant to Earth and humanity. Comparing the magnitude of deliberate radio broadcasts intended for messaging to extraterrestrial intelligence (METI) with the background radio spectrum of Earth, we find that METI attempts to date have much lower detectability than emissions from current radio communication technologies on Earth. METI broadcasts are usually transient and several orders of magnitude less powerful than other terrestrial sources, such as astronomical and military radars, which provide the strongest detectable signals. The benefits of radio communication on Earth most probably outweigh the potential harm of detection by extraterrestrial watchers; however, the uncertainty regarding the outcome of contact with extraterrestrial beings creates difficulty in assessing whether or not to engage in long-term and large-scale METI.     

NASA's integrated space transportation plan

Improvements in the safety, reliability and affordability of current and future space transportation systems must be achieved if NASA is to perform its mission and if the U.S. space industry is to reach its full potential. In response to Presidential Policy in 1994, NASA, working with our industrial partners, initiated several efforts including the X-33, X-34, X-37 and Advanced Space Transportation programs with the goal of demonstrating the technologies that could enable these goals. We have learned that emerging technologies will enable the needed advancements but that more development along multiple, competing paths is needed. We have learned that developing requirements diligently and in partnership with industry will allow us to better converge with commercial capabilities. We have learned that commercial markets are not growing as fast as projected earlier, but there are still possibilities in the near-term to pursue alternate paths that can make access to space more robust. The goal of transitioning NASA's space transportation needs to commercial launch vehicles remains the key aim of our efforts and will require additional investment to reduce business and technical risks to acceptable levels.     

Organizing space cooperation in the Asia-Pacific region

The time for regional cooperation in the Asia-Pacific region is now ripe. Steps have been taken towards this via a workshop sponsored by China - previously wary of cooperation but now seeming to acknowledge that, along with interested countries, it could contribute more to space in the region. The author examines areas of shared interest over which parties might collaborate and the best way to achieve this: a gradual approach emulating the development (but not the present configuration) of ESA is recommended. Finally, he examines the legal framework within which cooperation might function, using a liaison committee to formulate and coordiante proposals. Action must be taken now if the region is not to fall behind in the development of space technologies.     

Technology control regimes and the globalization of space industry

This paper provides theoretical underpinnings for further discussions on the future direction of the international aerospace community in an era of globalization. It points out that changes in the international distribution of resources are placing strains on the basic operating principles of the current technology control regime, but at this stage the social groupings do not appear to be in place to overturn the current paradigm. Instead, this paper suggests that current operating principles could be modified in order for the current regime to keep pace with globalization. These changes would include: (1) a shift in the monitoring mechanism of the Missile Technology Control Regime (MTCR) requiring looser supervision but greater transparency; (2) greater inclusion of private industry as a stakeholder in MTCR proceedings; and (3) much more focus on the list of prescribed technologies to include only those which are most critical to the development of military missiles.     

着陆缓冲技术综述

着陆缓冲技术是空间飞行器返回技术的重要组成部分。利用着陆缓冲装置可以明显降低降落伞的面积、减小回收系统的重量,同时大幅度降低飞行器着陆时的冲击载荷。近些年来,着陆缓冲技术有了些新的发展。文中对已有的着陆缓冲装置进行了分类,对每种类型的技术性能、使用范围作了评述。     

The commercialization of satellite imagery: Implications for cross-border conflict

The proliferation of commercial observation satellites offers opportunities to enhance regional stability as well as destabilizing possibilities for cross-border conflicts in the developing world. It is virtually impossible to anticipate whether observation satellites will be exploited for peaceful or destabilizing purposes, but there are clear benefits in maintaining symmetry in such capabilities. An International Satellite Monitoring Agency could be the best way to promote the positive aspects of satellite technology while minimizing the negative.     

动力学环境试验技术在航天器结构故障诊断中的应用

文章概括介绍了故障诊断领域的应用发展情况,并以某航天器结构故障诊断为例,详细介绍了运用多种动力学环境试验技术对故障原因进行诊断的过程。说明有效地运用动力学环境试验技术,不但可以暴露结构设计缺陷,还可对航天器的结构故障状态进行诊断分析,准确查找出故障产生原因,为设计人员改进设计、排除故障提供有力的依据。     

The space elevator in the context of current space exploration policy

The space elevator is an advanced space transportation system that someday could replace chemical rockets as humanity's primary means of reaching Earth's orbit. However, before this can occur, a number of enabling technologies will need to be developed, and a variety of economic and policy questions must be addressed. The goal of this paper is to examine the feasibility of the space elevator in the context of current space exploration policy. The paper reviews the space elevator's critical enabling technologies and presents their wide variety of applications. The challenges of funding the space elevator and of building support for the program are discussed. The potential for international cooperation is considered, and the role of the space elevator in the Vision for Space Exploration is examined. The paper argues that each of the space elevator's component technologies ought to be developed independently to meet separate nearer-term objectives. The space elevator should be just one of many applications considered in making decisions to pursue research and development related to each component technology. The enabling technologies, once mature, might eventually be integrated in the construction of a full-scale space elevator from the Earth's surface to geosynchronous orbit and beyond.     

Lunar precursor missions for human exploration of Mars--III: studies of system reliability and maintenance

Discussions of future human expeditions into the solar system generally focus on whether the next explorers ought to go to the Moon or to Mars. The only mission scenario developed in any detail within NASA is an expedition to Mars with a 500-day stay at the surface. The technological capabilities and the operational experience base required for such a mission do not now exist nor has any self-consistent program plan been proposed to acquire them. In particular, the lack of an Abort-to-Earth capability implies that critical mission systems must perform reliably for 3 years or must be maintainable and repairable by the crew. As has been previously argued, a well-planned program of human exploration of the Moon would provide a context within which to develop the appropriate technologies because a lunar expedition incorporates many of the operational elements of a Mars expedition. Initial lunar expeditions can be carried out at scales consistent with the current experience base but can be expanded in any or all operational phases to produce an experience base necessary to successfully and safely conduct human exploration of Mars.     

待发段火箭倾倒实时监测技术研究与实现

倾倒故障作为火箭待发段的一种故障形式，严重地威胁着航天员的安全。待发段倾倒应急救生的关键在于及时获取准确可靠的箭体姿态与倾倒信息，为指挥员实时提供可靠的逃逸判决依据。本文从应用角度，综合光学与计算机图像处理技术，提出了一种简单而实用的火箭倾倒监测技术，并简要介绍了应用此技术实现的系统主要功能结构与性能特点。本文介绍的技术也可应用于其他需要定位与姿态监视测量的领域。     

包覆药柱界面粘结质量的无损检测

利用错位电子散斑干涉技术，对包覆药柱界面粘结质量无损检测方法进行了研究，分析了影响检测结果的间距、图像判读、加载量、灵敏度和内应力等关键因素。试验结果表明，此方法可以检测最小直径3.6mm的人工脱粘区。     

IETM制作平台设计与应用

提出了一种用于大型装备的交互式电子技术手册(IETM)制作平台模型。介绍了平台的物理架构、功能架构和信息交换流程,给出了半结构化数据编辑、三维仿真和图形化故障隔离等关键技术。应用结果表明:基于新模型的IETM制作平台能快速实现电子手册制作,且展示效果和交互能力较强。     

The export of space technology : Prospects and dangers

The export market for space technology, goods and services is still in its infancy, but trends indicate definite economic growth in prospect. Private companies are increasingly keen to find a foothold or increase their share in the ever widening market. National goverments are undertaking a variety of measures to help and encourage them in the export of space technology. Competition for the older US producers is sharpening from foreign firms. Political conflict is arising based on this competition and on the potential dual use of some space technologies for civilian and military purposes. The main Western industrialized countries have recently agreed on common Guidelines to control the export of launcher technology that could be used for delivering nuclear weapons. The ‘Guidelines for Sensitive Missile-Relevant Transfer’ will affect the export of much space technology and equipment.     

橡塑复合半膜成型工艺

氟塑料具有良好的耐介质性能,橡胶材料具有良好的密封性能,将二者结合在一起生产成复合半膜可以达到长期贮存推进剂的目的。通过重复性的工艺试验和系统分析,确定了一套完整的橡塑复合半膜生产成型工艺,提高橡塑半膜之间的粘接强度,消除夹层中的气泡,保证橡塑复合半膜满足要求。     

太赫兹遥感技术综述

文章论述了太赫兹（THz）波基本概念,国际上近来研究情况,主要应用方向,未来发展建议和关键技术等。太赫兹（THz）波技术目前是一个正在蓬勃发展的技术,由于其波长与机理介于光学与微波之间,因而可以获取光学和微波所不可探测的信息。     

GPS系统抗干扰性能及抗干扰技术分析

分析了GPS系统具有的抗干扰能力(包括抗宽带阻塞、窄带和单频噪声).针对GPS系统本身的弱点,详细分析了一些可以采用的抗干扰技术,如窄带干扰的删除方法、单频干扰的时域抵消和频域干扰抑制等,为研究GPS抗干扰技术提供了一定的参考.     

LOX/LCH_4变推力发动机技术初步研究

对国内外变推力发动机和LOX/LCH4发动机的研究进展进行了总结,在此基础上,提出了一种LOX/LCH4变推力发动机系统方案。在深入分析的基础上,对此方案进行了功率平衡和推力室传热计算,结果表明该系统方案完全能够实现10:1推力变比。LOX/LCH4变推力发动机可以广泛应用于多种运载器和航天器中,对我国探月及后续的载人登月工程均可以提供技术支持,对LOX/LCH4发动机的技术发展和未来的载人登陆火星等任务都具有深远影响。     

Whose jurisdiction over the US commercial satellite industry? Factors affecting international security and competition

Within a global economy, export controls play a large role in hindering the proliferation of high technology. A company operating in a country that operates under more strict export controls than others is at a serious disadvantage in competing. This has been the case for commercial satellite (comsat) manufacturers in the USA since 1999, when Congress redefined comsats and all technologies associated with them from a dual-use export under the jurisdiction of the Department of Commerce to a munitions export that falls under the jurisdiction of the Department of State. Following this, there was a drastic drop in the market share of US comsat manufacturers in comparison to European manufacturers, who continued to define satellites as a dual-use technology. This paper examines the various factors that have affected US industry competitiveness and tackles the question of whether or not it continues to make sense to keep comsats under the more restrictive International Traffic in Arms Regulations (ITAR) controls. To accomplish this, comsats are subjected to a litmus test created by George Zaphiriou in 1992 to determine whether a technology should be placed under ITAR controls.