Lunar exploration and development--a sustainable model

A long-term goal of space exploration is the development of a lunar settlement that will not only be largely self-sufficient but also contribute to the economy of the Earth-Moon system. Proposals for lunar mining and materials processing developments, as well as tourism-based applications, have appeared in the literature for many years. However, so great are the technical and financial difficulties associated with sustained lunar development that, more than 30 years after the end of the Apollo programme, there have been no practical advances towards this goal. While this may soon be remedied by a series of proposed unmanned orbiters, landers and rovers, the philosophy of lunar exploration and development remains the same as it has for decades: conquer, exploit, and ignore the consequences. By contrasting the well-recognised problems of Earth orbital debris and the barely recognised issue of intentional spacecraft impacts on the lunar surface, this paper illustrates the need for a new model for lunar exploration and development. This new paradigm would assign a value to the lunar environment and provide a balance between protection and exploitation, creating, in effect, a philosophy of sustainable development for the Moon. It is suggested that this new philosophy should be an integral part of any future strategy for lunar colonisation.     

Magnetism, iron minerals, and life on Mars

A short critical review is provided on two questions linking magnetism and possible early life on Mars: (1) Did Mars have an Earth-like internal magnetic field, and, if so, during which period and was it a requisite for life? (2) Is there a connection between iron minerals in the martian regolith and life? We also discuss the possible astrobiological implications of magnetic measurements at the surface of Mars using two proposed instruments. A magnetic remanence device based on magnetic field measurements can be used to identify Noachian age rocks and lightning impacts. A contact magnetic susceptibility probe can be used to investigate weathering rinds on martian rocks and identify meteorites among the small regolith rocks. Both materials are considered possible specific niches for microorganisms and, thus, potential astrobiological targets. Experimental results on analogues are presented to support the suitability of such in situ measurements.     

机载雷达的多个分辨率信号处理技术

合成孔径雷达（SAR）利用通过时间积累和自身的运动所获得的很高空间分辨率，可以降低某一给定分辨单元中的背景杂波功率，从而探测出非运动目标。而地面动目标显示（GMTI）雷达为了探测则采用低得多的分辨处理，利用的是实际孔径与动目标和杂波之间的空．时响应的相对差别。因此，SAR和GMTI代表了两种不同的时间处理分辨尺度，它们对探测固定（在SAR情况下）或者外围杂波中的（在GMTI情况下）目标来说是最佳的，并已经单独验证过，能够很好地工作。基于机载雷达数据处理的这种多个分辨率说明，就有可能研究出一种探测技术，该技术将着手优化信号处理分辨尺度（比如时间积累的长度）来与所关注目标的动态情况相匹配。本文研究怎样利用长相参处理时间间隔（CPI）的信号处理技术来改善GMTI雷达的探测性能。     

细长旋成体单孔微吹气扰动控制的数值研究

利用三维可压缩Navier-Stokes方程,对亚临界流动范围内不同Re数下,细长旋成体大迎角下单孔位微吹气扰动控制进行了数值计算,通过对不同截面压力分布和侧向力系数的对比,发现单孔微吹气扰动对细长旋成体侧向力有明显的控制能力,并且这个控制能力要受雷诺数的影响。     

Role of the ionosphere for the atmospheric evolution of planets

We have synthesized current understanding, mainly observations, with regard to ion escape mechanisms to space from the ionosphere and exosphere of Titan and Earth-type planets, with the intent to provide an improved input for models of atmospheric evolution on early Earth and Earth-type planets and exoplanets. We focus on the role of the ionosphere and its non-linear response to solar parameters, all of which have been underestimated in current models of ancient atmospheric escape (4 billion years ago). Factors that have been overlooked include the following: (1) Much larger variation of O(+) outflow than H(+) outflow from the terrestrial ionosphere, depending on solar and geomagnetic activities (an important consideration when attempting to determine the oxidized state of the atmosphere of early Earth); (2) magnetization of the ionopause, which keeps ionospheric ions from escaping and controls many other escape processes; (3) extra ionization by, for example, the critical ionization velocity mechanism, which expands the ionosphere to greater altitudes than current models predict; and (4) the large escape of cold ions from the dense, expanded ionosphere of Titan. Here we offer, as a guideline for quantitative simulations, a qualitative diagnosis of increases or decreases of non-thermal escape related to the ionosphere for magnetized and unmagnetized planets in response to changes in solar parameters (i.e., solar EUV/FUV flux, solar wind dynamic pressure, and interplanetary magnetic field).     

高分辨力机载毫米波FM-CW SAR的研发

紧凑的FM—CW（调频-连续波）雷达技术和高分辨力SAR（合成孔径雷达）处理技术的结合将为体积小、重量轻且性价比高的成像雷达的发展铺平道路。然而，在空中观察地球表面这一领域中，将SAR用于FM—CW雷达是比较新颖的。通信传输和雷达国际研究中心（IRCTR）启动了一项关于FM—CW SAR的可行性研究。在该研究项目框架中，开发并测试了一种完全运转的机载FM—CW SAR验证系统。文中综述了地面测试的情况。此外，2004年6月在柏林附近的Strausberg机场进行了一次非常成功的空中试验。本文将介绍这些机载试验的初步结果。     

Space radiation enhancement linked to geomagnetic disturbances

Space radiation dosimetry measurements have been made on board the Space Shuttle. A newly developed active detector called "Real-time Radiation Monitoring Device (RRMD)" was used (Doke et al., 1995; Hayashi et al., 1995). The RRMD results indicate that low Linear Energy Transfer (LET) particles steadily penetrate around the South Atlantic Anomaly (SAA) without clear enhancement of dose equivalent and some daily periodic enhancements of dose equivalent due to high LET particles are seen at the lower geomagnetic cutoff regions (Doke et al., 1996). We also have been analyzing the space weather during the experiment, and found that the anomalous high-energy particle enhancement was linked to geomagnetic disturbance due to the high speed solar wind from a coronal hole. Additional analysis and other experiments are necessary for clarification of these phenomena. If a penetration of high-energy particles into the low altitude occurs by common geomagnetic disturbances, the prediction of geomagnetic activity becomes more important in the next Space Station's era.     

军事星中的铷和石英频率标准的性能数据——在模拟太空环境中地检和实际轨道中所得数据的比较

航天计划中将增加原子频标的使用,以获得精确的时间和稳定的频率。GPS系统所具有的卓越的导航功能主要是由系统中采用的原子频标带来的。新一代的军事通信卫星(Milstar)载有多路复合铷原子频标以满足各种通讯和操作上的需要。第一颗军用通讯卫星,DFS-1使用了复合多路石英晶体振荡器,第二颗军用通讯卫星,1995年发射的DFS-2,是第一颗使用铷原子频标的军用通讯卫星。这以后发射的卫星都使用了铷原子频标。     

Role of nutrition during long-term spaceflight

The authors discuss changes in macro- and micro-nutrients which occur in weightlessness and consider factors which help maintain appropriate nutrition during extended space flight. Basic energy requirements and metabolism are reviewed. The discussion of handling of foodstuffs includes protein, fats, carbohydrates, vitamins, folic acid, iron, and selenium. The discussion of fluids and minerals includes fluid intake, sodium, potassium, and calcium. Changes in gastrointestinal function are examined.