机载火控雷达在中远距空战中的抗干扰方法

根据机载火控雷达的性能特点,针对中远距空战面临的电子干扰环境,首先分析和探讨了机载火控雷达的抗干扰技术措施,给出了抗噪声干扰、距离欺骗干扰、速度欺骗干扰、角度欺骗干扰和消极干扰的一些具体方法。然后,从战术使用的角度探讨了机载火控雷达的抗干扰方法,提出了机载火控雷达与欺骗干扰协同、编队协同以及电子防护的战术抗干扰措施。     

Possible physical properties of the flow in the vicinity of the heliopause

An interface between the fully ionized hydrogen plasma of the solar wind (SW) and the partially ionized hydrogen gas flow of the local interstellar medium (LISM) is formed as a region where there is a strong interaction between these two flows. The interface is bounded by the solar wind termination shock (TS) and the LISM bow shock (BS) and is separated on two regions by the heliopause (HP) separating the solar wind and charged component of the LISM (plasma component below). The BS is formed due to the deceleration of the supersonic LISM flow relative to the solar system. Regions of the interface between the TS and HP and between the HP and BS were in literature named as the inner and outer heliosheaths, respectively. An investigation of the structure and physical properties of the heliosheath is at present especially interested due to the fact that Voyager-1 and Voyager-2 have crossed the TS in December 2004 (Burlaga, L.F., Ness, N.F., Acuna, M.Y., et al. Crossing the termination shock into the the heliosheath. Magnetic fields. Science 309, 2027–2029, 2005; Fisk, L.A. Journey into the unknown beyond. Science 309, 2016–2017, 2005; Decker, R.B., Krimigis, S.M., Roelof, E.C., et al. Voyager 1 in the foreshock, termination shock and heliosheath. Science 309, 2020–2024, 2005; Stone, E.C., Cummings, A.C., McDonald, F.B., et al. Voyager 1 explores the termination shock region and the heliosheath beyond. Science 309, 2017–2020, 2005) and in September 2007 (Jokipii, J.R. A shock for Voyager 2. Nature 454, 38–39, 2008; Gurnett, D.A., Kurth, W.S. Intense plasma waves at and near the solar wind termination shock. Nature 454, 78–80, 2008. doi: 10.1038/nature07023; Wang, L., Lin, R.P., Larson, D.E., Luhmann, J.G. Domination of heliosheath pressure by shock-accelerated pickup ions from observations of neutral atoms. Nature 454, 81–83, 2008. doi: 10.1038/nature07068.14; Burlaga, L.F., Ness, N.F., Acuna, M.H., et al. Magnetic fields at the solar wind termination shock. Nature 454, 75–77, 2008. doi: 10.1038/nature07029; Richardson, J.D., Kasper, J.C., Wang, C., et al. Cool heliosheath plasma and deceleration of the upstream solar wind at the termination shock. Nature 454, 63–66, 2008. doi: 10.1038/nature07024; Stone, E.C., Cummings, A.C., McDonald, F.B., et al. An asymmetric solar wind termination shock. Nature 454, 71–74, 2008. doi: 10.1038/nature07022; Decker, R.B., Krimigis, S.M., Roelof, E.C., et al. Mediation of the solar wind termination shock by non-thermal ions. Nature 454, 67–70, 2008. doi: 10.1038/nature 07030), respectively, and entered to the inner heliosheath.     

高真空低重力环境下液态工质排放地面模拟试验研究

针对航天器在空间高真空低重力环境下的流体回路液态工质排放有关问题,以月球环境为例,搭建了月球重力等效地面试验系统,开展地面真空排放试验,获取了工质排放过程中的管路压力和温度变化规律,分析了影响工质排放速率的因素。试验结果表明：工质排放过程中管路的温度基本不变,回路初始压力、工质沿程温度以及排放口温度对于排放速率的影响较小。     

太阳质子事件中短期预报模型研究

太阳质子事件通量的预测对航天器抗辐射加固设计和航天员出舱活动具有非常重要的意义.针对一年以下的航天任务,利用经验统计方法,确认太阳活跃年和太阳平静年期间,1——365天不同时间段内 > 10MeV,> 30MeV和 > 60MeV的太阳质子事件积分通量符合对数正态分布,且通量对数的标准偏差σ和期望值μ随任务期时间的变化满足对数函数形式.以此为基础,构建太阳质子通量的中短期预报模型.该模型能够针对太阳活跃年和太阳平静年,给出一定置信度下1——365天不同时间内 > 10MeV,> 30MeV和 > 60MeV的质子事件通量分布,从而为执行中短期航天任务提供太阳质子事件通量的预测,以规避不必要的风险.     

Ⅱ类甲醇脉泽的红外抽运研究

本文研究了Ⅱ类甲醇脉泽与周围红外源的关系,发现它们有很强的相关性。分析认为红外源很可能是Ⅱ类甲醇脉泽的抽运源。     

配置点谱方法求解非均匀介质内辐射传热问题

发动机内的燃气等高温介质随着组分和浓度的变化，会引起折射率在空间上的非均匀分布，从而导致辐射能束沿着曲线传播，其相应的辐射传热过程也更为复杂。为了避免射线追踪方法的复杂计算、提高计算效率，本文提出了配置点谱方法求解二维非均匀介质内辐射传热问题。在求解过程中，角向采用离散坐标法处理，空间采用配置点谱方法处理。通过将三种非均匀介质内辐射传热问题的配置点谱方法结果与文献结果进行对比分析，发现配置点谱方法可以在较少的节点数下，获得准确、有效地计算结果。并且，采用配置点谱方法求解三种算例的计算时间均消耗较少，均在20分钟以内。这将为进一步开展发动机复杂结构内高温燃气辐射快速仿真提供基础。     

Interplanetary scintillation observations of the high-latitude solar wind

Until the ULYSSES spacecraft reached the polar regions of the solar wind, the only high-latitude measurements available were from indirect techniques. The most productive observations in regions of the solar wind between 5R and 200R have been the family of radio scattering techniques loosely referred to as Interplanetary Scintillation (IPS) (Coles, 1978). Useful observations can be obtained using a variety of radio sources, for example spacecraft beacons, planetary radar echoes and compact cosmic sources (quasars, active galactic nuclei, pulsars, galactic masers, etc.). However for measurement of the high-latitude solar wind cosmic sources provide the widest coverage and this review will be confined to such observations. IPS observations played a very important role in establishing that polar coronal holes (first observed in soft x-ray emission) were sources of fast solar wind streams which occasionally extend down to the equatorial region and are observed by spacecraft. Here I will review the IPS technique and show the variation of both the velocity and the turbulence level with latitude over the last solar cycle. I will also outline recent work and discuss comparisons that we hope to make between IPS and ULYSSES observations.     

行星际空间环境对探测器可靠性影响分析

空间环境是影响航天器可靠性的重要因素。与地球轨道航天器相比,行星际探测任务可能会遭受更加恶劣的空间环境,例如极端温度环境,辐射环境,腐蚀性大气环境、宇宙尘等,再加上行星际任务寿命长,采用先进的器件和材料,空间环境对行星际探测器的可靠性构成严重的威胁,直接关系到探测目标能否实现。因此考虑空间环境对行星际探测器的影响,开展相关的预先研究无论是对于制定行星际空间探测计划,还是搭载仪器的设计都具有非常重要的意义。文章分析了极端温度、辐射环境和行星表面综合环境对探测器的影响,并对开展相关研究提出了建议。     

On the correlation of the solar wind observed at the L5 point and at the Earth

The L5 point is a promising location for forecasting co-rotating high-speed streams in the solar wind arriving at the Earth. We correlated the solar wind data obtained by the Nozomi spacecraft in interplanetary space and by the Advanced Composition Explorer (ACE) at the L1 point, and found that the correlation is significantly improved from that of the 27-day recurrence of ACE data. Based on the correlation between the two spacecraft observations, we estimated the correlation of the solar wind velocity between the L5 point and at the Earth, and found that the correlation coefficient was about 0.78 in late 1999, while that of the 27-day recurrence was 0.51. Eighty-eight percent of the velocity difference falls within 100 km/s between the L5 point and the Earth. This demonstrates the potential capability of solar wind monitoring at the L5 point to forecast the geomagnetic disturbances 4.5 days in advance.     

How Galactic Cosmic Ray models affect the estimation of radiation exposure in space

The radiation environment in space is a major concern for human spaceflight because of the adverse effects of high levels of radiation on astronauts’ health. Therefore, it is essential to perform radiation risk assessments already during the concept studies of a manned mission. Galactic Cosmic Rays (GCR) have been identified to be one of the primary sources of radiation exposure in space.