火星空间磁场结构特征

在火星空间模拟的单流体MHD模型的基础上, 研究了火星空间磁场结构及火星表面局部磁异常对磁场结构的影响. 在太阳风与火星相互作用的过程中, 形成弓激波和磁堆积区, 行星际磁场弯曲并向两极移动且被拖拽变形, 大部分磁力线从火星两极绕过, 通过火星之后在磁尾留下V字形结构. 火星表面附近局部磁异常也对火星磁场结构产生不可忽视的影响. 不同位置和强度的磁异常与太阳风相互作用形成结构及形态各异的微磁层, 如被拖拽的微磁层和存在开磁力线的微磁层等. 局部磁异常改变了近火磁场结构, 并可能改变等离子体的分布.      

镜模波识别方法研究及其在火星磁鞘中的应用

镜模波是温度各向异性等离子体中的一种波动结构,根据磁场和离子分布及波动特性可以进行识别.本文对比了只使用磁场数据与同时使用磁场及离子数据两种识别方法,分析了两类方法的特点.只使用磁场数据的方法基于磁场强度变化大、方向沿背景磁场的特征,通常使用磁场强度的波动幅度ΔB/|B|以及磁场变化方向与背景磁场的夹角θ_min,θ_max作为参数;同时使用磁场及粒子数据的方法利用的是磁场纵波特性、总压平衡和波动在等离子体坐标系下静止的特征.使用两种方法对MAVEN卫星在火星磁鞘内的数据进行识别,结果表明在某些情况下,只使用磁场数据会导致对镜模波的误判.通过研究改变上述参数阈值时识别结果的变化,发现当θ_min> 40°,θ_max < 40°,ΔB/|B|> 80%时,只用磁场数据可取得较好的识别效果.      

火星空间环境磁场探测研究——高精度磁强计

萤火一号卫星将对火星空间环境磁场实施探测。火星磁场对火星弓激波、磁鞘、电离层、大气等绝大多数空间环境效应都具有重要影响,萤火一号对火星磁场的探测是通过搭载于其上的科学载荷磁强计来实现的。此磁强计在工作原理及具体设计上,考虑了火星轨道严酷的工作环境和科学目标所需的测量要求。通过装星前的地面标定测试,验证了萤火一号磁强计可以在-130～75℃温度范围内测量±256nT以内的磁场,分辨率可达到0.01 nT,带宽内总噪声小于0.03 nT,能够满足萤火一号对火星空间环境探测的需求。     

火星空间环境磁场探测研究

萤火一号卫星将对火星空间环境磁场实施探测. 火星磁场对火星弓激波、磁鞘、电离层、大气等绝大多数空间环境效应都具有重要影响, 萤火一号对火星磁场的探测是通过搭载于其上的科学载荷磁强计来实现的. 此磁强计在工作原理及具体设计上, 考虑了火星轨道严酷的工作环境和科学目标所需的测量要求. 通过装星前的地面标定测试, 验证了萤火一号磁强计可以在-130~75°C温度范围内测量±256 nT以内的磁场, 分辨率可达到0.01 nT, 带宽内总噪声小于0.03 nT, 能够满足萤火一号对火星空间环境探测的需求.      

火星车磁通门磁强计技术

火星磁场测量是国际火星探测任务的焦点之一,中国首次火星磁测任务通过在巡视器(即火星车)和环绕器上同时搭载磁强计,实现对火星磁场的火–空联合观测。巡视器磁强计载荷选用双探头三轴磁通门磁强计,采用亥姆霍兹补偿线圈型探头技术和全数字闭环反馈电路技术,实现空间磁场的高精度同点测量。单机在设计上考虑了可靠性安全性设计和空间环境适应性设计。经地面标定,单机量程可达到±6.5万nT,噪声水平优于0.01 nT/√Hz,分辨率达到了0.01 nT。     

火星等离子体环境探测

萤火一号(YH-1)探测器将对火星空间环境进行独立而深入的探测研究,探测各空间区域的等离子体特性及其对太阳风扰动的响应,以及火星离子逃逸过程,研究太阳风对火星水体损失的影响。为了实现这一目标,萤火一号搭载了等离子体探测包,包括2个离子分析器和1个电子分析器,具有较高的时间分辨率、能量分辨率,可以探测0.02～10 keV的离子、电子,同时能够对粒子的入射方向及1～44 au(1 au=9.1095×10~(-31)kg)质量范围内的离子成分进行分辨。本文阐述了萤火一号等离子体探测的科学意义,并对等离子体包的工作原理,仪器设计进行了介绍。     

火星磁层顶形成和变化的理论研究

考虑太阳风动压与行星电离层中的带电粒子热压及磁压之和平衡,建立了有大气（电离层）的行星磁层顶形成的理论模型,结合卫星对火星的观测数据,对子午面内向日侧火星磁层顶位形进行了数值计算和分析,研究了火星磁层顶位形及其与太阳风动压之间的变化关系．结果认为,火星磁层顶位形与地球磁层顶相似．太阳风动压越大,火星磁层顶越靠近火星;太阳风动压越弱,火星磁层顶越远离火星．根据火星内秉磁矩从古到今逐渐减小的观点,探索了大尺度磁场（内禀磁矩）对火星磁层顶的贡献作用,结果认为大尺度磁场越强,火星磁层顶越远离行星．这对于进一步研究火星磁层的长期演化以及其他行星磁层的位形变化都具有重要的意义．     

近月空间带电粒子环境——“嫦娥1号”“嫦娥2号”观测结果

“嫦娥1号”（CE-1）、“嫦娥2号”（CE-2）都安装了1台太阳高能粒子探测器（High-energetic ParticlesDetectors,HPD）和2台太阳风离子探测器（Solar Wind Ion Detectors,SWIDs）,进行了月球轨道200 km和100 km空间环境探测,获得了月球轨道空间高能带电粒子（质子、电子和重离子）能谱随时间的演化特征、等离子体与月球相互作用特征以及太阳风离子速度、密度和温度参量。空间环境探测数据分析结果表明：太阳活动低年、空间环境扰动水平相对较低、月球处于太阳风中时,近月空间带电粒子环境的基本特征与行星际空间相比变化不大。CE-1、CE-2在轨运行期间,发现了多起0.1～2 MeV能量电子急剧增加事件,这些事件发生在月球从太阳风运动到磁尾的所有空间区域,其中20%的事件伴随着卫星周围等离子体离子加速。模拟和统计研究表明：能量电子急剧增加使得绕月卫星和月球表面电位大幅下降导致了离子加速现象的发生;能量电子总流量大于10¹¹ cm^-2时,绕月卫星和月球表面充电电位可达负的上千伏。此外,月表溅射与反射太阳风离子、太阳风“拾起”离子等空间环境事件的发现,揭示了太阳风离子和月球存在复杂的相互作用过程。     

美国载人火星飞行计划

美国载人火星飞行计划□□美国航宇局约翰逊空间中心最近提出了一个在２００７年（人类第１颗人造地球卫星发射５０周年）开始的载人火星飞行计划（具体见表１）。计划派一个６人乘员小组登上火星工作５００天，在此之前，需先在火星的适当位置建立一个可在两年内正常工作...     

国外火星探测的进展和现状

国外火星探测的进展和现状戴超（北京空间飞行器总体设计部）１前言□□在火星探测领域，航天科学家们已经付出了几十年努力，并取得了突破性、阶段性的进展，１９９７年７月４日，美国“火星探路者”探测器在火星成功登陆，人类对火星的探测进入了一个崭新的时期，为将来...     

火星磁场产生的原因及其分布

构建了一个可以得到火星赤道面上磁场分布的模型. 模型根据卫星观测数据, 提出了火星电离层、磁层顶和磁尾电流片上都各自通有电流的假设. 由电流的连续性条件可知, 这三种背景条件下的电流之间满足一定关系, 即火星磁层顶上的总电流是电离层上的总电流与磁尾电流片上的总电流之和. 这些电流产生的磁场与太阳风磁场共同构成了火星赤道面上磁场分布. 通过计算发现, 采用这种磁场模型得到的结果与目前卫星所观测的结果以及与采用其他方法得到的结果符合得较好.      

火星土壤物理力学特性分析

火星土壤既是火星表面探测活动的主要探测对象,也是表面探测器设计中需考虑的重要因素之一。火壤的物理力学特性将直接影响着陆器着陆缓冲系统、火星车移动系统等的设计。此外,在着陆器和火星车等表面探测器的地面研制过程中,需要研制模拟火壤,形成模拟的火星表面环境,开展相关的着陆器着陆缓冲性能、火星车移动性能等验证试验。迄今为止,人类已经有多个探测器登陆火星,获取了大量的有关火壤的信息,也研制了多种模拟火壤。通过对已有火壤和模拟火壤的物理力学特性分析,梳理出火壤物理力学特性的参数范围,可为我国火星探测器的研制提供参考。     

Martian obstacle and bow shock: origins of boundaries anisotropy

The origin of the anisotropy in the shape of the Martian obstacle and bow shock is analyzed using Mars Global Surveyor observations. The influence of MHD or ion pick-up effects on Martian obstacle position was to be small found, however, localized Martian crustal magnetization increases the thickness of the downstream planetary magnetotail by 500–1000 km in agreement with earlier Phobos 2 observations. A new analytical model is presented for Martian obstacle shape variation for different solar wind ram pressure. Elongation of the Martian BS cross-section in the direction perpendicular to IMF was confirmed while the shift of this cross section in the +Y direction of Martian interplanetary medium reference frame was discovered. The shift of BS cross section in the direction of interplanetary electric field was not revealed thus not conforming the idea that mass-loading play some role in BS control.     

基于MARSIS的火星低纬度电离层统计特性研究

在对欧空局火星快车探测器搭载的MARSIS雷达的浅表层探测数据进行校准过程中,获得了火星电离层的总电子含量(total electron content,TEC)观测数据。利用该数据,计算火星低纬度地区电离层的峰值电子密度和标高;并对其进行统计分析发现,在低纬度地区,火星冬季电离层的标高和峰值电子密度均较夏季高,即冬季电离层较夏季更显著,且春季电离层的电子密度梯度最大。     

Multifunctional Martian habitat composite material synthesized from in situ resources

The two primary requirements for a Martian habitat structure include effective radiation shielding against the Galactic Cosmic Ray (GCR) environment and sufficient structural and thermal integrity. To significantly reduce the cost associated with transportation of such materials and structures from earth, it is imperative that such building materials should be synthesized primarily from Martian in situ resources. This paper illustrates the feasibility of such an approach. Experimental results are discussed to demonstrate the synthesis of polyethylene (PE) from a simulated Martian atmosphere and the fabrication of a composite material using simulated Martian regolith with PE as the binding material. The radiation shielding effectiveness of the proposed composites is analyzed using results from radiation transport codes and exposure of the samples to high-energy beams that serve as a terrestrial proxy for the GCR environment. Mechanical and ballistic impact resistance properties of the proposed composite as a function of composition, processing parameters, and thermal variations are also discussed to evaluate the multifunctionality of such in situ synthesized composite materials.     

YingHuo-1——Martian Space Environment Exploration Orbiter

This paper gives a brief introduction of YingHuo-1 (YH-1), a Chinese Martian Space Environment Exploration Orbiter. YH-1 is a micro-satellite developed by Chinese Aerospace Industry,and will be launched together with Russian spacecraft, Phobos-Grunt, to orbit Mars in September,2009. Four payloads are selected for the mission, plasma package, including of electron analyzer, ion energy and mass analyzer; sat-sat occultation receiver; flux-gate magnetometer; and optical monitor.YH-1 mission focus on the investigation of the characteristics and its evolution of the Martian space Environment, and identifying major plasma processes, which provide channels for Martian volatiles escaping.     

Martian Buildings: Design loading

Multiplanetary life has been studied by scientists as a way to supply energy or sustain human life in the future. Mars is likely to be man’s first destination, colonization using onsite structural construction would be one of the main options. The first step to designing a reliable building is to know the applied structural loads and to have an accurate design load combination. Due to lack of complete knowledge, short span of recorded data, Martian environment, and hazardous environment that Martian structures face, constructed Martian structures should behave appropriately under the highest likely live, dead and environmental loads either simultaneously or as a worst-case scenario. The present study evaluated and calculated probable Martian structural loads, including live, internal pressure, snow, gravity (dead), dust accumulation, thermal stress, wind, marsquake, asteroid, and meteoroid impact loads and their effects. Information was gathered from previous studies and valid data from Martian landers, rovers and orbiters. Wind loads were calculated based on the over 6.5 years of data recorded by Vikings 1 and 2, temperature and winds for InSight (TWINS) sensor. A wind shear exponent and wind profile have been proposed for a Martian flat terrain construction site. Marsquake lateral loads, frequency content and seismicity were assessed using data from the seismic experiment for interior structure (SEIS) and the Viking 2 seismometer. Considering the high influx of micrometeoroids, their penetration distance, impact loads and their effects on structures were calculated. The annual probability of an asteroid impact on a settlement was assessed for a 30-year mission. A load map for Martian residential buildings that considers the worst-case scenario in which a Martian structure should be designed based on them has been proposed.     

Scientific Objectives and Payloads of Chinese First Mars Exploration

China plans to implement the first Mars exploration mission in 2020. It will conduct global and comprehensive exploration of Mars and high precision and fine resolution detection of key areas on Mars through orbiting, landing and roving. The scientific objectives include studying the Martian morphology and geological structure characteristics, studying the soil characteristics and the water-ice distribution on the Martian surface, studying the material composition on the Martian surface, studying the atmosphere ionosphere and surface climate and environmental characteristics of Mars, studying the physical field and internal structure of Mars and the Martian magnetic field characteristics. The mission equips 12 scientific payloads to achieve these scientific objectives. This paper mainly introduces the scientific objectives, exploration task, and scientific payloads.      

Optical properties of the Martian atmosphere and radiative heat exchange

Optical properties of the Martian atmosphere and its radiative heat exchange have been investigated. The role of the greenhouse effect mechanism in evolution of the Martian climate has been studied.