舰载直升机的腐蚀与防护

针对舰载直升机受海洋环境影响发生的腐蚀现象,分析了舰载直升机腐蚀发生的原因、机理,提出了防护措施。     

海洋温度剖面最优插值及其效果分析

声纳探测距离受海洋声速梯度影响很大,而温度是影响声速梯度的重要因素。为了更真实地反映海洋环境,尤其是声场分布,对海温进行同化研究就显得十分必要。文章提出了一种评估同化算法效果的方法,并分别用最优插值、反距离加权、Kriging插值3种算法对垂直温度剖面进行同化处理。仿真结果表明,最优插值算法的同化结果更接近真实数据,对温度剖面的最优插值有助于预测声纳探测距离。     

火星及其环境

火星环境类似于地球,而探索其生命存在是重大的科学任务。在火星探测中,对火星及其环境的了解与研究是重要的任务目标,事关探测任务的成功实施。文章对国外火星探测已发布的成果进行收集和整理,其中包含大量的相关数据。这些知识和数据是火星探测任务设计的输入条件,可为我国火星探测计划的制定提供参考依据。     

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。     

微波无源遥感有效载荷现状与发展

针对微波无源遥感有效载荷这一卫星有效载荷中发展最早、最成熟的子领域,对从20世纪60年代至今,世界范围内在轨与在研共17个具有代表性的载荷产品进行了研究。综合分析了微波无源遥感载荷在气象、海洋、陆地、大气环境及深空微波遥感等应用领域的发展现状,归纳出无源微波遥感有效载荷向定量应用、功能复合、主被动一体、体制混合、太赫兹探测等方向的发展趋势。总结了我国与欧美发达国家在系统应用水平、反演处理能力、关键部组件性能、研发条件等方面存在的差距,提出了后续发展静止轨道毫米波亚毫米波探测仪、一体化微波成像探测仪、太赫兹冰云探测仪、L波段土壤湿度微波探测仪、亚毫米波临边探测仪、行星探测仪等载荷的设想。     

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.     

火星车在松软地面上的蠕动步态研究

蠕动步态是解决火星车在火星松软表面行走或爬坡困难时提高牵引力的有效方法,合理设置蠕动步态对充分发挥火星车在松软地表上的移动性能至关重要。文章将Bekker等人的轮地力学理论用于整车蠕动步态的受力分析,通过建立火星车的运动学模型,分析关节的运动关系,得到蠕动步态的协调运动方案,并通过原理样机试验对该方案的作用效果进行验证,为主动悬架蠕动步态的轮速配合给出了合理的建议。     

火星表面大气环境下热球风速仪的对流换热模型及试验验证

火星表面大气环境与一般轨道航天器所处的空间环境存在差异。为了实现极端环境下热模型修正、早期故障筛除、性能测试等目的,一般需要在模拟的低气压有风环境下对火星巡视器进行热试验,试验涉及在1400 Pa左右压力的环境下对0～15 m/s风速进行模拟和测量。文章针对极低气压下的风速测量问题,使用无量纲数分析方法建立恒热流式热球风速传感器表面的换热模型,对其在低气压下的输出、自然对流影响等进行分析,并与低气压下的测试结果进行对比。试验结果显示,在1400 Pa低气压下,热球风速探头表面仍以强制对流换热为主,探头灵敏度约为0.1～0.2 mV/(m·s-1),可以用于极低压力下的风速测量。     

国外海洋盐度与土壤湿度探测卫星的发展

文章调查研究了国外海洋盐度与土壤湿度探测卫星发展情况、探测机理;重点对SMOS、Aquarius、SMAP等三颗最具代表性的土壤湿度和海洋盐度探测卫星进行了研究分析,比对了三颗卫星的主要技术指标,并总结了其技术发展特点和关键技术;最后结合我国技术基础对发展我国盐度与湿度卫星提出了建议。     

The contribution of local gravimetric geoid models to the calibration of satellite altimetry data and an outlook of the latest GOCE GGM performance in Gavdos

The use of geoid heights has been one of the available methodologies utilized for the independent calibration/validation of altimeters on-board satellites. This methodology has been employed for long in the Gavdos dedicated cal/val facility (Crete, Greece), where calibration results for the Jason satellites have been estimated, both for ascending and descending passes. The present work gives a detailed overview of the methodology followed in order to estimate a high-resolution and accuracy gravimetric geoid model for the wider Gavdos area, in support of the on-going calibration work. To estimate the geoid model, the well-known remove-compute-restore method is used while residual geoid heights are estimated through least-squares collocation so that associated errors are determined as well. It is found that the estimated formal geoid errors from LSC along passes 018 and 109 of Jason satellites, used for the bias estimation, range between ±0.8–1.6 cm. The so-derived geoid heights are employed in the determination of the Jason-2 altimeter bias for all available cycles (cycles 1-114, spanning the period from July 2008 to August 2011) together with the RioMed DOT model. From the results acquired the Jason-2 bias has been estimated to be +196.1 ± 3.2 mm for pass 109 and +161.9 ± 5.1 mm for pass 018. Within the same frame, the GOCE/GRACE-based geopotential model GOCO02s has been used to estimate the mean dynamic ocean topography and the steady-state circulation in the area around Gavdos. The so-derived DOT model was used to estimate the Jason-2 bias in an effort to evaluate the performance of satellite-only geoid models and investigate whether their spatial resolution and accuracy provides some improvement w.r.t. traditional local gravimetric geoids. From the results acquired with geoid heights from GOCO02s, the estimated Jason-2 bias deviates significantly from that of the local gravimetric model, which can be attributed to a possible mean offset and the low resolution of GOCE-based GGMs. On the other hand, when the newly estimated GOCE-based DOT was employed with geoid heights from the local gravimetric geoid model, the Jason-2 bias has been estimated to be +185.1 ± 3.2 mm for pass 109 and +130.2 ± 5.1 mm for pass 018.