行为控制月球车的虚拟主体避障技术

论述了基于行为代理体的月球车避障技术。由月球地形高程图得到当地水平面下二色障碍图及着色障碍图，利用月球车代理体在障碍图及着色障碍图中进行避障学习与控制，将获得的控制量投影到月球车体坐标系下得到真实地形上的控制量，达到避障控制与运动规划的目的。利用障碍入侵月球车安全线的径向距离作为避障控制器输入，并由月球车目标趋向行为及避障行为输出融合突现出趋向目标的避障行为。仿真结果表明基于代理体的避障控制器设计方法使运行于真实环境下月球车的避障具有很高的可靠性。     

双探针法测量月壤热物性参数的影响因素分析

针对双探针法测量月壤热物性过程,建立了探针与月壤组成的多层介质在太阳辐照加 热与月表辐射散热作用下的二维非稳态传热模型。通过数值模拟,分析了探针长度、直径、 中心间距和加热功率等因素对测量结果的影响。结果表明,若月壤导热系数在0.01W／
(m·K)左右,则月壤的弱导热性是双探针探测设计中需考虑的主要因素。在上述分析的基 础上,设计了双探针结构,对一导热性能较差的松散介质进行了地面测量实验,通过试错法 反演测量数据得到该介质的热扩散率与导热系数,为进一步应用研究提供了参考。     

一种基于UPF的月球车自主天文导航方法

介绍了月球车自主天文导航原理和传统的迭代解析高度差方法，提出了一种基于月球车运动模型和UPF（Unscented粒子滤波）的自主天文导航新方法。该方法仅需利用由星敏感器和惯性测量单元测量得到的恒星的天体高度，结合月球车的运动模型，通过UPF滤波，即可获得高精度的月球车实时位置信息。计算机仿真结果表明该方法与传统方法相比，定位精度有了大幅提高，同时对几个关键的精度影响因素的仿真分析显示该方法可以有效的减弱量测噪声，星历误差等对系统性能的影响，使系统具有更高的适应能力。     

月球探测中通信跟踪(C&T)技术遇到的新问题

以技术成熟的GEO以下近地轨道的C&T技术为参照点,提出月球探测遇到的新问题———长时间、远距离地月转移轨道测量、环月轨道段测量和月面登陆段测量中的新问题,给出解决这些问题的合理方法。     

嫦娥一号卫星CCD立体相机月表图像镶嵌

鉴于嫦娥一号CCD相机获取图像的特殊性, 选用投影的方法, 完成了Apollo12, Apollo14和Apollo15登月点区域的月表正视图像镶嵌. 在分析圆柱投影表象的基础上, 推导出了月球割35º Mercator投影公式. 首先读取单轨数据的经纬度和灰度, 进而根据四个角点的经纬度建立空图框, 并根据分辨率、长度比与月球投影理论分别在纵向和横向上进行网格划分, 实现图框的像元化. 通过单轨图像和图框的坐标匹配完成灰度镶嵌, 匹配误差控制在一个像元以内. 对重叠区域的灰度值进行平滑处理, 最终图像还原来完成月表图像的镶嵌. 该方法有普遍适用性, 可以用于其他轨道图像的镶嵌.     

Exploration life support technology challenges for the Crew Exploration Vehicle and future human missions

As NASA implements the U.S. Space Exploration Policy, life support systems must be provided for an expanding sequence of exploration missions. NASA has implemented effective life support for Apollo, the Space Shuttle, and the International Space Station (ISS) and continues to develop advanced systems. This paper provides an overview of life support requirements, previously implemented systems, and new technologies being developed by the Exploration Life Support Project for the Orion Crew Exploration Vehicle (CEV) and Lunar Outpost and future Mars missions. The two contrasting practical approaches to providing space life support are (1) open loop direct supply of atmosphere, water, and food, and (2) physicochemical regeneration of air and water with direct supply of food. Open loop direct supply of air and water is cost effective for short missions, but recycling oxygen and water saves costly launch mass on longer missions. Because of the short CEV mission durations, the CEV life support system will be open loop as in Apollo and Space Shuttle. New life support technologies for CEV that address identified shortcomings of existing systems are discussed. Because both ISS and Lunar Outpost have a planned 10-year operational life, the Lunar Outpost life support system should be regenerative like that for ISS and it could utilize technologies similar to ISS. The Lunar Outpost life support system, however, should be extensively redesigned to reduce mass, power, and volume, to improve reliability and incorporate lessons learned, and to take advantage of technology advances over the last 20 years. The Lunar Outpost design could also take advantage of partial gravity and lunar resources.     

中继卫星(TDRS)支持环月探测器的研究

给出了基于轨道根数的跟踪与数据中继卫星(TDRS)对月球探测器的可视算法,分析和比较了地面站和TDRS对月球探测器的测控跟踪能力.结果表明,与依靠地面站相比,使用TDRS后,在不考虑月球遮挡情况下,对环月探测器的测控覆盖率可由50%提高到99%.存在最大月球遮挡时也能达到60%,大大提高了对环月探测器的测控能力.最后讨论了TDRS跟踪环月探测器对TDRS卫星平台的要求,提出了地面站与TDRS相结合的测控方案.在当前TDRS天线运动范围受限情况下,仍能实现对月球探测器的大范围测控覆盖率.     

Lunar ground penetrating radar: Minimizing potential data artifacts caused by signal interaction with a rover body

Ground-penetrating radar (GPR) is the leading geophysical candidate technology for future lunar missions aimed at mapping shallow stratigraphy (<5 m). The instrument’s exploration depth and resolution capabilities in lunar materials, as well as its small size and lightweight components, make it a very attractive option from both a scientific and engineering perspective. However, the interaction between a GPR signal and the rover body is poorly understood and must be investigated prior to a space mission. In doing so, engineering and survey design strategies should be developed to enhance GPR performance in the context of the scientific question being asked. This paper explores the effects of a rover (simulated with a vertical metal plate) on GPR results for a range of heights above the surface and antenna configurations at two sites: (i) a standard GPR testing site with targets of known position, size, and material properties, and; (ii) a frozen lake for surface reflectivity experiments. Our results demonstrate that the GPR antenna configuration is a key variable dictating instrument design, with the XX polarization considered optimal for minimizing data artifact generation. These findings could thus be used to help guide design requirements for an eventual flight instrument.     

Traverses for the ISECG-GER design reference mission for humans on the lunar surface

This study explores the Design Reference Mission (DRM) architecture developed by Hufenbach et al. (2015) as a prelude to the release of the 2018 Global Exploration Roadmap (GER) developed by the International Space Exploration Coordination Group (ISECG). The focus of this study is the exploration of the south polar region of the Moon, a region that has not been visited by any human missions, yet exhibits a multitude of scientifically important locations – the investigation of which will address long standing questions in lunar research. This DRM architecture involves five landing sites (Malapert massif, South Pole/Shackleton crater, Schrödinger basin, Antoniadi crater, and the South Pole-Aitken basin center), to be visited in sequential years by crew, beginning in 2028. Two Lunar Electric Rovers (LER) are proposed to be tele-robotically operated between sites to rendez-vous with crew at the time of the next landing. With engineering parameters in mind we explore the feasibility of tele-robotic operation of these LERs between lunar landing sites, and identify potential high interest sampling locations en-route. Additionally, in-depth sample collection and return traverses are identified for each individual landing site across key geologic terrains that also detail crew Extra-Vehicular Activity (EVA). Exploration at and between landing sites is designed to address a suite of National Research Council (2007) scientific concepts.     

登月舱上升段最优轨迹设计

为了实现登月舱上升段轨迹的优化,建立了上升段登月舱动力学模型,用单位归一化技术建立了最优控制模型,并以燃料消耗为最优指标,利用Pontryagin极小值原理,将问题转化为时间自由的两点边值问题 TPBVP 。采用了一种基于初值预估方法和向前扫描法求解TPBVP,从而设计出登月舱上升段最优轨迹,并进行了数值仿真。仿真结果表明所设计的算法收敛速度快、可靠性高。