Electrostatic collection of tribocharged lunar dust simulants

Levitation and consecutive deposition of naturally charged particles on lunar surface were troublesome in previous NASA explorations. Protecting sensitive surfaces from dust deposition in the limiting condition of the lunar atmosphere is imperative for future space exploration. This study reports experimental investigation of the collection efficiency of an electrostatic lunar dust collector (ELDC). A dual-functional remotely controlled particle charger/dropper was designed for tribocharging 20 μm lunar dust simulants, and a system of Faraday cup connected to an electrometer working in the nC range was used to measure the particle charges. Tribochargeability of two lunar dust simulants was studied, and the process was found to be the most effective with the JSC-1A samples. Aluminum was verified to be a more effective plate material than stainless steel. For the tested range of electrostatic field strength (0.66–2.6 kV/m), the mass-based and charge-based collection efficiencies were in the range of 0.25–1% and 0.45–1.45% for the low vacuum (10⁻¹ Torr), and 8–35% and 12–54% for the high vacuum (10⁻⁵ Torr) conditions. The linear relationship between the applied voltage and ELDC collection efficiency predicted by the theoretical model was confirmed, and the collection pattern of the collected particles over the collection plate was consistent with the previously computed charge distribution on the collection plate. Aside from validating the predictability of the theoretical model, this study offers a novel method of particle charging inside a vacuum chamber with a variety of applications for studying chargeability of particles at different temperatures and pressures.     

月球探测 势在必行

月球作为地球唯一的一颗卫星，从古到今一直牵动着人类的梦想。月球之所以能吸引着人类对它进行探测和开发，是因为月球能够提供解决人类所担忧的能源资源的条件；月球作为一个永久性的空间站和其具有的特殊环境，为人类提供了开展深空探测活动的场所，并将成为新兴工业的基地。鉴于国外深空探测发展的历史和现状，特别是一度平静了２０多年的月球，而今又重新成为世界关注的焦点，登月的热潮又再度兴起，以及我国多年来空间科学和航     

Motion design of a hybrid wheeled/legged robot for lunar exploration

The robot consists of a quadruped mechanism and two active dual-wheel casters possesses the advantages of wheeled and legged mechanism, and can quickly move on the relatively plane ground with the wheeled mechanism, and can walk on the extremely uneven terrain with the legged mechanism. The effectiveness of the motion design of the hybrid robot is iHustrated by simulation results.     

月球车月面支撑通过性研究及车轮优化设计

车轮是月球车唯一与月面接触,并通过与月壤作用产生动力推动月球车在月面行走的部件,对月球车车轮的月面支撑通过性研究是保障月球车移动性能的关键环节.从提高附着力、控制沉陷量和减小滚动阻力三方面着手,分析了各因素的影响作用,据此提出了车轮优化方案,有限元仿真分析显示,该车轮方案具有较好的支撑通过性能.     

Sputtering of lunar regolith simulant by protons and singly and multicharged Ar ions at solar wind energies

We report preliminary results on sputtering of a lunar regolith simulant at room temperature by singly and multiply charged solar wind ions using quadrupole and time-of-flight (TOF) mass spectrometry approaches. Sputtering of the lunar regolith by solar-wind heavy ions may be an important particle source that contributes to the composition of the lunar exosphere, and is a possible mechanism for lunar surface ageing and compositional modification. The measurements were performed in order to assess the relative sputtering efficiency of protons, which are the dominant constituent of the solar wind, and less abundant heavier multicharged solar wind constituents, which have higher physical sputtering yields than same-velocity protons, and whose sputtering yields may be further enhanced due to potential sputtering. Two different target preparation approaches using JSC-1A AGGL lunar regolith simulant are described and compared using SEM and XPS surface analysis.     

Hydrogen ice within lunar polar craters

We might have overlooked the widespread presence of methanol on the Moon and hydrogen ice within lunar polar craters. Here we show that (1) US Moon Mineralogy Mapper (M³) cannot distinguish between hydroxyl radicals from lunar water and hydroxyl groups from lunar methanol because the absorption strengths of the two are all 2.9 μm, and there are no established methods to distinguish them using the 2.9 μm band. Water ice within lunar polar craters is worthy of renewed investigation. (2) The ‘surficial water’ illogically appears at the lunar equator based on M³ spectral detection, seriously shaking the credibility of M³ spectral data analysis. (3) Methanol and water brought about by the interstellar methanol ice react in lunar carbon-rich regolith using Ce/Cu/Zn–Al catalysts to produce massive molecular hydrogen. This molecular hydrogen escapes into the lunar exosphere and is transported to lunar cold traps, forming brown-black solid molecular hydrogen (hydrogen ice) that appears in snowflake patterns at the lowest temperature within lunar polar craters. (4) The author concludes with a model of the physico-chemical process chains on the lunar surface, which systematically elucidates the mechanism of lunar hydrogen ice formation. (5) Hydrogen ice within lunar polar craters can become a fuel base for interplanetary flight.     

模拟月球车复杂路面的可拓自适应控制方法

由于月球复杂的地形环境,月球车对于复杂路面自适应控制有很多问题有待解决。文中利用自适应控制善于处理不变和慢时变问题,可拓控制善于处理时变和突变问题的特点,将自适应控制与可拓控制二者结合起来,构建了一种新的智能方法——"可拓自适应控制"。设计了可拓自适应控制器。并对其进行了初步实验。实验表明,采用可拓自适应控制方法对模拟月球车驱动进行控制,较传统的自适应控制具有更好的环境适应性。     

具有解耦功能的二维倾角模拟装置

星球探测车是人类进行星球探测必不可少的工具,为了对星球探测车在实验室内进行崎岖地形上的模拟试验,采用一个具有二维倾角功能的运动平台,并搭配不平路面的模拟来实现崎岖的地形模拟。通过深入研究运动平台的二维运动特性,发现两侧均采用曲柄导杆机构驱动,并同时进行两个方向的倾斜运动时,此空间机构的二维运动具有耦合特性,于是使用补偿铰链来实现对二维耦合运动的解耦。通过对提出的机构进行理论推导分析,并使用仿真与试验进行验证,最终实现了运动平台的两个方向上同时倾斜运动并互不干涉,为星球车崎岖地形模拟试验奠定了基础。     

一种新型的可被动适应崎岖表面的六轮月球漫游车

本文针对复杂月球表面提出了一种新型的可折叠崎岖表面被动适应六轮月球漫游车.它由几组四杆机构的独特设计与组合以及弹性悬架组成,它具有较强的爬台阶,爬楼梯,在不规则路面上行驶和稳定性能力.并进行了稳定性和运动能力的分析.