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首页> 外文期刊>Journal of Geophysical Research. Biogeosciences >Evidence for Martian electrostatic charging and abrasive wheel wear from the Wheel Abrasion Experiment on the Pathfinder Sojourner rover
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Evidence for Martian electrostatic charging and abrasive wheel wear from the Wheel Abrasion Experiment on the Pathfinder Sojourner rover

机译：来自Pathfinder Sojourner漫游者的车轮磨损实验的火星静电荷和砂轮磨损证据

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The Wheel Abrasion Experiment (WAE) on the Mars Pathfinder rover was designed to find out how abrasive the Martian dust would be on strips of pure metals attached to one of the wheels. A specially modified wheel, with 15 thin film samples (five each of three different metals), specularly reflected sunlight to a photovoltaic sensor. When the wheel was rotated to present the different sample surfaces to the sensor, the resulting signal was interpreted in terms of dust adhesion and abrasive wear. Many data sequences were obtained. Ground tests of similar wheels in a simulated Martian environment showed that static charging levels of 100-300 V could be expected. To prevent the possibility of Paschen discharge in the low-pressure Martian atmosphere, charge dissipation points were added to the Sojourner rover and were shown in ground tests to keep charging levels at 80 V or less. Nevertheless, significant dust accumulations on Sojourner's wheels may be interpreted as evidence for electrostatic charging. Simple considerations of the expected maximum level of charging and electrostatic dust adhesion lead to an estimate for the size of the adhering dust grains. From the WAE data, it is hypothesized that the photoelectric effect is the most important mechanism for slow discharge in Martian daylight. Sensor signals obtained late in the Pathfinder mission show that significant wheel wear was seen on the metal wheel strips, with the most wear on the thinnest aluminum samples and the least on the thickest nickel and platinum samples. An estimate is made of the reflectance of the adhering Martian dust. The depth of dig of the WAE wheel shows that the dust is in some places very loose and in others tightly packed. Finally, comparison of the WAEresults with ground test results makes possible a comparison of the Martian soil with mineral grain types and sizes found on Earth and show that the Martian dust is fine-grained and of limited hardness.
机译：火星探路者火星车上的车轮磨损实验（WAE）旨在发现附着在其中一个车轮上的纯金属条带上火星尘埃的磨蚀性。一个经过特殊改装的轮子，带有15个薄膜样本（三种不同金属中的每种五种），将太阳光镜面反射到光伏传感器。当旋转砂轮将不同的样品表面呈现给传感器时，根据灰尘附着力和磨料磨损来解释产生的信号。获得了许多数据序列。在模拟火星环境中对类似车轮进行的地面测试表明，可以预期100-300 V的静态充电水平。为防止在低压火星大气中发生Paschen放电的可能性，在Sojourner流浪者车上增加了电荷耗散点，并在地面测试中显示了这些电荷耗散点，以将充电水平保持在80 V或更低。尽管如此，在旅居者的车轮上大量的灰尘积聚仍可以解释为静电的证据。对预期的最大充电量和静电粉尘附着力的简单考虑即可得出所附着粉尘颗粒尺寸的估计值。根据WAE数据，可以假设光电效应是火星日光下缓慢放电的最重要机制。在“寻路者”任务后期获得的传感器信号表明，在金属轮带上观察到了明显的车轮磨损，在最薄的铝样品上磨损最大，而在最厚的镍和铂样品上磨损最小。对粘附的火星尘埃的反射率进行估算。 WAE轮的挖掘深度表明，在某些地方灰尘非常疏松，而在其他地方则紧密堆积。最后，将WAEresults与地面测试结果进行比较，可以将火星土壤与地球上发现的矿物颗粒类型和大小进行比较，并表明火星粉尘是细颗粒且硬度有限的。

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