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首页> 外文期刊>Journal of Geophysical Research. Biogeosciences >Assessment of Mars Pathfinder landing site predictions
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Assessment of Mars Pathfinder landing site predictions

机译：评估火星探路者着陆点的预测

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Remote sensing data at scales of kilometers and an Earth analog were used to accurately predict the characteristics of the Mars Pathfinder landing site at a scale of meters. The surface surrounding the Mars Pathfinder lander in Ares Vallis appears consistent with orbital interpretations, namely, that it would be a rocky plain composed of materials deposited by catastrophic floods. The surface and observed maximum clast size appears similar to predictions based on an analogous surface of the Ephrate Fan in the Channeled Scabland of Washington state. The elevation of the site measured by relatively small footprint delay-Doppler rader is within 100 m of that determined by two-way ranging and Doppler tracking of the spacecraft. The nearly equal elevations of the Mars Pathfinder and Viking Lander 1 sites allowed a prediction of the atmospheric conditions with altitude (pressure, temperature, and winds) that were well within the entry, descent, and landing design margins. High-resolution (approx 38 m/pixel) Viking Orbiter 1 images showed a sparsely cratered surface with small knobs with relatively low slopes, consistent with observations of these features from the lander. Measured rock aboundance is within 10% of that expected from Viking orbiter thermal observations and models. The fractional area covered by large, potentially hazardous rocks observed is similar to that estimated from model rock distributions based on data from the Viking landing sites, Earth analog sites, and total rock abundance The bulk and fine-component thermal inertias measured from orbit are similar to those calculated from the observed rock size-frequency distribution. A simple radar echo model based on the reflectivity of the soil (estimated from its bulk density), and the measured fraction of area covered by rocks was used to approximate the quasi-specular and diffuse components of the Earth-based radar echos. Color and albedo orbiter data were used to predict the relatively dust free or unweathered surface around the Pathfinder lander compared to the Viking landing sites. Comparisons with the experiences of selecting the Viking landing sites demonstrate the enormous benefit the Viking data and its analyses and models had on the saccessful predictions of the Pathfinder site. The Pathfinder experience demonstrates that, in certain locations, geologic processes observed in orbiter data can be used to infer surface characteristics where those processes dominate over other processes affecting the Martian surface layer.
机译：以千米为单位的遥感数据和一个地球类似物被用来精确地预测以米为单位的火星探路者着陆点的特征。战神瓦利斯（Ares Vallis）的火星探路者着陆器周围的表面看起来与轨道解释一致，即它将是由灾难性洪水沉积的物质组成的岩石平原。该表面和观测到的最大碎屑大小似乎类似于基于华盛顿州海峡ab湾的埃弗拉特扇面相似的预测。用相对较小的足迹延迟多普勒雷达测得的场地高程在航天器双向测距和多普勒跟踪所确定的高度的100 m以内。 Mars Pathfinder和Viking Lander 1站点的高度几乎相等，因此可以预测高度，高度（压力，温度和风）在进入，下降和着陆设计范围内的大气状况。高分辨率（约38 m /像素）的Viking Orbiter 1图像显示了一个坑坑洼洼的表面，其小旋钮的斜率相对较低，这与着陆器对这些特征的观察一致。测得的岩石丰度在维京轨道飞行器热观测和模型预期值的10％以内。观测到的可能存在危险的大型岩石所覆盖的分数区域类似于基于维京号着陆点，地球模拟地点和总岩石丰度的数据根据​​模型岩石分布估算出的分数区域。从轨道测得的体积和精细成分热惯性相似根据观察到的岩石尺寸-频率分布计算得出的结果。一个简单的雷达回波模型基于土壤的反射率（从其堆积密度估算）以及所测得的岩石覆盖区域的分数，用于近似基于地球的雷达回波的准镜面反射分量和散射分量。使用颜色和反照率轨道器数据来预测与维京号着陆点相比，探路者着陆器周围相对无尘或未风化的表面。与选择维京登陆点的经验进行比较表明，维京数据及其分析和模型对探路者站点的轻松预测具有巨大的好处。探路者的经验表明，在某些位置，在轨道器数据中观察到的地质过程可以用来推断表面特征，这些过程在影响火星表面层的其他过程上占优势。

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