Magnetic properties experiments and the Surface Stereo Imager calibration target onboard the Mars Phoenix 2007 Lander: Design, calibration, and science goals
Magnetic properties experiments and the Surface Stereo Imager calibration target onboard the Mars Phoenix 2007 Lander: Design, calibration, and science goals
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DOI：
10.1029/2007je003014
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发表时间：
2008-10-07
影响因子：
4.8
通讯作者：
Shaw, A.
中科院分区：
文献类型：
--
作者：
Leer, K.;Bertelsen, P.;Shaw, A.
8月4日发射的第一个美国宇航局火星探测使命凤凰号将于2008年5月25日在火星北方北纬68度东经233度的地方着陆。科学有效载荷的一部分是磁特性实验（MPE），包括两个主要实验：改进的扫描磁铁实验（ISWEEP）和10套两个显微镜，电化学和电导率分析仪（MECA）磁体基板，嵌入不同强度的永磁体。ISWEEP实验，顾名思义，是两个火星探测漫游者（MER）精神号和机遇号上飞行的扫描磁铁实验的改进版本。扫描磁体是环形的，并且被设计为仅允许微粒子进入该结构的表面中心处的小圆形区域。该实验的结果表明，在MER上，在该环形磁体的中心区域几乎不能检测到任何颗粒。由此我们得出结论，火星大气中的所有粒子基本上都是磁性的，因为它们被永久磁铁吸引。为了提高扫频磁铁实验对弱磁或极弱磁粒子的探测灵敏度，ISWEEP拥有六个环形磁铁，比MER的扫频磁铁稍大，中心区域有六种不同的背景颜色。六种不同的颜色为这些背景颜色之间的改进对比度提供了新的可能性，即，任何推定的放射性粒子都应该使这些更容易检测。表面立体成像仪还将利用ISWEEP中的小清洁区域，并使用假定不变的颜色进行图像的辐射校准。MECA磁体在MECA显微镜实验中用作基底;它们被构建用于吸引和保持灰尘样品中的磁性颗粒。收集的灰尘将由MECA包中的光学显微镜和原子力显微镜进行检查。
The first NASA scout mission to Mars, Phoenix, launched 4 August will land in the northern part of Mars in the locality of 68 degrees N and 233 degrees E on 25 May 2008. Part of the science payload is the Magnetic Properties Experiments (MPE) that consists of two main experiments: the Improved Sweep Magnet Experiment (ISWEEP) and 10 sets of two Microscopy, Electrochemistry, and Conductivity Analyzer ( MECA) magnet substrates with embedded permanent magnets of different strength. The ISWEEP experiment is, as the name indicates, an improved version of the Sweep Magnet Experiments flown onboard the two Mars Exploration Rovers (MERs) Spirit and Opportunity. The sweep magnet is ring shaped and is designed to allow only nonmagnetic particles to enter a small circular area at the center of the surface of this structure. Results from this experiment have shown that on the MERs hardly any particles can be detected in the central area of this ring-shaped magnet. From this we have concluded that essentially all particles in the Martian atmosphere are magnetic in the sense that they are attracted to permanent magnets. In order to improve the sensitivity of the Sweep Magnet Experiment for detection of nonmagnetic or very weakly magnetic particles, the ISWEEP holds six ring-shaped magnets, somewhat larger than the sweep magnet of the MERs, and with six different background colors in the central area. The six different colors provide new possibilities for improved contrast between these background colors, i.e., any putative nonmagnetic particles should render these more easily detectable. The Surface Stereo Imager will also take advantage of the small clean areas in the ISWEEPs and use the presumably constant colors for radiometric calibration of images. The MECA magnets work as substrates in the MECA microscopy experiments; they are built to attract and hold magnetic particles from dust samples. The collected dust will then be examined by the optical microscope and the atomic force microscope in the MECA package.