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MSL Route Map
Ares57
post Yesterday, 03:35 AM
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The legend to this map shows "2m contour lines ...". What then do the figures "-4720, -4269 etc" adjacent to the contour lines mean? If the lines are 2m in elevation apart then the slope between -4720 and -4269 along the illustrated path of the rover is almost 30 per cent. Even if the legend is supposed to be 1 m, then the slope is 15 percent, which seems a dramatic increase on recent times.

Another question in regarding Curiosity's position relative to Vera Rubin Ridge: post #946 shows a cross section which appears to indicate there are two layers to the hematite ridge. The link for this cross-section includes a reference to PIA18781 which is a an overhead map of the region's geology. In the bottom right corner of this image are two ochre coloured sections that appear to correspond to the two layers in the cross section. The lighter higher section is labelled on the map "Hematite ridge" but the legend at the left side labels the darker ochre section as "Hematite ridge". This darker section has a narrow tongue leading towards the break in the dunes which Curiosity has recently traversed. As far as I can tell from the JPL maps, Curiosity has been travelling on this narrow section since Sol 1669 and along the eastern edge since Sol 1678, reaching the main dark ochre area on Sol 1700. If the PIA18781 map is accurate, then has Curiosity been able to detect hematite? I suspect the map may need revising, because several of the recent USGS updates have talked about continuing examination of Murray formation rocks, which according to the cross-section should by now be well covered by the hematite material.

I have searched for a more recent map than PIA18781, but without success.
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serpens
post Yesterday, 06:08 AM
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Basically to measure height (or depth) on Earth or mars you need a datum or agreed start point. On Earth we use averaged sea level as the datum. On Mars the equipotential surface based on MOLA data is used to define the datum. The floor of Gale crater is below the datum and therefore as Curiosity climbs the elevation in metres reduces. I gather you are referring to PaulH51's posted map and the 47-- figures are the contour line depth in thousands of metres, with one metre intervals. So Curiosity has climbed 7 metres over a run of some 80 metres which is around a 5 degree slope.

The HiRise images are amazing in their detail but it is extremely difficult to resolve the nature of the surface from images in isolation. CRISM identified that the erosion resistant ridge was rich in hematite. Relative erosion resistance plus hematite is a reasonable indication that water was involved. But there is no tongue of the hematite ridge leading to Curiosity's position although I can understand why the surface patterns inclined you to think that way.
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