Field Report From Mars: Sol 4333 - April 1, 2016
Posted by Larry Crumpler
26-04-2016 7:32 CDT
On this sol, here on the west rim of Endeavour crater, Opportunity has climbed west and up Marathon Valley in one of the final campaigns before moving on and beginning the summer field activities to the south southward.
Opportunity has travel more than 42 kilometers, 9.2 kilometers of which has been along the western rim of the 22 km-wide Endeavour crater. The field work being done here on the rim of Endeavour crater is the first of its kind. No one has ever walked along the rim of a 22 km-diameter crater and every outcrop is new science. This is physically and conceptually unknown terrain.
The latest drive on sol 4330 placed Opportunity on the edge of an area (shown with the red outline above) where orbital remote sensing says there is an exposure of minerals that typically form when water alters rock. This is one of the reasons we came to Marathon Valley, so we want to do a good job of finding out where the minerals are, how they relate to the rocks in which they occur, and what evidence there might be for how the alteration happened. This is my ongoing field geologic map, prepared just like a field geologic map here on Earth by looking at outcrops and mapping the occurrences of difference lithologies as determined from actual specimens and analysis—except with a rover we can only map near the rover traverse.
Check this out! At the end of sol 4332 while taking the rest of the Navcam panorama from this location a dust devil was caught in the act out on the floor of Endeavour crater. This is only the third or so dust devil ever seen by Opportunity. The image above is from one of the tools we use to see the image data geometry with respect to the rover. It also makes nice virtual scenes when there is something nice to see.
This is the original Navcam frame, a true iconic image capturing a scenic view down the valley, across the crater floor with the rover tracks in the foreground.
This is a plot of the power produced by the solar panels over a period of time. The steady increase as spring progresses and the sun gets higher shows how the seasonal variation in power really slows things down during the winter. The other blue line at the bottom of the top graph shows how dusty the atmosphere is. Lower is better in this case. And the bottom graph, labeled "dust factor" on the vertical axis, shows how dusty the solar panels are. 1 is perfect, and 0 is totally covered with dust. So a dust factor 0.86 as it is tosol, is very good. Notice that instead of getting more and more dust coated, the solar panels are getting less dusty! What the wind giveth, the wind taketh away. This trend has been going on all winter. Apparently being parked in Marathon valley all winter is like being in Tijeras Canyon just east of Albuquerque: Lots of downslope winds all winter.
Shown in red are areas where the detection from orbit of water-related minerals (from the Mars Reconnaissance Orbiter (MRO) Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument) are strong. Green is detection but not as strong. So Opportunity is doing a little "ground truth" to find out what the heck is going on here to cause a really strong occurrence of clay minerals in this one spot. The 1 meter relief contours are derived from stereo images from the MRO/HiRISE camera. Opportunity just climbed out of 20 degree slopes and is final perched on a a relatively flat surface (less than 10 degrees, which for Opportunity these days is "flat"). Oddly, it is where the flat surface occurs that the water-related minerals appears to be present. Hmmmmmmm...
Here is the planned "walk-about" from the uplink planning this morning. It shows roughly where Opportunity will be driving over the next week or so. At each station we will shoot some Navcam and targeted Pancam across the red area and then move on. After we complete the walk along the outcrop, just like you would here on Earth before sampling, we will drive back and look at a couple of exposures really carefully.
I went back and grabbed an image opportunity acquired way back on sol 3937 when it was overlooking Marathon Valley. I then plotted up the current location and the planned walk-about. So this gives better sense of where Opportunity is and what the lay of the land is here. Notice that Opportunity has been off the image to the left, down-valley, and on steeper slopes most of the winter.