Jezero Crater delta
At this week’s 50th Lunar and Planetary Science Conference in Texas, there were many papers detailing the geological, topographical, chemical, meteorology and biological circumstances at the landing sites for the 2020 Martian rovers, Jezero Crater for the U.S.’s Mars 2020 and Oxia Planum for Europe’s Rosalind Franklin.
Most of these papers are a bit too esoteric for the general public (though if you like to delve into this stuff like I do, go to the conference program and search for “Jezero” and “Oxia” and you can delve to your heart’s content).
These papers do make it possible to understand why each site was chosen. I have already done this analysis for Rosalind Franklin, which you can read here and here. Oxia Planum is in the transition between the southern highlands and the northern lowlands (where an intermittent ocean might have once existed). Here can be found many shoreline features. In fact, one of the papers at this week’s conference mapped [pdf] the drainage patterns surrounding the landing ellipse, including the water catchment areas, as shown by the figure from that paper on the right.
With this post I want to focus on Jezero Crater, the Mars 2020 landing site. The image above shows the crater’s most interesting feature, an impressive delta of material that apparently flowed out of the break in the western wall of the crater.
This image however does not tell us much about where exactly the rover will land, or go. To do that, we must zoom out a bit.
The annotated image on the left was created from two images taken by the context camera on Mars Reconnaissance Orbiter (MRO), found here and here. The white box shows you the location of the first image above. The black ellipse shows you the landing area for Mars 2020. Their plan is to land on the flat crater floor to the east of that delta. From there it is quite clear from all of this week’s papers that the goal will be to then drive west and up onto that delta. (For scale, I estimate based on another image of the delta that the distance across the delta from its head to the rim to be between three to five miles.)
If this rover lasts as long as designed, it will hopefully even be able to travel up beyond the delta into the break in the crater wall and into the drainage valley beyond. In anticipation of this, one paper this week [pdf] even mapped the watershed above the crater. Any water in that watershed would have drained into the crater to form a lake there, which in turn would have drained to the east out into the northern lowlands.
As with almost all past landers/rovers, the scientists here have chosen a location in the transition zone between the northern lowlands and the southern highlands, as shown in the overview to the right. This gives them the best location for quickly seeing a wide variety of geology. Moreover, the delta will also contain material from the west, increasing the range of data they can quickly gather.
This location however is not necessarily the best for future human exploration or colonization. It might contain water, but this is not obvious. The delta itself might be a form of mud, which one paper [pdf] this week suggested would flow almost like lava on Mars. If so, there might be water in it.
Other sites, however, have far greater potential both for water and for building a good initial colony. As I have noted previously, our exploration strategy on Mars has so far been dominated almost entirely by scientific concerns, which while very important and essential, do not always coincide with exploration and settlement concerns.
As our knowledge grows, however, and the competition to get to Mars increases, the focus will shift. Once the first human missions are just over the horizon, the need to explore good colony locations will become primary, and the unmanned scouting missions will start heading that way.
In the meantime, the journeys that will occur in Jezero and Oxia beginning in 2020 will be more than spectacular. There will be no need to complain from an explorer’s perspective.
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