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Although a rumor came out about a week and a half ago that Gale Crater was the scientists’ preferred landing site for the Mars Science Laboratory, officially NASA says the finalists are now down to two: Gale and Eberswalde craters. The final selection will likely be made sometime this month, no earlier than July 11. As of now, MSL, a.k.a Curiosity scheduled to head to Mars during a Nov. 25 to Dec. 18, 2011 launch window.
Gale Crater contains ancient lakebed deposits and sitting in the middle of the crater is an enticing 5-kilometer-tall mound of rock, stacked with layers. This could provide the rover a study a variety of environments that produced clay deposits near the mountain’s base to later environments that produced sulfate deposits partway up the slope.
Eberswalde is the site of what scientists think is a former river delta, where organic materials could be waiting to be analyzed. NASA says that as a clay-bearing site where a river once flowed into a lake, Eberswalde crater offers a chance to use knowledge that oil industry geologists have accumulated about where in a delta to look for any concentrations of carbon chemistry, a crucial ingredient for life.
Officially out of the running are Mawrth Vallis and Holden Crater, the other two finalist sites.
The spacecraft will arrive at Mars in August 2012, and land via its unusual “sky crane” landing system. (See a video of it here.) Researchers will use the rover’s 10 science instruments for at least two years to investigate whether the landing area has ever offered environmental conditions favorable for microbial life.
Source: NASA
Gale seems to be safer to land. I think they will go there. Destroyed lakebed with a mountain is very enticing. But, Eberswalde delta seems equally interesting and Holden crater is close on the map, but I guess it’s too far away for Curiosity.
Land on whichever has the most magnetic field. In theory, life would be more protected there.
What theory would that be? Because I don’t see it:
First, magnetic fields tries to trap charged particles. Their main effect on an atmosphere is to lower leakage due to solar wind or CME ablation, or ionized hydrogen escape.
What protects life from charged particle radiation such as cosmic radiation is locally the atmosphere, not primarily the magnetic field. An atmosphere also conveniently provide some protection from impactors. (Not much on Mars, granted.)
So presumably the best protection for this would at the site with the densest atmosphere. Probably the most low lying, cold, enclosed (more dust and water vapor) spot.
Second, protection against charged particles is presumably not the main problem for life here. What oxidizes the uppermost soil and the atmosphere is UV. Because the main blocker, again atmosphere, is comparably thin.
When you dig some few centimeters below ground to get away from the zone that breaks down organics, presumably the little difference in charged particle protection between sites will rapidly dwindle to zero.
If Mawrth is out, which uniquely covered a very early period (and so was messed up), I would prefer Gale:
– “The delta at Eberswalde does not represent a significant portion of martian history.”
– “The total amount of time recorded in the mound is unknown, but the lower mound seems to be constrained to the early Hesperian based on crater counting.” [On Gale.]
[From here.]
Gale “seems” to probe an earlier part of martian history, which is good for the main purpose of looking for early habitability, organics, fossils. But also good for geohistory, I would think.
Also, Eberswalde adds the uncertainty of no visible shore line. Flooding events are good for trapping organics or fossils, but very narrow in time. Gale integrated all that for a long period. More signal, less noise.
What is found in Gale would incorporate Eberswalde (similar general circumstances). The reverse doesn’t hold.
Oh dear lord, I hope it works. This skycrane idea is the craziest landing scenario I’ve ever heard of, and that includes fiction. I wish we had a camera on the ground to capture it…