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MSL landing sites
Oren Iishi
post Jun 12 2007, 09:43 PM
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I'm surprised that no one has talked about landing near the newly discovered Martian blackholes or possibly the guyser at the pole (although they may be too dangerous). At the very least, MSL should land somewhere that is not favorable to solar powered rovers.
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algorimancer
post Jun 17 2007, 03:51 PM
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Considering the moderately persuasive argument supporting the notion of a past ocean in the northern hemisphere, as reported in the current issue of Nature (http://www.nature.com.libux.utmb.edu/nature/journal/v447/n7146/full/nature05873.html - if you have access), I would be inclined to shift my preference to a landing site which would be near exposed sediments from the floor of that ocean, perhaps in delta deposits. To me, the odds are that if any macroscopic life ever evolved on Mars, it would have been in this ocean, and sedimentary deposits from the bottom of the ocean would be the best places to look for fossils, as well as a sedimentary sequence which tells an interesting story. I'm not sure whether there would be any benefit to traversing the remnant shoreline itself.

I'm having trouble matching landing site candidates with the map in the paper, but Nilo Syrtis and Marwth Vallis might be good.
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ngunn
post Jun 18 2007, 09:35 AM
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Agreed. In the absence of large scale drilling equipment it would be useful to visit a relatively fresh crater that has excavated through marine sediments.
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ynyralmaen
post Jun 18 2007, 10:39 AM
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QUOTE (algorimancer @ Jun 17 2007, 04:51 PM) *
... but Nilo Syrtis and Marwth Vallis might be good.


Mawrth, not Marwth. It's Welsh for, er, Mars. mars.gif

I hope I'm not appearing to be super-pedantic here; it's just that this is a very common spelling mistake (looks like it derives from a MEX OMEGA Science paper, and some related press releases where they got it wrong.). rolleyes.gif

If you're wondering about the pronunciation, it's similar to "Martha" without the second "a"!
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algorimancer
post Jun 18 2007, 01:12 PM
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QUOTE (ynyralmaen @ Jun 18 2007, 05:39 AM) *
Mawrth, not Marwth. It's Welsh for, er, Mars. mars.gif
...
If you're wondering about the pronunciation, it's similar to "Martha" without the second "a"!


Funny, I actually went to some effort to get the spelling right, and still missed it. Pronunciation sounds like "Mars" with a lisp smile.gif. Perhaps all lispers are Welsh? wink.gif
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ynyralmaen
post Jun 18 2007, 02:53 PM
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QUOTE (algorimancer @ Jun 18 2007, 02:12 PM) *
Perhaps all lispers are Welsh? wink.gif


No, but having a lisp often helps! wink.gif

Now that I've had longer to think about it, forget Martha... the pronunciation's exactly like "mouth", but with an "r" slipped in before the "th".

(Don't get me started on Pwyll crater on Europa!)
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Guest_AlexBlackwell_*
post Jun 18 2007, 06:06 PM
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QUOTE (ngunn @ Jun 17 2007, 11:35 PM) *
Agreed. In the absence of large scale drilling equipment it would be useful to visit a relatively fresh crater that has excavated through marine sediments.

Hmm. Where have I heard that before? Someplace named Gusev or something.
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ngunn
post Jun 18 2007, 07:59 PM
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Aye, and the other one. wink.gif
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Guest_Geographer_*
post Jun 22 2007, 07:15 PM
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Why does elevation matter in designing the rover? I can understand latitude mattering because of communications with an orbiter, but elevation?
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djellison
post Jun 22 2007, 07:17 PM
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The higher you go - the less air your parachute has to work with. 'lower' altitiudes make for an easier landing.

Doug
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Guest_AlexBlackwell_*
post Jun 22 2007, 07:18 PM
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You might want to take a look at the latest version of the MSL engineering constraints document, which discusses the elevation limitations.
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edstrick
post Jun 23 2007, 05:01 AM
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The more pounds per square foot (grams per square centimeter) of vehicle you have behind a heatshield (and a bigger vehicle is more or less inevitably deeper, front to back with more "column mass"), the less the atmosphere can slow you down before you do "ares-braking" instead of "aero-braking"...

zip..... CRUNCH!

I'm going to be off by a factor of a few times, but here's a zero'h order armwave...

Earth. 1 atmosphere surface pressure. 14 pounds (mass) of air per square inch.

Mars. 1/200'th atmosphere surface pressure. That's about 10 ounces / 30 grams per square inch. Double that (roughly) to compensate for gravity. How many ounces per square inch is the MSL in it's heat shield? There's only so many pounds of atmosphere in the way of a so many pound entry vehicle trying to slow it down.

When an entry vehicle masses more than a column of atmosphere of the same diameter between surface and space, it just can't slow down a vehicle before the vehicle hits. Would a column of atmosphere (along an entry trajectory) massing the same as an entry vehicle slow it down 50%... very very roughly, I think so (ignoring gravity).
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PDP8E
post Jul 13 2007, 03:25 PM
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After looking at all the MRO landing site images and counting rocks and such, it just makes sense to this complete amateur that the only place to set down MSL is on/near the famous ice packs of Elysium Planatia.

water? / ice? / extant life?

What would I add to the mission?
...bring an industrial sized RAT and BRUSH

for more info, Google: ice packs mars

Attached Image


Attached Image


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CLA CLL
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Phil Stooke
post Jul 13 2007, 03:53 PM
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Elysium Planitia (AKA ice pack) might look like a good landing site, but there are some problems with it. First, it might be classed as a "special region", which MSL will not be sufficiently sterilized to land in. In the event of a crash, the RTG could encounter ice and create a warm water oasis (not very big, certainly, but still viable). This is not allowed for MSL. (Phoenix should encounter ice, but it will remain very cold).

Second, MSL's instruments don't suit it. A drill might be needed to get to any ice. This could be an ideal spot for a thoroughly sterilized deep drill mission in the future.

Also, Elysium Planitia is really a one target site. Once you have looked at one location, what is there to do? It's quite uniform. MSL is designed to explore up and down a stack of sediments, or a similar multi-target site. For this reason, MSL would also be wasted on one of the 'windows' mentioned in a post above.

An ideal MSL site will have dozens of distinct targets within about 10 or 15 km of the landing site, plus a potential for a really good extended mission with many more targets over a much longer traverse.

Phil


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... because the Solar System ain't gonna map itself.
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climber
post Jul 13 2007, 04:06 PM
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QUOTE (Phil Stooke @ Jul 13 2007, 05:53 PM) *
Elysium Planitia (AKA ice pack) might look like a good landing site, but there are some problems with it. First, it might be classed as a "special region", which MSL will not be sufficiently sterilized to land in.

Can somebody explain me why some part of Phoenix are sterilized at 300.000 spore/m² while the arm is at 1 spore/m² (source Phoenix-Launch-presskit)?
I mean, why can we sterilize MSL with the later value at least for the parts in contact with Mars ?

PS : not only there is a risk of crash for MSL RTG's but also the Crane (or whaterver you call it) will definitively crash anyway.


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