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First 2009 MSL Landing Site Workshop
The Messenger
post Apr 26 2006, 03:20 PM
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If we really wanted to know if there are viruses on Mars, we would have Bill Gate's design the software.
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Stephen
post Apr 28 2006, 09:20 AM
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QUOTE (MaxSt @ Apr 25 2006, 05:11 PM) *
That's correct. But if the rover's goal is 100m per day, that's plenty of time to "stop and think" every 2-3m. Using a lot of RAM should help too. MRO has 20 Gb of memory, so I guess it shouldn't be a problem.
Well...yes. But how much of that 20 GB will actually be available in practice?
Data is stored in a 160 Gbit (20 GB) flash memory module consisting of over 700 memory chips, each with 256 Mbit capacities. This memory capacity is not actually that large, considering how much data is going to be acquired; for example, a single image from HiRISE camera can be as big as 28 Gbit [3.5 GB].

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Stephen
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djellison
post Apr 28 2006, 09:36 AM
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And - that storage is the slower non-volatile type. It's not 'Ram'.

If you want to process a lot of images for navigation purposes, you need plenty of ram with which to do it.

Strangely, I've never seen any reference to Hazcam's for MSL - I'm assuming they'll be installed front and rear- but will they be MER heritage, or fish-eye'd versions of the Mastcam electronics?

Either way - I think with improvements in software, we can get better at this than we are now. Compare current driving to, say, the drive to Bonneville crater - AND - we are due another MER software update in the not too distant future.

Doug
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Guest_BruceMoomaw_*
post Apr 29 2006, 08:59 AM
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Here's yet another personal estimate from me as to some of the particular interesting abstracts at this workshop. (Proceed at your own risk.)

http://marsoweb.nas.nasa.gov/landingsites/...SL_workshop.pdf : Nice summary of the general scientiic criteria for picking landing sites -- including the varying potentials of different types of rocks and minerals for preserving ancient fossil evidence.

http://marsoweb.nas.nasa.gov/landingsites/...SL_workshop.pdf : A related piece concluding, from analysis of Earth minerals, that sulfates actually do a much better job of preserving fossil organic compounds than hematite does. This is important -- and it may be related to Dawn Sumner's argument that what's likely to destroy fossil organics in an environment like Meridiani is the dissolved ferric iron in the water, more than the sulfuric acid: http://repositories.cdlib.org/cgi/viewcont...text=postprints

http://marsoweb.nas.nasa.gov/landingsites/...SL_workshop.pdf : The OMEGA team repeats its case for choosing one of the small areas of exposed Noachian phyllosilicates as the best possible places to look for fossil biological evidence. I still find this convincing.

http://marsoweb.nas.nasa.gov/landingsites/...SL_workshop.pdf : A proposal that MSL might land on the floor of a large crater with gullies on the walls and roll up to inspect the bottoms of the gullies. "In the Wirtz Crater in particular...there are well developed gullies with at least one impact crater on a gully apron deposit suggesting sufficient antiquity to satisfy possible constraints on investigations due to planetary protection requirements (i.e. there might be no threat that the gully with the impact crater can become active in modern times)." Maybe.

http://marsoweb.nas.nasa.gov/landingsites/...SL_workshop.pdf : Proposal to land in Arabia Terra, a very interesting region which is not only very rich in layered rocks that seem to be highly hydrated, but which may be one of Mars' main sources of methane.

http://marsoweb.nas.nasa.gov/landingsites/...SL_workshop.pdf : Proposal to land in Athabasca Valles, which -- on top of its other interesting attributes -- is showing some slight evidence of hydrated minerals in OMEGA's maps ( http://www.lpi.usra.edu/meetings/lpsc2006/pdf/1477.pdf ).

http://marsoweb.nas.nasa.gov/landingsites/...SL_workshop.pdf : Proposal to land in Nili Fossae, a site extremely rich in Noachian phyllosilicates nd just plain intereting all the way around. I suspect this will end up as one of the frontrunners.

http://marsoweb.nas.nasa.gov/landingsites/...SL_workshop.pdf : Proposal to land in Aram Chaos, a hematite site that may be more interesting (and acid-free) than Meridiani. (But see the cautions above about looking for fossil evidence in hematite deposits.)
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edstrick
post Apr 29 2006, 10:46 AM
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"...Proposal to land in Arabia Terra..."

I would be extremely negative on that for the MSL mission, though I would extremely strongly support it for one of a netlander type mission station.

Viking IRTM InfraRed Therml Mapper data showed that non-polar Mars is divided into essentially two types of areas: Low thermal inertia and Intermediate to High thermal inertia. Much of Arabia is a moderately high to high albedo reddish terrain consisting almost entirely of low inertia surfaces. Very few features within Arabia (such as isolated dark "splotches" in a few craters) have intermediate or high inertia. Much of Tharsis, including the 4 great shield volcanoes are in low inertia terrain, as is much of eastern Amazonis.

A low inertia areas' surface is essentially entirely covered to a depth of at least a few centimeters with uncemented dust with a probable mechanical consistancy of cement powder. They heat up very rapidly during the day and cool off very fast at night. Intermediate inertia surfaces have thermal properties of fine sand or somewhat cemented dust, while relatively rare high to very high inertia surfaces have thermal properties of coarse sand or well cemented, probably mechanically hard material. Viking, Pathfinder, and MER all landed in intermediate to moderately high inertia terrain.

Thermal inertia is primarily measured by sampling the diurnal heating cycle. An afternoon and a predawn measurement are enough for a decent estimate, though daytime surface albedo measurements help a lot to put absolute values on the numbers. Really accurate numbers require the entire day/night heating/cooling curve, not accessible to polar orbiting sun-synchronous orbiters.

Viking could also detect "brightness temperature" differences between the short wavelength thermal channels and the long wavelength one. Large cobbles and rocks cool off slower than fine sand or dust at night, and the surface -- if you could see it in infrared color -- would be studded with glowing "bluish" hot-rocks on a dully glowing "reddish" cold backgrouind. Signal-to-noise on the data was soso, and the rock abundance maps were crude, but matched the Viking landing sites well. MGS TES data have supplanted the Viking data in resolution and SNR, and the rock abuncance estimates match pathfinder and MER decently.

What does this mean? ..... Arabia and the low inertia regions in general have near-zero calculated rock abundance. They're buried or mantled with dust. This dust is *NOT* the last few years's dust storm dust. It does have weak geographic thermal and matching albedo variations, while areas of recently deposited dust in Viking images (pre-vs-post 1977 storm images) are uniform in areas where they appear thick and nearly continuous .... till wind starts eroding the fresh fallout. Instead, it's probably some dust mantle deposited during some recent climatic cycle and not eroded. Arabia seems to be heavily mantled with dust in MOC and THEMIS images, but this is not necessarily the same unit, since the low inertia deposits that control color and albedo in the low inertia regions are sensed to a maxium depth of a very few centimeters, and mantling maps do not seem to precisely match low inertia region boundaries.

Either way, in most any area in Arabia and any low inertia region, geologic exposure of material "of interest" to MSL will be atrocious at best and non-existant at worst. Like the entirely dusted high-albedo regions on the floor of Gusev (that Spirit most fortuitiously missed!) only far worse.
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Guest_BruceMoomaw_*
post Apr 29 2006, 12:55 PM
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Except that there seem to be a lot of areas in Arabia where there are very extensive displays of layered sedimentary rock -- and, given the small size of MSL's landing ellipse, the odds of its actually hitting one of them is vastly better than for past landers.
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edstrick
post Apr 30 2006, 07:29 AM
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The thermal data indicate that much of the rock is very poorly exposed. A meter to centimeters of caked-on dust or dust mantle would be utterly invisible in current imaging except indirectly, as color/albedo/thermal patterns, which is what seems to be the case.

here *are* exposures of higher inertia within Arabia, for example dark splotches with intermediate albedo margins on the floor of Henry crater lie on the crater bottom to either side of the *BIG* layered sedimentary pile in the middle of the crater, but these are rare and limited.

The layered sedimentary rock in the crater itself seemed in the Viking data to have the same inertia as typical Arabia material.

Full resolution HiRISE images and hyperspectral composition maps across the transitions between dark splotches, intermediate albedo / intermediate inertia reddish borders and the higher albedo / low inertia materials of Arabia will shed a lot of light on the problem.

I'd really love to put a netlander type payload down in absolutely representative Arabia terrain and give us some ground truth on these important regions, but that's not going to happen any time soon
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ustrax
post Jun 1 2006, 03:48 PM
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From Space.com:

Grant said that the current site constraints are very broad and allow consideration of sites at a range of elevations and latitudes not considered by Spirit and Opportunity Mars rover planners, for example.
...
Some scientists here are backing the Holden Crater region. Others suggest that Gale Crater is a feature likely to rise to the top of the must do list. Many point to a "no brainer" of an exploration hot spot—the huge canyon landscape of Valles Marineris.

"Valles Marineris looks good now … but remember the cold feet that the engineers got about this with Spirit and Opportunity. I wouldn’t be surprised if Valles Marineris eventually falls out of favor for engineering reasons," predicted one Mars researcher taking part in the workshop.



http://space.com/news/060531_msl_destination.html


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"Ride, boldly ride," The shade replied, "If you seek for Eldorado!"
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RNeuhaus
post Jun 5 2006, 01:27 AM
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Wrong place for the topic. Removed the post.

Rodolfo
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