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Posted by rgregoryclark on April 15, 2006, 3:43 pm
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rgregoryclark@yahoo.com wrote:
> With each factor of 10 improvement of visual resolution of Mars has
> come revolutionary changes in our understanding of the role of liquid
> water on Mars. What revolutionary improvement over the discovery of
> possibly currently forming gullies by MGS might we predict for MRO?
> I suggest small ponds will be observed by MRO on Mars, oases if you
> will. These will be analogous to Don Juan pond in Antarctica. Note that
> Don Juan pond is able to remain frozen year round down to perhaps -45 C
> temperatures because of abundant salts. The MER rovers suggest such
> salts are also abundant on Mars.
> I believe that such ponds have been seen by MGS, but they have been
> hard to prove at the resolution of MGS. I'm suggesting they will be
> proven by MRO. Note that the Malin-Edgett gullies were not discovered
> by Viking orbiter imaging, but the fact that THEMIS on Mars Odyssey has
> been able to detect them at similar resolution to the Viking orbiter
> resolution suggests they were visible by Viking, just not provably so.
>
> A *possible* example of ponding seen by MGS:
>
> Mars Orbiter Camera (MOC) High Resolution Images:
> Seepage and Ponding within a Southern Hemisphere Crater
> http://www.msss.com/mars_images/moc/5_27_98_agu_release/
>
> My guess for where they will be found is at near equatorial areas that
> are known to have low lying fogs or clouds:
>
> Clouds in Noctis Labyrinthis on Mars.
> http://www.photovault.com/Link/Universe/Planets/Mars/UPMVolume01/UPMV01P0=
2_06NoctisLabyr.html
>
> Note that the frost deposition on the MER Opportunity rover was
> observed in connection with clouds over the site. The fogs/clouds seen
> over Noctis Labyrinthis are much denser and closer to the surface.
> Indeed they look more like cumulus clouds than thin cirrus clouds,
> which is why I'm suggesting visible surface ponds with better
> resolution imaging. To be precise, I'm predicting such ponds will be
> seen during the period such low, dense fogs are seen over these near
> equatorial locations.
>
> Here is another image of the western end of Valles Marineris showing
> dense low lying fogs/clouds:
>
> http://img.villagephotos.com/p/2005-4/986073/marsiswet.jpg
>
> taken from:
>
> Adsorption water-driven processes on Mars.
> D. M=F6hlmann, DLR-PF, Berlin.
> FIRST MARS EXPRESS SCIENCE CONFERENCE. 21-25 February 2005, ESA/ESTEC
> http://sci.esa.int/science-e/www/object/doc.cfm?fobjectid=3D36779
>
>
> Another possible location for ponding is in Newton crater:
>
> Evidence for Recent Liquid Water on Mars:
> Channeled Aprons in a Small Crater within Newton Crater.
> http://www.msss.com/mars_images/moc/june2000/newton/
>
> At 41 S latitude, this is not a near equatorial site, but there are
> abundant low lying fogs in the image and the connection with gullies is
> suggestive.
>
> Another possible site may be the Hellas crater basin since this also
> presents frequent low lying fogs or clouds.
>
> Some MGS images of Hellas are here:
>
> MOC Narrow-Angle Image Gallery: Mars Chart 28: Hellas
> http://www.msss.com/moc_gallery/m07_m12/mc28.html
>
>
> Bob Clark
According to this news release, MRO comes to within 100 km of the
Martian surface at closest approach during aerobraking:
Mars cameras debut as NASA craft adjusts orbit
MISSION STATUS REPORT
Posted: April 13, 2006
"The orbiter is currently flying in very elongated loops around Mars.
Each circuit lasts about 35 hours and takes the spacecraft about 27,000
miles (43,000 kilometers) away from the planet before swinging back in
close.
"On Wednesday, a short burn of intermediate sized thrusters while the
orbiter was at the most distant point nudged the spacecraft to pass
from approximately 70 miles (112 kilometers) to within 66 miles (107
kilometers) of Mars' surface."
http://www.spaceflightnow.com/news/n0604/14mro/
At its final orbit it will be about 300 km above the surface. At that
distance the high resolution camera HIRISE is expected to have a
resolution of 0.28 meters per pixel.
But at the 100 km distance the resolution would be 1/3 this - 3.6
INCHES PER PIXEL(!)
Can MRO take high resolution imaging at closest approach during
aerobraking?
Bob Clark
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