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Mars Express Results
remcook
post Feb 20 2005, 11:24 AM
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http://physicsweb.org/articles/news/9/2/10/1

QUOTE
he latest results from Mars Express reveal that the surface of the red planet is much more diverse than previously thought, with evidence for the presence of hydrated sulphates, silicates and various rock-forming minerals. Space scientists working on the European Space Agency mission have just analysed the first nine months of data from the OMEGA instrument and published six papers that give the first detailed inventory of the entire Martian surface. Last year Mars Express identified frozen water at both the north and south poles of the planet.
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imran
post May 8 2005, 05:59 PM
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Jon Clarke's summary of Mars Express findings from the Vienna Conference.

QUOTE
Hi all

I have just got back from an amazing European Geoscience Union conference in Vienna. There must have been 10,000 people there. The titles alone of the talks require some 440 pages. Subjects included hydrology, atmospheric sciences, geophysics, sedimentology, petrology, oceanography, and planetary science. The pressures of time precluded me from seeing all I wanted to, plus I was there for work, so could not go to as many planetary science sessions as I wanted. Those I did attend were mainly on Mars, but I got to a few on the moon, Iapetus and Titan as well. I will post a few threads on these in the next day or so, but will start with current Mars missions. Make of them what you will

Jon

There were many papers on the results of Mars Express. Some highlights.

OMEGA (first V-NIR spectrometer sent to Mars, 300 m resolution) sulphate mapping presented by Gendrin et al. Extensive hydrated sulphates identified at various location and Valles Marinaris, in the north polar dune sea, and of course Terra Meridiani. There is very strong correlation between sulphates and layered terrain, down to single pixels. However not all pale layered units are sulphates. Strong correlation exists regionally between sulphates and iron oxides, locally they occur in different but juxtaposed beds. Opportunity landed some 400 km away from the thickest sulphate deposits in terra Meridiani, which include at least 100 m of very pure epsomite. The locally high abundance of epsomite in the polar erg was unexpected, suggests that some of the dunes are cemented by sulphate, supported in a poster by Schatz et al.. At low latitudes there is a good correlation between high levels of hydrogen reported in neutron spectroscopy and sulphates. It is possible to explain all the hydrogen as being near surface hydrated sulphates, although this does not preclude the presence of ices at depth, consistent with other evidence. The presenter also reminded the audience that not all hydrated sulphates are sedimentary – they can form via weathering and hydrothermal processes.

HRSC mapping of Gusev crater were presented by Pinet et al. HRSC reveals much greater variation in surface properties than identified by MOC and THEMIS, largely because of better resolution. Overall the properties resemble those of Apollinaris Patera to the north, this is consistent with the predominantly basaltic nature of the surface seen by Spirit. At 100 m resolution imaging of the Spirit site, three types of surface were identified – basalt, dunes, and the hills, confirming what was identified by the rover and allowing extrapolation to other areas beyond the rover’s reach.

HRSC and OMEGA investigations of Cerberus Fossae were presented by Voucher et al. MOLA data shows this area as having a very low (less than 0.1 degree) eastward slope, defining a very low relief shield volcano. The most recent basalt flows in the area arise from a series of tectonic fissures but not the most recent ones, giving the region its name. Water flows are, however from these recent troughs, giving rise to Athabasca Vallis. The shield volcano is probably 2 Ga, the most recent lava flows 10 Ma, as are the fluvial features.

Preuschmann et al. compared the morphology of parts of Valles Marinaris as revealed by HRSC with terrestrial subadjacent karst, where dissolution of soluble rocks underneath insoluble cap rocks causes collapse. A number of basalt plateaus overlying limestones in the Middle East show morphologies similar to those seen on Mars.

Van Gasselt et al. presented a very interesting poster on polygons in the South Polar Trough using MOLA and MOC data. The authors noted significant changes over a three-year period, clearly pointing to active permafrost.

A summary of the status of Mars methane was even by Encrenaz et al. She reviewed previous work to date, resent observations using the M-E PFS and future prospects. She considered the Formisano detection as marginal because of the poor spectral resolution and the Kransnopolsky study as marginal because of poor detection limits. The Mumma study (unfortunately the only one not yet fully published) was the best because of good spectral and spatial resolution. However, her attempts to duplicate this using the ME PFS observations were unsuccessful, although getting indicates of 10 ppb methane. However a few runs gave 20 ppb methane, suggesting that high methane production might be not only localized but also episodic. The best hope for Mars methane work in the short term appears to be in better ground based observations because of their better spectral and spatial resolution.
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ustrax
post Sep 7 2005, 02:05 PM
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Humm...

http://news.bbc.co.uk/1/hi/sci/tech/4219858.stm

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tty
post Sep 7 2005, 05:49 PM
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QUOTE (imran @ May 8 2005, 07:59 PM)
Extensive hydrated sulphates identified at various location and Valles Marinaris, in the north polar dune sea, and of course Terra Meridiani. There is very strong correlation between sulphates and layered terrain, down to single pixels. However not all pale layered units are sulphates. Strong correlation exists regionally between sulphates and iron oxides, locally they occur in different but juxtaposed beds. Opportunity landed some 400 km away from the thickest sulphate deposits in terra Meridiani, which include at least 100 m of very pure epsomite. The locally high abundance of epsomite in the polar erg was unexpected, suggests that some of the dunes are cemented by sulphate, supported in a poster by Schatz et al.. At low latitudes there is a good correlation between high levels of hydrogen reported in neutron spectroscopy and sulphates. It is possible to explain all the hydrogen as being near surface hydrated sulphates, although this does not preclude the presence of ices at depth, consistent with other evidence. The presenter also reminded the audience that not all hydrated sulphates are sedimentary – they can form via weathering and hydrothermal processes.


Now that is interesting since we know that the Meridiani sulphates are waterlaid evaporites. Such a thick evaporite layer means either a very deep brine pool (very unlikely considering the lack of topographic relief), or (more likely) a long period of evaporite deposition, or (most likely) a large number of shallow water evaporation episodes.
Were there any hints what the other pale layered deposits are? They could of course be eolian, but also non-sulphatic evaporites.

Also if the total depth of evaporites is <100 m thick near Opportunity it means that Victoria crater may have punched right through the evaporite layer and the underlying deposits might occur in the ejecta and be visible in situ in the crater.

tty
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antoniseb
post Sep 7 2005, 06:01 PM
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QUOTE (tty @ Sep 7 2005, 12:49 PM)
Also if the total depth of evaporites is <100 m thick near Opportunity it means that Victoria crater may have punched right through the evaporite layer and the underlying deposits might occur in the ejecta and be visible in situ in the crater.
*

And if not, what does that say about the maximum depth of the water that deposited these evaporites? Pretty deep, I'd say. How many meters of Earth Ocean water do you have to evaporate to get a meter of salt? (about 625). I'll grant that we don't know what the salinity was, but it still gives an order of magnitude idea of the depth.
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tty
post Sep 7 2005, 06:10 PM
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QUOTE (antoniseb @ Sep 7 2005, 08:01 PM)
And if not, what does that say about the maximum depth of the water that deposited these evaporites? Pretty deep, I'd say. How many meters of Earth Ocean water do you have to evaporate to get a meter of salt? (about 625). I'll grant that we don't know what the salinity was, but it still gives an order of magnitude idea of the depth.
*


No, because we have plenty of cases here on Earth where deep evaporite deposits were definitely created in a shallow water setting, as shown by sedimentological indications. It is the amount of water evaporated that matters, not the depth at any particular time.
Commercial salines produce vast amount of salts, but they are not deep, instead they evaporite a shallow layer of water again and again.

tty
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dvandorn
post Sep 7 2005, 07:55 PM
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QUOTE (tty @ Sep 7 2005, 12:49 PM)
...if the total depth of evaporites is <100 m thick near Opportunity it means that Victoria crater may have punched right through the evaporite layer and the underlying deposits might occur in the ejecta and be visible in situ in the crater.
*

We may not need to get all the way to Victoria to find examples of rocks ejected from below the evaporite layer.

Erebus is a larger crater than Victoria, albeit much, much older. And it may well have formed before the evaporite layer was complete (and thus its ejecta may have been covered with more evaporite, as well as having been altered by the standing water that must have covered it).

But we ought to expect to see fragments of Erebus ejecta embedded in some of the evaporite around Erebus. Some of it ought to have eroded out of the evaporite by now. It would look like, I don't know, cobbles of obviously different composition from the evaporite surrounding it, and also different from the basaltic dust and hematitic dust and concretions that make up the remainder of the ground mass.

In other words, I'm proposing that the dark cobbles we've been seeing in the interdunal areas are actually samples of the material that lies below the evaporite layer, that were ejected during the Erebus impact and have since been aqueously altered and embedded in evaporite. They've now been eroded out of the evaporite and are sitting out on the ground for Oppy to examine...

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dvandorn
post Sep 7 2005, 08:28 PM
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Following up on the idea I just proposed about the evaporite near Erebus incorporating Erebus ejecta, it now seems clear that the dark clasts we saw in the RAT holes Oppy made recently (someone suggested they might be incompletely-generated concretions) may actually be sand- and pebble-sized grains of Erebus ejecta that were embedded in the evaporite. I bet we see a higher percentage of such clasts in the evaporite "floor" as we approach the rim of Erebus.

That would definitely, *strongly* suggest that Erebus was formed before the evaporite deposition process was complete. Since the Erebus rim materials seem to be made, at least in part, of evaporite, I'd think that there had to have been evaporite there when the crater formed -- so the process had started. But finding Erebus ejecta incorporated into more recent layers of evaporite would almost be proof that Erebus was flooded, altered and eroded by liquid water, and partially covered by more evaporite before the waters receded for good.

The Erebus impactor may actually have impacted into water... though, at this stage of degradation, I don't know how you'd establish that.

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Rakhir
post Nov 5 2005, 09:54 PM
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Burned-up meteors add to Martian atmosphere

"A previously unknown layer has been detected in the atmosphere of Mars, which scientists believe is created when meteors burn up high above the planet's surface."

http://www.newscientistspace.com/article/d...atmosphere.html

Rakhir
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ljk4-1
post Feb 10 2006, 01:59 PM
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From ESA Bulletin 119:

ESA Portal Brings Europe’s Mars Adventure to Millions

Fulvio Drigani & Jurgen Scholz

http://www.esa.int/esapub/bulletin/bulleti...ul119_chap7.pdf


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Guest_AlexBlackwell_*
post Feb 16 2006, 05:55 PM
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The following paper is being published in the February 17, 2006, issue of Science:

Plasma Acceleration Above Martian Magnetic Anomalies
R. Lundin, et al.
Science 311, 980-983 (2006).
Abstract

Note: As I post this, I don't think the online embargo for this issue, which permits full access to the papers, has been lifted yet. I believe this is an automated feature of the website. Access should be available in a few hours.

Second note: Many ASPERA-3 papers are also currently in press with Icarus.
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Rakhir
post Feb 17 2006, 04:54 PM
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Light and shadow on the surface of Mars
http://www.esa.int/SPECIALS/Mars_Express/SEMG35MVGJE_0.html

Images, taken by the High Resolution Stereo Camera (HRSC) on board ESA’s Mars Express spacecraft, show the fast-moving shadow of the moon Phobos as it moved across the Martian surface.


Mars Express studies possible aurorae above Mars
http://www.esa.int/SPECIALS/Mars_Express/SEMSR5MVGJE_0.html

ESA’s Mars Express spacecraft has seen more evidence that aurorae occur over the night side of Mars, especially over areas of the surface where variations in the magnetic properties of the crust have been detected.
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elakdawalla
post Feb 17 2006, 06:28 PM
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QUOTE (Rakhir @ Feb 17 2006, 08:54 AM) *
Light and shadow on the surface of Mars
http://www.esa.int/SPECIALS/Mars_Express/SEMG35MVGJE_0.html

Images, taken by the High Resolution Stereo Camera (HRSC) on board ESA’s Mars Express spacecraft, show the fast-moving shadow of the moon Phobos as it moved across the Martian surface.


One of the images in this posting is a Flash animation of several frames of Phobos moving across the surface of Mars. Does anybody here know of a way to grab the animation in any save-able format? They don't provide a .gif, .avi, or .mov version to download.

--Emily


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Guest_AlexBlackwell_*
post Feb 17 2006, 06:40 PM
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QUOTE (elakdawalla @ Feb 17 2006, 06:28 PM) *
One of the images in this posting is a Flash animation of several frames of Phobos moving across the surface of Mars. Does anybody here know of a way to grab the animation in any save-able format? They don't provide a .gif, .avi, or .mov version to download.

I'm not sure if there is a freeware or shareware program available for this. However, you might try the trial version of "Flash Saver" to see if it works.

Of course, if you're willing to pony up the dollars, then there are a few programs to grab Flash animations. Sometimes, you can even manually scan through your browser cache and snag the files.
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Guest_AlexBlackwell_*
post Feb 17 2006, 10:48 PM
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QUOTE (Rakhir @ Feb 17 2006, 04:54 PM) *

The only thing that surprises me about this press release is that ESA doesn't claim that Mars Express is the first spacecraft to have imaged Phobos' shadow on the martian surface from orbit.

Mon dieu! Merde! Someone in the ESA press office must be asleep at the wheel! tongue.gif
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