Phoenix on Mars - Page 15

01101001 · #**421** (**permalink**) 02-August-2008, 04:38 PM

Quote:

Originally Posted by RGClark

On freezing, most of the salt is forced out of the ice matrix, so that the water ice can still be pure H2O even with salts present in the sample.

But, as it warmed in the oven, from its baseline temperature, up towards 0C, well before 0C, with the brine-making salts present, why didn't it liquefy? Or when Boynton says the ice melted at 0C, does he mean -10C or such?

===

It's time for useful links again. That last page filled fast.
NASA Phoenix Mission
University of Arizona Phoenix Mars Mission
University of Arizona Phoenix Mars Mission: Lander Gallery
JPL Phoenix Mission News
NASA Phoenix Twitter Feed
NASA Phoenix Multimedia
CSA Phoenix Mars Mission
Planetary Society: Phoenix Mission
Planetary Society: Phoenix Non-SSI Raw Images
Planetary Society: Phoenix Sol-By-Sol Summary
Planetary Society: Weblog
Emily Lakdawalla Ustream video chat (Wednesdays)
Texas A&M University Phoenix SSI Raw Images Directory
Unmanned Spaceflight Forum: Phoenix 2007/8
Google Mars landing site
NASA TV (or NASA TV Yahoo! source or high-resolution)
NASA TV Media Channel

nutant gene 71 · #**422** (**permalink**) 02-August-2008, 04:52 PM

Quote:

Originally Posted by 01101001

No. Again, the ice wasn't melting in Mars atmosphere. It was inside a sealed oven, and before it melted it probably sublimed some in the increasing warmth, as well as other volatile matter, if present, like CO2, turning gaseous. Inside that sealed compartment, the pressure was unlikely to be as low as Mars ambient.

(And, Mars air pressure is about 1% of Earth's 1 atmosphere.)

NASA Phoenix Mission Multimedia: June 20 Briefing Transcript:

Uhh... right, it's "melting" not boiling point. My Dumb-meter is set on 'high' today... need that second cuppacoffee.

01101001 · #**423** (**permalink**) 02-August-2008, 04:57 PM

Quote:

Originally Posted by nutant gene 71

Uhh... right, it's "melting" not boiling point. My Dumb-meter is set on 'high' today... need that second cuppacoffee.

It was boiling, too, after first melting, during the first heating to about room temperature. That's how they detected water vapor.

RBG · #**424** (**permalink**) 02-August-2008, 05:43 PM

I understand that relatively pure water ice can coexist with salty soils because the salts can be forced out of the ice while it is forming. That is probably one of the reasons I was reading that the ice-soil interface can be extra rich in various compounds.

I take it then that all the talk of the great variety of salts as quoted a few pages above is true, but what wasn't said then was that all these salts are in extremely low concentration.

I also take it that these low salt concentrations have nothing to do with the quotes from scientists about Mars being ideal soil with all the nutrients needed for growing asparagus, etc. Correct?

RBG

Olowkow · #**425** (**permalink**) 02-August-2008, 06:18 PM

Quote:

Peter Smith:
Only if the oven goes above, uh -- yes, actually, it probably does go through a liquid stage. As we heat the oven up above zero, uh, it will liquefy because the pressure is high enough. But remember, the boiling point of water on Mars at-at this pressure is four degrees Centigrade. So there's only a few degrees in which that-that material can go from ice to liquid and then to gas.

So the oven is "pretty much sealed", but not pressurized prior to heating? The pressure would be dependent then on the temperature and the amount of water. Kind of confusing given the bolded portion.

01101001 · #**426** (**permalink**) 02-August-2008, 06:25 PM

Quote:

Originally Posted by Olowkow

So the oven is "pretty much sealed", but not pressurized prior to heating? The pressure would be dependent then on the temperature and the amount of water. Kind of confusing given the bolded portion.

Peter Smith's not the TEGA guy, and this was extemporaneous; it's awkward phrasing not suitable for strict interpretation. To me, it's clear the bolded part, "this pressure", refers to Mars atmosphere, which is not the condition in the sealed oven.

With the Ideal Gas Law in mind, it's unsurprising that pressure would depend on temperature.

01101001 · #**427** (**permalink**) 02-August-2008, 08:26 PM

Quote:

Originally Posted by RBG

I also take it that these low salt concentrations have nothing to do with the quotes from scientists about Mars being ideal soil with all the nutrients needed for growing asparagus, etc. Correct?

Many nutrients can present themselves to roots as salt ions within salt solutions (for instance: potassium chloride or ammonium nitrate). I'm not sure to which specific low concentrations you refer -- I don't recall seeing a breakdown of the MECA WCL results -- but I'd expect some of them to be considered nutrients.

JonClarke · #**428** (**permalink**) 02-August-2008, 11:34 PM

Quote:

Originally Posted by RGClark

On freezing, most of the salt is forced out of the ice matrix, so that the water ice can still be pure H2O even with salts present in the sample.

Bob Clark

If you have pure ice in the presence of salt crustals the melting point is still depressed. That is why people put salt on roads, to melt pure ice. Iff the ice melted at zero degrees then there were no salts in the sample.

Jon

JonClarke · #**429** (**permalink**) 02-August-2008, 11:41 PM

Quote:

Originally Posted by RBG

I understand that relatively pure water ice can coexist with salty soils because the salts can be forced out of the ice while it is forming. That is probably one of the reasons I was reading that the ice-soil interface can be extra rich in various compounds.

I take it then that all the talk of the great variety of salts as quoted a few pages above is true, but what wasn't said then was that all these salts are in extremely low concentration.

I also take it that these low salt concentrations have nothing to do with the quotes from scientists about Mars being ideal soil with all the nutrients needed for growing asparagus, etc. Correct?

RBG

The first MECA wet cell showed that there was ~1000 ppm salts. That is low. So far we we have no evdience for a great veriaty of salts being present in any quantities. Hence the earlier comment about asparagus. Garden vegetables don't grow well in salty soil.

Jon

RGClark · #**430** (**permalink**) 03-August-2008, 12:25 AM

Quote:

Originally Posted by JonClarke

If you have pure ice in the presence of salt crustals the melting point is still depressed. That is why people put salt on roads, to melt pure ice. Iff the ice melted at zero degrees then there were no salts in the sample.

Jon

As you said, there was only a small amount of salt, so overall there would only be a small amount of freezing point depression. And there would also likely be some amount of ice that did not contact the salt.

Bob Clark

RGClark · #**431** (**permalink**) 03-August-2008, 01:08 AM

According to New Scientist, William Boynton suggested in the news conference that salts may have melted the ice in the soil to cause it to stick to the scoop:

Phoenix Mars lander 'tastes' first sample of water ice.
Updated 19:43 01 August 2008
"On 15 July, the team used a sort of drill called a rasp attached to the scoop to cut cores out of Snow White and collect the shavings in a compartment on the back side of the scoop. But when the scoop was turned upside down, the sample stuck to the walls inside. Martian salt may have melted the ice and made the soil sticky, says Boynton."
http://space.newscientist.com/articl...water-ice.html

Note that the ice just turning into a gas would not make the soil sticky. Keep in mind also that salts also depress the pressure requirements for liquid water as it does the temperature requirements.
Anyone have the transcript of the conference where Boynton says this?

Bob Clark

01101001 · #**432** (**permalink**) 03-August-2008, 07:20 AM

Quote:

Originally Posted by 01101001

Sol 67 Raw Images

In the batch were many kinda cool images from the MECA Optical Microscope (cousin of the provocative MECA Wet Chemistry Lab, the Phoenix instrument preferred by 4 out of 5 White House science advisors), like:

And the Optical delivery:

And, near Dodo-Goldilocks, the new Cupboard trench, which probably contributed the Optical sample:

Procyan · #**433** (**permalink**) 03-August-2008, 03:30 PM

Could someone explain what sorts of organics TEGA can detect? I understand that if you heat oils or perhaps PAH's, tholins etc volatiles will take off and then be "weighed" by the mass spec. But what about sugars, amino and nucleic acids or other really interesting organic molecules? Would they be volatilized too or just decompose at high T?

Also, could the conductivity meter on MECA discriminate among the possible group of:

pure ice, salty ice, salty water? If I had an ohm meter and a freeze dryer could I devise a simulation?

Finally why are the microscope pictures so fuzzy? At the modest magnification level we see, it should be razor sharp

Thanks

John Jones · #**434** (**permalink**) 03-August-2008, 05:26 PM

Amino acids (for one) would mostly decompose, but would release more nitrogen as the temp increased. The temperature at which this release occurred would be revealing.

suntrack2 · #**435** (**permalink**) 03-August-2008, 06:11 PM

What about water freezing point on mars, is it different in the central region as compare to the polar region! where it is learnt that "ice caps are present on mars in the polar region" !

01101001 · #**436** (**permalink**) 03-August-2008, 07:05 PM

I see Mars Phoenix her own self (or the Phoenix JPL-news-service-manager team member speaking through the lander sockpuppet), has twittered about the White House briefing, in reverse-chronological order, MarsPhoenix Twitter:

Quote:

@ganeshpuri89 That paragraph was referring to the team's June 26 announcement at http://tinyurl.com/5rajef Not same as finding life. about 12 hours ago from web in reply to ganeshpuri89

[...]

Reports claiming there was a White House briefing are also untrue and incorrect. about 13 hours ago from web

Heard about the recent news reports implying I may have found Martian life. Those reports are incorrect. about 13 hours ago from web

New York Times: Phoenix to Earthlings: I’ve Landed! Awesome! is about the MarsPhoenix Twitter page, and the voice behind it.

01101001 · #**437** (**permalink**) 03-August-2008, 08:07 PM

More factoids to chew on, skeptically:

Wired: Science Blog: Rumors Abound About 'Potential for Life' on Mars

Quote:

Wired.com reached Sam Kounaves, the mission's wet chemistry lab lead, by cell phone this morning. He quickly directed us to speak with NASA's PR representatives, but not before he said, simply, "Rumors are rumors."
[...]
Over at LiveScience, David Leonard hints, without sourcing or attribution, that a paper on the work is going to come out in the journal Science.

"The reason that all this seems so hush-hush is due to a future paper and press release that appears likely to pop out of the American Association for the Advancement of Science (AAAS) and its Science magazine," Leonard writes. "Whatever the poop is from the scoop that’s been studied by Phoenix, that information is purportedly going through peer-review."

LiveScience, Leonard David: Phoenix on Mars Life - Message From MECA

Quote:

[As recounted above]
All this delayed news seems like a replay of the August 1996 announcement regarding the “Mars rock” - ALH84001 - when AAAS/Science magazine tried to keep it all under embargo. And just like before, the Phoenix news seems to be leaking out around the edges.

Procyan · #**438** (**permalink**) 03-August-2008, 09:17 PM

Quote:

Originally Posted by suntrack2

What about water freezing point on mars, is it different in the central region as compare to the polar region! where it is learnt that "ice caps are present on mars in the polar region" !

My two cents: If the salt is 1 PPT, that is way too dilute to affect melting point is a significant way. The melting/freezing point for pure water will remain zero C. Pressure becomes significant when very high. Under high pressure water melts at lower temperature (as in ice skater who glides on thin film of water) But on Mars the ATM pressure is even lower than earths so the melting temperature remains zero celcius.

If enough salt is present then then the melt/freeze temp is depressed downward to -21 C. Colder and it all goes to solids. Good chart at http://www.ucalgary.ca/~kmuldrew/cry...o_chap6_1.html
so all water, pure or salty on Mars is solid, gas or chemically bound until it gets above -21, enough to melt saturated salt water if it exists.

But from my reading of some previous posts, or at least I think one possible argument is that beneath the soil, at the point were the soil meets the ice "bedrock", there may be a salt rich interface where liquid water may exist. In direct sunlight some heat would transfer into that layer. The thin air insulates. If there is enough salt and enough heat there there will be melt water. It could exist for short periods. As it vaporized it would cool the bulk liquid and it could refreeze into an aggregate of soil and ice in the scoop thingy.

Every 20 million years or so the Mars axis tilt increases to some 40 degrees off vertical. The cap melts and reforms over that time scale. The case can be made for extreme repeated freeze concentration of salt layers at the soil water interface creating boundary layers of extremely pure ice as well as saturated briney ices and precipitated solid salts. and for sufficient heat to release liquid salt water. Interesting things happen at boundary layers.

But at 8 mBar and say -20 C even saturated salt water would not last long. It would boil and refreeze or have such a high vapor pressure, it would soon evaporate. Dissolved salts reduce water vapor pressure but not enough to stablize liquid at Mars ATM. So no stable liquid water unless there is an extraordinary subterranean cycle to replace it or the humidity was very high. I can't find any humidity data on the Canadian site. Is that currently measurable on Mars? It must be very low because the extreme low temperatures that the south pole currently pulling out water and co2, right? Hope this makes some sense.

What I don't understand is why doesn't the solid ice bedrock sublime away? Do that have a temperature of that ice in situ?

I have a freeze dryer and too much time. I might try something. Unless its all been done. So please stop me before I break something.

This just in from WH: "Mars...its a Plant ...up in the sky. The General at NASA saw a lot of wet nutrinos . We own 2/3 NASA and so half that plant is mine. Run a Google on that!"

01101001 · #**439** (**permalink**) 03-August-2008, 09:25 PM

Sol 68 Raw Images have just begun to arrive. There are 4 so far, from MECA Optical Microscope.

John Jones · #**440** (**permalink**) 03-August-2008, 11:19 PM

Four words:

Molal Freezing Point Depression.

01101001 · #**441** (**permalink**) 04-August-2008, 12:22 AM

Quote:

Originally Posted by 01101001

Sol 68 Raw Images

And now comes the trench Neverland, at about the 12 o'clock position, between Cupboard (10 o'clock) and the old Snow White (2 o'clock):

I think it's time to include our trench map, the two new ones, Cupboard and Neverland, in yellow:

01101001 · #**442** (**permalink**) 04-August-2008, 01:10 AM

Emily Lakdawalla takes her turn at the Phoenix habitability rumor mill:

Planetary Society Weblog: Apparently there's something more exciting yet to be announced by Phoenix

Quote:

I don't have any more information on these rumors than is available elsewhere on the Internet. To summarize briefly: there is apparently some result from the Wet Chemistry Laboratory that is very interesting, having to do with the "past habitability" of Mars.

That's a little different: "past habitability". I still don't get that emphasis from Covault's Aviation Week article:

Quote:

Rather the data relate to habitability--the "potential" for Mars to support life--at the Phoenix arctic landing site, sources say.

01101001 · #**443** (**permalink**) 04-August-2008, 08:56 AM

Sol 69 Raw Images have begun arriving.

fredquimbo456 · #**444** (**permalink**) 04-August-2008, 10:53 AM

Quote:

Originally Posted by 01101001

That's a little different: "past habitability". I still don't get that emphasis from Covault's Aviation Week article

Same emphasis on "past habitability" from a new twitter entry:

Quote:

@bradinvegas My goal is to determine if Mars may have been habitable. There's lots of data to analyze on that, and no clear answer yet. about 2 hours ago from web in reply to bradinvegas

Briefing also denied again:

Quote:

@ganeshpuri89 Few days? I was here last night. I'm still busy collecting science data, lots to analzye as always. No WH briefing, though. about 2 hours ago from web in reply to ganeshpuri89

KaiYeves · #**445** (**permalink**) 04-August-2008, 01:43 PM

One year since launch- happy anniversary, Phoenix!

01101001 · #**446** (**permalink**) 04-August-2008, 03:55 PM

Oh, I like this headline, and the illustrious source the reporter consulted (waves):

Sydney Morning Herald: NASA's next small step may be into Martian manure

Quote:

HAVE they found poo on the Red Planet?
[...]
Jon Clarke, a geologist with Mars Society Australia, a group dedicated to Martian exploration, said the report had triggered a frenzy of interest. [...]

Asked to speculate yesterday on what it may have now found, Dr Clarke said the instrument was designed, among other things, to spot dissolved ammonium and nitrate salts.

"On Earth, if you have a lot of ammonium and nitrate it usually means there is organic activity. We excrete it as waste and other organisms use it."

It has a good wait-and-see ending:

Quote:

Dr Clarke said the predicted announcement "obviously … has to be bigger than the asparagus [announcement]". But it "could all be a storm in a tea cup". Just in case, "our ears are perked. We can't wait."

fredquimbo456 · #**447** (**permalink**) 04-August-2008, 08:08 PM

According to space.com the Covault story is dead in the water.

fredquimbo456 · #**448** (**permalink**) 04-August-2008, 10:16 PM

Nasa press release: perchlorate

01101001 · #**449** (**permalink**) 04-August-2008, 10:32 PM

[Oh no. I edited when I meant to quote. Now I have to reproduce the article I wiped. Excuse me while I cry... OK, here's my reconstuction...]

The perchlorate press release (from JPL): NASA Spacecraft Analyzing Martian Soil Data

Quote:

Within the last month, two samples have been analyzed by the Wet Chemistry Lab of the spacecraft's Microscopy, Electrochemistry, and Conductivity Analyzer, or MECA, suggesting one of the soil constituents may be perchlorate, a highly oxidizing substance. The Phoenix team has been waiting for complementary results from the Thermal and Evolved-Gas Analyzer, or TEGA, which also is capable of detecting perchlorate.
[...]
Confirmation of the presence of perchlorate and supporting data is important prior to scientific peer review and subsequent public announcements. The results from Sunday's TEGA experiment, which analyzed a sample taken directly above the ice layer, found no evidence of this compound.

"This is surprising since an earlier TEGA measurement of surface materials was consistent with but not conclusive of the presence of perchlorate," said Peter Smith, Phoenix's principal investigator at the University of Arizona, Tucson.

So, is the news perchlorate: yes, or perchlorate: no? Or is it perchlorate: yes, at the surface, but near the ice: no, not so much?

On my scorecard, I've got it:

2 MECA WCL samples: probably perchlorate.

First TEGA sample, surface: probably confirmatory of perchlorate.

Second TEGA sample, near ice: maybe not perchlorate everywhere.

Quote:

NASA will hold a media teleconference on Tuesday, Aug. 5, at 11 a.m. PDT (2 p.m. EDT), to discuss these recent science activities.

Teleconference, at NASA News Audio Live Streaming:
Tuesday, August 5, 1100 PDT
Tuesday, August 5, 1400 EDT
Tuesday, August 5, 1800 UTC

===

And what does this mean for my planned asparagus farming operation?

American Chemical Society, Science News: Perchlorate found in produce from around the world

Quote:

Just one serving of some fruits can contain enough perchlorate to exceed the National Academy of Sciences (NAS) safe daily dose by more than 25%, and wines and beers pack a bigger perchlorate punch than waters, according to a new study that measures perchlorate concentrations in fruits, wines, and beers from around the world. The findings are further evidence that risk models for what is turning out to be a widespread contaminant need to be revised.

High levels of perchlorate were found in cantaloupe and grapes from Central and South America. Perchlorate is well known as a major component in rocket fuel, but the chemical also forms naturally. In sufficient amounts, perchlorate disrupts the thyroid by inhibiting the uptake of iodide, an essential component of thyroid hormones.

Broker, sell all my shares of Green Valley Martian Asparagus Farms Ltd. Place all proceeds into Gottago Martian Rocket Fuel Mining Inc. Now.

01101001 · #**450** (**permalink**) 04-August-2008, 11:20 PM

Emily Lakdawalla to the rescue...

Planetary Society Weblog: The Phoenix flap

Quote:

The Wet Chemistry Lab component of the MECA instrument has now analyzed two Mars soil samples. In both (I think), the MECA results indicate that one of the components of the soil may be an ion called perchlorate (ClO4-), which is an oxidizer. Oxidizers can do bad things to organic molecules, so its presence -- if confirmed -- would suggest that the past environment preserved in the soil at Phoenix' landing site was not conducive to life.
HOWEVER, the TEGA instrument is also capable of detecting perchlorate. There have been two analyses of samples by TEGA. In one, the data could have been consistent either with the presence or absence of the perchlorate ion in the soil. In the other, the data suggested that perchlorate was NOT present.
The Phoenix team is currently working -- but is not yet done with the process -- to rule out the possibility that the perchlorate detection by MECA could have resulted from contamination brought from Earth.

There. That's it. An interesting result from chemical analysis by one instrument that was contradicted (or at least not confirmed) by another one. Data from a spacecraft that's difficult to understand, causing (I assume) head-scratching and internal debate on the science team. They're no doubt hashing it out in their science meetings, tossing around possible interpretations, devising tests that the spacecraft can perform that can confirm or refute their interpretations. It's the scientific process in the middle of operating.

Later...

Quote:

Somehow, though, late last week, this non-story blew up on the Internet into the possible detection of life on Mars. How did that happen? The Phoenix team was minding its own business, doing, in my opinion, a good job with public communication.

Of course, there are also unofficial channels. Reporters are always in communication with people in mission press offices and people on science and engineering teams. Reporters who have been in the business for a while often have friends inside mission operations, people they're on good terms with, who can be trusted to comment on or off the record to clarify a story or to give a heads up that something interesting is coming down the pipeline.
[...]
The problem is that no special briefing happened. Without that, the "discovery concerning the potential for life' is suddenly much less interesting. [...]

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