Phoenix surface mission

3488 · Jun 17, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Images from teleconference.Color of Dodo and Goldilocks,Elevation of Dodo-Goldilocks.Pink is highest, Blue is about 20 cm (7-8 inches) below.The trenches have been combined. At the back is the edge of a polygon with ice/salt. Note there is none in the front which is in a trough.MW Posted by MeteorWayne</DIV>Cheers Wayne,Had problems last night with my connection. BTW happy anniversary of your birth.. <img src="http://sitelife.space.com/ver1.0/Content/images/store/0/6/904a46d2-5a3d-4765-b66f-33f87befb32e.Medium.gif" alt="" />  <img src="http://sitelife.space.com/ver1.0/Content/images/store/15/0/bf149089-13e4-4d92-906a-f4a17cf6488f.Medium.gif" alt="" /> <img src="file:///C:/DOCUME%7E1/ADMINI%7E1/LOCALS%7E1/Temp/moz-screenshot-1.jpg" alt="" /><img src="file:///C:/DOCUME%7E1/ADMINI%7E1/LOCALS%7E1/Temp/moz-screenshot-2.jpg" alt="" />Does anyone know when the next formal update is due, audio or NASA TV?Sol 21 Weather Report. <img src="http://sitelife.space.com/ver1.0/Content/images/store/4/13/54755e55-3e8a-4ef5-9d82-7c27a767fd7f.Medium.jpg" alt="" />  Getting colder.Sol 21 Max -30 C / -22 F.Sol 21 Min: -81 C / -113.8 F. Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

duke_the_nuke · Jun 17, 2008

Oh boy yet another Mars lander to send us back pics of, surprise, more red sand and rocks, complete with giddy JPL nimrods naming the rocks after nursery rhyme characters...oh look at bugs bunny daffy pooh rock..and that hole we just dug is humpty dumpty's fluffy pooh bed! gag me.. at least the Viking crews behaved like adults. <div class="Discussion_UserSignature"> </div>

a_lost_packet_ · Jun 17, 2008

A couple of questions:  It's my understanding that the TEGA-MS threshold limits for water vapor would be on the order of sub-parts per billion.  Is that correct?There are 8 single-use TEGA ovens?How far up on the charts is confirming the existence of water and would oven "shots" be redelegated to specifically searching for water if we continue to draw blanks?  Or, is there a point at which other science takes precedent and analysis for water vapor won't be actively pursued?Pardon my ignorance.  I haven't been keeping up with this stuff like I should.PS - Happy B-Day MW!  Have a cold one on me!  <div class="Discussion_UserSignature"> I put on my robe and wizard hat... </div>

a_lost_packet_ · Jun 17, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Oh boy yet another Mars lander to send us back pics of, surprise, more red sand and rocks, complete with giddy JPL nimrods naming the rocks after nursery rhyme characters...oh look at bugs bunny daffy pooh rock..and that hole we just dug is humpty dumpty's fluffy pooh bed! gag me.. at least the Viking crews behaved like adults. Posted by duke_the_nuke</DIV>It's better than.."There's rock #1.""There's rock #2.""There's rock #3.""Which rock was #1?""ARRGH, you made me loose count!"Actually, naming the rocks helps everyone, particularly the public, get "into" it.  They become a bit more personal and it's easier to look at them as "special" rather than just staring at Rock#A-134 for six hours.  I like their naming conventions for rocks.  It'd be interesting to find out who had the final word on that.  "That looks like Fred's butt!""Sorry, Ted.  "Fred's Butt" is not acceptable."  <div class="Discussion_UserSignature"> I put on my robe and wizard hat... </div>

Mee_n_Mac · Jun 17, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>How quickly can they get a sample into that TEGA oven without all the volatiles sublimating away? Would it be possible to practice the manoever with the engineering model on earth and then send the series of commands to dig, dump close oven door in one sequence without waiting for confirmation of each little move which seems to take hours. It seems that speed may be the essence if the want to get a near pristine sample into that oven. I'm probably missing something but its just a thought. Posted by MarkStanaway</DIV> Aside from the quickness, I think I'm missing something as well. In my usual long winded fashion let me ask a question.  TEGA sample #1 didn't show any signs of water.  Supposition is that it sublimed away while sitting on the mesh awaiting entry to TEGA.  Does this make sense ?  I ask because I (no doubt wrongly) think of things this-a-way.  If there's any water ice in the near surface soil, it hasn't sublimed away because the temperature is too low and pressure is too high. I can't believe there's that big a pressure differential between the surface and the lander's topside. The only way I can see a temperature differential is if the solar gain of the lander's topside is significantly greater than the soils (or the lander through it's electrical consumption is warmer near TEGA's mouth).  Is there any measurement (or engineering calculations) to confirm this ?  Otherwise water ice, if it can survive in the near surface soil, should be just as "happy" on the lander as it is on the surface.  Can "we" put any quantitative substance behind our sublime speculation* ?Related question : Do "we" know what the subsurface temperatures are, for perhaps the 1'st few meters below the surface ?(*or is it just so obvious that I'm a poopie head for not seeing it) <img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-laughing.gif" border="0" alt="Laughing" title="Laughing" /> <div class="Discussion_UserSignature"> -----------------------------------------------------Ask not what your Forum Software can do do on you,Ask it to, please for the love of all that's Holy, STOP ! </div>

MeteorWayne · Jun 17, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>A couple of questions:  It's my understanding that the TEGA-MS threshold limits for water vapor would be on the order of sub-parts per billion.  Is that correct?</DIV>Got me on that one!Replying to: <DIV CLASS='Discussion_PostQuote'>There are 8 single-use TEGA ovens?</DIV>That is correct, so care must be taken in selecting material.Replying to: <DIV CLASS='Discussion_PostQuote'>How far up on the charts is confirming the existence of water and would oven "shots" be redelegated to specifically searching for water if we continue to draw blanks?  Or, is there a point at which other science takes precedent and analysis for water vapor won't be actively pursued?Pardon my ignorance.  I haven't been keeping up with this stuff like I should.</DIV>I think it's just too early to say. Figure there's about 10 weeks left in the primary mission, so one every 10 days would be an average. But they still have done no digging yet in the "National Park". The next sample will come from the center of a polygon, and would be expected to contain water ice when they get deep enough. I really don't think finding water ice to analyze will be a problem if this site comes out as they expected.Replying to: <DIV CLASS='Discussion_PostQuote'>PS - Happy B-Day MW!  Have a cold one on me!  Posted by a_lost_packet_</DIV>Thanx, the next one is yours!! <img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-laughing.gif" border="0" alt="Laughing" title="Laughing" /> <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

silylene old · Jun 17, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Aside from the quickness, I think I'm missing something as well. In my usual long winded fashion let me ask a question.  TEGA sample #1 didn't show any signs of water.  Supposition is that it sublimed away while sitting on the mesh awaiting entry to TEGA.  Does this make sense ?  I ask because I (no doubt wrongly) think of things this-a-way.  If there's any water ice in the near surface soil, it hasn't sublimed away because the temperature is too low and pressure is too high. I can't believe there's that big a pressure differential between the surface and the lander's topside. The only way I can see a temperature differential is if the solar gain of the lander's topside is significantly greater than the soils (or the lander through it's electrical consumption is warmer near TEGA's mouth).  Is there any measurement (or engineering calculations) to confirm this ?  Otherwise water ice, if it can survive in the near surface soil, should be just as "happy" on the lander as it is on the surface.  Can "we" put any quantitative substance behind our sublime speculation* ?Related question : Do "we" know what the subsurface temperatures are, for perhaps the 1'st few meters below the surface ?(*or is it just so obvious that I'm a poopie head for not seeing it) Posted by mee_n_mac</DIV>The rate of sublimation depends on:Surface area - scraped particulate ice has maximum surface areaRate heat is transferred into the ice.  Ice particles exposed to sunlight will be absorbing  infrared light, and subliming.Temperature and pressure and humidity. Again, Mars is actually rather warm in the sunlight, near the surface.  And the low pressure of its atmosphere gives a high sublimation rate, especially if the air above it is swept away to maintain a very low humidity.Basically, leaving ice scrapings in an open scoop for a few days, exposed to the sun, is a very good way to maximize the sublimation rate. All that said, i always thought these were salts, and not ices.  But had they been ice, we may have lost the ice before it was analyzed. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center">- - - - - - - - - - - - - - - - - - - - - - </div><div class="Discussion_UserSignature" align="center">I really, really, really miss the "first unread post" function. </div> </div>

thor06 · Jun 17, 2008

New images.  Am I correct, this is the new trench in national park? <img src="http://sitelife.space.com/ver1.0/Content/images/store/6/8/264b782d-b673-45ed-a825-6eb5bd5b3763.Medium.jpg" alt="" />I found this one interesting as well <img src="http://sitelife.space.com/ver1.0/Content/images/store/9/8/19c4dbaa-e9bf-4435-88e2-1cd6593b070b.Medium.jpg" alt="" /> trough in a trough..... thruster? shovel? natural?These are raw, I'm looking forward to andrew and rbl's magic.  <div class="Discussion_UserSignature"> www.watchnasatv.com ONE PERCENT FOR NASA! </div>

MeteorWayne · Jun 17, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>New images.  Am I correct, this is the new trench in national park? I found this one interesting as well  trough in a trough..... thruster? shovel? natural?These are raw, I'm looking forward to andrew and rbl's magic.  Posted by thor06</DIV> What's the source? <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

3488 · Jun 17, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'> Related question : Do "we" know what the subsurface temperatures are, for perhaps the 1'st few meters below the surface ? (*or is it just so obvious that I'm a poopie head for not seeing it) <img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-laughing.gif" border="0" alt="Laughing" title="Laughing" />Posted by mee_n_mac[/QUOTE]Hi mee_n_mac. No not at all, it is a very sensible question. Myself I do not know the correct answer, but I think I can give an educated guess. As silylene pointed out, the martian surface can get quite warm (not sure at this latitude though). I know at the Mars Pathfinder site in Ares Vallis, the ground got up to about 10 C / 50 F, but 1.5 metres above that it was -7C / 19 F, a drop of 17 C in the space of the height of a person (you could keep your feet warm, but your head could freeze), another reading by MPF was ground temp 0C / 32 F, 1.5 metres up - 17 C / 1 F, so the difference appeared to not change much, except at night, when they were near enough equal, approx -90 C / -130 F.To me, this suggests only the top most layer warms up, but a short way down, it remains cold. My guess therefore, is for the first few metres down, it is frigid cold, almost cryonic. Deeper stil, many a few tens of metres, like caves (away from volcanic areas) on Earth, tend be be a fairly constant moderate temperature. Obviously much lower down, it probably warms up again as one approaches the mantle, but that is many km down.  Replying to: <DIV CLASS='Discussion_PostQuote'>New images.  Am I correct, this is the new trench in national park? I found this one interesting as well  trough in a trough..... thruster? shovel? natural?These are raw, I'm looking forward to andrew and rbl's magic.  Posted by thor06</DIV>Hi thor06,I see the new Sol 22 images are down, must go & look myself. Yes I think you are correct. Looking at the first image it does look like a new thrench has been oped in 'National Park' Regarding the second image IMO, they are thruster blast striations. Their orientation would fit with that theory. The small stones are interesting, if that is indeed what some of them are, as they look so bright, ice or salts?????????  But lighting geometry can make normal stones appear bright!!!!!!! I will have a go with the images, see what I can do.Andrew Brown.  <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

Mee_n_Mac · Jun 17, 2008

Let me argue a few points below and perhaps learn something ...  Replying to: <DIV CLASS='Discussion_PostQuote'>The rate of sublimation depends on:Surface area - scraped particulate ice has maximum surface area. Posted by silylene</DIV>True but this would imply that the water ice, if present, hadn't already had sufficient time since it formed to sublime away.  I guess I could believe it if ice were forming at night and subliming away during the day but I didn't think this was the case. I thought the ice, if present, would have formed last winter and been subliming away since unless ... (see below).Replying to: <DIV CLASS='Discussion_PostQuote'>Rate heat is transferred into the ice.  Ice particles exposed to sunlight will be absorbing  infrared light, and subliming. Posted by silylene</DIV>Agreed but is this expected to be much different in the scoop or on TEGA's topsides vs on the surface ? I thought we were dealing with soil from only a few CM deep. Would the temps be that much different from surface to a few CM deep ? Or from a few CM deep to sitting in the scoop ?  The RA has a temp probe on it. Does anyone have the data from when it was in contact with the surfave vs when it was sitting poised above TEGA ?Replying to: <DIV CLASS='Discussion_PostQuote'>Temperature and pressure and humidity. Again, Mars is actually rather warm in the sunlight, near the surface.  And the low pressure of its atmosphere gives a high sublimation rate, especially if the air above it is swept away to maintain a very low humidity.Basically, leaving ice scrapings in an open scoop for a few days, exposed to the sun, is a very good way to maximize the sublimation rate. All that said, i always thought these were salts, and not ices.  But had they been ice, we may have lost the ice before it was analyzed.  Posted by silylene</DIV> So if the soil somehow made a non- or semi- permeable covering over the underlying ice, I can see how the sublimation rate would be different. Do "we" think that's a possibility ?  I can see how increasing the surface area increases the rate but if all the water was gone in a few Sols could the difference in rates be that large or is it better explained by the no ice scenario ?  Wouldn't ice from last winter already have sublimed away in the top few CM of soil ?  Is ice a better absorber of insolation than the soil ? If not, then barring the lander have a higher temp for the aforementioned reasons then how much more heat would have been delivered to the sample vs when it was on the surface ? I guess I'm playing the devil's advocate here to see if the present thinking holds water (<img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-foot-in-mouth.gif" border="0" alt="Foot in mouth" title="Foot in mouth" />).  No doubt when another sample is processed in a way that would minimize the potential for sublimation, we'll know for sure.  Until then it's all good fun to muse over it. <div class="Discussion_UserSignature"> -----------------------------------------------------Ask not what your Forum Software can do do on you,Ask it to, please for the love of all that's Holy, STOP ! </div>

Philotas · Jun 17, 2008

Now this is weird; about three or four of the sol 22 images were made avaible on the Phoenix site at least 10 hours ago. <div class="Discussion_UserSignature"> </div>

MeteorWayne · Jun 17, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Now this is weird; about three or four of the sol 22 images were made avaible on the Phoenix site at least 10 hours ago. Posted by Philotas</DIV> Which Phoenix site (there are at least 3) and which images? <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

3488 · Jun 17, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'> No doubt when another sample is processed in a way that would minimize the potential for sublimation, we'll know for sure.  Until then it's all good fun to muse over it. Posted by mee_n_mac</DIV>That's partly the fun about these things. This is a totally alien environment compared to what we are used to on Earth. Also we have not had a successful landing on Mars this far from the tropics in either hemisphere before. Phoenix is some 44 degrees north of the Tropic of Aquarius, (on Tuesday 24th June 2008, the Sun will rise to 46 degrees above the southern horizon, only just over half way up in the martian sky) or 68 north latitude, or only 22 degrees south of the North Pole. After next Tuesday, the Summer Solstice at the Phoenix site, well the entire northern hemisphere of Mars in fact, the sun will start dropping back, though there will not be much change for a little while. We have never before been to a site quite like this, so the interplay of soil particles, ice, 38% Earth gravity, vastly reduced solar energy (averaging 44% of Earth's) etc is all new stuff here at this northerly location on the Red Planet. Both MERs landed in the tropics, Mars Pathfinder & the Viking Landers in the mid latitudes, so this is very different with Phoenix. Andrew Brown.  <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

thor06 · Jun 17, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>What's the source? Posted by MeteorWayne</DIV>Hey MW, I'm sure you have them now but if not:http://phoenix.lpl.arizona.edu/gallery.php sorry for not posting the link before. note:  The site changed since I looked at it 1hr ago.  before catagories were sol based 21 22 etc. and showed all the raw images.    Weird... <img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-tongue-out.gif" border="0" alt="Tongue out" title="Tongue out" /> ahahaa im an idiot here they are:http://phoenix.lpl.arizona.edu/imageCategories_lander.php <div class="Discussion_UserSignature"> www.watchnasatv.com ONE PERCENT FOR NASA! </div>

thor06 · Jun 17, 2008

I'm chomping at the bit to get a new pic of the "chunk".  Is it still there?....If not, it's likely  it is an "ice chunk" that sublimated.correct?  <div class="Discussion_UserSignature"> www.watchnasatv.com ONE PERCENT FOR NASA! </div>

MeteorWayne · Jun 17, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>I'm chomping at the bit to get a new pic of the "chunk".  Is it still there?....If not, it's likely  it is an "ice chunk" that sublimated.correct?  Posted by thor06</DIV> Well there don't appear to be any images of there on Sol 22, and on Sol 21, it appears they might have done more digging. In any case, the location of the chunk would have been in the shadow, so we wouldn't have been able to see it.From previous comments, I can't believe they would have diturbed it, since leaving it there and watching would yield some EXTREMELY useful data. Just can't tell yet. Images without context only tell you so much.... <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

thor06 · Jun 17, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Well there don't appear to be any images of there on Sol 22, and on Sol 21, it appears they might have done more digging. In any case, the location of the chunk would have been in the shadow, so we wouldn't have been able to see it.From previous comments, I can't believe they would have diturbed it, since leaving it there and watching would yield some EXTREMELY useful data. Just can't tell yet. Images without context only tell you so much.... Posted by MeteorWayne</DIV> Agreed, I'm itching to call, but don't want to bother them.  I don't have credentials/affiliation, yet....  <div class="Discussion_UserSignature"> www.watchnasatv.com ONE PERCENT FOR NASA! </div>

thor06 · Jun 17, 2008

It is National Park, full story:http://phoenix.lpl.arizona.edu/ <div class="Discussion_UserSignature"> www.watchnasatv.com ONE PERCENT FOR NASA! </div>

Philotas · Jun 18, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Which Phoenix site (there are at least 3) and which images? Posted by MeteorWayne</DIV> The Arizona site. (http://phoenix.lpl.arizona.edu/images.php?gID=0&cID=78) Three images were out; all of the new trench. <div class="Discussion_UserSignature"> </div>

MeteorWayne · Jun 18, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>The Arizona site. (http://phoenix.lpl.arizona.edu/images.php?gID=0&cID=78) Three images were out; all of the new trench. Posted by Philotas</DIV> Excerpt from the Snow White trench image explanation.June 17, 2008 -- NASA's Phoenix Mars Lander began digging in an area called "Wonderland" early Tuesday, taking its first scoop of soil from a polygonal surface feature within the "national park" region that mission scientists have been preserving for science. The lander's Robotic Arm created the new test trench called "Snow White" on June 17, the 22nd Martian day, or sol, after the Phoenix spacecraft landed on May 25. Newly planned science activities will resume no earlier than Sol 24 as engineers look into how the spacecraft is handling larger than expected amounts of data. During Tuesday’s dig, the arm didn't reach the hard white material, possibly ice, that Phoenix exposed previously in the first trench it dug into the Martian soil. That's just what scientists both expected and wanted. The Snow White trench is near the center of a relatively flat hummock, or polygon, named "Cheshire Cat," where scientists predict there will be more soil layers or thicker soil above possible white material. The Snow White trench is about two centimeters deep (about three-quarters of an inch) and 30 centimeters (about a foot) long. The Phoenix team plans at least one more day of digging deeper into the Snow White trench. <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

silylene old · Jun 18, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Let me argue a few points below and perhaps learn something ... True but this would imply that the water ice, if present, hadn't already had sufficient time since it formed to sublime away.  I guess I could believe it if ice were forming at night and subliming away during the day but I didn't think this was the case. I thought the ice, if present, would have formed last winter and been subliming away since unless ... (see below).Agreed but is this expected to be much different in the scoop or on TEGA's topsides vs on the surface ? I thought we were dealing with soil from only a few CM deep. Would the temps be that much different from surface to a few CM deep ? Or from a few CM deep to sitting in the scoop ?  The RA has a temp probe on it. Does anyone have the data from when it was in contact with the surfave vs when it was sitting poised above TEGA ?So if the soil somehow made a non- or semi- permeable covering over the underlying ice, I can see how the sublimation rate would be different. Do "we" think that's a possibility ?  I can see how increasing the surface area increases the rate but if all the water was gone in a few Sols could the difference in rates be that large or is it better explained by the no ice scenario ?  Wouldn't ice from last winter already have sublimed away in the top few CM of soil ?  Is ice a better absorber of insolation than the soil ? If not, then barring the lander have a higher temp for the aforementioned reasons then how much more heat would have been delivered to the sample vs when it was on the surface ? I guess I'm playing the devil's advocate here to see if the present thinking holds water ().  No doubt when another sample is processed in a way that would minimize the potential for sublimation, we'll know for sure.  Until then it's all good fun to muse over it. Posted by mee_n_mac</DIV>Replying to  mee_n_mac:<div class="Discussion_PostQuote">The rate of sublimation depends on:Surface area - scraped particulate ice has maximum surface area. Posted by silylene</div> mee_n_mac: True but this would imply that the water ice, if present, hadn't already had sufficient time since it formed to sublime away.  I guess I could believe it if ice were forming at night and subliming away during the day but I didn't think this was the case. I thought the ice, if present, would have formed last winter and been subliming away since unless ... (see below).Yes, the putative ice would have formed last winter and is subliming away.  Subliming ice tends to form low surface area deposits.  Assume the putative ice is opriginally present as a nodule below the surface.  The shovel then disturbs and scrapes the ice, turning it into scrapings, vastly increasing the ice surface area.  What we saw in the shovel was a white dust, and if this was ice it was frosts and/or scrapings.+++++++<div class="Discussion_PostQuote">Rate heat is transferred into the ice.  Ice particles exposed to sunlight will be absorbing  infrared light, and subliming. Posted by silylene</div> mee_n_mac: Agreed but is this expected to be much different in the scoop or on TEGA's topsides vs on the surface ? I thought we were dealing with soil from only a few CM deep. Would the temps be that much different from surface to a few CM deep ? Or from a few CM deep to sitting in the scoop ?  The RA has a temp probe on it. Does anyone have the data from when it was in contact with the surfave vs when it was sitting poised above TEGA ?Ices covered by opaque soils are shaded from direct sunlight.  The ices buried under a few cm of soil, before the trench was dug, are shaded.  Thus they are not exposed to direct sunlight.  In addition, the very cold permafrosts below the near-surface ice deposits are a huge heat sink, and these will moderate the temperature from the daily heating / cooling cycles, basically just keeping the sub-surface ices uniformly cold.On the other hand, putative ice shavings in the scoop are exposed directly to sunlight, and have no giant thermal sink to moderate the daily warming temperatures.  And the Martian air blowing over the soil sample in the scoop is very, very dry.+++++++++<div class="Discussion_PostQuote">Temperature and pressure and humidity. Again, Mars is actually rather warm in the sunlight, near the surface.  And the low pressure of its atmosphere gives a high sublimation rate, especially if the air above it is swept away to maintain a very low humidity.Basically, leaving ice scrapings in an open scoop for a few days, exposed to the sun, is a very good way to maximize the sublimation rate. All that said, i always thought these were salts, and not ices.  But had they been ice, we may have lost the ice before it was analyzed.  Posted by silylene</div> mee_n_mac:  So if the soil somehow made a non- or semi- permeable covering over the underlying ice, I can see how the sublimation rate would be different. Do "we" think that's a possibility ?  I can see how increasing the surface area increases the rate but if all the water was gone in a few Sols could the difference in rates be that large or is it better explained by the no ice scenario ?  Wouldn't ice from last winter already have sublimed away in the top few CM of soil ?  Is ice a better absorber of insolation than the soil ? If not, then barring the lander have a higher temp for the aforementioned reasons then how much more heat would have been delivered to the sample vs when it was on the surface ?Again, the putative ice below the top few cm of soil is in contact with a huge thermal sink (the frigidly cold ice and rocks below it), and this very much moderates the daily heat/cool cycles.  And it is shielded from direct sunlight by opaque soil above it.  And finally, the local humidity within the soil a couple mm above the ice is much higher than the humidity in the Martian atmosphere.Next winter, if you live in a location with cold winters, on some day when the air temperature is below -20C or so, do some experiments:  ice nodule vs shaved ice vs ice covered by soil vs ice in the sun vs ice shaded vs ice with an enclosed higher humidity environment, etc.  Observe and measure the sublimation rates. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center">- - - - - - - - - - - - - - - - - - - - - - </div><div class="Discussion_UserSignature" align="center">I really, really, really miss the "first unread post" function. </div> </div>

exoscientist · Jun 18, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>The rate of sublimation depends on:Surface area - scraped particulate ice has maximum surface areaRate heat is transferred into the ice.  Ice particles exposed to sunlight will be absorbing  infrared light, and subliming.Temperature and pressure and humidity. Again, Mars is actually rather warm in the sunlight, near the surface.  And the low pressure of its atmosphere gives a high sublimation rate, especially if the air above it is swept away to maintain a very low humidity.Basically, leaving ice scrapings in an open scoop for a few days, exposed to the sun, is a very good way to maximize the sublimation rate. All that said, i always thought these were salts, and not ices.  But had they been ice, we may have lost the ice before it was analyzed. Posted by silylene</DIV>  The TECP instrument is planned to be used when they sample Wonderland in the next few days. Looking forward to those ground temperature readings.   Bob Clark   <div class="Discussion_UserSignature"> </div>

3488 · Jun 18, 2008

Cheers everyone for your updates & comments on here today. I am really not feeling well right now, in fact my condition has played up quite badly today, though I'm feeling much better now than earlier today. I have'nt chimed in, as I would just post gobbydegook crap (so no change there then) as simply I cannot think that straight right now. Replying to: <DIV CLASS='Discussion_PostQuote'> Excerpt from the Snow White trench image explanation.June 17, 2008 -- NASA's Phoenix Mars Lander began digging in an area called "Wonderland" early Tuesday, taking its first scoop of soil from a polygonal su.......Posted by MeteorWayne</DIV>Cheers Wayne again, for your excellent notes from the Sol 21 (I think, just being a bit woolly headed right now) update. Also Wayne, do I have your permission to copy & save your notes in Word? They are a very good written record of the progress of the Phoenix Surface Science mission. I really do appreciate them. Cheers silylene for you input & suggesting that sublimation experiment. It is a good explanation as to the possible sublimation of ice on the martian surface.  Replying to: <DIV CLASS='Discussion_PostQuote'> The TECP instrument is planned to be used when they sample Wonderland in the next few days. Looking forward to those ground temperature readings.   Bob Clark   Posted by exoscientist</DIV>Yes I too am looking forward to those readings Bob. Will be interesting to see if the gradient between ground & mast top is as great as for Mars Pathfinder at the far more southerly location in Ares Vallis? I suspect not, being this far north, but we won't know for sure till we get that data.There are no Sol 23 images etc, as there has been a temporary cessation in science for this sol, as handling of data by Phoenix was causing concern. I think Sol 23 was a 'sort out the data' sol. There's nothing wrong, in fact this is due to how well things are going, the data Phoenix is obtaining & relaying is far greater than expected pre launch, so no cause to worry & the mission continues in earnest on Sol 24 tomorrow.  I hope in the next download which IIRC will include some backed up data (MRO failed to relay some frames including some Mission Success panorama frames on Sol 20, dunno if its related to the UHF radio problem or something else, I will try & find out when I'm feeling a bit better). Hopefully I will be back tomorrow feeling my usual self & be posting more again & hopefully there will be Sol 24 material to discuss on here. Andrew Brown.  <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

MeteorWayne · Jun 18, 2008

Andrew, you can keep anything you want from me. More info on the data overload problem, just out on the U of A page:<h1>NASA Mars Lander To Dig; Team Probes Flash Memory</h1>June 18, 2008 NASA's Phoenix Mars Mission generated an unusually high volume of spacecraft housekeeping data on Tuesday causing the loss of some non-critical science data.  Phoenix engineers are analyzing why this anomaly occurred.  The science team is planning spacecraft activities for Thursday that will not rely on Phoenix storing science data overnight but will make use of multiple communication relays to gain extra data quantity. "The spacecraft is healthy and fully commandable, but we are proceeding cautiously until we understand the root cause of this event," said Phoenix Project Manager Barry Goldstein of NASA's Jet Propulsion Laboratory. Usually Phoenix generates a small amount of data daily about maintaining its computer files, and this data gets a high priority in what gets stored in the spacecraft's non-volatile flash memory. On Tuesday, the quantity of this data was so high that it prevented science data from being stored in flash memory, so the remaining science data onboard Wednesday, when the spacecraft powered down for the Martian night after completing its 22nd Martian day, or sol, since landing, was not retained. None of that science data was high-priority data.  Almost all was imaging that can be retaken, with the exception of images taken of a surface that Phoenix's arm dug into after the images were taken. Read More <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

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