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NASA Phoenix Media Telecon - June 5
Listen to audio Images for June 5 Media Telecon

Image 1. Scale of Phoenix Optical Microscope Images

Image 2. Highest Resolution Image of Dust and Sand Yet Acquired on Mars

Image 3. Martian Particles on Microscope's Silicone Substrate

Image 4. Possible Nature of Particles Viewed by Mars Lander's Optical Microscope

Beginning of recorded material

Male Voice: I would now like to turn the call over to the Jet Propulsion Laboratory. You may begin.

Jane Platt: Thank you very much. And hello, everybody. Welcome to another Phoenix media telecon. I'm Jane Platt with the media relations office at NASA's Jet Propulsion Laboratory in Pasadena, California. And, we will be joined by the University of Arizona in Tucson.

Today, we'll here briefly from four panelists. And, after that, we'll take questions from reporters. The visuals for this briefing are online, so you can follow along. I'll give you the url. It's That's P, as in Peter, H, P, as in Peter. I'll read that once again. And, there is another URL from Arizona, which, uh, my colleague will give you in just a moment.

And, a reminder, during the presentations, if you do have a question for any of the panelists, please press *1, and we can get you in the queue to ask your question. Uh, before I introduce the University of Arizona, I did want to tell you that we have one of the panelists here with us today at JPL. And, that is, Chad Edwards, who is the Chief Telecommunications Engineer for JPL's Mars Exploration Program.

But, now, I'd like to turn things over to Sara Hammond of the University of Arizona. Sara?

Sara Hammond: Thank you, Jan. Good morning, everyone. And, first, uh, let me start with a-a sec-second Web site where you can find the images. It's And, on the left, if you scroll down, there's, uh, under recent press release images, Sol 11, and the four images are there.

So please, let me introduce our panel from Tucson this morning. First, we have Michael Hecht, his last name is spelled H-E-C-H-T. He's the Lead Scientist for the Microscopy, Electrochemistry and Conductivity Analyzer, also know as MECA. Also Tom Pike, P-I-K-E, the Geology Theme Group Lead from Imperial College, London. And, Chris Lewicki, L-E-W-I-C-K-I, the Phoenix Mission Manager from the Jet Propulsion Laboratory. And, to start out this morning is Michael Hecht.

Michael Hecht: Thank you very much. Phoenix has already brought you, with the surface stereo imager, pictures of-of landscapes with polygons meters across. It's brought you, with the Robot Arm camera, pictures of-of scoopfuls of, uh, clumps of dirt that are maybe millimeters across. We're going to call smaller and smaller yet.

I'm going to be talking to you about microscope images that are the sizes of small grains of sand. Uh, they'll be images with resolution 10 times better than the m -- than the microscopic imager on the recent MER mission. And-and about 10 times better than the Robotic Arm camera, uh, images.

So let me tell you first how you get these particles, uh, from a large scoop and large robot arm onto a very, very small microscope slide. If you'll look at the first slide, the -- in the upper left-hand corner, you'll see the edge of the box containing the microscopy electrochemistry and conductivity analyzer instrument suite. We call that MECA.

And, that corner is where the samples get introduced for the microscope. And, what you see is-is the, uh, the edge of the-the wheel that contains these microscope slides just peeking out from that slot. This is an image, actually, uh, taken on Mars when we were preparing to-to look at these particles. Now, as you go down from the upper left to the lower right, you'll see increasingly close pictures of that same -- that same system.

The rest of them are taken on Earth. So you'll see the s -- the six little [disks] of different kinds prepared to receive the substrates. Those are three millimeters across prepared to receive the samples. You'll see the holes that those substrates got inserted into. The little red squares show you the height of the images. We turn this wheel around to take images next to each other, so we can paste together mosaics of the entire substrate.

A sample image is shown in the lower right. That's just an image of scribe marks on the wheel. And, in the lower left, you can see what this image would capture if it had the largest sand grains and the smallest sand grains that geologists would call sand. So this will look, uh -- a sand grain you would find on the beach would look very large on the scale of this image.

Okay. So let me, uh, talk a bit about the experiment I'm going to describe. This is, in a sense, a checkout of the instrument and, in a sense, it's an insurance policy. We recognize the fact that, when Phoenix lands, the thrusters would kick up a lot of dust and small particles into the air that would then rain back down onto the deck where the instruments are stored.

So we thought we would begin our experiment with our -- uh, our microscope slides in the position that they would normally receive a sample. So they would catch some of this rain of particles from the landing. And, we can look at those as our first surface samples just in case we had delays or other problems trying to get a sample from the Robotic Arm.

And, that's what we're looking at here. Now, because it was captured during landing, we don't have a guarantee that these are, indeed, Martian particles as opposed to something that might have fallen on the substrates [in cruise]. But, as you will hear, uh, what we see are very consistent with the particles we're seeing on Mars on a larger scale. And, we think we, indeed, have the first images showing the diversity of mineralogy on Mars at a scale that is unprecedented in planetary exploration.

The next image shows one of our targets, one of our, what I've been referring to as, microscope slides. This is a silicone target we've pieced together by combin -- by putting four images of slices, uh, adjacent to each other. And, one of those is a color image that has been created by taking the same picture under red, green and blue illumination and combining them into one picture.

And, all the particles you see in this picture, uh, are particles that were not there when we launched and, to the extent we can determine, were not there on the cruise between Mars and Earth. So if we go to the third slide now, you'll see, in fact, a before and after picture. And, like all good before and after pictures in advertisements, the before picture is in a grainy black and white. And, the-the after picture is in -- is in a colorful, high-resolution image from the surface of Mars.

The point of the before image, it was acquired on the trip to Mars to verify that the sample was clean, the substrate was clean when we landed. And, now, I'll turn the discussion over to my colleague Tom Pike, who is the head of the Geology Theme Group. And, he'll tell you a little bit about what we think we've learned from these particles.

Tom Pike: Okay. Well, the first thing is that we have a very wide variety of particles, both in coloration and in size. Uh, if you look in closely at the silicon substrate, this is a sticky substrate. It was designed to be able to, uh, capture and, uh, have the particles adhere to it from, uh, the landing.

And, in the background, there is a wide variety of very small particles. Now, I've highlighted three sets of rather larger particles. At the top, a very pale particle, looks somewhat, uh, translucent, semi-p -- semi-transparent, uh, one of the largest particles that we're likely to see in our microscope station. The entrance to the box in-in which we do the microscopy is a slot, which is 200 microns in height.

To give some sort of scale, uh, uh, the width of a human hair is a little less than 100 microns. So it's -- we're looking at very small particles. The largest of those, uh, we're seeing here, 150 microns across. Uh, below that, a really what looks more like a-a classic Martian reddish-brown particle, uh, very, uh, reminiscent of the material that we're seeing all the way round the Lander.

Uh, even in this, uh, close-up, you can see the smaller particles, which are scattered into the background. And, then, below that, the third, the lowest image, is showing much darker, almost black, uh, glossy-like particles that have been kicked up by the [retro] rockets. Then, moving over to the last slide, just to give a sense of scale, we're looking in the Robot Arm scoop here at, uh, about 10 centimeters across.

And, you're seeing m-most of the material here is the reddish-brown material of Mars. And, what was very interesting in this scoop was that there were -- there was a scattering of these paler, white particles towards the right-hand side. Now, there's a variety of possible explanations for this.

It could be ice. It, uh -- it-it could be a mineral. Uh, when we take the, uh, particles inside the microscope station, it takes several hours before -- uh, from the digging to the actual observations. And, we believe, during that time, that the ice would probably melt. So the white particles that we're looking at [that are] about the scale in the Robot Arm, uh, camera, in the scoop, that we're seeing on the substrate, probably minerals rather than ice.

Uh, two p -- major possibilities for that could be, uh, uh, uh, a salt-like deposit, or it could be quartz. And, when we look, uh, in close to that, we see now, at 150 microns, one of the larger particles, uh, uh, of this pale material. Now towards the bottom of the image on the - on the bottom right-hand corner, you can see that there's two dark shadows.

Now, these are the tips of the atomic force microscope. Our microscope station contains two types of microscope, an optical microscope, uh, very much familiar w-what you would be using, uh, uh, in school to look at the biology, to look at cells. We also have an atomic force microscope that can go in, uh, at several orders of higher resolution yet.

And, we hope to be using that later in the mission to be able to zoom in to these particles and to look at the substructure of the larger particles and to image these very fine particles that we see in the background, which are scattered all over the substrate and probably make up the, uh, largest proportion of what is being lofted into the, uh, Martian atmosphere and gives it its distinctive pink color.

So later on, we're hoping, not just to get this-this primary [air] sample, but to get samples directly from the scoop. And, we'll be looking to see, when we get those images, whether we see again these white, pale particles reappearing. And, then, we'll be able to say with come certainty that we're looking at Martian material at this, uh, very high resolution rather than anything that may have come from the spacecraft during the, uh, rigors of entry, descent and landing. Okay.

Sara Hammond: Thank you, Michael and Tom. And, we'll hand it back to the Jet Propulsion Laboratory.

Jane Platt: Okay. And, we've got Chad Edwards, Chief Telecommunications Engineer for JPL's Mars Exploration Program.

Chad Edwards: Okay. Let me give you just a very brief, uh, status update on our, uh, relay communications. Uh, as you probably know, yesterday, around the time of this t -- uh, press conference, our Odyssey orbiter went into a safe mode. Uh, we believe that this was caused by just a single event upset that, uh, affected the computer memory.

And, the spacecraft responded properly, put itself into a very safe state. Uh, and we're, uh, currently bringing the spacecraft back into nominal operations. It has high-rate communications back to Earth. Uh, and it's assum -- it's resumed its normal science-data-gathering attitude. Uh, and we're expecting, in the next day or two, that we'll be able to resume relay services with Odyssey.

Uh, in the interim, Phoenix has had to, uh, transition to use of the Mars Reconnaissance Orbiter for its relay services. And, so, uh, last night, we had a, uh, communications pass, a relay pass with MRO that went very well. Uh, we returned about 22 megabits of data from the Lander. And, also, uh, we m-m -- j -- more importantly than, uh, sent forward commands to the Lander to update its relay communications plan and transition its communications over, primarily, to the Mars Reconnaissance Orbiter for the next couple of day while Odyssey is recovering from, uh, from its safe mode.

Uh, and so, uh, as we speak, there's a-a -- on a -- in the Martian morning at Phoenix, uh, there's commands being delivered for Sol 11 activity on the surface of the planet. And, you'll hear more about that from Chris Lewicki. Uh, so let me just turn it over to Chris now.

Jane Platt: Okay. Chris, go ahead please.

Chris Lewicki: Okay. So the Sol 10 plan, we were going to, uh, we were pre-preparing to acquire a sample with the Robotic Arm and deliver that to the TEGA instrument, uh, at which point we would verify, uh, tonight that, uh, we got an acceptable amount of sample. And, we're ready on the next Sol to finish delivering that sample to TEGA by dumping it onto TEGA's cell number four.

Uh, also, in the Sol 10 plan, we had planned some coordinated science with the Mars Reconnaissance Orbiter in the, uh, instruments that, uh, are on it. And, this is a, uh, science activity by which Phoenix looks up in the sky at the time when MRO will be overhead and makes t -- some observations with its LIDAR and SSI instruments as well as the TECP instruments on the end of the Robotic Arm.

And, at the same time, MRO does similar measurements looking downward. So it gives us an opportunity to look at the same column of sky, uh, on the northern, uh, plains of Mars in both directions. Uh, so we didn't succeed, as, uh, Chad had indicated, in getting that -- those commands to the spacecraft on Sol 10. So Sol 11, on the Phoenix [finding] team, was a little bit easier because the plan was just to try it all again.

Uh, we had to make some-some time adjustments to work around the different time of day that our afternoon communications pass to MRO was going to be. But, other than that, it was largely the same plan. And, we have, uh, successfully sent that to MRO and confirmed that it is on board the, uh, Mars Reconnaissance Orbiter. And, in about 10 or 15 minutes, we should know, uh, whether our first opportunity to relay that to Phoenix has succeeded for the morning of Sol 11.

Sara Hammond: All right. Thanks, Chris. Uh, let's take it back to JPL for questions.

Jane Platt: Okay. Thank you, Sara, and thank you to all our panelists. Uh, again, anybody who has a question, please press *1, and you'll be asked to give your name and affiliation. We'll get you in the queue to ask a question. And, I do want to remind our panelists, since there are four of you today, uh, the four voices, to help our reporters follow along, please identify yourself when you do respond to a question.

And, as a reminder, we do archive these, uh, media telecons. They'll be -- I'll give you a phone number later and a url where you can listen again if you would like to. Let's take our first question from Joe Palka of National Public Radio. Joe?

Joe Palka: Thanks for taking the call. Uh, my question has to do with the comment that Tom Pike meant -- made about the sample, uh, uh, heating up and the time it took for the, uh, if I understood this properly, in the time it took for the optical microscope to take its picture. And, I wonder if-if either you, Tom Pike, or Michael Hecht could e -- describe, uh, just once the -- once the particle lands on the substrate, does it then cycle inside the Lander where its warmer? Or is it just that it's warmer on the deck of the Lander? Or, uh, why is it warming up?

Tom Pike: Yes. Uh, I'll take that. This is -- this is Tom here. Uh, the ice -- uh, any ice that we would collect will be slowly subliming, turning directly from a solid to a gas under the, uh, reduced Martian atmosphere. Once it's, uh, uh, revealed from the underlying, uh, soil. Now, that will be the situation if we're scooping the material up.

What we would have here, uh, c -- in-in -- with the [retro] rockets actually lofting this material is a-a rather unique situation. But, in both cases, it's being -- uh, uh, it will be, uh, probably hours, uh, in-in this case days before we will be -- we-we have actually seen the material that has come out from underneath the surface of Mars.

And, in that period of hours to days, we would expect ice of-of this sort of size, a-a few hundred microns, uh, at largest, uh, to have sublimed, to basically have-have, uh, turned into a gas. And, we wouldn't be able to see it in the optical microscope. Now, it is just possible when we do, uh, future digging, that we can do a very quick turnaround with the optical microscope.

And, there is the possibility that we could get from scoop to image in a short enough period of time that we will be able to see, uh, ice within the microscope itself. But, for this particular sample, almost certainly, the ice will have disappeared if there is any there.

Joe Palka: I got it. I wonder if I could just follow up the -- since you mentioned this subliming and this-this interest in whether the feature that people are calling Holy Cow is ice. Uh, it seems to me, if it were shrinking, you'd be more confident that it was ice as opposed to revealed mineral. Uh, uh, are people going to be looking for that?

Michael Hecht: Uh, this is, uh, Michael Hecht. I'll take that. The difference between what we see in the Robotic Arm scoop or under the microscope and the Holy Cow feature is that, in the first two cases, we have isolated particles out in the Martian atmosphere, which is very dry. Uh, and [there have] been free to warm up relatively quickly.

If indeed you expose the-the ground ice on the ground, that's connected to a cold, a very, very cold, thick, extensive sheet of ice, if that's what we're looking at. And, that would, in fact, stay cold and not be modified by the -- by the atmosphere very quickly, if you will. It's packed in ice, so it stays cold.

Joe Palka: Got it. All right. Thanks.

Jane Platt: Thank you. And, the next question, Dave Perlman at the San Francisco Chronicle.

Dave Perlman: Yeah. Hi. I may have missed this, uh, but I'm interested in whatever -- what the status is of that, uh, bulky left, uh, door on TEGA. Uh, did this warmer day, uh, loosen it? Or did you have to nudge it? Uh, or is it still stuck?

Chris Lewicki: Uh, this is Chris Lewicki. I'll take that, uh, question. We did, uh, monitor that with both the Robotic Arm camera as well as the SSI camera, uh, on Sol nine. And, we noticed no movement, uh, over that, uh, cycle. We thought maybe a temperature cycle would free it up. It didn't move.

Uh, what we've done in the meantime is tested, in our payload interoperability test bed, a delivery to our, uh -- our engineering model of that instrument. Uh, some sample with the door in the state that it's in. And, the TEGA team has demonstrated that it will work perfectly fine. And, we can get all the sample that we need, uh, in the amount of open door that we have.

Dave Perlman: Okay. Thanks. Uh, uh, just, uh, to follow up. Uh, the dimensions of the mesh screen, was it the -- was I right that it was a millimeter, the-the holes in the screen?

Chris Lewicki: I'm not familiar with that exact dimension, but that sounds approximately correct.

Dave Perlman: Okay. Good. Thank you.

Jane Platt: Okay. And, thank you, Chris. And, we're going to go to a question now from David Brown at the Washington Post.

David Brown: Yeah. Thank you. Uh, a couple of questions. What Earth day are you, uh, expecting to put the sample into TEGA? And, then, just following, uh, the, uh, the subject of subliming, uh, if you, uh, uh, uh, you know, expose a block of ice that is underground, wh -- doesn't the ice sublime from the surface of that even if it remains connected to a huge, cold block that's further buried?

Chris Lewicki: This is Chris again. I'll take the-the first question. Uh, today, uh, for the Sol 11 plan, we, uh, executed the first of two parts for acquiring and delivering that sample. Uh, so that will be happening today, Thursday on Earth. Uh, if all goes well with that plan, and we're able to confirm we got the amount of sample that we need, and, uh, uh, everything is cooperating with the three of our spacecraft at Mars, we will deliver that sample into TEGA, uh, on Sol 12, which will be -- uh, which will happen on Friday.

Michael Hecht: And, this is Michael Hecht. I'll follow up on the sublimation question. The rate at which something s-sublimates is primarily dependent on how warm it is, uh, as-as you can imagine, just like evaporation. The difference between the sheet of ice on the ground that may be exposed is that it is still very, very cold. So it wouldn't be sublimating as quickly as some -- as some particles you might pick up separately and allow to warm in the sun.

Tom Pike: Just to -- this is Tom here. Just to add to that, of course, one very important difference between looking at the ice underneath the Lander and what we are looking at in the microscope station, is one of scale. You may see an -- uh, particles 200 microns completely sublime.

Uh, but at the same time, that amount of sublimation for a large block of material underneath, you would not be able to see. So we're able to see processes under the microscope that would be almost, uh, uh, indiscernible in, uh, in larger blocks, which are further away from the Lander.

David Brown: Great. Thank you.

Jane Platt: Okay. We're going to take a question now from John Johnson at the Los Angles Times.

John Johnson Uh, just following up on that, uh, I just -- I mean, uh, the plan is to dig into that layer of ice and then to deliver particles to the instruments. I mean, won't they sublime, you know, once you get them off of the sheet of ice and into smaller configuration?

Tom Pike: Yeah. I'll take that. This is Tom. Uh, they will And, that's why we will need to get a sample in very short order to be able to look at ice particles with the microscope. But, what we will be able to see for certain, that this ice -- this ice is unlikely to be pristine. It's going to be full of, uh, rock particles itself. So even if the ice is subliming, we will see the residue that will melt the-the sublimation [of the solid] residue from the, uh, th-that are embedded inside of the ice. So the microscope will be able to look at what is within the ice, uh, even if it can't see the ice itself.

John Johnson: Well, it won't -- it won't be then water, I mean, because that will have gone away. I mean, there -- the -- what' within the ice will be what? Will be particles of, uh --

Tom Pike: That'll be the-the minerals, which have been mixed in with the ice, uh, with the, uh, the-the subsurface, uh, processes that are taking place.

John Johnson: Okay.

Michael Hecht: And, this is Michael Hecht. If I can add to that, in fact, this will work to our advantage because it's one way we can easily distinguish ice from other white crystal and translucent materials, such as we're talking about today. The ice will go away. The other materials will not.

John Johnson: Okay. Well, I mean, s-some of this, I-I admit, is a little bit of surprise. I guess, you know, I-I -- the sublimation issue seems bigger than, uh, that I had expected it to be. This -- I mean, uh, how can you tell, for instance, that ice was there if it sublimes and all you have left is-is, uh, the minerals left behind?

Michael Hecht: Michael Hecht again. Uh, the microscope experiment was not primarily, uh, uh, designed to address issues of ice particles. We'll see large sheets of ice. We don't expect to learn a great deal more from looking at tiny particles of ice than we do from large-large sheets of ice. The focus off of the microscope is in mineralogy. If we do see ice particles, that's a little bonus. But, it's not -- it's not he design.

John Johnson: Okay.

Jane Platt: Okay. The next question is Anne Ryman from Arizona Republic. I'm sorry. Did somebody else have something to say? No?

Male Voice: No.

Jane Platt: Okay then.

Anne Hyman: Hi.

Jane Platt: Go ahead, Anne.

Anne Hyman: Hi. I had a question on you mentioned that these are the h -- y -- these are what you believe are the highest resolution images of dust and sand yet acquired on Mars. And, I wondered if you could give us, uh, some perspective before these images today that you're releasing, uh, what were the closet images that we even taken on Mars. And, I'm-I'm curious what mission that would have been.

Tom Pike: Okay. Uh, I'll take that. This is Tom. The Mars Exploration Rovers that are still operational, uh, have on board microscopic images. And, those, uh, are able to look at the surface -- they don't have substrates. So they're looking at material, uh, on the surface of Mars. And, they can, uh -- they have a resolution of about 30 microns or so at-at the best resolution. Our resolution is four microns. So just a little lest than a factor of 10 times better.

Anne Hyman: And, one-one follow-up question on, uh, the-the-the samples that we're seeing here, could -- uh, would they even be visible, like to the naked eye. Or, you know, if, uh -- would we even be able to see them? Are they th -- are they that small?

Tom Pike: No, you wouldn't be able to -- the-the finest particles of w -- are below what you would be able to see.

Anne Hyman: Okay. Great. Thank you.

Jane Platt: All right. Next question is from Chicago Tribune and Jeremy Manier.

Jeremy Manier: Uh, thanks. So, uh, I have a question about [the enter], uh, how do you get the samples that you look at? Uh, these-these obviously were just kicked up into the air. But, uh, but as you go forward with this, how are you going to get the, uh, the particles that you want to look at into that.

It seems like a [okay] job because like a -- how do you -- how do you avoid smushing the whole, uh, background, uh, with particles? How do you get a thin enough layer to actually look at something meaningful? And, are-are -- you've only got so many chances to put samples into those holes?

Michael Hecht: Let me take the second question first. We have 10 different sets of substrates we can use. And, then, in principle, we can reuse them when they're done. So we get a number -- quite a few chances. Uh, how we get it into a -- to make a thin layer. You're quite right. to do microscopy properly, you don't w-want just a big mound of particles.

You want a sparse field of particles on a substrate. And, when we first designed the instrument, we disc -- we discovered that a convenient way to do this, uh, would be actually to take your microscope slide -- we fist did it with a slide. You stick it in a bucket of dirt. And, if you pick it up and hold it vertically, you find that only see a small film of particles clinging to it.

So actually, between the time the material is placed by Robot Arm scoop onto the substrates and the time we image it, it's turned from horizontal to vertical. Now, we also have what we refer to as a blade. When we retract that wheel into the box, particles larger than two tenths of a millimeter, 200 microns actually get rushed off. So we start with a thin layer to begin with. Then, we turn it vertically to have even more fall off.

We do have these sticky substrates, so that it doesn't all fall off. But, as you know, it's much easier to make something dirty than to make it clean.

Jeremy Manier: Uh, just a-a-a quick follow-up on the previous question. Uh, when you said, uh, the resolution is about 4 microns, is that the visic -- visible microscope of the atomic force [micron]. What's the difference between their resolution?

Michael Hecht: That's the visible microscope is four microns per pixel. So really, it would be very difficult to resolve a f -- the shape of a four micron, uh, particle. All you would see is one pixel. But, uh, the-the, uh -- so the re -- the real resolution might be a little bit larger than that. The atomic force microscope can get, perhaps, uh, 40 times betters resolution we feel right now in the configuration on Mars. In an Earth laboratory, it can do much, much better.

Jeremy Manier: 40 times better than?

Male Voice: Than the op -- than the optical microscope.

Jeremy Manier: Okay. Thanks a lot.

Jane Platt: Okay. And, thank you to Michael Hecht for replying to that question. And, the next question comes from the Tucson Citizen and Alan Fischer.

Alan Fischer: Hi. This question is for Dr. Pike. Uh, Earlier, Dr. Pike, you said that-that the white particles in the scoop that the Robotic Arm camera is seeing on the substrate are probably minerals rather than ice with two major possibilities being salt materials or quartz. Does that mean that you have kind of dismissed the thought that those white materials could possibly be ice in the scoop?

Tom Pike: Well, let me -- let me, uh, clarify a little. We are not looking at the material from the scoop. We're looking at the material that has been kicked up by the [rectory] rockets and has been out -- it-it's taken several days. So we will not see ice. Any-any white material that we are seeing at the moment is definitely minerals. So we know that there are white minerals underneath the Lander.

That does not necessarily mean that that Robot Arm sco -- what was in the scoop was not ice. Uh, there could be w -- th -- it-it -- there's a very distinct possibility that we have white minerals and ice underneath the Lander itself. In fact, salt deposits and ice very often go together. So I don't think that one necessarily precludes the other.

Alan Fischer: Very good. Thank you, sir.

Jane Platt: Okay. And, our next question is from Eric hand at Nature. Eric.

Eric Hand: Hi. Yeah. I guess my first question is for-for Chad. And, I had a follow-up with Chris. Uh, Chad, if you could explain, uh, a little bit more clearly what the problem is with Odyssey and how, uh, this, uh, safety mode, uh, was different from the transient event, uh, that caused, uh, MRO to-to safe, uh, uh, a week ago? And-and then, how long, uh, you think this problem on Odyssey might persist?

Chad Edwards: Okay. Uh, reviewing the [telemetry] from Odyssey after the [safety] event, it appears that what happened in that, uh, uh, an energetic particle caused a-a single event upset in the computer memory on board the-the spacecraft. So this was not related to the relay payload itself but to the orbiter's, uh, flight computer, uh, and [fall] protection on the -- on the spacecraft properly put the spacecraft into a safe mode.

Uh, but that basically interrupts its normal sequence of both the -- Odyssey's own science acquisition as well as the relay services its providing to Phoenix. This, uh, appears to be very similar, uh, to an event that's occurred two or three times previously in flight on Odyssey. Uh, and so we have a lot of, uh, experience and confidence that, uh, you know, we-we understand, uh, the safe recovery path that we're on now. Uh, and our expectation is that we'll be back in operations within a day or two.

Eric Hand: Uh, so it sounds like this is the same sort of event that occurred on-on MRO.

Chad Edwards: No. So it-it's a completely different event than what happened on MRO. It-it's similar to events that have occurred over the-the, uh, many years that Odyssey's been in operations at Mars. Uh, the event on MRO was related to the, uh, uh, the radio itself, the relay radio itself, called Electra.

Eric Hand: Okay.

Chad Edwards: Uh, and, uh, since, uh, since Sol 3, we haven't seen any recurrence of that issue with, uh, MRO's relay radio. And, uh, last night was the first time in a few Sol's that we'd used MRO for relay communications. And, that pass, uh, uh, came off, uh, very successfully.

Eric Hand: Okay.

Chad Edwards: So we're confident and encouraged that-that, that -- that MRO is providing good relay services for us at this point.

Eric Hand: Okay. Thank you. And, then, a quick follow-up for-for Chris. Uh, this is the second down day you've had in the mission now, uh, because of-of-of the orbiters. What-what can you -- how -- were you planning on these down days? And-and at a certain point, do they become a problem, uh, in, uh, the mission's lifetime? Uh, and-and what can you do to increase, uh, [run-out] instructions, so that science can still happen on-on these down days?

Chris Lewicki: Yeah. It-it's a good point. We-we-we do exactly that. So on Sol 10, we-we ran, uh, a-another run-out sequence that, uh, exist on board to run just in this case. So, uh, Sol 2 is the first time we ran that. We ,uh, acquired two slices of our 28 slices of our mission success pan. And, on Sol 10, we acquired two different slices of that -- the success pan. And, we'll be [playing] that back out slowly over the next several days.

So we-we kind of, uh, continue to put up, uh, as we did today, uh, instructions to take two different parts of this. And, we'll actually continue to evolve exactly what we do on these kind of, uh, uh, down days that we get on the spacecraft. We also kind of use them as down days for the team, uh, because we've been working p-pretty steadily since we've landed. And, that gives people a chance for a little bit easier of a day.

Eric Hand: I mean, how --

Chris Lewicki: [In turn to-to] address -- go ahead. Eric Hand: How-how many days have you planned, uh -- planned for in the -- in the nominal 90-day mission?

Chris Lewicki: In the nominal 90-day mission, we, uh, have prepared to lose up to one third, uh, of our days. Uh, we, uh, believe we've worked out the schedule that we can get to, uh, all of our success criteria, uh, in about 60 days or so. Uh, and all the rest of the days are for the unforeseen. And, we have been experiencing some of the unforeseen so far. So we --

Eric Hand: Thank you.

Chris Lewicki: Okay.

Jane Platt: Okay. And, we do have several of you who are in queue for questions, so just, uh, bear with us. The next question comes from Leo Enright at Irish Television.

Leo Enright: Uh, thanks, Jane. Yeah. This-this -- uh, going back to the last slide again and this crystal skull, I suppose I might call this. Uh, to-to try and understand what this might be telling us about the [rack] images both in the trench and in the scoop. Uh, I-I think I'm beginning to understand Peter's point about, uh, impassioned discussion.

And, is it -- is it right for me to assume that some people, at least, must have been expecting that if these -- if this white material was ice in the scoop or in the trench that it would have sublimated and that we would have seen that by now. Uh, and that the fact that we're seeing these lumps of white and the fact that you're seeing, uh, this, uh, crystal whatever in the -- in the microscope, that all this seems to add up to something different from ice?

Uh, and following up on a point, uh, Tom Pike has mentioned, uh, uh, quartz. I-I presume you're not remotely suggesting that there's some vast sea of quartz underneath the, uh, the Lander.

Tom Pike: No. Uh, what we're -- what we're seeing in the microscope with these-these very fine particles is, as I said, it's almost certainly not ice. It-it-it's really inconceivable that it would remain, uh, as that material. Now, if we have ice, it's probably has got dissolved solids in it. And, as the ice sublimes, as we actually lose the water from it, it will leave behind salt deposits.

So I don't see that there is necessarily a direct contradiction between seeing white, salty minerals and seeing ice. They-they will frequently be seen together. Uh, what we were looking at in the Robot Arm, uh, that-that first scoop. Now, that was a test scoop. So after that picture was taken, that was -- that material was dumped.

So what we are going to be doing in the future is looking at time series to see how any white particles either remain constant or disappear over time. So this sublimation gives us, uh -- the-the sublimation process that will take place with ice gives us some good clues as to its presence or not in-in what we're seeing. The-the problem with the optical microscope is that this process for these small particles just happens very, very quickly and is very difficult to capture the ice before we see it disappear.

So, uh, yeah. There is -- there are certainly discussions within the science team here. But, uh, I think we're open to a-a-a variety of interpretations as to what this m -- white material could be without necessarily saying that, either we have huge deposits of quartz underneath the, uh, Lander, which is not going to be the case. Or that all that-that we're seeing at-at -- or any white material that we're seeing is ice as well. Those are kind of a-a-a big [stream at].

Leo Enright: Uh, and just to-to clarify the size of this 150-micron piece, is-is that the size of a grain of salt? Would that -- or is it smaller than that?

Tom Pike: The size of a grain of salt, I -- it-it's about that size. There's a -- they're about 100 microns or so.

Leo Enright: Okay. Thanks very much.

Jane Platt: Next question, Kelly Beatty at Sky and Telescope.

Kelly Beatty: Uh, first, for Chad, if I might suggest, uh, the whole protocol for these, uh, relays is a little opaque to me. And, if you've got a background or something that you can post for our benefit, I think it might save a lot of Q&A down the road. My question is actually for, uh, Michael or Tom. Uh, the landing site is-is pretty low in elevation, uh, three and a half or four kilometers below the [mean datum].

My understanding was that that puts it below the [triple] point of water. Why would you not expect crystals of ice to melt, especially if you're sampling them in midday when, let's face it, we're getting about as warm as we're going to get in this location?

Michael Hecht: Uh, this is Michael. I'll take that one. Uh, what's going on in Mars is rather what goes on in your frost-free freezer. Uh, and I'm old enough to remember the time before the fro-frost-free freezers where we had to defrost them. If you could warm those crystals up very rapidly above 0 centigrade, they would indeed turn to water before they evaporated. But, even at temperatures well below zero, sublimation is going on.

And, uh, for particles that size, they will disappear long before you ever get them up to 0 degrees C. So you could certainly take a chunk of Martian ice, put it in a pot, light the fire under it and make a kettle of water with no problem. But, uh, we generally would not be able to apply heat in the -- in-in the native Martian conditions that would accomplish that, uh, without-without a big assist from us.

Jane Platt: All right. We're going to take a question now from Astronomy Magazine and Bruce [Muma]. Bruce.

Bruce [Muma]: Uh, yes. A quick barrage of questions. Uh, first of all, did I hear you say that, uh, s-samples will be dumped in the TEGA oven four as well as oven one? Second, I understand that the plan is, uh, for the actual spectrometer on TEGA to analyze a sample of Martian atmosphere before you turn on the oven and analyze any of the gases in the samples. And, I've got a couple of follow-ups in addition to those. But, I'll start with those two.

Chris Lewicki: Okay. This is Chris Lewicki. I can answer, uh, the first couple of questions about TEGA. We are delivering it to, uh, TEGA cell number four, which is the one that we opened the door on --

Bruce [Muma]: Uh --

Chris Lewicki: Uh, previously. Uh, one thing to note about, uh, our plans for, uh, the next Sol is that, while we will deliver the sample to TEGA, they will not immediately an -- uh, analyze it. And, it-it's for the reasons that you've just pointed out is that we want to get, uh, on TEGA an atmospheric measurement, uh, with the evolved gas analyzer, uh, both during the daytime as well as at nighttime.

Uh, because before we start introducing a bunch of, uh, potential volatiles into that instrument, we want to have kind of a nice, clean background, uh, so that we can -- we can measure the rather tenuous quantities of, uh, water vapor in the atmosphere. And, once we analyze our first s -- uh, soil sample with the EGA, our sensitivities, uh, will-will be swamped by, uh, what we expect to find in the soils.

Bruce [Muma]: Okay. And, two more questions relating to the ice. First of all, I understand now that the, uh, uh, I -- the [latest] sample from the ice layer and the c -- judging from Mars Odyssey, it is almost certainly ice or the [fault], uh, will be, uh, loaded into both the TEGA instrument and the microscopy station. Is there any plan to dump a sample of ice into, uh, one of the wet chemistry cells on the MECA instrument?

Michael Hecht: I'll take that. This is Michael Hecht again. Yes, of course, we will go ahead and do the chemistry. Uh, it's-it's in the queue. Uh, we'll first do TEGA. Then, we'll do microscope. And, we would anticipate it would probably be about, I'm guessing, about a week and half from now before we get ready to do that experiment.

Bruce [Muma]: But, you would dump a-an ice sample into, say, the fourth of the, uh, wet chemistry cells on the MECA?

Michael Hecht: We are having -- I'll use the expression again -- impassioned discussions about just which samples we will use for our four wet chemistry cells. We only get four chances.

Bruce [Muma]: [Right].

Michael Hecht: Uh, originally, ice was fairly low on the list because dissolving ice in a beaker of water doesn't necessarily teach you very much. But, it certainly is on the list because there would be interest in what salts might be, uh, at -- between the grains of that ice. But, the -- our first priorities will actually be to get the dry soil, perhaps, for example, from the surface, from the boundary of the polygons that we seem to be -- to have landed on, from the surface just above the ice and perhaps the fourth one might be an ice sample.

Bruce [Muma]: And, finally, uh, there was considerable concern, especially mentioned in the Phoenix blogs, about the extent to which since the, uh, landing engines would, uh, shut down only at landing, they'd spray ammonia exhaust all over the surface of the soil and that it might, in particular, tend to cling chemically to, uh, the ice. Uh, is -- ho -- just how much concern is there over the possible contamination of the, uh, soil samples and the ice samples by ammonia from Phoenix's engine exhaust?

Michael Hecht: Uh, this is Michael again. Uh, we have tested this in the laboratory actually by firing the engines and looking at the residue. We've also looked at similar tests that were done way back in the 70's by the Viking mission. And, yes, there is the possibility of ammonia being released but in very, very small quantities. We'd be extremely surprised if we got larger, uh -- q-quantities large enough to make a significant impact on the chemistry experiments.

And, moreover, we have a sensor specifically to detect ammonia. So from our-our expectation is that the only negative impact of any ammonia will be a compromise of our ability to detect nitrogen-containing compounds. And, we have -- we have accepted that a long time ago as-as not -- as-as, uh, an area of investigation that-that we may be -- uh, that is not likely to be fruitful.

Bruce [Muma]: I see. So that's why you --

Jane Platt: Okay. Bruce, I'm going to jump in here.

Bruce [Muma]: Okay.

Jane Platt: Because we have people who have been waiting [in line].

Bruce [Muma]: Sure. That-that-that's fine.

Jane Platt: If you do have a follow-up, you can, you know, let us know. And, we'll get you back in when we go to the second round.

Bruce [Muma]: That's fine.

Jane Platt: Just trying to be fair to everybody. Uh, next question will go to Aaron Mackey at the Arizona Daily Star.

Aaron Mackey: Thank you. Uh, I had a question, uh, for Mike. Uh, you began the press conference talking about an unprecedented diversity of g-geology that you were seeing, uh, with these microscopic views. I was wondering if you could explain that a little bit further and how that fits in with, uh, other geologic and mineral features that you guys have found in previous missions.

Tom Pike: Yeah. This is Tom here. Uh, well, when you're look -- when you're zooming in at these high resolutions, you're able to, uh, look at what would appear to be just, uh, an overall brownish mass. You're actually seeing the individual mineral grains. So just because of the high resolution that we're using here, we're able to fractionate and see different mineralogy.

So it's pro -- uh, it's almost certainly all -- it-it'll be all there for the other instruments to look at. But, this is -- well, to be able to analyze, this is the only instrument that we'll be able to look at the, uh -- this fractionation at this sort of a scale. So we are able to make, uh, uh -- to be able to discern the difference between the various minerals that we are likely to see on Mars within this dust and soil.

So the difference between, say, the Mars exploration Rovers that were able to see larger scale features, uh, the-the famous [Bluberries] that they -- that they were able to image. Uh, they were able to see at that level what, uh, is -- what formations can occur. But, the soil up to this point has really been taken as a -- as a whole. Very difficult to see the individual fractionations.

So it is just by getting down to this [link] scale that we see -- and you can see straight away from the images that we're presenting just the-the amount of variety that there is in what appears, uh, otherwise just to be a reddish-brown soil.

Aaron Mackey: All right. Thank you.

Jane Platt: We're going to go to Sally [Rail] of the Planetary Report. Sally.

Sally [Rail]: Hi. Thank you. Uh, I've got a couple of quick ones, I think, regarding the, uh, communications. Haven't you been using MRO's [electra] anyway within the last week and a half and after the Sol 2 event?

Male Voice: So, uh --

Sally [Rail]: The downlink?

Male Voice: Yes. Since the Sol 2 event, uh, we've used MRO several times, uh, for comm -- for direct communications with Phoenix. But-but most of Phoenix's, uh, command and telemetry services were-were moved over to Odyssey while we were investigating the, uh, the anomaly.

Uh, in the -- in the interim, we exercised the radio numerous times, uh, during opportunities when-when Phoenix was not re -- s -- planning to respond. And, all of those tests, uh, went very nominally, uh, and gave us confidence that the payload is healthy, uh, that the radio is healthy on board, uh, MRO.

Sally [Rail]: Okay. And, so generally, uh, it-it, uh -- Phoenix will return to MRO's [electra] then?

Male Voice: No. I think at this point, uh, once Odyssey returns to service in the next few days, uh, we'll probably go back to [with this] encouraging result on MRO, we'll go back to, uh, a nominal use of both orbiters, which, uh, gives the Lander some flexibility in the times at which it can communicated and also, obviously, just the robustness of having those two redundant, uh, relay [paths].

Sally [Rail]: Okay. Great. Thank you. And, I had a question about the particles, I think, for Tom. I believe you mentioned that, uh, it looks like the classic reddish-brown, uh, Martian --

Tom Pike: Mm-hmmm.

Sally [Rail]: Uh, but you wanted to confirm that that indeed was a classic Martian brown particle. And, what I'm wondering, is-is there anything else it could be? I mean, is there anything from the spacecraft that could have created such particles? [crosstalk] And, is that in your thinking at all?

Tom Pike: Well, it is unlikely. But, if we're going to say something definitive about the particles that we're looking at, at the moment, we would like to see it reproduced in material that we know for sure is delivered from the scoop. So with the benefit of hindsight, we'll be able to go back to this material, confirm that it is consistent with what we're seeing, uh, from the surface of Mars. And, then, we will know for sure.

Uh, it's just that-that the entry, decent and landing is a very violent event inside the spacecraft itself. And, particles, for sure, are going to be produced. So before we can say that any individual particle, we know that it comes from Mars, we really want to-to cross check with a future -- uh, uh, a future sample who's provenance we're-we're absolutely certain about.

Sally [Rail]: And, one other quick one. I know that you mentioned that, uh, you're-you're sending the sample to oven number four on TEGA because that's where you opened the doors. But, why number four and not one through three or five through eight? Why-why was number four chosen to be the first over to --

Chris Lewicki: Uh, this is Chris. [crosstalk] I-I don't exactly know the answer to that. So we'll have to follow up with you.

Sally [Rail]: Thank you, Chris. Thank you. [crosstalk]

Jane Platt: All right. We're going to go to Kevin [Austin] of

Kevin [Austin]: Uh, yes. Good morning, everybody. I was just wondering -- I know Tom referenced earlier the atomic force microscope was going to be coming on. Uh, I was just wondering if there was a time table, uh, where we could expect to see images, uh, back from that?

Tom Pike: Uh, we haven't got an exact timing because as-as you have seen today, uh, that things, uh -- things do happen to spacecraft. And, uh, the schedule does get pushed on. We are hoping, probably within the next 10 days, to be able to use the atomic force microscope. And, uh, the first step, of course, was to get these-these optical microscope images because we're going to be using the optical microscope images to target the areas that we zoom in with, a particular area of the substrate.

Uh, it's a thin stripe of the substrate near to where you can see the tips of those shadow that is acc-accessible to the atomic force microscope. So we use that to se -- we use the, uh, uh, optical microscope images to select and area. And, we've just got those in. and we still need to complete the checkout of the atomic force microscope. All looks good so far with it, but we need to do some test scans before we get on to the actual Martian material. And, as I said, that'll be probably a-a matter of a week to 10 days.

Jane Platt: Okay. We've got a couple of, uh, other first-time, first-round questioners. And, a couple of you have been waiting for follow-up questions. Let's go now to Astrobiology Magazine and Henry Bortman.

Henry Bortman: Hi. Uh, back to the microscope, uh, [can] you say, apart from variety among the grains, what it is you're looking for when you look at these grains and how that fits into figuring out the habitability story of this site?

Michael Hecht: Uh, this is Michael. I'll take that. There's a wide range of things we're looking for. And-and it's partly habitability. It's partly just understanding the history. So for example, with the salts, the size -- if-if this indeed is a salt crystal and we see more like it, so we can confirm that there's some link between what we see in the microscope and things we excavate. Uh, we can start looking at things like the transparency of the particles, the size of the crystals.

And, these will all say something about how they formed, whether they formed in water, whether they, you know, they p -- that [p] -- and-and segregated out when ice froze. Uh, that's the sort of thing we're looking for. You can look at a particle. at the surface of a particle, at the fractures, at the shape, at the roundness, and you can answer questions about whether it came to be where it is by a process of just blowing around and striking other particles or whether it -- whether it came that way by, for example, interaction with water.

So what we're looking for is really to-to use these particles as a way to read the history of the site and the history of the minerals in the site as well as the history of the water.

Henry Bortman: And, you're not willing to say anything yet about the particles you're looking at because you're not confident that they're actual Martian particles?

Michael Hecht: That's right.

Henry Bortman: Okay. Thank you.

Jane Platt: And, we're going to go to Ken [Cramer] of Space Flight magazine.

Ken [Cramer]: Hi. Thank you. A couple quick questions. I want -- I'd like to know, uh, the particle size in-in this scoop, it looks a little bit big. If -- do you have any concern that these grains will clog up the screen? And, I'd also like to know if we are officially in the science phase of the mission? Or is this still the characterization phase? And, do you have any preference for using Odyssey versus MRO for the transmissions?

Chris Lewicki: Let's see. [I think I'll] answer the two of those that I-I-I felt I can answer. This is Chris. Uh, we officially have, uh, two more days of progress we need to make in the characterization phase. Uh, today, we uplinked, uh, the first of those days in-in the, uh -- in the, uh, telecon we've had here. I can confirm that our, uh, Sol 11 plan did make it into the spacecraft through MRO and, uh, got into Phoenix at about 20 to 4:00 in the morning.

Uh, so Phoenix is restless overnight as it often is. Uh, but it's got its instructions for Sol 11. Uh, on Sol 12, we will, uh, hopefully, be able to continue on the second part of those -- uh, of that plan, which will be, uh, delivery, uh, of that sample to TEGA and then, uh, starting on Sol 13, we will begin into the-the-the -- as -- no earlier than Sol 13 will be our-our normal science phase of the mission where we have done all of the engineering and instrument checkout, uh, necessary to kind of start with the normal plan.

Michael Hecht: And, this is Michael. I'll take the TEGA question. The TEGA screen is at a very steep angle. It also has a device that vibrates it. It's been tested on many, many different kinds of soil. And, so far, clogging of the screen has not been an issue. Those large particles will just be vibrated off, uh, and to-to make way-way for the smaller particles that can get through the screen.

Tom Pike: And, I'll just add -- this is Tom here. Just, uh, if you look at the image from the, uh, Robot Arm scoop, you will see at the front edge of the image that the -- there is a, uh, a fine covering of particles in front if these rather large lumps that are in the main body of the scoop. So as expected, we're-we're seeing, uh, particles on a wide variety of scales. And, so as well as being able to get the particles, to get the material into the TEGA, uh, it's-it's -- we're-we're-we're pretty confident that we'll be able to get these fine particles when we load into the microscope as well.

Chad Edwards: This is Chad Edwards at JPL. You're-you're last question was about preferential use of Odyssey or MRO for relay services.

Ken [Cramer]: Yes.

Chad Edwards: And, uh, those -- we-we consider them equal partners. Uh, they offer us different contact times. Uh, and so, ideally, Phoenix, uh, you know, it benefits from being able to use, uh, both of them on a given Sol.

Ken [Cramer]: So the higher data return from MRO is-is really not, uh, of any consequence then?

Male Voice: They have comparable performance on the relay link. Uh, MRO has a higher data rate on the link back to Earth. So that saves us a few minutes in terms of latency in getting the data back, uh, to Earth but, uh, not a big difference.

Jane Platt: Okay. And, we're going to be -- actually, before we got to Emily Lakdawalla of the Planetary Society, I just sort of want to do a last call because we're about to go into our bonus round, which is follow-up questions. And, if you do have a question again, just press *1, and we'll get you into the lineup. But, let's go ahead with a question from Emily.

Emily Lakdawalla: Uh, first of all, I'm wondering if there is anything else in the run out plan beyond the, uh, number of images that came down. I see from Sol 2, there's only about 28 images that came down in that run out plan. I was wondering if there's anything else that happens aboard Phoenix, uh, on a run out day. Uh, my second question is, if the TEGA background atmospheric measurements will use up ovens or if you'll be able to reuse those ovens later.

Chris Lewicki: Yeah. This is Chris. I can answer both of those questions. Uh, and the run out day includes, uh, in addition to a number of images to support the [success pan] slides -- and I can't say exactly how many that is -- uh, we take a-a measurement of, uh, the sky brightness in order to determine how much dust is in the sky or the optical depth, uh, as we refer to it.

Uh, we also do an image of, uh -- imaging of the [tell tale] on top of the meteorological [mast]. And, that's what's currently in our run out. Uh, the science team is working on expanding that as we, uh, uh, find ourselves using these days, uh, more often perhaps than we, uh, were, uh, were-were predicting. Uh, but that's, uh, essentially the composition of the run out [cell].

And, the thing is, it has to be a very generic day that can kind of work no matter what the condition of all the instruments are. So we're-we're limited to a-a relatively constrained set of activities. Uh, I'm forgetting your second question.

Emily Lakdawalla: TEGA background measurements using [crosstalk]

Chris Lewicki: TEGA background measurements. Yes. Those don't use the ovens at all. Uh, that takes in, uh, a sample from the atmosphere through a separate port.

Emily Lakdawalla: Uh, and if I could ask one more question, I'm just wondering if you're using Mars Express at all for communications.

Chris Lewicki: Chad, do you want to answer that?

Chad Edwards: Yeah. This is Chad. Uh, we've conducted a number of, uh, demonstration passes with Mars Express both with the Mars Exploration Rovers prior to Phoenix arrival as well as, uh, uh, a couple of passes during the characterization phase. At this point, uh, we're not -- we do -- we don't have operational plans to use Mars Express. But, uh, having demonstrated that interoperability, it gives a-a third redundant asset that we could turn to in an emergency.

Jane Platt: All right. Thanks, Chad. The next question, we're going to go back to Dave Perlman at the San Francisco Chronicle.

Dave Perlman: Mm-hmmm. Surprise. Uh, thank you very much. No. This is a -- this is kind of a fanciful question. But, if you did move a particle of ice into the -- either one of the two microscopes, how fast would you have to go before it all sublimated? Uh, or does that depend on the size of the particle?

Michael Hecht: Exactly. It depends on the size of the particle. This is Michael Hecht.

Dave Perlman: Yeah.

Michael Hecht: Uh, the largest particle we normally accept through this blade is 200 microns. And, at the temperatures we expect to be operating, that would last about an hour. Smaller particles would disappear progressively faster.

Dave Perlman: All right. Then, it's not a matter of seconds. You don't have to zip it in and zip it out.

Michael Hecht: No. But, you'd be surprised how quickly an hour goes by with all the steps in the operation.

Dave Perlman: All right. Well, thanks very much.

Jane Platt: I'm going to back now to the Washington Post and David Brown.

David Brown: Yeah. Thanks. Uh, o-once the -- uh, a sample is dropped in TEGA, uh, how-how long does it take to-to run, to heat it up and do the mass spec? Does that all happen in a couple of hours? Does it take a whole day? Does it take more than a day? A couple minutes? What?

Michael Hecht: Michael Hecht again. I-I don't know the details. It takes multiple days, uh, to-to do this. Uh, the different days will go through different parts of the t -- of the heating cycle. And, there's also a, what we might call, a ground in the loop, looking at the results for the first day to-to get some-some additional information about just how you might structure the analysis for the -- for the higher temperature day. So what is it? I think it's about -- I think it's three days for the-the full analysis.

David Brown: Okay. And, I should -- can-can I just ask one more thing? And-and you can -- you'll be able to, uh, measure and characterize many different volatile compounds? You'll -- a whole lot of fractions will come off, and you'll be able to capture a couple dozen or more?

Male Voice: If that's the case. Now, we actually select which species, which masses we're going to monitor in any given run. And, I-I would have to, uh, to refer to the TEGA team for the details of how many we can monitor at a time.

David Brown: Okay. Thanks.

Jane Platt: All right. We're getting ready to wrap up. We'll take one final question from Bruce [Muma] at Astronomy magazine.

Bruce [Muma]: Uh, this is just a short follow-up on the ammonia contamination problem. The Vikings shut off their engines at 10 feet altitude to avoid contaminating the soil. And, uh, I was wondering then why there was no consideration given to shutting off Phoenix's engines at, say, five feet to avoid soil contamination? Is it just that it wasn't considered [an] adequately serious problem?

Chris Lewicki: Uh, this is Chris. I can take a -- take a crack at answering that. Uh, the-the design of the spacecraft was for a particular, uh, uh, touchdown velocity. And, there-there wasn't any way to maintain that touchdown velocity and keep stable all the way down to the surface. Uh, the other thing that should, uh, should be noted is that, uh, the design of the Viking thrusters, uh, was more diffuse, uh, than the thruster [plume] that's coming out of the Phoenix thrusters.

Uh, and that just has to do with, uh, you know, the development of the hardware that's available to us, uh, and what is space qualified and still has companies in business to support those. And, uh, the thrusters that we have on Phoenix were, uh, thrusters that were available, uh, for the Mars Surveyor 2001 Mission in, uh, in 1998 or so when its design phase started.

Bruce [Muma]: Okay. Thank you.

Jane Platt: Okay. And, I want to thank all our panelists for joining us today here at JPL and at the University of Arizona. This telecon will be archived for one week. You can hear it by phone and online. The dial-in numbers are 1-800-945-7497. For international callers, it's 203-369-3507. And, we'll be posting an MP3 file online in -- within the hour. So it's a couple of Web sites including

Our next media telecon like this one is tomorrow, Friday, at 11:00 a.m. Pacific and Arizona time. And, we do have a lot of information and images from Phoenix online at and at Any additional media requests, please call us here at the JPL media relations office at 818-354-5011. Or Sara Hammond in Arizona at 520-626-1974.

Thanks for joining us, and have a great day.

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