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NASA - NASA Phoenix Media Telecon - August 5
August 5, 2008
 

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Today's speakers:
Michael Meyer, chief scientist, Mars Exploration Program, NASA HQ
Peter Smith, Phoenix principal investigator, University of Arizona
Michael Hecht, science lead for the Microscopy, Electrochemistry and Conductivity Analyzer, Jet Propultion Lab
William Boynton, science lead for the Thermal and Evolved-Gas Analyzer, University of Arizona
Images for today's briefing:
'Snow White' Trench
Color View 'Dodo' and 'Baby Bear' Trenches
Animation of TEGA Sample Delivery and Analysis
Animation of Wet Chemistry Laboratory
Animation of Wet Chemistry Laboratory



Beginning of recorded material

Male Voice:
Now, I would like to hand the conference over to your host for today, Mr. Dwayne Brown.

Dwayne Brown:
Thank you. Good day, everyone. Again, my name is Dwayne Brown with the Office of Public Affairs at NASA headquarters here in Washington. I would like to start up front that replays of this telecon will run all this week. And,, at the conclusion of this, I will give out that number.

Before I introduce today's speakers, I'd like to kind of set the stage here. I believe some of the speakers may echo in a different format some of my comments. There were reports over the weekend that indicated NASA had a major finding that it was withholding from the public.

Speculation caused by these reports fueled a host of rumors. Today's briefing will set the record straight. Phoenix science team will be presenting information that quite frankly has not been through as much review and validation as they would like.

They're responding to public affairs request. We're doing this in the spirit of openness about research although still at an early stage and hopefully provide a better understanding about how science is done. When we get to the Q&A part of this telecon, the answers to many of your questions may be we are still looking at that, still analysis is underway, and we just don't know at that this time.

Unfortunately, that's part of the tradeoff for making this research public earlier than planned. Some of the presenters will be referring to some images on the Internet. Let me give you two links.

I'm sure many of you are familiar with them. The first is www.nasa.gov/phoenix. Again, that's www.nasa.gov/phoenix. Of course, the University of Arizona's Web site at phoenix.lpl.arizona.edu. Again, phoenix.lpl.arizona.edu. Look under the images and videos found on the recent press images, Sol 70.

Let's get to the speakers here. First, you will here from Mike Meyer, who is the chief scientist for the Mars Exploration program at NASA headquarters in Washington. Then, of course, we'll go down to ground zero where all the incredible work is being done in the mission operations center at University of Arizona.

We will have three key presenters, but there are other team members in the room. Depending on the question, they may need to respond to your respective question. I would ask that they would give their name and their title if need be if they have to answer a question.

But, the key presenters down in the University of Arizona, of course, Peter Smith, the principal investigator, Michael Hecht, co-investigator and science lead for the Microscopy, Electrochemistry and Conductivity Analyzer or as you all well know, MECA, from the Jet Propulsion Lab, and William Boynton, the co-investigator and science lead for the Thermal and Evolved Gas Analyzer, otherwise known as TEGA, from the University of Arizona.

So with that, I'll toss the baton to Mike Meyer.

Michael Meyer:
Thank-you very much, Dwayne. There have already been many exciting discoveries from Phoenix. There will be many more. The specific discovery discussed in the media over the past few days could be significant.

But, the instrument results have not been resolved among the scientists of the Phoenix team. The team is hoping for a corroboration on the discovery through additional measurements by TEGA and for peer review by the scientific community. Because of this, NASA did not include perchlorate findings in last week's press conference.

So we are here today to announce a non-announcement. More experiments and time are needed to resolve the interesting findings from the soil chemistry. In keeping with the open, communicative nature of the Phoenix mission, such as through blogs, Web presence, press releases and mid-mission press conference, we have representatives of the science team here to answer your questions.

I assure you this and any other discoveries Phoenix finds will be publicized widely once confirmed. So to give us more detail on the science and the timeline of events, here's the principal investigator of Phoenix, Peter Smith.

Peter Smith:
Thank you, Mike. The Phoenix project has decided to take an unusual step and break with scientific tradition that has been followed for many years. Today, we're opening a window into the project to allow the public to see our scientific process in action.

Tradition has been bypassed because of the extreme interest that has been exhibited towards Phoenix and the really camaraderie that has developed among our followers in our search for a habitable environment on the northern plains of Mars. Rather than the speculation that has become rampant on the Web, I promise you insight into the investigations that are underway inside the operations center.

However, I must caution you that we have not completed our process. But, at Sol 70, we are about halfway through the data collection phase. Started but not yet complete is the analysis and laboratory work with samples using our engineering models. After that would traditionally come the writing of science articles that are peer reviewed by scientists who are not involved in the project before the final publication in the science journal and released to the public.

These steps have not taken place. We are still at the stage where multiple hypothesis are being examined. But, even so, we have substantial evidence that are soil samples contain perchlorate. That's carbon with four oxygens. I'm sorry. Chlorine. I can't read my own writing.

That's chlorine with four oxygens. On the earth, perchlorates are found in the Atacama Desert in Chile and association with nitrates that are mined for fertilizer. This desert is a hyper-arid environment that rarely sees rain has no vascular plants.

It is often used by scientists, as a matter of fact, as a Martian analog site. These compounds are quite stable in soil and water and do not destroy organic materials under normal circumstances. In fact, there are species of perchlorate reducing microbes that live on the energy provided by this oxidant.

Therefore, this is an important piece in the puzzle as we attempt to determine whether habitable conditions exist for microbes on Mars. In itself, it is neither good nor bad for life. There are other substances that are being looked at and can produce some of the signatures that we see in our MECA and TEGA instruments.

MECA adds water to the soil sample then looks at the ions that go into a solution with special sensors. TEGA, on the other hand, heats small samples in a tiny oven and identifies the gases released as the temperature is increased up to 1800 Fahrenheit. Both instruments are independently looking at the same soils and are used to assess the chemistry and mineralogy.

As I said, we're part way through this process. Before being certain on an unexpected identification, we must be sure that we have not introduced this material into either the instruments or the environment. A group of propulsion experts is investigating this possibility.

Although, I must say, it seems rather remote since our fuel is hydrazine and contains no chlorine. But, there is a slight chance that the perchlorate oxidizer used in the third-stage rocket motor on the Delta II could have migrated inside our spacecraft before leaving the Earth environment.

Again, this is a very low probability. But, it's certainly being investigated. Next, we plan to test our hypothesis in the laboratory for both instruments to verify that we can reproduce the signatures that we have seen.

This will take some time since the individuals who would do this lab work are those same ones operating the flight instruments on Mars. Finally, we are not yet able to perform an exact comparison between the samples collected for the same location using our two instruments. This is a high priority for our next sample to TEGA.

We will take a surface sample right in the same area that we took one for the MECA instrument and specifically look for perchlorate signature. Now, to present the evidence for perchlorate and MECA is the lead scientist for MECA, Michael Hecht.

Michael Hecht:
Thank you, Peter. Before I begin my presentation, I'd like to make a brief statement. As many of you know, the wet chem lab, which we sometimes call WCL was developed by a consortium of institutions in my adopted state of California, the Jet Propulsion Lab, my institution, which let the effort, the SpaceDev corporation, the NASA Ames Resource Center and institutions in my original home state of Massachusetts, the Thermo Fisher corporation and Tufts University.

Now, in view of this Massachusetts, California connection and all the rumors on the Internet about the doings and whereabouts of the MECA team, I want to categorically deny that we had anything whatsoever to do with the recent trade of Manny Ramirez from the Boston Red Sox to the Los Angeles Dodgers. That's all I have to say on that subject.

Okay. As you know, MECA is suite of instruments that includes the four wet chemistry cells, a thermal probe at the end of the robotic arm and two microscopes. We're starting to get very nice results from the atomic force microscope.

I hope we'll have an opportunity to talk about that in coming weeks. But, today, we're going to focus on chemistry. There are some very nice animations and still images of WCL operation available on the Web site prepared by Eric [DeJong's] team.

I encourage you to look at them. The basic recipe is simple. We first saw a container of a calibration and soaking solution that consists mostly of water. We dispense it into our instrumented beaker and wait a while for all our sensors to recover from their long, frozen trip to Mars.

We then add soil. We simmer for several hours stirring frequently. Throughout the measurement, we monitor the 26 sensors that line the walls of the beaker. Now, the majority of these sensors are ion-selective electrodes, which means that they mostly respond to a particular type of ion, such as sodium, magnesium, potassium, chloride or perchlorate.

The mostly is important. We always need to eliminate unusual sources for the signals. That's part of the reason it can take us so long to report on the data. The perchlorate that Peter discuss was discovered with a multi-use sensor that also has a small sensitivity to other ions such as nitrate, which is, in fact, part of our calibration solution.

So let me explain what I mean by multi-use. If we had a tiny signal from that sensor, it could mean that we had a little bit of a perchlorate, or it could mean that we had a lot of nitrate. But, a big signal from the same sensor is almost certainly from perchlorate because even if our entire sample were made of nitrate, it wouldn't be enough to produce a response that large.

Okay. So when we got our first soil sample, Rosy Red, back on Sol 30 and saw a big signal from the perchlorate sensor, we naturally assumed it wasn't working properly. Surely, there couldn't be that much perchlorate in the sample.

But, a flurry of laboratory work in subsequent days convinced us that the sensor was indeed working properly. We were able, in fact, to reproduce the readings with solutions that we had intentionally spiked with perchlorate. Now, our second WCL cell was used on Sol 41 to analyze a sample called Sorceress that was scraped from just above the ice in the Snow White trench.

When we saw a very similar response from the perchlorate sensor in that cell, we were convinced, in fact, that it was a real indication of perchlorate in the sample. Because we had now, a, reproduced the signal on Mars, b, reproduced it in the laboratory and, c, eliminated the other likely explanations, such as interfering ions.

But, we still had three more tasks to do before we ready to make a scientific or a public announcement. One was to eliminate some of the more unlikely explanations because it's an unusual finding. So in fact, we need to entertain unlikely explanations. A second was to increase our understanding of the result by discussing it in detail with the rest of our colleagues on the Phoenix science team.

That is ongoing. A third was to verify that the result is consistent with other Phoenix measurements and observations. Let me elaborate on that a bit. Just as we reach conclusions as human beings using all our senses, our sight, our sense of smell, our hearing, Phoenix was designed with an array of different tools to evaluate soil properties.

In particular, while WCL, if you will, tastes the sample. TEGA has the ability to sniff it. We hadn't done that yet. Now, you think we'd be smart enough to smell something before we tasted it, but frankly, I've made the same mistake with sour milk any number of times.

So in a moment, Bill will tell you about the results of the TEGA test. So why all the excitement just because our chlorine is surrounded by a few more oxygen atoms than we expected? Well, in part, it's just because, as scientists, we're fascinated by things like that. That's why we had trouble getting dates in high school.

But, mostly, it's because the different types of perchlorate salts have interesting properties that may bear on the way things work on Mars if - and that's a really big if - the results from our little teaspoon full of soil are representative of the whole planet or even significant portions of the whole planet.

Let me give you one example. We don't know what mixture of perchlorate salts we actually have in our solution. There are many different types, sodium perchlorate, magnesium perchlorate, ammonium perchlorate.

But, let's take as an example magnesium perchlorate. Now, first of all, it's a very effective desiccant, a drying agent, which means that it's like a sponge for soaking up water, like the little silica gel packets you sometimes find inside boxes when you buy electronics. Now, when these desiccants are just a little bit wet or a medium amount of wetness, they actually control the humidity around them.

That's how a cigar humidor works, for example. If it gets very wet, in this case the magnesium perchlorate, when it's very wet, it forms a sticky substance that freezes at very low temperature like anti-freeze. So we've only begun to think about some of these ideas and what their implications might be.

But, I can say that they could potentially keep a lot of graduate students busy for a very long time. With that, I'd like to turn the microphone over to my colleague, Bill Boynton.

Bill Boynton:
Thank you, Michael. Well, on Sol 25, TEGA analyzed the first sample delivered to a Phoenix instrument. This sample was called Baby Bear. The location is shown in one of the images on the Web site.

In this sample, we found a high-temperature release of oxygen. At the time, we suggested just within the Phoenix science team, that this oxygen release could be due to perchlorate. What we also pointed out, there were a few other possibilities that were still open.

Some, but not all, perchlorate salts will release chlorine as well as oxygen upon heating. But, during the analysis of this first sample however, we did not look for chlorine. Since we really were not expecting it to be released as a gas, we didn't program the mass spectrometer to be looking for it.

Well, since the discovery by MECA, or at least the suggestion I guess we should say now for the perchlorate, we changed our programming. A few days ago, we analyzed another sample called Wicked Witch. Here, we did look for the chlorine gas.

Had we seen it, the identification of perchlorate would have been rock solid. But, in the second TEGA sample, we did not see any sign of a release of chlorine. This observation could simply be that this particular salt of perchlorate in the Mars soil is not one of those that releases chlorine.

As I mentioned earlier, some perchlorate salts do release chlorine. Others do not. It also could have just been simply because the sample came from a different location where perchlorates were not present. So as Michael and Peter have mentioned, we have much more work to do.

You'll get a final story on this sometime in the future. I'll now turn things back to Peter.

Peter Smith:
Yes. Let us set the record straight. We've identified perchlorate in the MECA wet chemistry instrument. It has yet to be verified inside the TEGA instrument. It's a stable chemical. It does not preclude life on Mars.

In fact, it is a potential energy source. Our science develops slowly, as we are a small team and need to operate our spacecraft as well as pursue the science analysis. So I ask the media to be patient with us.

Let the science team proceed at a proper pace. We will share results as we have confidence that they're correct. Back to you, Dwayne.

Dwayne Brown:
Well, thank you all. Operator, let's open it up for Q&A.

Male Voice:
Yes, sir. At this time, if you would like to ask a question, please press *1. To withdraw your request, you may press *2. Once again to ask a question, the command is *1. One moment while we wait for our first question. Our first question comes from Craig Covault of Aviation Week. Your line is open.

Craig Covault:
Hi. Good afternoon. Can you hear me okay?

Male Voice:
Yes, we can.

Craig Covault:
Okay. My question is for Michael Hecht and also Peter. Back after the first MECA soil results, in the briefing, you commented that the soil was very Earth-like and generally supportive, in a mineral sense, of what could sustain certain types of life at least.

Given the perchlorate measurement of the initial wet chemistry test, was there any significant debate at that time whether you should have gone that far in your characterization of the soil? In hindsight, after the second wet chemistry test, do you wish you had not gone that far in the soil characterization earlier? Thank you.

Michael Hecht:
This is Michael. When we reported on the first soil delivery, we reported on what we knew. As I mentioned, at that time, we did have, you know, some various anomalies with some of the sensors. We were trying to understand.

So we reported what we knew at the time. There was nothing incorrect about what was reported. When we saw our second soil sample, and that gave us confidence that we had a perchlorate signal, at that point, we went into the process Peter described of careful confirmation, careful laboratory backup tests, waiting until it was the proper time to announce those additional results. No regrets.

Craig Covault:
May I quickly follow my -

Michael Hecht:
Certainly.

Craig Covault:
One part of the question there was there any debate whether or not you should go forward as you did do there some weeks ago?

Michael Hecht:
No. None whatsoever. There were debates about the degree we should be specific on things, for example - okay. I can give you something. We debated whether we should come out with a specific number for pH.

We knew it was slightly basic, and we knew people would ask for numbers. There, we felt we were skating on a little thinner ice. So there was the debate of that sort but not on the content of what we were releasing.

It was things we were confident about in broad terms. We were quite prepared to go to the public with them.

Craig Covault:
Thank you very much.

Male Voice:
Our next question comes from David Perlman of the San Francisco Chronicle. Your line is open.

Dave Perlman:
Hi, all of you. Thank you very much. Is there any possibility from either instrument, either TEGA or MECA, of determining which salts are the perchlorate, whether it's magnesium or any of the other perchlorate salts?

Michael Hecht:
I'll quote Mark Twain on that. This is Michael again. Mark Twain wrote, "I was gratified to be able to answer promptly. I said I don't know."

Bill Boynton:
This is Bill Boynton. One thing I could add is, if we do see chlorine gas emitted simultaneously with oxygen in any of our samples, that will suggest it's either magnesium, calcium or iron perchlorates. Those are the only ones that will release chlorine gas.

Dave Perlman:
Can you repeat those three? Magnesium, which and which?

Bill Boynton:
Magnesium, calcium and iron.

Dave Perlman:
Oh, okay. Thanks.

Michael Hecht:
This is Michael again. I can add that it is likely as not we have a combination of different perchlorate salts in there. So I doubt the answer will be one.

Bill Boynton:
Correct. I agree.

Dave Perlman:
Thank you.

Male Voice:
Our next question comes from Miles O'Brien of CNN. Your line is open.

Miles O'Brien:
Hello, gentlemen. Peter, question for you. You said at the outset that this apparent discovery is neither good nor bad for those who would like to find some sort of telltale signs of life on Mars. I've been to the Atacama Desert, and it's pretty darn dead.

Is that really accurate to say? Isn't this stuff kind of a life killer though really?

Peter Smith:
Richard, do you want to answer that?

Richard Quinn:
Sure.

Peter Smith:
Richard Quinn is here. He's an expert on oxidants. He has also been to the Atacama Desert. I'd like to ask him to answer this.

Richard Quinn:
Sure. An interesting thing happened, I've spent a lot of time in the Atacama as Peter just mentioned. There were some initial reports on the scientific literature that the Atacama was very Mars like. They couldn't find organics. They couldn't culture microbes.

But, then, as research continued and we looked a little closer, we found organics in the nitrate deposits in association with perchlorates. When we looked closer, we found microbes. So it sort of turned around when we looked at the Atacama.

Now, we know that microbes can exist quite happily in oxidizing conditions. I would say that the story possibly could turn out to be the same for Mars. We don't know yet, but we will continue our research along those lines.

Miles O'Brien:
But, is it accurate to say they exist in spite of the oxidizer? Or do they somehow feed off of it?

Richard Quinn:
Well, the interesting thing is perchlorate is a relatively inert oxidant. It can be either or. There are some microbes that actually use it as an energy source. Then, there are the microbes that just simply coexist with it. It causes them no problems.

Miles O'Brien:
So marching forward, Peter, what's next? First of all, you have conflict with your two instruments. Are you going to scoop up one sample and try to put dirt from one sample into both instruments to see if you can at least get a control on that aspect of the experiment?

Peter Smith:
Well, Miles, I'm not sure we have a conflict. We just haven't quite got a handshake. We expect to go back to the exact same spot where MECA got its first sample and saw a very strong signal and put a sample of that same material into TEGA. TEGA will focus its investigation specifically on perchlorate signatures. So this will give us, I think, the final confirmation.

Bill Boynton:
Miles, this is Bill Boynton. I'd like to add to that. For our first sample, we did see a release of oxygen, which ties in very well with the WCL findings. The fact that we did not see chlorine really, in no way, refutes the argument for perchlorates.

It just says it's not a pure form of any one of those three I mentioned earlier. So it really is, in no way, negating or showing any conflict with the WCL results.

Miles O'Brien:
Final thought here from Peter, what's it been like being on the inside of this as this rumor has kind of taken on a life of its own? On the one hand, I suppose it's the kind of attention scientists sometimes wish for. But, I guess you've got to be careful what you wish for.

Peter Smith:
Yes, that's right. I guess I have some mixed feelings. The perchlorate is something that caught me by surprise. Nobody had ever mentioned the possibility of perchlorate in our soils to me.

I had to go straight back to the textbooks and try and figure out what this material is. It's quite a fascinating material when you start searching into it. I think we're all learning a lot about perchlorates, what the situation could possibly be on Mars as well as how perchlorates work on the Earth.

It's been quite an education over the last few weeks. Unfortunately, there was a story out that we were hiding something. Of course, as soon as that story goes out, then people speculate. Speculations lead to all kinds of wonderful discoveries that I wish we'd made, but we haven't. [laughter]

So we're quite happy now, I think, to release our perchlorate story. This isn't the way we prefer to do it. Our policy from the beginning, Miles, has been to show all our pictures as they come down and try and involve the world along with us in exploring Mars and looking for a habitable zone and understanding what Mars is about.

This is really a human endeavor and not just a group of special scientists locked into a room or ivory tower, if you like. We really feel, I think, it's time to let everybody know what we're finding and give that window into our project.

Male Voice:
Our next question comes from Bill Harwood of CBS News. Your line is open.

Bill Harwood:
Yes. Hi, gentlemen. Can you hear me again? I'm sorry to ask.

Male Voice:
Yes.

Bill Harwood:
Thank you. I'm not a chemist. I was just wondering if one of you could please tell me - I'm a little bit baffled by the news conference in general to be quite honest. I'm wondering if one of you guys can tell me what the possibilities of or the overall significance of perchlorate either pro or con habitability because I don't understand that.

Peter, you've said that it doesn't necessarily mean that it's toxic to life. You read it about it on the Web a little bit, and it sounds like it is. What are the range of possibilities of something like this or maybe some end points for me?

The second question from me is, what can Phoenix say about anything beyond the immediate landing site? In other words, how can any result you find be generalized down the road to the broader context of large areas or Mars in general? Thanks.

Samuel Kounaves:
This is Sam Kounaves. I'm a professor at Tufts University and a co-investigator on Phoenix. I'm the lead chemist. On your first question, it's very interesting that, as the more that we've looked into this and I've looked into it, that there are actually a large number of plants that concentrate perchlorate that grow in perchlorate at certain levels.

There are a variety of species of bacteria that utilize perchlorate as a substrate, as a metabolism. So in itself, it could be compared, for example, to nitrates. It provides oxygen, and its potential for oxidation is very close to that of oxygen.

Again, it doesn't indicate anything that would be hostile to the extent, for example, if it was sulfuric acid or chlorine or something really lethal to organisms. It's another constituent. Here, on Earth, it exists in the background, like we earlier mentioned in the Atacama and probably in other places in the deserts of the South Pole, etcetera.

So it's a benign chemical in terms of most organisms. As to your second question -

Michael Hecht:
Can I field the second one, Sam?

Bill Harwood:
Can the first speaker spell his name for me please? Thanks.

Samuel Kounaves:
Kounaves, K-O-U-N-A-V-E-S.

Michael Hecht:
Let me field the second one, which is a question of how representative this material might be of Mars as a whole. Again, this is Michael Hecht. There are, as I mentioned earlier, a suite of different instruments on Phoenix and as part of MECA. One of things we try to do is to ascertain, in fact, how similar the soil is that we're seeing at the Phoenix site to what has been measured by other missions.

That's a process that will continue with the Mars Science Lander in future missions. So far, I think we've seen very little with cameras or with microscopes that suggest that the soil, at least, looks terribly different from elsewhere on the planet. What we see in our microscope is primarily a matrix of very small particles that are small enough to be carried in the air as dust.

We know that dust storms can cover the whole planet. So I think that, in general, that there's a sense that what we look on the surface is common to the rest of Mars. But, that doesn't say that the chlorate component, for example, might be very local.

So that's exactly the question we're asking. Like the first question that you asked, it's a very interesting subject that will be fodder for a lot of future research.

Bill Harwood:
Thank you.

Male Voice:
Our next question comes from Mark Carreau of the Houston Chronicle. Your line is open.

Mark Carreau:
Thanks. I had two questions. One, would it make any difference whether the perchlorate was found in the surface or in the samples studied deeper in the ground?

[Bill Boynton]:
Well, you realize that we're only capable of digging down about two inches into the soil. So, if you like, it's all surface. Then, there's ice underneath with more or less soil mixed into it. But, we can't get deep into that ice. We can maybe a few millimeters into it, and that's about it.

So basically, we're looking at soil surface samples with all of our samples. There is a slight profile, if you like, between maybe a little bit of a crusted soil at the top and a little looser soil underneath. That's a possibility. But, basically it's all surface soils.

Mark Carreau:
Okay. I had another question about the potential for contamination. You mentioned the Delta II rocket. Are you talking about the solid rocket boosters as a source of contamination potentially? If that's so, could you explain just a little bit how you would go about trying to eliminate that?

Is there some sort of - I'm not sure - some sort of signature that would indicate the chemistry came from Earth than Mars? Is that really a serious potential or just something you really need to try to eliminate?

[Bill Boynton]:
We have propulsion experts that are looking into the way that those fuels are emitted out of the solid rockets. The third stage does have a perchlorate fuel in it. That's the one that gives us the final boost towards Mars.

Is there some way that those uncombusted products can get around and into our spacecraft? It's very unlikely. But, we're certainly going to look at it. It is a special type of perchlorate. It's ammonia perchlorate.

I think, perhaps, that would have some signatures that we could see in our wet chemistry cell. But, also, realize that when we start our analysis inside of MECA, we do a calibration first. That does not show any perchlorate.

So it hasn't gotten inside of the instrument, for instance. Our robotic arm has dug for months now on the soils of Mars and is pretty well cleaned of any Earth contaminants if might have had. It's very hard to see how this could happen. But, it's due diligence to make sure that we look at this question and analyze it carefully.

Male Voice:
Our next question comes from Patrick Peterson of Florida Today. Your line is open.

Patrick Peterson:
Yes. Thank you. Is there some level of toxicity that perchlorate has that you've been able to measure on Earth? How does that compare with what you've found in your sample on Mars? Do you know the concentration of the perchlorate in your sample?

Samuel Kounaves:
This is Samuel Kounaves again. We have not really completed our process for determining the exact concentration. So at this point in time, we don't really know the levels. Here on Earth, it's a different story [for those]. But, we are not at that point yet.

Patrick Peterson:
Okay. I guess the other question is, I suppose, what do you have to do to confirm or deny that this sample is accurate?

Michael Hecht:
This is Michael Hecht. I outlined that process a bit. We've done within MECA the obvious things. We do want to go back into the laboratory and, for example, make up a cocktail that we think represents what we're measuring on Mars and put it into our instrument and see if we get exactly the same responses out.

We want to look at some more exotic species that could be possibly be fooling our sensors. Primarily, we want to make sure we can reconcile our result with results from other instruments on Phoenix.

[Peter Smith]:
Bill, do you want to add to that?

Bill Boynton:
I think what we'll be doing with TEGA is going back and looking for other samples, surface samples and look more carefully for chlorine and do things like that.

Patrick Peterson:
Thank you.

Male Voice:
Our next question comes from Keith Cowing with NASA Watch. Your line is open.

Keith Cowing:
Yes. Question for Peter Smith. You're quite the guy for the cameras. I don't think anybody would ever accuse you of not being available to the media. But, you had mentioned that you're now going to open up this process so that people can get insight.

Were you going to do that before Craig Covault's article hit the Internet? If it had not, would you have opened it up anyway? Did I have a -

Peter Smith:
What we were doing is we were waiting for TEGA confirmation, so we could be absolutely sure of our identification. That's, I think, the only changes that TEGA didn't exactly verify - huh? No.

Female Voice:
No. No. I'm -

Peter Smith:
What are you doing? [laughter] Anyway, what we were waiting for before we went public with the story was a verification from TEGA. Because so many other stories were coming out that we found all kinds of outrageous things, it was a little bit ahead of when we would have done it otherwise but not much.

Keith Cowing:
My follow-up here, and it's a rhetorical question. Perhaps Michael Meyer would like to handle it. After a decade of the Internet as a driver of stories starting with Pathfinder and so forth, why is it that you all still find yourself caught off guard by this strange thing called the Internet? Why have you not had a chance to come up with different ways to do stuff? Or is this just going to be a factor of life?

Michael Meyer:
Keith, I'm actually not sure what you mean by the question. I think everybody on the team using the Internet.

Keith Cowing:
You're always caught off guard when stuff leaks out. You're upset about rumors. Yet, the sources are almost always within the program. I'm just fascinated that you guys are still upset about - I can understand why. But, you're still upset after all these years, and that you haven't come up with better ways to sort of keep the information from prying ears.

Michael Meyer:
Yeah. I understand. But, we're dealing with a group of scientists that are working on a result. So it's kind of hard to herd them all in one direction. It is one of those things where we hope that we have time to work out a better understanding of results that are coming back from the instruments.

I think, no matter what the media is, we're going to be somewhat upset when you have to kind of talk about the story before you're really ready for it.

Michael Hecht:
This is Michael Hecht from the scientists' perspective here. We don't want to come to you, to media, and say, "We found chocolate on Mars," and two weeks later, flip flop and say, "Oh, we made a mistake. It was strawberry."

That hurts our reputation. That hurts your reputation. We want to make sure we get it right. Now, when we see something on the Internet that, in fact, is a speculation that is attributed to us and that's wrong, that does indeed change the equation a little bit. But, all of us here, I hope on both sides of this microphone, have the same objective, which is to send a consistent story to the public and one which we believe is correct.

Male Voice:
Our next question comes from Alan Boyle of MSNBC.

Alan Boyle:
I had a basic question and then a trick question. I guess the basic question would be people hearing about perchlorate would wonder what's the significance of it. I'm hoping to be able to explain why this is something that is worthy of debate. I guess it has to do, perhaps, with a whole different sort of chemistry that's going on that may or may not point people in a different direction.

But, perhaps someone can just kind of explain in basic terms what's the big deal about perchlorate. Then, the trick question would be is there something else, for example, from the microscope that people are looking at that are interesting that might actually generate that kind of buzz in the future?

Michael Hecht:
Michael Hecht here. I certainly hope this isn't the last big interesting story from Phoenix. I hardly expect it will be in answering your second question. They will come out, as with this case, when we feel confident about the particular conclusions.

Why is perchlorate important? Boy, [I can] hardly think of a branch of Mars science in which it might have some influence depending on how much, where it is, how widely distributed and what type of perchlorate salts are involved. I mentioned a few possibilities.

Certainly, the way magnesium perchlorate and water interact is interesting and could affect many things from how land forms are formed to whether, in the distant past, there was ever precipitation. There are widespread implications. They may all turn out to be nothing. They may turn out to be very important.

But, it's just as if it opened up a whole new research chapter for us. We could talk about any one of those potential applications at length. I think we're not ready to do so yet. I hope that answers the question.

Alan Boyle:
This is something that, I guess, one of things about this is that it came out of the blue is that it is a whole new door that no past probes had picked up anything on this before Phoenix?

Michael Hecht:
Maybe I could ask my colleague Richard Quinn to address that.

Richard Quinn:
Yes. This is Richard Quinn speaking. The other probes had different focuses than the MECA WCL does. MECA WCL is looking for soluble salts and perchlorate is a very soluble salt, which ties into the whole history of the chemistry at this landing site and, as Mike mentioned, the interaction of waters.

So I simply would agree with Mike that this is, in some sense, it's a new chapter on how we look at least at this landing site, the chemistry that is occurring these.

Samuel Kounaves:
This is Sam Kounaves. I would add that this is a very unique instrument in that the previous instruments mostly looked at the elemental composition of the planet. This basically tasted the planet by adding water to the soil and analyzing the ionic components.

So it's an aqueous instrument, which is, of course, what most humans are interested in is the interaction of the Martian soil with aqueous systems, not just the dry system. That's why this is a very unique instrument that is providing very fresh, new, interesting and exciting information.

Alan Boyle:
Thank you.

Male Voice:
Our next question comes from Leo Enright of Irish Television. Your line is open.

Leo Enright:
Thank you. I was just curious about perchlorate. They're ubiquitous in the United States. I'm trying to work out and maybe asking you to work out how hard it would be to exclude Earth contamination.

I mean, somebody goes to a Fourth of July party. They get perchlorates on their eyebrows. Somebody's airbag inflates. I mean, is there not an endless chain of possible contamination incidents? How do you close off that?

If I may ask a second question for Richard Quinn, and that really is just to explain how do perchlorates arrive in the Atacama Desert just to give us some idea of the geological context. I mean, how does this sort of stuff appear outside of my airbag?

Michael Hecht:
This is Michael Hecht. Are you suggesting that there are no perchlorates in Ireland?

Leo Enright:
[laughter]

Michael Hecht:
Peter, did you prefer to take that?

Peter Smith:
Hi, Leo. It's been a while. Nice to hear your voice.

Leo Enright:
Hi, Peter. Hi. Congratulations on everything that you guys [have done].

Peter Smith:
The inside of our spacecraft, we take great care to keep out materials that we don't want to go with us to Mars. We have a whole process that we go through. This is not just slapping it together in a garage.

These are inside the clean rooms. We take great pains to protect our instruments from any type of chemicals of this sort that might be reactive or give us a bad result. As well as we protect our spacecraft against microbes, so that we don't send microbes to Mars as part of our planetary protection policy.

So we actually sample the surface materials off the spacecraft. We examine them - can't read it - calibrate. Anyway, there's a whole set of processes we go through. We're very sure that we did not bring a perchlorate-infused spacecraft to Mars at least in our laboratory and our assembly rooms.

Samuel Kounaves:
This is Sam Kounaves. I will add as I had previously that the wet chemistry cells, we had [calibrants] that we added first. We did a first leeching solution that we added to it. We measured, and there was no perchlorate in that.

We added a [calibrant] to calibrate, and there was no perchlorate in that. So these were calibrated on Mars. They showed no perchlorate before the analysis of the soil.

Richard Quinn:
This is Richard Quinn speaking. The answer to your second question about perchlorate formation. In the Atacama Desert, the source of both the nitrates and the perchlorates, they're created in the atmosphere due to the interaction of aerosols or dust particles by sunlight.

They then dry deposit down onto the surface of the desert. They stay at the surface because the Atacama Desert is very arid. In other parts of the world where it rains, because perchlorates are chemically inert, they cannot bind to things.

They move through the soil very quickly in the presence of water. So this ties back to Mars. One of the fascinating things is perchlorates will tell us quite a bit about the history of water, not just at the Phoenix landing site but in other parts of Mars as we continue our exploration.

Currently, we've seen the perchlorates at the surface. I think a future line of research will be to look at where else they are on the planet and whether or not water and salt mobility was involved in that transport.

Michael Hecht:
We're quite prepared to send MECA to any part of Mars that NASA cares to take us.

[Peter Smith]:
Nice try, Mike. [laughter]

Male Voice:
Our next question comes from Irene Klotz with the Discovery Channel. Your line is open.

Irene Klotz:
Thank you very much. I have two questions. The first is for Peter. Time is going to be limited for what you have left to do with Phoenix. I'm wondering if you have an idea of how much of your resources and your time will be devoted to investigating the perchlorate readings versus some of the other mission goals.

Peter Smith:
Well, perchlorate, of course, is what we're working on right now. But, we have other goals, as you point out. Even though time is short, our robotic arm is short too. We can only reach a few places. So we will be trying to sample other locations once we're finished with the Snow White area where we've been working so far.

We'll try and get into the troughs between polygons. Perhaps, we can get deeper into the soil there, and maybe some of the perchlorates have concentrated in the lowest areas if they've been interacting with liquid water. We'll be also thinking about looking under rocks where we're protected from the kind of processes that the soils would see if exposed directly on the surface.

So there's a lot for us to do. We have at least a couple months left to get our samples into the instruments and do the analysis. This is the data collection time of the mission. We want to make sure we get the right data. Then, we'll continue science analysis and laboratory work for some months afterwards to really try and fully understand what we've got.

Irene Klotz:
Thank you. My other question is for Mike Meyer. Did this [finding] for any sort of conversation in any government entity, the executive branch beyond NASA?

Michael Meyer:
Certainly, OSTP was interested to find out they were supposedly briefed on this. Dwayne, you might know what's happened since the story has come out since you're there at headquarters, and I'm on [added] review.

Dwayne Brown:
Yes. This is Dwayne, Irene. Let me just state up front that neither the White House or the President's science advisor were briefed on this, on any of the findings from the Phoenix mission. Now, that's certainly [we're] talking today what you guys are hearing, I would probably assume that they have been briefed now. This is where we are at this point.

Irene Klotz:
[unintelligible] really good reporter, and he's the one that said that there was a White House briefing.

Dwayne Brown:
Well, let me just be clear. You guys have your sources. My sources say no one was briefed at that time.

Irene Klotz:
Okay. Thanks.

Male Voice:
Our next question comes from Eric Hand of Nature. Your line is open.

Eric Hand:
Hi. Yeah. I was hoping you could put this in the context of previous probes. I think someone else asked this question. But, maybe you could describe how this perchlorate finding is different from what Viking found.

They didn't find this. There's been a lot of debate over what the oxidizer was that Viking found. A lot of folks thought it was hydrogen peroxide. Does this suggest that perchlorate is the main oxidizer on Mars. How does this relate to what Viking found?

Richard Quinn:
This is Richard Quinn speaking. You're absolutely right about the statement of Viking. The leading hypothesis for what was seen in the Viking biology experiments was the presence of small amounts of peroxide or superoxide. For those who are not familiar with it, it was the light detection experiment.

What they saw was, when they wetted the soil, they saw a small amount of oxygen released. They saw some decomposition of some of the organic nutrients that they brought with them. Perchlorate is very different. Perchlorate is typically not very reactive in solution.

It would not typically give off oxygen when wetted. So the perchlorate is not likely, in my opinion, it is not responsible for the Viking biology experiment. It's not the same compound. But, I do think that it all does point to a very interesting photochemistry that I mentioned earlier.

The hypothesis with Viking is that the small amounts of peroxide were also produced in the atmosphere photochemically and then deposited down on the surface. So again, yeah, I think that there will be some very interesting ties in the future to these types of compounds, how they interact with water and how they move through soils and what the implications are there.

Eric Hand:
If I might ask a quick follow-up, I think Peter mentioned that these could concentrate further down in the soil profile. But, earlier on, there was a lot of discussion that ice and this ice-soil interface could neutralize many different types of oxidants and that ice, in fact, could be a sheltering environment from the oxidizer. So I wonder if you think that still is true.

Richard Quinn:
Yeah. I think that what Peter said was absolutely right. Going back to the Viking biology experiments, when you wet the sample, the peroxide, if that's what it was, decomposed. So in a soil in the close proximity of ice, if there's a lot of water activity or if there's water activity, it would quench these more aggressive oxidants like hydrogen peroxide.

But, because perchlorate is chemically inert, it persists. It simply is soluble. It moves through the soil, so it may redistribute itself depending on how water moved in that soil.

Eric Hand:
So bottom line, the ice could still be sheltering from harsher oxidizers but not this particular one.

Richard Quinn:
I would say that that's quite plausible. Yes.

Male Voice:
Our next question comes from Kenneth Chang of the New York Times. Your line is open.

Kenneth Chang:
Hi. Thank you very much. I guess I have two more perchlorate 101 questions. I guess one, why is it so surprising that it was found here since it has been seen in the Atacama, which of course was like Mars?

Secondly, I guess, from what everyone's been saying, it sounds like this is the discovery of an unexpected mineral that has very little directly to do with the habitability of Mars. It's mainly just giving you another avenue to look at its geological chemistry. Am I mishearing something?

[Peter Smith]:
No, that's right. How this perchlorate in the soil affects habitability is a complex question that we certainly don't have the final answer on. It is a very stable material. It's not likely to tear apart organic materials unless you heat it very high temperatures.

So it really doesn't limit us in our search for habitability in this icy soil. If we were lucky enough to see some organic signatures, it would not be a huge surprise. I think that they were coexisting with perchlorates as I understand it. I don't know what else to say. Did I - [crosstalk]

Michael Hecht:
May I answer the first half of the question.

[Peter Smith]:
Yeah. Go ahead, Michael.

Michael Hecht:
Which was why we were surprised to see this. As Sam Kounaves pointed out a few minutes ago, this is a very different kind of experiment than what we've done before. If you will, we are making tea out of the Martian soil, and we're not so concerned about what was in the tea leaves but what's in the tea itself.

Now, all we had to go on was what has been seen mineralogically in the past by previous missions that are looking at the bulk material, looking at the atoms in the material. That would have led us to expect to see, you know, lots of sulfates, lots of other compounds based on the mineralogy.

Now, in hindsight, what is soluble and what's there in the bulk before you put it water don't have to be the same. But, to the extent we had expectations, that's what they were based on. When the results turned out rather different, we were surprised.

Kenneth Chang:
Okay. Can I just ask one thing quickly to make it explicit? Would the presence of perchlorates change your view of the habitability up or down at all?

Male Voice:
No.

Male Voice:
I don't think so.

[Michael Hecht]:
We polled a number of people on this team, all of whom who have strong opinions, but they all come down to no.

Kenneth Chang:
Thank you.

Male Voice:
The fact that they coexist with organisms implies that it's -

[Peter Smith]:
It probably comes down to the positive side rather than the negative because of that.

[Michael Hecht]:
But, it certainly comes down [to the] different, and that's what makes it very interesting.

Kenneth Chang:
Okay. Thank you.

Male Voice:
Our next question comes from Alan Fisher of the Tucson Citizen. Your line is open.

Alan Fisher:
Thank you. This question is for Peter Smith. When we spoke a couple of weeks ago, Peter, you said that you were putting together the final proofs on some research that would, as you said, surprise many people. I was wondering if the perchlorate story is what you were alluding to or if we should wait for another shoe to drop here. [laughter]

Peter Smith:
I was talking about perchlorates. I find the story fascinating myself. I've been looking up perchlorates. It just seems to take you in all kinds of fun directions as you look into all the different properties associated with perchlorates. Just exactly how perchlorate reacts on Mars is yet for us to determine, but on the Earth, it's certainly a very fascinating material.

Alan Fisher:
Okay. Thank you, Peter.

Male Voice:
Our next question comes from Richard Kerr with Science Magazine. Your line is open.

Richard Kerr:
Thank you. For Richard Quinn, what are the levels of the abundance of perchlorate in the Atacama Desert? If Phoenix landed there, could it detect those levels?

Richard Quinn:
If Phoenix landed in the Atacama Desert, yes, it could detect the perchlorate there. In the Atacama Desert, it's also characterized by large nitrate deposits, which the MECA would also detect.

Richard Kerr:
What kind of concentrations in the soil of perchlorate?

Richard Quinn:
In the Atacama Desert, it's dominated by nitrate. That's simply because nitrogen is the dominant chemical in the atmosphere, and it's photochemically produced in a dry deposit. As far as WCL, we're still in the process of quantifying the amount of perchlorate, so I can't say at this time.

Richard Kerr:
I mean, the concentration of perchlorate in Atacama soils.

Richard Quinn:
Oh, that tends to be parts per million levels. Primarily, that's because the source of the chlorine is from the nearby ocean. It's in much smaller quantities than the nitrogen.

Richard Kerr:
Okay. Thank you.

Male Voice:
Our final question comes from Mark Kaufman of the Washington Post. Your line is open.

Mark Kaufman:
I have a question. But, also, it was kind of frustrating a while back when a question was asked about whether or not this means that it's more or less likely that there would be life. There were a lot of answers, but nobody identified themselves.

You were saying interesting things, but we don't know who said what. One person said that this would probably come onto the positive side. Could you just give a sense of who said that?

Peter Smith:
That was me, Peter Smith. Me, that doesn't help, does it? [laughter]

Mark Kaufman:
Who was it who said that there was a consensus agreement that this would not necessarily affect the habitability one way or the other?

Michael Hecht:
That was probably me, Michael Hecht.

Mark Kaufman:
Okay. Okay. Okay. Well, my question is this. I'm going back to the Atacama. I'm a little confused. Is perchlorate something that is generally associated with extremely dry climates? I'm a little confused about that.

Richard Quinn:
I can address that. The reason that it's associated - [crosstalk] Oh, I'm sorry. I'm Richard Quinn. [laughter] The reason that the perchlorate accumulates in the Atacama Desert is because of the aridity, because it is so dry.

This comes back to some of the things that were said earlier. Perchlorate is a very soluble salt. So it moves readily in soils in the presence of moisture. So this is going to be a very important and interesting marker as we go on to study the Martian soils and look to see whether or not different soil types contain perchlorate or they don't.

Mark Kaufman:
Okay. On Earth, would perchlorate also be found in non-arid environments?

Richard Quinn:
It is found, but it's very small amounts. Actually, it tends to end up in streams and in water systems because it is so soluble.

Mark Kaufman:
Okay. Thank you.

Male Voice:
This concludes today's question and answer session.

Dwayne Brown:
Operator, may I close out please?

Male Voice: Yes, sir.

Dwayne Brown:
Again, folks, I want to thank you all. I know we still had several questions in the queue. But, we wanted to keep this to an hour. Obviously, you can call my number or Sara or JPL to try to get additional questions answered for follow-ups. [Obviously], there's going to be a part two.

Please go to the Web. The replay number is 800-229-6331. 800-229-6331. Thank you all again. Bye.

End of recorded material

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