Planetary Radio: Space Exploration, Astronomy and Science - Chris McKay on the Phoenix Mission's Big Surprise

Episode Date: June 1, 2009

Chris McKay on the Phoenix Mission's Big SurpriseLearn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Chris McKay on the Phoenix mission's big surprise this week on Planetary Radio. Hi everyone, welcome to Public Radio's travel show that takes you to the final frontier. I'm Matt Kaplan of the Planetary Society. Why is the discovery of rather nasty chlorine compounds in the sands of Mars a good thing? Famed planetary scientist and astrobiologist Chris McKay will give us the exciting answer. Bill Nye is just as excited about proof of a way to discover worlds with oceans like our own. And Bruce Betts brings his teddy bear along

for our weekly What's Up tour of the night sky. Think fast. How many people live on the International Space Station? The answer, for the first time, is six. And what do they drink? Well, and this is another first, they drink water that has been recycled from everything they do up there.

It's really a pretty big milestone, since the near 100% reuse of resources will be essential on a trip to, say, Mars. And speaking of the Red Planet, take out your red and blue 3D glasses and check out the images from the CTX or Context camera on the Mars Reconnaissance Orbiter. Sure, the ultra-sharp high-rise camera gets most of the press, but its field of view is so narrow that it sometimes misses the forest for the trees. An odd metaphor, considering it's Mars we're talking about. Some great Context camera images are available in a recent Planetary Society blog entry from Ken Edgett.

It's at planetary.org, of course. Happy anniversary to our Berkeley friends who run SETI at Home, the project that allowed millions of ordinary folks and their computers to join the search for extraterrestrial intelligence is 10 years old. Here's Bill. Hey, hey, Bill Nye the Planetary Guy here, Vice President of the Planetary Society. This week, I want to call attention to a story that hasn't gotten a lot of play. We are using

the Deep Impact spacecraft. Maybe some of you came out to Glendora, California with me and astronaut Rusty Schweigert as we watched a copper sphere get smashed into a comet, looked for the debris to figure out what the comet was made of. Well, that spacecraft is still out there. And it's been renamed, the mission's been renamed Epoxy. Extra Solar Planet Observation Experimental Investigation. And so what we're doing is using the cameras on these solar-powered spacecraft to take pictures of the Earth for the purpose of determining what a planet would look like if it had an ocean.

Now, when I was in college, as you may know, I had the great privilege to study under a very famous astronomer, one of the founders of the Planetary Society, Carl Sagan. And Sagan often asked us, what it would be like if we were aliens and looked back at the Earth? How would we know whether or not there was, if I may, anything going on here? Well, whether there was life, whether there were plants, whether the atmosphere was created by living things, largely. Well, these are excellent questions, and we really haven't had the means to figure it out, except by inference, except now using the Epoxy mission, formerly Deep Impact Spacecraft, we are taking pictures that in a

few years, a decade or so, will be used by other scientists using the Terrestrial Planet Finder Spacecraft, Spitzer Space Telescope, the Hubble Space Telescope, to determine not only whether or not a planet is blue, like the famous, famous Voyager picture, the Hubble Space Telescope, to determine not only whether or not a planet is blue, like the famous, famous Voyager picture, the pale blue dot, but whether or not that planet's got oceans and continents, shores, estuaries, things like that. Things that give rise to living things like we're familiar with. If we could find a planet like that, my friends, this is making very good use of human tax dollars. And this little story may, in a few years, help us, dare I say it, change the world. Well, thanks for listening. I've got to fly. Bill Nye, the Planetary Guy.

Our last visit with Chris McKay was in the middle of California's Mojave Desert. He was there as the leader of a great program for middle and high school science teachers. The Mojave, though, is a walk in the park compared to some of the extreme environments Chris has visited, searching for and studying the life forms that manage to survive in them. The planetary scientist and astrobiologist has been based at the NASA Ames Research Center ever since he got his Ph.D. in the early 80s. We don't have nearly enough time to talk about all the projects and missions he has worked on. It's his assignment as a co-investigator on last year's Phoenix Mars Polar Lander mission that led to our conversation a few days ago about a revelation that reverberates across the 33 years since the Viking Mars landers touched down on the Red Planet. First of all, glad that we can talk a little bit about Phoenix.

You know, Peter Smith has come on the show a couple of times, and we've talked about some of the results, the masses of data that are still being analyzed as a result of this mission. But we haven't talked all that much about what it all means, and I guess that's still being figured out. It sure is, Matt. And for me, the most important result, the result that has the most ramifications for our understanding of Mars and for our interpretation of results from other missions, is the discovery of perchlorate in the soil. So perchlorate's in the soil, and just below that, water ice. It's a fascinating combination. That's right. And perchlorate was a big surprise. We knew that there were chlorine molecules in the soil. We had directly detected the chlorine molecule with Viking, with Pathfinder, with the MER rovers, also from orbit with Odyssey and their gamma ray spectrometer.

So we knew Mars had chlorine. That was not a surprise. But we had assumed that the chlorine on Mars in the soil was in the form of sodium chloride or magnesium chloride, harmless everyday salt. But Phoenix landed, and to its surprise, to our surprise, Phoenix found that virtually all the chlorine in the soil at that site is not in salt. It's in this highly oxidized form of chlorine, the most oxidized form of chlorine called perchlorate. Big surprise. So there's soil on Mars, red stuff, 1% of it is a very oxidized form of chlorine. What does this mean for finding organics, or for that matter, any evidence of biological activity? Well, it's kind of puzzling because, and important, to look back and think about the Viking results. Remember Viking.

Viking landed on Mars, scooped up some soil, put it in an oven, heated up that oven to 350 or 500 degrees, and then looked at the fumes that came out of that heating to search for any organic fragments that could be released by that heating. Well, we now look back on that and the failure of Viking to detect anything. One of the big surprises of Viking was that that instrument, the GCMS with the pyrolysis release, thermal release, found nothing, no organics at all in the soil. And that was a surprise, obviously. If we knew there were no organics in the soil, we wouldn't have spent many millions of dollars to set an instrument there to characterize them.

So it was a big surprise. And that result, the null result by the Viking GCMS, which at the time was interpreted as a limit of a part per billion in the soil. There could not be organics in the soil at a part per billion. That negative result was the main reason that the entire science community supported a non-biological explanation for the Viking results. How could there be life on a planet if there was no organics? So the reactivity of the Viking biology experiments, the reactivity seen in the LR experiment, the reactivity seen in the gas exchange experiment, were attributed to chemistry, not biology, primarily because the Viking GCMS, the gas chromatograph mass

spectrometer, did not detect organics at a concentration of a part per billion. That was the perceived limit. Now, fast forward to Phoenix, many years later, decades later, we now realize that there's perchlorate in the soil. And we know that if you take perchlorate and organics, they can sit together happily at room temperature. But if you take perchlorate and organics, they can sit together happily at room temperature. But if you heat them up to 500 degrees, 300 degrees, the perchlorate decomposes, becomes extremely reactive, and will destroy any organics there. So I think the perchlorate forces us to reevaluate our 20 years more interpretation of the Viking results. As I remember, there were people, even after the Viking results were in,

while many said, okay, that's it, no organics, that there were a few folks, if I remember correctly, including Carl Sagan, who said, well, now wait a minute, this may not be that conclusive. Have we now reached a point where there are indications that he was right? Well, that's an interesting historical point. There were people who criticized the Viking GCMS results, and they were criticized at the time and over the last couple decades for two reasons in two areas. One, the possibility that the instrument didn't work.

It was broken. And I think we can put that one aside. There's every indication that the detectors, the columns, the mass spectrometer on the GCMS work flawlessly. There's no indication that there was any technical malfunction with the instrument. The second area in which they've been criticized, the results were criticized, was that maybe the organics in the soil were too refractory, too coal-like. They were like coal, like tar, and that heating them to 500 degrees wasn't hot enough to release them into the vapor phase. If you heat a very tar-like organic like asphalt, even to 500 degrees, you don't get much out of it. like asphalt, even to 500 degrees, you don't get much out of it. So those two comments have been around for a while, but neither of them really argued against the fact that if there were biology in the soil, it can't all be made out of asphalt. It's got to have some light organics in it,

sugars and amino acids, and those should have come out at 500 degrees. So there was a persistent problem with interpreting the Viking results as organics in the soil, even despite the criticism. So up until the Phoenix results, there was no plausible explanation for why the Viking mission didn't see organics. So now with Phoenix, we find an enormous amount of perchlorate in the soil compared to expected levels of organics. The amount of perchlorate in the soil is a percent. So 1%. Now that sounds like a small amount, but that is, let's see,

100 million times more perchlorate than the upper limit set by the Viking on organics. Wow. Which means that there could have been a million times more organics, easily a million times more organics than we've been thinking, and they could have all been destroyed by the perchlorate when they were heated up in the Viking oven. There's something tragic about that. Now, this doesn't prove that there are organics on Mars. But what it does is it corrects our upper limit from a part per billion, probably up to

about a part per thousand. That's a factor of a million correction. Even astronomers worry about factors of a million. That's NASA planetary scientist Chris McKay. He'll be back in a minute to tell us more about the new hope for finding the building blocks of life on Mars. This is Planetary Radio. I'm Robert Picardo. I traveled across the galaxy as the doctor in Star Trek Voyager.

Then I joined the Planetary Society to become part of the real adventure of space exploration. The Society fights for missions that unveil the secrets of the solar system. It searches for other intelligences in the universe, and it built the first solar sail. It also shares the wonder through this radio show, its website, and other exciting projects that reach around the globe. I'm proud to be part of this greatest of all voyages, and I hope you'll consider joining us.

You can learn more about the Planetary Society at our website, planetary.org slash radio, or by calling 1-800-9-WORLDS. Planetary Radio listeners who aren't yet members can join and receive a Planetary Radio t-shirt. Our nearly 100,000 members receive the internationally acclaimed Planetary Report magazine. That's planetary.org slash radio.

The Planetary Society, exploring new worlds. Welcome back to Planetary Radio. I'm Matt Kaplan. Has Mars been fooling us for more than three decades? Does that planet harbor lots of organic compounds that we simply look for using the wrong tools? That's what we've been talking with NASA planetary scientist Chris McKay about. Among many other things, Chris is a co-investigator on the Phoenix Mars Polar Lander mission that found huge amounts of perchlorates in the Martian soil. So what does this mean as we continue to look for organics on Mars?

I mean, after all, we're now, with the delay in the mission, a couple of years out from sending the most sophisticated laboratory ever to that planet. I think the perchlorate has at least three important new implications. First, that we need to start realizing that the upper limit set by Viking was not a part per billion, but is probably more like a part per million. That's first. Second implication is that the way to detect organics is not by putting a soil in an oven and heating it up. That's the way Viking did it.

That's also the way Phoenix tried with the TIGA instrument, thermal evolved gas analyzer. The reason we do it that way is because that's the way Viking did it. That's also the way Phoenix tried with the TIGA instrument, Thermal Evolved Gas Analyzer. The reason we do it that way is because that's the easiest way. We would never analyze organics on Earth that way because it's not the most accurate way. On Earth, we analyze organics in soils by extracting the organics in a liquid, in a solution. Well, solutions are difficult on spacecraft, so we try to avoid them. But fortunately, MSL, the Mars Science Laboratory Organic Detection Instrument, called SAM,

does have a liquid extraction. So that's the second important implication, which is, on MSL, our chance for getting around this problem is the liquid extraction. And then the third implication for future missions is when we go to Mars to look for organics, don't bring ovens. Leave the ovens at home. Yeah, do your baking here. Let's say that MSL goes up there in a couple of years and does find some significant portion of organics in the soil, what are those potentially going to tell us about the red planet? Well, if MSL finds organics, that will be a great day. It will tell us, it'll open up a new chapter, I think, in interest in the astrobiology of Mars. But it's only the first step. Organics do not equal life. Just like

people say, follow the water, sometimes they confuse the fact that just finding water isn't the same as finding life. But organics is an important step toward it. The next step would be to characterize those organics and determine if they are biological or if they are, on the other hand, non-biological. We know that the solar system is full of organics that are not biological. Meteorites have organics in them. Titan has organics in its atmosphere. The moons of Saturn, Jupiter, they have organics, but they're not necessarily biological. Comets have organics.

On Earth, the vast majority of organics we see are biological. Comets have organics. On Earth, the vast majority of organics we see are biological. So the question on Mars, if we find organics, the question will be, are those organics like Earth's organics, biological in origin, or are those organics like the organics in meteorites, non-biological in origin? That will be the next step. We can't expect MSL to do both of those steps, but if MSL detects organics, there'll certainly be a lot of interest to go back with another mission to characterize those organics and determine if they are biological or non-biological in origin. What would you be looking for? Would it be as simple as finding an odd imbalance in those organic components? That's probably the best approach, indeed. One of the peculiarities of life on Earth is that it uses certain types of

organic molecules and not others. For example, the amino acids that appear in proteins, that life uses in proteins, life just uses the left-handed amino acids. It doesn't use the right-handed amino acids. In meteorites, where chemistry produces the amino acids, there's both left and right. A way to think about it is life being organized and orderly drives on one side of the street, the left side in this case, whereas chemistry drives on both sides of the street, disorganized and disorderly. And if we saw that sort of preference for one type of amino acid over another in the organics we found on Mars, that would be a smoking gun for a biological origin.

Chris, you've spent a lot of time now looking for what you like to call that parallel or second genesis. Still hoping that we're going to find it, if not on Mars, someplace else in the solar system? If we search and search Mars and we don't find organics, then I'd say it's time to move on, go out to those worlds in the outer solar system where we know that there are organics. Enceladus, organics coming out of its geysers. Titan, organics in the atmosphere and on the ground.

We would go there. Certainly, follow the water is the important first step, but follow the organics is the next step. It's always a pleasure to talk with you, Chris. I hope we can do this in the desert again someday. You bet. Very good, Matt. Chris McKay is a planetary scientist with the Space Science Division at NASA Ames, the Ames Research Center in Northern California, which is where he has spent most of his research life. Co-investigator on the Mars

Phoenix lander mission. The data from that mission, as you've heard, still being analyzed. He's also a co-I on the Mars Science Laboratory, just renamed Curiosity at the suggestion of a child who won a contest. He is also the deputy project scientist for robotic lunar exploration, the Robotic Lunar Exploration Program by NASA. And I don't expect you're hoping to find many organics there. Yeah. Thanks again, Chris. You bet, Matt.

We'll be right back with Bruce Betts for this week's edition of What's Up. It is time for What's Up on Planetary Radio. We're going to take a look at the night sky and some other stuff out there, out there in the great black, the black, as they used to say on Firefly. Hey, welcome. Welcome. Up in the sky, as much as I don't like the pre-dawn, it is where things are happening. Venus is spectacular over in the east. Can't miss it.

Brightest star-like object. Much brighter than the brightest star in the sky. Below it is much, much dimmer Mars. Mars will keep getting brighter and higher in the sky. Below it is much, much dimmer Mars. Mars will keep getting brighter and higher in the sky over the coming weeks and months. And then Jupiter is up very high in the southeast in the pre-dawn, also brighter than any star in the sky, but still much dimmer than Venus. In the evening, we do have Saturn. Saturn's always cool, especially if you can check it out with a small telescope and see the rings. It is still in Leo, and it is up in the west after sunset and in the early to mid-evening.

We move on to this week in space history. Mars Express was launched in 2003, and it is still quite happily functioning at Mars. I always like to remind people we have five spacecraft working at Mars, four from NASA, one from ESA. Kind of impressive to just monitoring Mars all the time. Also, much farther back in time, 1965, Ed White took the first American spacewalk on Gemini 4. I remember that. I was a kid, and I do remember that.

Very exciting. It was indeed. It had that cool little handheld thing to move them back and forth. That was cool, but really, even at the time, I thought it looked kind of rinky-dink. It looked like something Wham-O would make. I think they were a NASA contractor at the time.

It was later followed up by Ronco. And the advantage was that the later ones actually sliced and diced your vegetables on board but wait there's more but wait there's more don't order yet we'll also throw in one anti-gravity boot what am i gonna what am i gonna do with one anti-gravity boot, I guess. You got ordered, too. I could just hop, I guess. Trying to move us on to random space. You were just too much for your microphone there, but you just can't bottle this stuff. You can't really capture it. It's like the Grand Canyon.

Ooh, gosh, it would be cool to record it across the Grand Canyon. Yeah, that would be fun. Maybe I can get an echo thing that simulates that. What would it sound like with echo? I mean, we never heard... I'll work on it. All right, random space fact. Kepler up there

starting to monitor a big expanse of sky for the next few years, looking for periodic little tiny dips in starlight that occur as planets circle in front of their stars, partially block the light. Did you know its 95-megapixel camera is the largest ever launched into space, and it can detect tiny changes in a star's brightness of only 20 parts per million? Yeah, I think some of that came up. I don't know if we mentioned that it's the biggest camera measured in megapixels

that's ever gone into space. But some of this came up on our recent show when we talked about Kepler. But very good. Well, yes, it's a spiffy keen thing. Let us go on to the trivia contest. And we asked you, how many space shuttle launches, space shuttle launches have there been? This is interesting. Now, some people, I think, just looked at the mission designation numbers, and that threw them off somewhat. Other people did a little bit more

research. One of those was Joe Massey. Joe Massey of Gaithersburg, Maryland. You know, I'm not sure if he's won before or not. If he has, it's been a good long while. He said 126 shuttle flights, or rather launches, which is what we actually asked for. include Enterprise, which never really launched. It just took off on the back of the 747, for those who remember those tests that were done, lo, those many years ago. Was 126 correct? That is correct. With this most recent space shuttle launch, it was 126. That's a lot. Yeah, it sure is. A lot of people marveled at that. Do you know, I'm going to throw one at you here. Ready? My little trivia question. Random space fact. No, but go ahead. Which shuttle has flown the most missions?

I'm going to go with Atlantis. Eh. But I said it with confidence. I didn't keep the complete list, but it's Discovery. I think Atlantis was number two. Now, this is purely from the listeners, but a couple of them agreed on this. Discovery, 36 missions in all. Not bad.

Yeah, I guess Atlantis, when it just flew, was its 30th mission. Yeah, I do think that that, I'm pretty sure that made it number two. Now, we also had a couple of people who said, well, what about Buran? Buran, Buran, Buran. Yeah, well, I suppose Buran, the Soviet version of the space shuttle, was sort of a space shuttle, but they didn't call it the space shuttle. So I'm going to go with no, but I suppose if that had really come up in random.org, I would consider giving it to the person. Well, Joe did come out on top, according to random dot org. So we're going to send him the Planetary Radio T-shirt and a rewards card from Oceanside Photo and Telescope.

And let me do this before you move on to the next question. I'm not even sure I sent it to you. I hope I did. Did you see the picture of Andy Fleming posing with the other members of his astronomy club and Andy is wearing his Planetary Radio t-shirt. Yes, that was very cool. Okay, now you know what was even better, because I know I sent you John Gallant's one. This was not American Gothic, but Planrad Gothic.

There was John and his wife in front of the barn. I don't know which I like better, the pitchfork he was holding or the chicken that she was holding. It was inspired actually i know what i like best the fact that they were both in planetary radio t-shirts i hope we can post that i hope we i've got to get a blog gotta have a place to put this stuff all the uh cool things that people send us anyway now please go on to the next trivia question and i'm sorry to everyone i just can't get enough of this, how many of this, that, and the other thing these days. So especially in honor of the fact that just this last week, we went from ISS, International Space Station crew of three to six, and here's a bonus random space fact thrown in just for you,

and all five space agencies that are partners in the space station are represented in those six people on board ISS. But here's a tricky question. How many, including those, the latest people that go to the space station, how many different people have visited the International Space Station? Oh, that's very tricky. It is. It is. That does not necessarily, they didn't have to stay there. So, visited aboard the shuttle is groovy. How many people have visited our outpost in space, International Space Station? Go to planetary.org slash radio. Find out how to enter and to win your Planetary Radio t-shirt so you can do simulations of great works of art while wearing the T-shirt. Yeah, keep those photos coming. Now, does this include the tourists? And they hate being called tourists. Yes, any human who showed up at Space Station for any period of time, we are counting.

Non-humans, we are not counting. All right, humans and non-humans, you've got until Monday, June 8th at 2 p.m. Pacific time to get us this entry. All right, everybody, go out there, look up at the night sky and think about stuffed buddies, stuffed animals, friends to all. But they don't count in the contest of the space station. Thank you and good night. Are there stuffed animals that have been brought up? Are a couple of mission specialists sleeping with Teddy? stuffed animals that have been brought up.

I are a couple of mission specialists sleeping with Teddy. That's a whole other trivia contest and investigative report. Bears in space. Bears in space. He's Bruce Betts, the director of projects for the Planetary Society,

and he joins us every single week for What's Up. Join us next week for another visit with Alan Stern, former NASA Associate Administrator and the ongoing leader of the New Horizons mission to Pluto. Planetary Radio is produced by

the Planetary Society in Pasadena, California. Have a great week. Thank you.