Date: December 25, 2011
Title: A ChemCam Conversation
Podcasters: Andy Shaner & Friends
Description: ChemCam is part of the Mars Science Laboratory instrument suite onboard NASA’s Curiosity rover. The night before launch, the Lunar and Planetary Institute’s Andy Shaner sat down with ChemCam science team members Jen Blank, Nathan Bridges, and Nina Lanza for a ChemCam conversation.
Bios: Jen Blank is an astrobiologist with a PhD in Geochemistry from Caltech, and she studies environments here on Earth that may be good analog settings for Mars. She’s a NASA contractor at NASA’s Ames Research Center and works for the Bay Area Environmental Research Institute in Mountain View, California.
Nathan Bridges’ research focuses on surface processes in the Solar System, principally wind erosion and transport. His work incorporates field studies, wind tunnel investigations, theoretical treatments, and planetary data analysis. Currently a Senior Scientist at the Applied Physics Laboratory, Dr. Bridges worked at the Jet Propulsion Laboratory from 1997-2009.
Nina Lanza is a geologist working on the ChemCam project as a postdoc at Los Alamos National Laboratory. She is broadly interested in surface processes on Mars that involve liquid water. As a youngster she saw Halley’s Comet through a telescope and has been hooked on space science ever since.
A ChemCam Conversation
Andy: This is Andy Shaner with the Lunar and Planetary Institute in Houston, TX. I am the education and public outreach lead for the Chemistry and Camera, or ChemCam, instrument, part of the Mars Science Laboratory instrument suite onboard NASA’s Curiosity rover. ChemCam is an international instrument, designed and built by scientists and engineers from both the United States and France. It will use a laser to vaporize rocks and soils on Mars in order to determine their chemical composition. I sat down the night before Curiosity’s launch for a ChemCam conversation with team members Dr. Jen Blank from the NASA Ames Research Center, Dr. Nathan Bridges from the Applied Physics Laboratory at Johns Hopkins University, and Dr. Nina Lanza from the University of New Mexico and the Los Alamos National Laboratory.
Andy: What is ChemCam?
Nathan: OK, I can start out and my other team members can add and subtract from what I say. ChemCam, its primary function is to determine what things on Mars are made of; by things I mean rocks and soils. People who would watch the old television show “Star Trek” remember Mr. Spock had something called a “tricorder” and he could determine what things around him were made of by magic. Well, we sort of have that magic, but it’s not magic it’s actual science, actually science and engineering. We have a laser, and the laser will actually vaporize rocks and soils out to a distance of about 20 feet. And by looking at the light from that vaporized rock and soil we can determine what the material is made out of, what elements it is made out of. And, in addition, we use the same optics that are used to fire that laser to actually take a high-resolution image of what we are trying to examine.
Jen: Yeah, so it’s really simple, a simple way to think about it is it’s a chemistry measurement and a camera in the same instrument.
Nathan: And hence the name.
Jen: Chem-Cam. It’s pretty easy to remember and it’s the first interplanetary laser, which is really cool, and it can zap rocks that are up to 25 feet away from the rover and make a super-small, I guess a plume of plasma, the size of a pinhead, and then the detectors back on the Curiosity rover look at that light and from that, we’ll be able to tell which elements we’re seeing in the rocks. And where the magic part comes in (laughing) is, really, Nina has probably the most experience of us doing this is, taking the data that tells you all about the elements, and all about the light emission from the different elements and translating that into rock chemistry. So that’s something that we’re all being trained on…trained to do…and we have about 10 months to get better at it. (laughing) Some us are better at it than others right now, I think Nina is one of the better ones!
Nathan: Nina’s the best.
Nina: I appreciate your confidence! Well, it’s true that it’s really difficult to, in many ways, to go from chemistry to mineralogy because geologists are really not interested so much necessarily in just the chemistry, but how are these elements arranged, what are the structures, and, maybe this is inconvenient or convenient, but most rocks are only made out of a maximum of ten elements. There aren’t that many elements that build up most rocks. Now, there are a lot more elements, of course, that could be in a rock but the main building blocks are actually, there are very few of them so actually that kind of narrows down, you know, what are we going to be looking at but then it makes it more complicated to recreate what the minerals are because there are many minerals that have the same chemical composition, but different structure. So that’s one of the challenges that we’re gonna be facing, that we’ve been working on of course, before launching.
Jen: Right, so as we look at the ratios of elements from the ChemCam data, then have to back out what we predict the mineralogy to be.
Nina: That’s right, because to be able to tell what a rock is, we need to know the mineralogy. So chemistry is a very important part of that. There are other instruments of course that do mineralogy on this rover, most notably CheMin, but you’ll need to take that material and put it inside the rover, so ChemCam can actually sample many more rocks than we can ever put into the rover, or ever touch. So we really need to get pretty good at being able to recreate minerals from chemistry. I think we’re doing a pretty good job, so far.
Nathan: And if I could add to that I think it’s really important for the public to realize that we are sort of the “chemical eyes” of the rover. So whereas, what Nina was just describing, the CheMin instrument, there’s another instrument called SAM, those are great investigations but it requires us to get samples and put it in the rover. And all those samples that will be investigated by those payloads, were first investigated by ChemCam remotely. But in addition, we’ll be doing hundreds, thousands of more analyses on Mars, remotely. So, determining what things are made of during our drive.
Jen: So ChemCam’s kind of like the scout. It’s going to help the scientists figure out where we want to go on Mars.
Nina: Because sometimes you can look at a rock in a picture and say “well that looks really interesting” but you get up to it, it may not be as interesting as all that. Whereas something very boring might be the find of the century, right, changes everything and so we won’t really be able to really know that unless we’ve sampled it and ChemCam can do that remotely so it can actually help us. It’s very difficult to drive the rover. I remember when I first realized that rovers drove, you know, so slow that you can barely see them move. I was really surprised. You imagine them zipping around, you know, backing up sort of like a car but actually we drive very slowly just because there’s a delay in communications so it could have, you know, it can hurt itself pretty badly before we even know anything’s happened so we actually drive very slowly. So it’s important to know why we are going a certain direction, before we start going there. We don’t just drive because it looks nice over there, we use something like ChemCam to say, look, chemically it’s actually very interesting.
Andy: So, tell us a little a bit about what you do as a member of the ChemCam team.
Nina: So, I am currently a post-doc; I guess a starting post-doc with LANL. And what my primary job will be is to measure any sample sent to me by another MSL team member who wants to have some ChemCam data. So that will be my primary responsibility; is to do all the measurements in the laboratory, that we want to do before and of course during launch because sometimes we don’t necessarily have a material in our library. So if we see something that is very mysterious we want to be able to measure other materials that we know what the composition is here on Earth to be able to better understand what we are seeing on Mars.
Nathan: I came into this project seven years ago as sort of a geomorphologist and ChemCam can address that because it has a very high-resolution imaging part of the instrument. And so I’m very interested in correlating what we see in the images to the elemental data that we will get from our LIBS laser.
Jen: I guess what I’ve been doing related to ChemCam is studying how to use the chemistry instrument on ChemCam, the LIBS instrument, and also testing some materials that might be relevant for samples that have organic matter. I’m also studying an area we call a Mars analogue site. We think it has rocks that might be very similar to the types of rocks we’re going to be finding on Mars.
Andy: Alright. So let’s kind of look ahead a little bit to landing and operations. So Gale Crater was chosen from dozens of potential landing sites for Curiosity. What made Gale crater stand out and how will ChemCam contribute to the investigation of this particular landing site?
Nina: Gale has everything, right? All kinds of really fascinating features that have been observed singly on the surface of Mars, are all in this one area. And, I mean, for me, I have some personal favorites. You know, what appears to be an alluvial fan; a fan that is a deposit of material that was probably emplaced by a liquid. Then also so-called inverted channel deposits so this is material that was deposited by a stream.
Jen: Well that, and the fact that there’s a huge amount of stratigraphy exposed. So this, this is a site where we could, from remote data, interpret a continuous stratigraphy that probably lasted half a billion years, or longer (right?) on Mars. And going back to some of the earlier rocks to, when there might have been water on Mars to later periods of time. And also, Gale, as a crater, has had a lot of material excavated so that also helped to, helped to expose deeper material in the stratigraphic horizon.
Nathan: Well, what I think, in particular with Gale, is getting to the layers. We will be essentially, if you want to think of the Grand Canyon, almost starting at the bottom of the Grand Canyon, instead of the top. So we land at the bottom of the crater and there’s this big mound in the middle of the crater that we’ll be driving up. So we’ll be going from the oldest layers to the younger layers. And ChemCam is really nice for that because its laser-size is about a millimeter; very small. So we can actually measure the composition of even the very smallest layers. And so we’ll be doing this through the mission. So it will be like a Grand Canyon exploration.
Andy: Well you all are very, obviously excited about this.
Jen: We’re talking so quickly because we’re so excited because the launch is tomorrow!
Andy: This is, it is an exciting mission and that’s actually a great segue into my next question I want to ask is, so we are, as we record this, less than 24 hours from the launch of Curiosity. So real quickly, what is going through each of your minds as we get down to zero hour, so to speak?
Nina: Well the first thing is that I don’t know how I’m going to get up that early. You know I live in New Mexico so we’re two hours behind and we have to get on those buses pretty darn early. But I guess the thing that I’m hoping for, and that I’m sure will happen, is that we have a very uneventful launch, that it will go off as we planned around the time we planned it to happen. So, that’s what I’m hoping for.
Nathan: Yeah, I can’t second that enough. We hope for a successful launch and I’m very confident we will have a successful launch; the Atlas 5 has a perfect launch record. And I can say somewhat selfishly I really hope it goes tomorrow because I’m leaving Sunday. I desperately want to see this launch. So that’s the main thing on my mind; that we actually go tomorrow.
Jen: Well and I would agree with both of you but also, I’d say that I am having no problem getting up early in the morning. I’ve been waking up, I’m from California, and I’m still waking up at 5:30 here on the east coast because I’m so excited! And, I mean, just from all the science fiction books I read as a kid, to seeing the historical movies of the Apollo program and other programs, it’s so exciting. And I think it’s funny, first of all, I’m very honored and happy to be here, but I think it’s sort of ironic that I never had an opportunity to see a shuttle launch, so now I’m coming to wish success for the launch of a robot. But I’m happy…
Nina: A very special robot!
Nathan: A very special robot.
Jen: A very special robot and it’s exciting.
Nina: That’s a really good point, you bring up a really good point. This is actually, for me, and I’m sure for all of us, this is sort of the culmination of a dream, right? This is the final…I’ve always wanted to do this. I mean, I remember when I first was interested in space was when I say Haley’s Comet as a child. And I realized there is a lot of stuff out there that we have never seen and don’t know anything about, and that’s where my interest came from. And I, I remember just always thinking, I want, how do I do this. I want to do this. I want to be part of a mission. And so now finally, you know, to be able to be here as part of this mission it feels amazing.
Andy: The Curiosity rover successfully launched the morning of November 26, 2011. Depending on your time zone, the Curiosity rover is expected to land at Gale Crater the night of August 5, 2012 or early in the morning on August 6th. For more information regarding the ChemCam instrument, please visit www.msl-chemcam.com. For more information on Curiosity and the Mars Science Laboratory mission, please visit NASA’s Mars exploration website at mars.jpl.nasa.gov.
End of podcast:
365 Days of Astronomy
The 365 Days of Astronomy Podcast is produced by the Astrosphere New Media Association. Audio post-production by Preston Gibson. Bandwidth donated by libsyn.com and wizzard media. Web design by Clockwork Active Media Systems. You may reproduce and distribute this audio for non-commercial purposes. Please consider supporting the podcast with a few dollars (or Euros!). Visit us on the web at 365DaysOfAstronomy.org or email us at info@365DaysOfAstronomy.org. Until tomorrow…goodbye.