Conversation with Mars geologist Matt Smith — Parts 3 & 4
Matt Smith of UW and I talked over lunch one bright Spring day last year when Spirit passed away gently without suffering to praises sung all over the world. Today its sister Opportunity is celebrating 8 years of going strong, and we finish the conversation. (Previously, part 1 and part 2.)
Part 3 of 4
TOAD: How many people at the UW are studying Mars?
MATT SMITH: Probably about five faculty, maybe not full-time but in some capacity. And grad students — seven? There’s not a very big planetary community at UW. I was one of the first.
TOAD: Did you have to convince your adviser to let you do it?
MATT SMITH: No, he started off actually doing Mars stuff. He worked at JPL in Pasadena, and so he did a lot of early Mars satellite analysis. And then he did a lot of Earth stuff after that. And then he started thinking about Mars again, just because he has a really good remote sensor. And he was excited to have a grad student who’s excited about it. So we kind of got back into it together. And since then, we’ve gotten a couple of faculty who are really dedicated to Mars science, and they’re really good actually, so it’s become a really good department.
TOAD: What kind of problems or phenomena are they studying? What’s most of interest on Mars today?
MATT SMITH: On Mars today? One is my co-adviser Josh Bandfield and he’s looking at hydrated altered minerals just on the surface, the same stuff I’m doing. And kind of identifying what’s the history of water, how much water was there, how long was it there? Those are the important questions if we’re to send the next rover there — where do we want it to go? A lot of Mars science is about guiding where you want the next really deep in-situ stuff to happen. Another guy (Steve Wood) is looking at completely different stuff. So, the Earth has an obliquity to it, and it wobbles a little bit. But on Mars there are these really steep obliquity shifts, because it’s a lot closer to Jupiter, and Jupiter has a stronger influence on it. And so when it goes upright all of its atmosphere freezes at the poles, and the atmospheric pressure drops. So he’s looking at what happens to the crust, when your atmosphere goes away. Right at the surface, you’ve got this really porous material that doesn’t transmit heat very well, so you’ve got the geothermal heat still coming up from the core and moving through the crust. But then it can’t radiate away very effectively. So you get these really steep thermal gradients right at the surface. So he’s looking at what are these gradients? How do they affect the thermal history of the crust? Can it drive off water in the minerals? Those are the two big guys that are working on it right now.
TOAD: You mentioned a new rover mission planned. Where is it going?
MATT SMITH: There’s the Mars Science Laboratory which has launched actually in November last year. But it’s way over budget and way over time and it’s just this behemoth of a project. It’s the size of a small car. It’s got tons of sampling stuff on it. It’s got all these crazy instruments that haven’t been on previous rovers, like a laser spectrometer. It shoots a laser, which turns the surface into plasma right where it hits, and then it looks at that plasma I can’t remember in what wavelength range. But the plasma emits certain wavelengths depending on what gets ablated. And it can figure out what was in that rock based on that. So it’s got one of those, it’s got all kinds of crazy instruments on it.
TOAD: Just one rover this time?
MATT SMITH: Just one. The MER rovers (this is Spirit and Opportunity) landed with this complicated airbag system. They got packed in airbags and they just kind of bounced. They slowed themselves down pretty well but then they just inflated these airbags and bounced on the surface. The MSL is too big for the bounce, so it’s got this sky crane. It will get into the atmosphere, this crane will come out, hover, and then lower a cable to lower the robot onto the surface.
TOAD: Are you serious?
MATT SMITH: Which is insane. And it goes through this really complicated air braking process where it follows a really elliptical orbit: it dips into the atmosphere over and over to slow itself down once it actually gets to Mars. So it gets to Mars, it starts to orbit, it skims the atmosphere over and over. Each time it skims it, it slows itself down by drag, until it slows itself down far enough that it actually can land. And so during this aerobraking process they can figure out where they want to go. They’ve decided now to go to Gale Crater. But there’s so much politics in figuring out where they want to go that everyone was lobbying really hard.
TOAD: Is that because different teams are focused on different aspects of the planet, and that’s where the concentration of interesting stuff is?
MATT SMITH: Exactly. And because a certain team studies a spot for so long, they know everything about that spot. And of course they want to go there because then they’re the experts in that spot, right? I’m proposing the spot that I’m looking at now for my dissertation as a landing site for the next rover after that, the one that will actually get a sample. Of course I want them to land there, because then I’ll know everything about it! After studying it for so many years.
TOAD: There is already a development stage for the mission that will come after the Mars Science Laboratory?
MATT SMITH: They plan stuff out years in advance.
TOAD: So when is that one for?
MATT SMITH: 2018. Eventually they want to return a sample from Mars. Right now, except meteorites, there are no other samples. But we don’t know where those came from.
TOAD: So that would require—
MATT SMITH: It’s complicated.
TOAD: Not only depositing the thing on a cable, but then also picking something back up. Would something be in orbit the entire time?
MATT SMITH: I’ve heard so many different ways of going about it. So there’s one. Ultimately what they have to do is go down with a drill, drill in, take a sample, which is about the size of a piece of chalk. Put it in some sort of capsule. Now there’s planetary protection concerns. There’s all these concerns that you don’t want to contaminate Earth with Mars stuff.
TOAD: Apparently it’s okay to contaminate Mars with Earth stuff…
MATT SMITH: I know, right? But they have to sterilize Earth stuff pretty well before they send it out. So the sample, it needs to be wrapped in several layers, and there has to be a certain number of layers that have never been in contact with Mars. And so they have this capsule on the surface, and they have to shoot it back up, and there’s another thing that’s orbiting that catches the capsule as it comes back up. I’ve heard it described as a kind of big basket that would catch it like a ball. And then from there, it packages the sample up again and sends it back to Earth. But that thing would cost a fortune. And so they’re trying to break up these steps into successive missions. The one that just gets the sample and stays there. And then a later one that gets the sample from that first one. I mean, even a rover like MSL costs over a billion dollars, and it’s just a really big rover. Which is something we’ve already sent. So imagine something that we haven’t done at all. Get a sample, send it back. It will cost billions of dollars.
TOAD: It’s amazing. I didn’t think about it until you mentioned it, that they sterilize the probes and everything that goes to Mars, because obviously you don’t want to bring life back from Earth and then find it again: oh look!
MATT SMITH: Exactly! Oh, we found them!
TOAD: Carbon-based life forms! How strange!
MATT SMITH: I think a lot of people are worried about that, about insufficient sterilization. But then, well, it’s traveled, it’s been in an inhospitable environment for so long, maybe it cleanses itself of the residual stuff. But maybe things can survive…
TOAD: When the Mir space station was to come back down to Earth, people were worried because they found these fungi growing on Mir. I think there was something. In the latter years when it was already degrading.
MATT SMITH: Really?
TOAD: That’s what I read.
MATT SMITH: I believe you.
TOAD: So I would be cautious.
MATT SMITH: I don’t think that being in space for a long time means sterilized. But I think Mir was kind of in low Earth orbit, you know, …
TOAD: It wasn’t in inter-planetary space.
MATT SMITH: Yeah. So I think there was still a protective electromagnetic field a little bit, that might have shielded it. And Earth has a much stronger magnetic field than Mars does.
Part 4 of 4
MATT SMITH: There’s a history of Mars missions that met with huge failures.
TOAD: That crashed into the planet?
MATT SMITH: Crashed into the planet, missed completely.
TOAD: Missed Mars altogether? Did they just continued onward?
MATT SMITH: They got the trajectories wrong, so they just slingshot around Mars. We’ve really honed their ability to get to Mars really well at this point. And if you look at Mars missions today, the ones that they plan, they’re really crafted to include as much stuff that’s been already done, that’s gone before if possible. They really highly prize things that have been successful and done good science in the past.
TOAD: Because they want to maximize the chances of success this time. They keep doing stuff that we know how to do.
MATT SMITH: Exactly. Which I totally agree with.
TOAD: Yeah. And add on one more thing that we don’t know how to do?
MATT SMITH: Yeah. Like the Phoenix lander. It landed in 2008. But it landed at high latitudes. And it was digging into the permafrost. It found ground ice which we thought was there but didn’t really know. So there is this big buried ice all over the Northern hemisphere. That mission included a lot of technology that was on the Mars Climate Sounder. And there was an even earlier mission. I think it was the one that had mixed up metric for English units, remember that?
TOAD: Oh yeah.
MATT SMITH: And crashed into the planet because of that. But they used a lot of stuff that was already developed for that on the new one, which worked. So with this kind of reuse not only is it going to be successful, but it’s so much cheaper because you don’t have to do all this development to get it up to speed. Which is kind of a good argument for two rovers instead of one rover too. Just make two parallel rovers, and just send them both. Why not, you know?
TOAD: Develop them in parallel.
MATT SMITH: Sadly, if you look at the history of Mars science, it’s a lot of Russian missions that have crashed into the surface. They did a lot of the groundwork for the NASA missions. There’s this figure, it shows all the missions that made it, either crashed, flew by and took data while they were flying by, went into orbit, landed or roved, and there’s a lot in the initial timeline, and early on it’s just all crash-crash-crash-crash-crash-crash-flyby-crash.
TOAD: But were those designed crashes?
MATT SMITH: No.
TOAD: What did they mean for them to happen: land?
MATT SMITH: I think they were meant to orbit. But then – crash-crash-crash-crash-crash. But it’s really hard, when you do something for the first time like flying to Mars. I’m actually really impressed when they go some place new like Saturn for the first time, and they’re in orbit and have a lander that lands on a moon. It’s like: really? Okay. Well done! So I think they got a lot of stuff figured out based on crashing into Mars, or at least they’re a lot more careful about what they do before they send it out.
TOAD: The history of what we thought was happening on Mars, that’s also fascinating. Tell me.
MATT SMITH: There was an early astronomer named Schiaparelli. He was Italian, and he looked at Mars and he saw all these linear features on Mars which he named “canali” which in Italian means “channels”.
TOAD: But people thought it meant “canals”.
MATT SMITH: Yeah, yeah, Percival Lowell who was working in Arizona at the now named Lowell observatory saw the same linear features. And these linear features themselves are kind of interesting because apparently it’s this optical illusion where if you see a lot of dots you tend to connect them into lines. On Mars there’s a lot of craters and so they’re connecting into lines. But he had this really complicated system worked out based partly on Schiaparelli’s observations where he thought they were all canals. And he’d envisioned this world which was drying out over time and so they were having to come up with these canals to transport water from the poles to the equator so they could maintain their agriculture.
TOAD: The Martian agriculture?
MATT SMITH: The Martians, exactly. And this is so… There was a prevailing theory for a long time that there’s a civilization up there. And then slowly over time that waned and then people thought that there were maybe plants, or moss there.
TOAD: We’re talking what century at this point?
MATT SMITH: When Lowell made his observations that was I think late 1800s early 1900s. And then over the course of the next fifty-sixty years, I think it fell out of favor, this kind of crazy Martian civilization hypothesis. And then they actually sent the Mariner satellites there and they observed the surface and —
MATT SMITH: It looks like the Moon. It’s basalt, it’s dead. There are zero things there. And then… they still thought: well, maybe there’s lichen or moss or something that’s kind of nondescript, and that’s why they sent the Viking landers there. The Viking landers were pretty much designed to look for life, they had all this tech for life detection, and they came back negative on all fronts. And that’s when the Mars program pretty much died.
TOAD: And that’s in the seventies?
MATT SMITH: That was in the seventies. And then until mid-90s when they found that meteorite that they thought was evidence for life there was pretty much no Mars research. But I like the idea of …
TOAD: You like the idea of a civilization building canals?
MATT SMITH: Yeah, the idea that it’s a totally normal thing that no one has any issue with. You know, people probably had issues, I’m sure it was contentious. But…
TOAD: But at the time did people think that the Solar system was all there was in the Universe? Or not anymore?
MATT SMITH: I don’t know. I don’t know the history of astronomy.
TOAD: But I’m sure Mars was so far away, that….
MATT SMITH: But if you’re still thinking of a God-created universe at that point, and we’ve always been this kind of people-centric…
TOAD: Right. But if you’re people-centric then it makes perfect sense that there should be people on other planets. No?
MATT SMITH: Really? But I mean, it’s always devolved from, you know, Sun orbiting the Earth and we’re the center of everything.
TOAD: Oh yeah, but this is I think an independent thing. It’s science-fiction, right? H.G. Wells wrote about Martians invading Earth.
MATT SMITH: But that was fiction. This guy was thinking that there actually were civilizations. That he had to think about this whole civilization thing out there.
TOAD: Yeah, you’re right. It’s weird.