Steve Squyres – On Exploring Mars, and Other Celestial Objects

Steve Squyres is the principal investigator for the Mars Exploration Rover Program, which gave us the plucky and productive rovers Spirit and Opportunity. With the latter on life support and the former no longer with us, I spoke with him about his amazing run on Mars and what he’s working on now. It’s all out-of-this-world stuff on this most recent episode of Miles To Go.

[maxbutton id=”5″ ] [maxbutton id=”8″ ]

Help us improve this podcast: take our short survey.

TRANSCRIPT

Miles O’Brien: Hello and welcome to another edition of Miles To Go, I’m Miles O’Brien. And I suspect you might’ve been wondering if there ever would be another edition of MTG… So, in addition to offering you a podcast, I’m also here to offer you an apology and an explanation.

And, like Dr. Sagan, he has a great knack of explaining science to the rest of us…

Miles O’Brien: Steve Squyres great to have you with me on Miles To Go. I know what everybody is thinking right now. They’re thinking what Steve Squyres is up to right now. No, actually what they’re thinking is, what about for Opportunity and — let’s talk about Opportunity first and —

Steven Squyres: Sure, sure, let’s do that.

Miles O’Brien: And give us a few words on this. This is the rover that had the — was it a 30-day warranty?

Steven Squyres: No! Come on, it was 90 man!

Miles O’Brien: A 90-day warranty! I think it’s a little beyond that. It’s done okay.

Steven Squyres: 14 years.

Miles O’Brien: That’s not so bad, but just bring us up to date, what are you hearing from the team in La Canada.

Steven Squyres: I’m hearing an awful lot more from the team than we are from the rover. Mars from time to time experiences global dust storms where the entire planet gets blanketed by dust. There has been raging on Mars for several months now, probably the worst storm that has hit Mars since the early 70s. And what that does is it darkens the sky, it blackens the sky from the vantage point of our little solar-powered vehicle and with not enough solar power, it runs the battery down and the vehicle goes silent. So, the storm is beginning to decay now, it’s starting to ease off and if the rover has survived the storm, we expect to hear from it pretty soon. That is significant if. This is a very tough event for a vehicle like this to go through, especially a really old rover. I mean this thing has been on Mars 14 plus years, so it’s been through some bumps along the way, but we still have some optimism that we’re going to hear something from it.

Miles O’Brien: So, really, after all these years, you’re still not given up. There is a chance Opportunity will continue to send back signs.

Steven Squyres: Miles, you could have lost a lot of money over the years betting us to Opportunity. This has been a very tough vehicle. I can’t make a prediction because I don’t enough information. The thing to realize is it’s not low power that would kill the vehicle, it’s low temperature. And, what happens is if you don’t have enough electrical power then you can’t run the heaters to keep the vehicle warm at night. Turns out though that during a dust storm, the night times on Mars get warmer because that dust in the atmosphere changes the weather, changes the temperature of the air. So, there’s chance. There’s a chance that we made it. I certainly have not grown pessimistic yet. I think it’s still early days and we’re listening on a regular basis.

Miles O’Brien: Alright, you’ve lost your other Martian child Spirit, now, I think about seven years ago, 2011 I think.

Steven Squyres: Yeah, about that.

Miles O’Brien: And, Spirit got stuck in basically a Martian sand trap, although we’re not certain there’s golf on Mars. I’d say probably not —

Steven Squyres: No, no, golf but there certainly is plenty of sand. I think the way I would put it is we wore Spirit out. I always sort of felt that there were two honorable ways for a mission like this to end. If the mission ends because we drove it over a cliff, that’s bad. One good way to put a mission to end is for us to simply wear the vehicle out, to just wear it out to the point where it just can’t function anymore because we pushed it as far as the thing could be pushed. That’s what happened with Spirit. What happened with Spirit is one of the wheels failed. It’s a six-wheeled vehicle. The right front wheel failed and so it would no longer turn and we had to drag it through the soil as we drove. And then after a while, a second wheel failed as well and with two dead wheels, the thing won’t move. So, it wasn’t so much that we were in particularly nasty terrain, we were in terrain, we were in material that the rover could have just powered right through if it had six good wheels. But because we wore the thing out, we couldn’t move it and it was impossible to drive the rover onto slopes that would tilt the solar rays towards the sun during the winter months and that was something that we had done in prior winters, we weren’t able to do it with wheels that wouldn’t turn and that was what have ultimately kill the vehicle.

Miles O’Brien: So, Spirit’s long gone, Opportunity maybe, this is time for the eulogies. I don’t want to hex the outcome in anyway by doing this in advance, but sometimes it’s nice to do a eulogy while the person is still alive, so give us your thoughts on Opportunity and what do you say, it, she, her, what is it?

Steven Squyres: We tend to use she for no particular reason that I can give and that’s what typically done for ships. Well, this is a tough one for me. This thing has been, it’s been part of my life for 30 years and I’m really close to it. It’s very, very hard for me to assess the legacy of something like this. It’s a hard question for me to even try to answer. I mean, I could reel off for you the scientific discoveries made, but what those add up to, I think it’s too early. I think time will tell. One thing that I do know is that it has sort of ingrained its way into the public consciousness. I teach freshmen at Cornell now that can’t remember a time when there wasn’t a rover on Mars. And to me, that’s just extraordinary. And, I know that the fact that we maintain robotically this presence on Mars has been a source of inspiration to people. I can’t tell you the number of young engineers who have come up to me at conferences and said, “I just want to let you know that I chose my career path because I saw you guys on TV jumping up and down like a bunch of knuckleheads when you first landed and you’re jumping up and down like you won the Super Bowl and it looked like fun.” And it was. It’s had impacts that include science but are not limited to science and it’s hard for me, Miles, to still even wrap my head around it. Give me another 10 years and ask me the question then.

Miles O’Brien: Could you, would you have ever predicted that we’d be having this discussion with living albeit in peril rover all these years later?

Steven Squyres: No. Absolutely not and if anybody claims that at the start of the mission they thought it was going to last this long, they are flat out lying, Miles. None of us expected this. Not one of us.

Miles O’Brien: How cool is that, right?

Steven Squyres: Yeah, yeah.

Miles O’Brien: Yeah, right. We could tick through all the scientific accomplishments and that would be the end of the podcast, but for those who haven’t thought about it so much because I think we are almost at the point now where we sort of take for granted what Spirit and Opportunity have added to our knowledge about Mars, we now can say with great certainty this was once a warm and wet place and Spirit and Opportunity were right at the center of that statement.

Steven Squyres: Yeah, and I think that’s — part of the legacy of those rovers is going to be that realization that early Mars was a very different place from Mars today and that it was warm and that it was wet and we’ve added detail and nuance to that story. We can talk about the chemistry of the water. We can talk about was it acid or was it neutral. We can talk about the form that it took, was it hydrothermal systems or water flowing across the ground or was it present in this ground, water, what was the chemistry, what was happening. We’ve added an enormous amount of detail to that story and what that does is it enables you to put meaningful limits on how habitable a place was early Mars. There were times and places in early Mars that absolutely were habitable in the sense that we know of organisms that exist on earth today that could have survived and thrived in those environments. Now, habitable and inhabited are two entirely different things. We know that the conditions would have been suitable for some simple forms of organisms whether or not there were any organisms there, we don’t have a clue. But it has dramatically, I think, changed our view of Mars as a potentially habitable world in the past.

Miles O’Brien: So, there’s two ways of looking at this, I suppose. One group of people might say, “Well, Spirit, Opportunity and now Curiosity, which by the way operates within RTG, which is essentially a nuclear power plant and that’s why it doesn’t worry about dust storms in the same way, they make a strong argument that do we really need to send a human being there,” and I know you have some interesting thoughts on this. I’d like for you to share this, it might surprise some of our listeners.

Steven Squyres: Sure. I’m a robot guy. I’ve devoted my career to robotic exploration of the planets and Mars in particular, but human exploration in Mars can’t happen soon enough for me. I’m a huge fan of human exploration and there are a couple reasons for that. One is that despite what our amazing robots can accomplish, a human on the ground would be far, far, far more capable. I’ve told a story many times and I won’t relate it in detail now but I did sort of a quasi experiment once where I compared what our rovers could do in a day to what a capable human geologist could do and it turns out that what the rovers can do in a day, Spirit, Opportunity, Curiosity, take your pick, a human might be able to do, you and me, Miles, if we went to Mars, you and I would be able to do in 30, 45 seconds, something like that. So, humans are far, far more capable. Humans are much better at improvising. The human hand, eye, brain, combination is incredibly powerful, it’s been honed over millions of years of evolution to offer this powerful capability for sort of testing ideas right on the spot, evaluating them, trying something new. Trying to do that with a robot, especially when you’ve got one-way light time, time it takes for the radio signal to travel, that’s 10, 15, 20 minutes, it’s really slow and painful and tedious. Humans are always going to be far better explorers than robots. The other thing is, somebody once famously said, “Nobody’s ever going to give a robot a ticker tape parade.” Humans have a capability to inspire that robots are just never going to have. Spirit and Opportunity were built by people like me who grew up during the 60s and the 70s watching Mercury and Gemini and Apollo on TV and dreaming of sending spaceships to Mars someday and now we do. But a lot of our inspiration came from watching humans venture out into space. If your criterion is purely scientific paying(ph) for the buck, then yes, you might conclude that robotic exploration is cost-efficient, but we explore for reasons far beyond scientific paying(ph) for the buck.

Miles O’Brien: Do you think that message gets lost in the discussion about where to go next in space? What you talk about it, it’s very much an x-factor, and it’s something I think when you explain it to people, they immediately get it, but it doesn’t lend itself well to a balance sheet as it were. So, do you think we need to get this into the discussion more?

Steven Squyres: I think we do. People like you Miles play a big role in that sort of thing. It shouldn’t get lost. Okay, because it lies at the heart of why we do these things. It lies at the heart of why it actually makes sense to spend these billions of dollars to try to rise and meet these challenges. And so, I think it will be a terrible shame if messages like that weren’t constantly part of the dialogue and I think those of us who have the opportunity via podcast like this or anything else to get the message out to people who have a responsibility to do so.

Miles O’Brien: You know, oftentimes, I think NASA comes to the conclusion that the only way to maintain support and sort to sell the program is to remind people of all the space age spinoffs that make your eggs not stick to a pan or, the orange, you know, they didn’t invent Tang, but you get the idea. When in fact, what really excites people is that component of human exploration.

Steven Squyres: That’s right.

Miles O’Brien: And yet it’s seldom stated as clearly as I like to see it stated.

Steven Squyres: Yeah. That’s right. I mean, the spinoff thing sure some of that happens but not enough if it happens to justify the money that we spend and it is not the reason we spend the money. It’s a little side benefit. The way I’ve described the rovers is we don’t produce spinoffs. I don’t think that there’s any spinoffs at all that come from the rovers. We don’t fill in the potholes. We don’t put roofs on the schools. We don’t put textbooks in the libraries. We put knowledge in the textbooks.

That’s what we do. Take it or leave it. I sleep really well at night having spent the money that our project spent and generated the knowledge that we have generated. I mean, what we’re trying to answer is really fundamental questions that any thinking person is going to be to some level captivated by how does life arise? Are we alone? These are big, big, big questions, and I’ve always felt the society like ours that is wealthy enough to take care of the basic needs of most of the citizens. I know we don’t do a perfect job with that, but wealthy enough to do a reasonable job of that has a certain mandate to spend some fraction of our resources on things that for lack of a better phrase enriched the human spirit. Things like investing in the arts. Things like investing in basic research that is not going to maybe payoff for tens or hundreds of years, and things like investing in exploration that seeks to understand things like the nature of the origin of life

We’ve spent 800, 900 million on the Mars exploration rover project, and I sleep just fine at night having spent that given what the rovers have attempted to do.

Miles O’Brien: It’s an easy target for politicians trying to make hey though.

Steven Squyres: Sure.

Miles O’Brien: Who would say, “Well, we’ve got all kinds of problems right here on Earth, let’s solve those.”

Steven Squyres: Yup.

Miles O’Brien: And I say, “Yes, let’s do both” is what I usually say because we can.

Steven Squyres: And that’s been the way I’ve viewed it too. Miles, I have always taken this issue very, very seriously. I mean, when we first land, there has been an opportunity. If you took the number of days that we expected the rovers to last on surface and you divide the cost of the project by that number of days, it worked out to about $4.5 million a day, and I hammered that number into my team’s head. You know, it’s very easy to go, “Oh, that’s only three slices of pizza for every American. No big deal.”

“No, man! You could do a lot of good in the world with 800 or $900 million”, and I was not going to let the team off the hook. And so, I wanted everybody come into work thinking, “Oh, man! We got to get $4.5 million worth of science done today.” And there were days that we didn’t, but there were also were days that we did.

Now, given that the mission is less 14 years, we’re down to a number of much, much, much lower than that and the return of investment is pretty good, but you can’t let yourself off the hook. I think those of us who do these missions, we have a responsibility to get as much knowledge as we can out of them and to convey that knowledge to the taxpayers, the people who are footing the bill in a way that makes sense.

Miles O’Brien: So, would you go?

Steven Squyres: To Mars?

Miles O’Brien: Yes.

Steven Squyres: In a heartbeat. Once I can come back —

Miles O’Brien: Will you bring me?

Steven Squyres: As long as you want to come back too. I’m not going to leave you there Miles.

Miles O’Brien: I totally want to do a two-way trip. There’s no question. Those people are doing those one-way trip out, you can have that one, but —

Steven Squyres: Makes no sense to me at all.

Miles O’Brien: I mean, I know you’re the kind of guy who’ll climb up a frozen waterfalls near Cornell. You’re just crazy. Can you see —

Steven Squyres: We have those in New York. Yes, we do.

Miles O’Brien: Can you see yourself hiking around Mars with that, you know, a pick and a couple of geology tools and just checking it out?

Steven Squyres: Sure, I love to. I mean, what the rovers arose from me was my frustration with an inability to get down on the surface. My initial training as a scientist years ago, I mean 18, 19, 20 years old was as a field geologist. Put on your boots, pick up your hammer and go out and bang on some rocks and figure out what happened. You know, a field geologist is a forensic science. You’re like a detective at the scene of a crime, and you’re looking at the clues in the rocks and trying to figure out what happened. That was how I learn to do science. And then I got fascinated by Mars at a time when Mars was viewed primarily from orbit. Then, you will get these pictures of these wonderful vistas on Mars of these fantastic scenes and you’d see this wonderful stuff in the pictures, and I look at it with my geologist eyes, and I’d say, “Well, it could be this, but it could be this and it could be this and it might even be that.”

And I just knew that if I could just get down on the surface with my boots and a hammer for five minutes, I could figure it out, but I couldn’t. There was no way to get there myself. And so that frustration with my inability to use the tools that I was familiar with and to get in a virtual sense at least down on the Martian surface, that was what ultimately led me to pursue Mars rovers.

Miles O’Brien: So, here we are, you mentioned important point that young people probably don’t fully appreciate when Pathfinder landed on Mars was at ‘96, ’94.

Steven Squyres: Yeah.

Miles O’Brien: Mid ‘90s. We had the previous Mars landing mission was Viking and landed on ’76.

Steven Squyres: Yup.

Miles O’Brien: So, we had a long stretch there and now we have this long continuous stretch on Mars.

Steven Squyres: Yeah.

Miles O’Brien: And that’s really fantastic because I know when it comes to science, 90% of it is showing up, right? You got to be there and you got be there for a long period of time to really learn some things.

Do you think that’s the ultimate payoff that we’re seeing right now?

Steven Squyres: Well, I think the payoff from the extraordinary engineering has been the longevity of these missions. As we said earlier, nobody expected the things to last this long. Not even the engineers who build them but, yeah, the payoff has been that longevity. The thing about the longevity, when you have a mobile vehicle, when you have the ability to do what you and I would do if we were there, Miles, and that is look around and say, “Okay, let’s go climb that hill and see what we see.” And you know, then we get there, we’d say, “Oh! That looks interesting. Let’s go there.” I mean, that’s almost at a gut level the definition of exploration, is go somewhere new and find stuff out. And as long as you can move, then you can keep discovering new things as long as the environment still has new things to show you. I think one of the most surprising things, people ask me, “What’s the most surprising things about the mission?” Well, partly is that it lasted this long. But other thing that I have found extraordinary is that we keep finding new stuff.

Mars has turned out to be far more complicated, far more intricate, far more diverse than I ever imagined. And so, this longevity has led to just a continuing string of discoveries. I used to have this comforting notion that at some point during the mission, we can start to sit back and, you know, cross our arms and sigh with contentment and say, “Well, we did it. We’ve learned everything we can about Mars at these two places with these two rovers” and that ain’t happen, and I don’t think it’s ever going to happen. It didn’t happen with Spirit. It’s not happening with Opportunity. What I’ve come to realize and this happen with Spirit and maybe it’s happening with Opportunity now, is no matter when the vehicle dies, whether it’s today or 10 years from now, there’s always going to be this tantalizing, fascinating thing just out of reach that we didn’t get to because there’s always something new. That to me as been one of the biggest surprises is that Mars just has a lot more to offer scientifically than I ever imagined.

Miles O’Brien: Yeah, I suspect right about now you would hope that opportunity had a drilling rig, right? Given what we’ve learned about the potential for aquifer.

Steven Squyres: Drilling is hard. Drilling is really, really, really hard. You know, Opportunity can drill a few millimeters. Curiosity can drill a few centimeters. Some of the questions that drive me now would require drilling hundreds of meters and you got to take a lot of pipe. You know, it just requires a lot of metal to drill that deeper. It requires an enormous amount of power. The power and mass that require for deep drilling are really, really, really difficult. It’s very, very difficult to achieve deep drilling robotically. It’s just awfully hard. I think it’s going to be a great test for humans.

Miles O’Brien: There is no lightweight easy solution to a drilling rig is there?

Steven Squyres: Not that I found. You got one, talk to the people in the oil business. They’d probably be happy to hear from you.

Miles O’Brien: What would sort of you putting a footprint in the regolith. What would you say would be the next mission to Mars? Would it be sample return and this is my way of segueing into what trip up to now but go ahead and talk a little bit about Mars?

Steven Squyres: Yeah, to me it would be, and that statement, you know, sample returned, getting materials from the surface of Mars back to Earth. Me saying that now, I almost feel like I’m in the same place now that I was 30 years ago when I got frustrated with orbital data and decided I want to get down on the surface. Despite everything that we have learned with these wonderful rovers that we’ve sent to Mars and all the measurements that they could make, the scientific instruments that we can put on these vehicles just pale in comparison to what you can do with return samples.

State of the art laboratory, equipment is just so far ahead of what you can put on the top of a rocket. Because you put on top of a rocket, you got to miniaturize it, you got to ruggedize it, and then once you launch it, that’s it. You can’t go in and upgrade the technology, maybe you can change the software, but that’s it. whereas, you have laboratory equipment, you can keep making it better and making it better and making it better. One of the key things about samples, first of all, you can do way, way better science back on Earth.

The other is that samples are this gift that just keeps on giving and giving. If you look at the lunar samples that were collected by the Apollo Program in 1969,1970, 1971, the best science ever done with those sample is being done today by scientists who had not been born when the rocks were collected, using instruments nobody could have dreamed off at the time. So, if you preserve some of your sample for analysis by later generations of scientists, with later generations of instruments, you can do marvelous things. So just as I got frustrated with the orbital view and wanted to get down on the surface, I’m finding myself now frustrated with the surface view and I want to get stuff back in the laboratory.

Miles O’Brien: Well wait a minute, all you need to do is go to Antarctica and pick up some rocks there. And we know there’s the promise — wouldn’t that solve them thing for a lot cheaper?

Steven Squyres: No, no, and we’ve done that, and there’s good science that comes out of those Mars rocks that you’d find, but there are two problems. One is they are completely out of context. They literally fell from the sky, we don’t know where on Mars they came from so putting them into context is — a geology context is everything and that makes it very difficult.

The bigger problem still, Miles, is the only rocks that make it from Mars to Earth are the ones tough enough to make the trip. Because what has to happen is those things have to survive being blasted off of the surface of Mars at kilometers per second. They’ve got to survive being out in space for tens or hundreds of millions of years, and then they’ve got to survive entry through the Earth’s atmosphere. And the only rocks that survive that trip are dense, hard, crystalline igneous rock. All of the Mars meteorites that we have are these dense, hard basaltic or igneous rocks. And interesting rocks, the ones that contain the clues, and I know this from years of operating rovers now, one of the things we’ve learned is that the rocks that best preserve evidence of former climate, water, habitability, they tend to be these soft, crumbly, layered sedimentary rocks.

And those kind of rocks, they’re never going to make the trip. We don’t have any rocks like that in our collection of meteorites, because they just don’t make it, they don’t survive. So you need to select the right kind of rocks and you have to select them in the context around them, so that you understand what story they’re trying to tell you. So there’s a big, big difference between the science that you can do with return samples that you’ve selected carefully, versus the science that you can do with meteorites that we have in our laboratories now.

Miles O’Brien: So a sample return mission is not a cheap or easy mission, is it?

Steven Squyres: It is not. It’s hard.

Miles O’Brien: And there’s currently not one officially on the books, correct?

Steven Squyres: There is no Mars sample return mission fully on the books. Now what is on the books is the Mars 2020 rover mission, which is going to collect a suite of samples for eventual return, and cache them on the Martian surface. It’ll collects its samples, drives around, does the drilling, takes the samples, puts them on the surface.

And then the intention is that a subsequent mission will come and pick those samples up and brim them back. But the whole suite, the whole series of missions that’s necessary to pull that off has not been fully planned out and funded yet.

Miles O’Brien: So, it’s a sample without the return, or it’s just like that one-way mission you were talking about in that respect?

Steven Squyres: Well, it’s the first step. It’s a necessary but insufficient first step, the Mars sample return mission, because you have to land on Mars and drive around. It’s not enough to just grab one rock off the surface. Okay, we’ve got Martian meteorites. You got to have the right rocks collected from the right places in the right ways. That becomes an extremely complex thing that actually requires a sequence of missions to land, rove, collect, launch and then transport it back to Earth. And it’s probably two or more likely three different multi-billion dollar missions to pull that off.

Miles O’Brien: Well, we’ll have to stay tuned on that one.

Steven Squyres: Yeah, it’s tough. It’s a tough one.

Miles O’Brien: Let me ask you a question, if the money to do that were taken away from efforts to put humans on the surface, would you take that trade?

Steven Squyres: The money that’s required to do robotic sample return is a very small fraction of what it’s going to take to put humans on the surface, very small.

Miles O’Brien: So again, do both.

Steven Squyres: Yeah.

Miles O’Brien: Okay.

Steven Squyres: You got it.

Miles O’Brien: When in doubt, Steve Squyres says, do both. And while we’re at it, why not the comet astrobiology exploration sample return mission. Caesar, all hail Caesar, that’s your current thing based out of the Goddard Space Flight Center just outside DC. You’ve never done a mission out of there, have you.

Steven Squyres: No, no.

Miles O’Brien: So, this is new digs for you.

Steven Squyres: The first year we get selected.

Miles O’Brien: You’re a man who comes from the place I call Disneyland for nerds, the Jet Propulsion Lab, I don’t know what they call Goddard.

Steven Squyres: It’s pretty much Disneyland for nerds too.

Miles O’Brien: It’s the East Coast version. It’s Disney World. Disney World for nerds.

So sample return from a comet. Why don’t you lay out the proposed mission? You are vying with one other mission.

Steven Squyres: Yeah.

Miles O’Brien: And you will be, the term is down selected folks.

Steven Squyres: The term is down select.

Miles O’Brien: In a year, right? So tell us about this?

Steven Squyres: It’s a very competitive process. So NASA has these missions that they — it’s call their New Frontiers program and it consists of missions that are proposed by teams of scientists and engineers. And it’s a very, very intense competitive selection process. Three of those missions have flown so far. One is the spectacular New Horizons Mission which flew by Pluto and just returned gorgeous data. Another one is the Juno Mission, which is in orbit around Jupiter right now doing great, some amazing images and lots of other good data from that one as well. And then there’s one called OSIRIS-REx, which is just kind of creeping into the news now and is going to be in the news in a big way soon. That is a sample return mission, and it’s returning a sample from an asteroid. So NASA has selected, built and launched three of these missions, and sometime back they decided to select a fourth.

I’ve always been interested in sample return and I’ve always been interested in comets. And we’ve put together a team to try to compete successfully for that opportunity. About a dozen proposals were selected. They were reviewed. The announcements were made back in December. And at that point, NASA down selected from 12 proposals to two. Caesar is one of them, the other is a mission called Dragonfly, which is a mission to Saturn’s moon Titan. And the competition now is between just these two, and on December 14, we have to submit what’s essentially our second proposal. And those will be reviewed and then NASA will down select to a single mission sometime in the summer probably of next year.

Our mission is about returning a sample from the nucleus of a comet, and it’s a fiendishly difficult thing to do. You have to — comets tend to be in very eccentric, elliptical orbits or elongated orbits.

You have to be able to fly to the comet and match orbits with it. When you look at a comet in the sky, you see this spectacular display of gas and dust and there’s the coma and the tail. What you’re looking at is the debris that is being shed from a tiny little object, called the comet nucleus, which might be just two, three, four, five kilometers in size. Little thing, it’s got organic material, it’s got ices in it, it’s got stuff that are very, very, very hard to sample and bring back to Earth. And so what you got to do is, you got to match orbits with this thing. And what we do is, we wait until it gets really far from the sun. It actually goes out beyond the orbit of Jupiter, and once it gets out beyond the orbit of Jupiter, that’s where it gets cold. And because it’s cold, it’s far from the sun, it’s now it’s not boiling away and shedding all this gas and debris. It gets quieter and it gets safer and it gets easier to approach.

So when it it’s icy cold, we go down and we grab a piece of it. We put it into a container, and we try to keep both the icy stuff and the more solid stuff cold and safe and separate and package it up in such a fashion that we can bring it safely back to Earth.

It’s a really hard, really fun job.

Miles O’Brien: before we talk about this particular comet, let’s talk about, and you alluded to it, how important are comments scientifically? I’ve heard, you know, they’re basically, I’ve heard them described as dirty snowballs. But they also really, I’ve also heard them described as kind of leftovers from the creation of our, if not universe, certainly the solar system. It’s kind of the deep freeze of all the ingredients that might be what makes us, us, right?

Steven Squyres: Exactly, exactly. And the key thing is that they are the most primitive leftovers that we have. They’re the ones that are least altered from the birth of the solar system. They still retain organics, they still retain icy materials, they still retain stuff that if you heat it off, just sublimates away and it’s gone.

They certainly retain materials from the birth of the solar system, they almost surely retain materials that came in from before the birth of the source, so things called pre-solar grands. Comets were incredibly important we believe in creating some of the circumstances necessary for the emergence of life on Earth. Comets were probably significant source of the Earth water. Okay? Comets were probably a very significant source of organic molecules to the early Earth. We, living organisms were made of comet stuff, okay. And so, if you ever hope to understand how the planets formed, if you ever hoped to understand how life first emerges, you need to understand what the starting conditions were. What were the starting ingredients, and comets are our best way of getting at the answer of that question.

Miles O’Brien: Now, this comet, this is a comet we’ve been to collectively as humans, as human —

Steven Squyres: Let me here you say the name, come on, do it.

Miles O’Brien: It’s 67P.

Steven Squyres: No, no, come on Miles.

Miles O’Brien: Churyumov–Gerasimenko.

Steven Squyres: Very good, yes, Churyumov–Gerasimenko. It’s a jaw breaker of a name. Comets are named for their discoverers and those are the names of the discoverer of this comet.

Miles O’Brien: They weren’t Tom, Dicks, or Harris on that day.

Steven Squyres: No, no, they were not. Yeah, this is — it’s a remarkable object in many respects the thing that drew us to it. The reason we chose this comet is because it was spectacularly well characterized by the European mission Rosetta. What that mission did is produced a map of the comet nucleus. It actually even dropped a little lander down under the surface. Kind of bounced around and it provided a wealth of information about what that particular comet is like.

One of the things about comets, each comet has its own history, what the orbit has been, what the spin rate is been, a lot of these things have changed overtime.

And because comets will undergo this sublimation process of shedding gas and dust when they get heated up, every comet has its own unique history, every comet nucleus looks really different. There is no, “Hey, this is what a comet nucleus looks like.” They’re all different from one another.

So, say Miles that you are an engineer, okay. And I come to you and say, “Miles, I want you to design for me a device that will successfully acquire 100 grams of sample of the nucleus of a comet.” And you’ll say, “Okay, sure Steve. So, tell me what the surface of this comet is like. How hard, how strong is it, what’s the particle size, distribution of the particles on the surface.” If I say to you, “Miles, I haven’t got a clue, just design me something that’s going to work”, you’ll laugh at me. But, if I got data from a spacecraft that says, “Here is the particle size frequency distribution, here’s the bearing capacity of this surface material. This are engineering parameters that an engineer can work with.”

And so, by going to this one comet whose properties are known, were able to design our system for the conditions that we know exist on the nucleus of that particular comet.

Miles O’Brien: I remember that little lander. Philae, I think it was, it’s that right?

Steven Squyres: Philae yeah.

Miles O’Brien: It landed but then I think they lost contact if I recall correctly. Is that what happen? But I do recall the discussion of how difficult it is to land on something with such a limited amount of gravity. Tell us a little bit about that?

Steven Squyres: Yeah. Landing on a very low gravity is extremely difficult and that’s why we’re not even going to try on CAESAR. We use a very different technique for sampling and we call it touch and go or tag sampling and it’s the same kind of sampling that’s being done by the OSIRIS-REx mission. It’s effectively as zero gravity object. The way I described it was that the Philae lander had a massive washing machine and a weight of a sheet of paper. Try to wrap your head around that, but that’s what it’s like, right?

And so, rather than trying to land on the surface, rather than rely on gravity to hold you in place because on an object that small it probably won’t, the other forces are just too large.

What you do is you fly in a controlled fashion down to the surface, you contact the surface for a short period of time, in the case of CAESAR it’s something like five to ten seconds. And during that period of contact you gather in your sample and then you lift off of the surface. And at no point you even try to actually land. It’s grab and go.

Miles O’Brien: Pilots will call it touch and go.

Steven Squyres: And that’s what we call it, it’s touch and go sampling, TAGSAM. TAGSAM by the way is the name of the sampling device that is used on OSIRIS-REx.

Miles O’Brien: We’ve done something similar to this. There was a mission called Stardust back in ‘99. Tell us the differences between these two?

Steven Squyres: Stardust was a real trail blazer of a mission. It sampled a comet but it did it very differently. So as I said, when a comet comes in close to the sun and its surface heats up, begins to undergo sublimation, the gasses stream away and it carries particles of dust with it. And it produces this cloud of debris around the nucleus it’s called the coma.

00:35:05

And what Stardust did was fly through the coma of a comet with some collection devices and these things was going kilometers per second and it would gather these tiny, tiny micron and submicron sized particles of comet dust into this collection material. Think of it as like sort of sticky material like fly paper, okay. And it was catching these tiny, tiny little grains at very, very high speed. It’s really elegantly simple way of gathering a sample and it was a first time a comet was ever sampled.

Now, the down sides of that are, first of all, you’re going to get a very, very small quantity of material. No, it doesn’t mean you can’t do a lot of good science. There is enormous amount of science that could be done with these very, very tiny grains.

The other thing that was the grains are heated, very substantially and the process of being collected. They’re whacking into the spacecraft collector surfaces at — I think the number was six kilometers per second but it was very, very high speed.

So, there is a lot heating and things are melted. Certainly all the ices and most of the organics are going to be gone. You really cook these things in the process of collecting them. Great mission, produce some terrific results on comets. We’re trying to take the next quantum step beyond that and that is to go down to the surface, get some of that material, pick up a coffee cups worth of this material off the surface, preserve it and bring it back.

Miles O’Brien: And it’ll land in what fashion?

Steven Squyres: Oh, when we get back to Earth?

Miles O’Brien: Yeah.

Steven Squyres: We have a sample return in capsule. It’s actually being built. Again, and all this is if we get selected. But our sample recurring capsule will be provided by JAXA. The Japanese Space Agency and it’s based on a design that they have successfully flown. They flew a mission called Hayabusa some years ago to an asteroid, collected some samples, brought them back and had a sample return in capsule that came down through the Earth’s atmosphere. It hits the top of the atmosphere and going about 12 kilometers per second. Makes this fiery descent through the atmosphere.

And remember, you’re trying to keep this comet sample on the inside frozen. It makes this decent through the atmosphere then when it gets down near the surface you deploy a parachute and while you’re on the parachute what we do is we drop the front heat shield. And so, all of that heat in the heat shield, the heat shield out of surface goes up to like 3,000 degrees during entry. We drop that and it falls away and then the thing slowly decent too and lands on the surface. And it lands in Utah.

Again, if we’re selected to land in the Utah testing training range just to the Southwest of Salt Lake City on the 20th November 2038. So, mark your calendar.

Miles O’Brien: I hope to be there reporting live on that one.

Steven Squyres: You know, Miles, I’m eating foods and I’m riding my bike. I’m getting a lot of exercise, I’m taking good care of myself, I hope I’ll be there too.

Miles O’Brien: How’s the cycling going?

Steven Squyres: You know, I haven’t been doing as much lately because I’ve been so busy with this comet thing but I do still ride quite a bit and then I’m in swimming a lot too. Easier on the joints.

Miles O’Brien: Yeah, I’m finding that as I get older but. The triathlons are good and I’m so — I’m not liking the run so much.

Steven Squyres: Oh, the run is the toughest. My knees just don’t take that anymore.

Miles O’Brien: We digress.

Steven Squyres: As we tend to.

Miles O’Brien: If I asked you in 2001 or ‘02, what are the big questions you want to answer with Spirit and Opportunity. I’m sure you would had a short list and probably there are many questions you answer that wouldn’t have been on the list. But I’m curious, what are your top three questions on your mind as you think about this mission? What do you hope to answer?

Steven Squyres: There is so many different kinds of science that you can do with a comet sample that the answer you’re going to get to that is going to depend on the scientific linings of the person that you ask.

Given my scientific linings, I’ve always been very much driven by questions having to do with the emergence of life. And so, the questions that most motivate me for CAESAR and these are only a fraction of the science that we’re going to do, but the once that motivates me are things like, what role did comets play in delivering water to the Earth’s oceans.

Where comets really, really important for creating the oceans or where they a sideshow. Another big question is what were the organic molecules that were delivered and to what extent did those organic molecules include fundamental building blocks of life.

So for example, amino acids are known to exist in some comets. What’s the inventory, what’s the full inventory of amino acids that are present and other potential biological building block molecules that are present in comet.

So, comets as contributors to the emergence of life on Earth. Those are the questions that most motivate me. I’ve got other people on my team who — what they’re really interested in is the nature of the interstellar medium, the mass that’s presents between the stars and some of that is going to be present probably in this sample in the form of pre-solar grands.

Steven Squyres: And so, you can look at the processes that were involved in producing some of the first solid material in the universe with these kinds of missions. So, there’s a lot of very diverse science that you can do with comet sample. But for me, it’s the life thing which is why that astrobiology word is in the name of our mission.

Miles O’Brien: For me, that’s always the big question. And it seems to me with comets we wouldn’t be having this conversation.

Steven Squyres: I would assert that without comets we might not even be here.

Miles O’Brien: That’s really what I meant.

Steven Squyres: Say, we ain’t get any life.

Miles O’Brien: We would not exist.

Steven Squyres: Right, so, I want to test the validity of that assertion.

Miles O’Brien: That’s a good one. That’s worth your price of admission right there I think.

Steven Squyres: How important were comets, yeah.

Miles O’Brien: All right. So, good luck. We’re not going to talk about the other mission because we assume its inferior in every way, right? Is that it?

Steven Squyres: No, it’s not. It’s actually —

Miles O’Brien: It is a good mission?

Steven Squyres: It’s actually a very exciting mission and it’s a team of scientist and engineers that I admire and they got a great idea and we’ll see what happens.

Miles O’Brien: Well, the correct answer is do both.

Steven Squyres: I hope that will happen.

Miles O’Brien: All right, before I leave you and our listeners leave us there’s one little detail, one little fact about Steve Squyres which you may not know. He is a very famous brother, academy award winning brother.

Steven Squyres: That’s right.

Miles O’Brien: Yeah, tell us a little bit about you brother and what he does because I think it’s kind of cool. You guys are each in your own realm have risen to the top.

Steven Squyres: Yeah. My brother Tim is a very successful, influential film editor. He has worked for many years with the director Ang Lee. Tim was responsible for the editing on movies like Life of Pi, Crouching Tiger, Hidden Dragon, Sense and Sensibility. Most of Ang’s major films, and the Tim’s work with a number of other directors, they’ve worked with Jonathan Demme for example.

But yeah, he has received two Academy Award nominations for Crouching Tiger and for Life of Pi and made our mom proud. So yeah, he’s had a very successful, very interesting career quite different from mine, and yeah, that’s what my brother does.

Miles O’Brien: Is it completely different or are there — is there something that ties those two siblings together here, you know?

Steven Squyres: Yeah, we’ve talked about that some and I think the science and engineering stuff that I do is more creative than most people realize. And I think the artistic stuff that Tim does is more technical than most people realize. So, what we do — what the two of us do for a living that’s quite different, there’s more in common than you might think. And when we get together at Thanksgiving or whatever and we start about what we is just a total geek fest, it really is.

Miles O’Brien: Are your parents still with us?

Steven Squyres: My mom passed away just this past year. My dad is and he’s an avid follower of both the movie business and the space business.

Miles O’Brien: She must have been proud. He, I’m sure he is proud of the both of you. There must have been something good in the water and good in the household there in New Jersey growing up. Thank you, Steve and I wish you well on this. I know you’re crazy busy and I appreciate you giving me even 45 minutes of your time right now and we wish you well. We’ll root for you on this mission and would it be nice if we can get both? That would be good too.

Steven Squyres: Yup, it would. It’s always fun to talk to you Miles. It really is. I appreciate this opportunity.

Miles O’Brien: All right, take care.

And we appreciate the opportunity he helped create: the one sitting on Mars, waiting for some wind to clear off those solar panels. November is the beginning of the wind season on Mars, so stay tuned. I know they sure will be doing just that at the Jet Propulsion Laboratory.

Thanks for listening, I’m Miles O’Brien. I promise I’ll be back sooner rather than later.

Banner image credit: NASA/JPL-Caltech.