Planetary Radio: Space Exploration, Astronomy and Science - Planetary Radio Live! – Celebrating Curiosity on Mars

Episode Date: April 25, 2018

Join us for an utterly fascinating live conversation with Emily Lakdawalla about her brand new book, The Design and Engineering of Curiosity: How the Mars Rover Performs Its Job. Also joining us at Caltech were Curiosity Project Scientist Ashwin Vasavada and JPL Research Scientist Abigail Fraeman. Bruce Betts and Mat Kaplan close out the evening with a live edition of What’s Up, including the space trivia contest.  Learn more about this week’s topics and see images here: http://www.planetary.org/multimedia/planetary-radio/show/2018/0425-2018-planetary-radio-live-lakdawalla-book-curiosity.htmlLearn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Everything you always wanted to know about Curiosity, this week on Planetary Radio. Welcome, I'm Matt Kaplan of the Planetary Society, with more of the human adventure across our solar system and beyond. A very special extended edition this week, as we welcome Planetary Society Senior Editor Emily Lakdawalla for a live celebration of her terrific new book about the Mars Science Laboratory rover. You'll also hear from MSL project scientist Ashwin Vasavada and JPL research scientist Abigail Freeman. We'll close with a live edition of What's Up featuring Bruce Betts. Back to our regular format next week when we'll visit with the leader of the next mission to Mars, InSight Principal Investigator Bruce Bannard. This is Planetary Radio Live. Nice. I'm Matt Kaplan.

We are on the beautiful campus of the California Institute of Technology. And inside one of the most impressive and hallowed structures on that campus, the Athenaeum is essentially Caltech's faculty club, where you can stand in the buffet lunch line with Nobel Prize winners in front of you and behind you. It's safe to say that some of the greatest science discoveries and engineering accomplishments in the history of humanity were first scribbled on napkins in this building. We're here for a celebration, the celebration of a book that I will describe with an overused word that is utterly appropriate in this case. That word is awesome, as is its author.

in this case. That word is awesome, as is its author. She is the Planetary Society Senior Editor and Planetary Evangelist, spreading the passion, beauty, and joy of planetary and space science wherever she goes. Please join me in welcoming my colleague and friend, Emily Lakdawalla. And indeed, welcome. Thank you, Matt. Always a pleasure to be here. And of course, she has been a part of many Planetary Radio Lives and is heard regularly on Planetary Radio during her short segments. As I told you when I saw you this afternoon, I finished the book on the train up to Pasadena today. It is amazing.

Thank you, Matt. And it's possible that you are the only person who's read the whole book except me, Ashwin Vasavada, and Guy Webster, the former public information officer for JPL. Oh, yes, Guy, who's now retired and well-earned, the Mars guy in the public information office there. The book is called The Design and Engineering of Curiosity, How the Mars Rover Performs Its Job. I got to say, I don't know anybody else personally who would have had the patience, the dedication, the skills, or the knowledge to create this book. It is truly amazing as both a chronicle of the mission and the deepest dive imaginable, at least for a single book, into the workings of this intricate, marvelous mobile laboratory. Yeah, for better or for worse, it is just about the deepest possible dive you can imagine, so much so that it wound up turning

into two books when I meant to only write one. Yeah, that's what I was going to start with because you explained right up front there are almost no science results in this book. There's very little. So this book is about the design and engineering of the rover, and it turns out that for this,

it's true for most space missions that you really need to understand how the spacecraft works in order to get a handle on the results. But a rover mission, even more so. You can't understand any of the results that it brings back until you understand what the rover is capable of and also what its limitations are. And these rovers, they're at the very limit of what people can accomplish. And they do get limited. And these rovers, they're at the very limit of what people can accomplish. And they do get limited. A lot of the time on Mars, things happen.

Things go wrong. And still, the scientists and engineers working together, they persevere to get science done. And they manage to learn things despite all of those challenges. And so that's a story that overcoming all of those challenges as the story, the narrative, is something I'll be telling in the second book about the science results of the mission. This book is the background that I needed to know in order to be able to write the second book. You know that old cliche, lavishly illustrated? Do you have any idea how many images and charts and tables are in the book? There are 200 figures, yes.

I don't know how many tables, but there are 200 figures. That's a lot of figures. I figured that if people got a little tired of my exhaustive explanations, they could at least look at all the figures and all the captions. As we talk more about the book, it's going to become more obvious

why it took so long to create. But let me hear it in your words. Five years. A long time. It took a long time. It was a lot of effort. And actually, I am exceedingly grateful to the Planetary Society, to my bosses, and to the members who, after all, pay my salary for supporting me in this awesome work that I knew would take a couple of years. I did not anticipate how many years it was going to take. And still, they've stood behind me and supported me through this process, and even allowed me to take a sabbatical

last year in order to make significant progress, which is why we're here today. Just talk a little bit about how the book is organized. Sure. So I begin at the beginning with when the mission was started, which kind of came out of the wreckage of NASA's Mars program, literally. I mean, NASA had two spacecraft in 99 that were sent to Mars and did not make it alive in either to orbit or to the surface. And everything could have ended then, but it didn't. And a whole suite of missions was selected at that point. Selected is the wrong word. It has a very specific meaning to NASA. But a whole suite of missions was announced. And this rover was one of them. It was originally

going to be launched in 2007, finally was launched in 2011. Now, I think it represents a turning point in the exploration of Mars. The first chapter is that story about how this mission came to be in the first place and all of the struggles that happened along the way. It was nearly had half of its science instruments de-scoped, thankfully most of them were put back, and then it goes on to describe the challenges of launch, cruise, entry, landing, and all of the equipment required in order to do all of those things. It describes very briefly the surface mission and then goes into exhaustive detail on every aspect of how the machine works, how all of its systems work, everything from its wheels to its brains to its

circulatory system. Do you know this rover has a circulatory system? And then to all of its science instruments and finally ends because it wasn't enough to have 350 pages I had to have 42 pages of detailed uh saw by saw summary of what the rover has done. Saw by saw Martian day day by day there's a table that goes on for pages. Yeah it's a lot. And it is exhaustive detail but also thrilling detail. I kept reading stuff like, you know, there'd be something about a particular instrument. And I think, well, but I want to know this. And you turn the page, and there was that. There was that explanation. There was only one spot in the book where I have a bone to pick with you, one thing that you were missing.

And that was in the section, which we'll probably talk about more later with our other guests who are going to join us, who are part of the Curiosity team. And that was when you were describing ChemCam. And ChemCam, as probably a lot of you know, is this amazing remote. It's all amazing. This remote sensing instrument that, well, I'll let you tell people what its function is. It's the part of the rover that's the laser beam on the rover's head. It has a freaking laser beam on its head. It zaps rocks. It turns them into plasma. And plasma

has bright colors. And so then it uses an instrument called a spectrometer to detect which colors are in the plasma. And from that, they can figure out the chemical composition of the rock. And so they use it for a remote sensing of rock chemical compositions. And it helps the rover walk around, find good spots to go up and put its arm down on. It's a very cool instrument. And yes, there is exhaustive detail about ChemCam. And every section about an instrument

or other function of the rover talks about anomalies that it's run into. But the one thing that you don't tell us about this ray gun on Mars is how powerful it is, and much more important than that, can you set it to stun? You can't set it to stun, and I don't know, you're the one wearing the Marvin the Martian tie. So what is the component that he was looking for to fire in order to make his ray gun work? Oh dear, yeah, right, right, yeah.

So we don't have one of those. This is a little bit of the book from what is probably the most dramatic section of the book. I didn't tell Emily I was going to do this. And this, of course, is right out of, most of you will remember, the Seven Minutes of Terror. So we're almost down to the surface now. And this section, it's section 2.3.10, by the way, sky crane and landing 412 to 432 seconds. So with your permission, I'm going to read about this. Go right ahead. The descent stage switched from decelerating at a constant rate to descending at a constant rate of 0.75 meters per second, so required less rocket power. Out of concern that the descent stage rocket exhaust could impinge on the rover, the four engines canted at only five degrees were throttled down to one percent,

the other four throttling up to compensate. The descent stage wobbled a bit in response to the sudden change in the descent engine's activity. The spacecraft allowed 2.5 seconds for those wobbles to settle out before proceeding, of which it needed only 1.25 seconds. See, exhaustive detail. At 5.1738, at an altitude of about 21 meters, with the descent stage stable and descending at 0.75 meters per second. Three pyros fired to separate the rover from the descent stage. The weight of the rover pulled on three nylon vectran cords wrapped around a confluence point pulley and then around a spool attached to the descent stage called the bridle umbilical device, C-figure 2.30. A break within the spool controlled the rate of descent. The rover had pulled the

cords to their full length of about seven and a half meters in five seconds. Along with the three strings of the bridle, the bridle umbilical device also deployed an umbilical cable that allowed commands to be passed from the rover computer to the descent stage. An artist's concept of the extended bridle and umbilical can be found in figure 1.2.1. The tapered shape of the spool made it spin at a higher angular rate as the rover descended, and the faster it spun, the more the brake resisted the motion. This controlled the rate at which the rover descended under Mars' gravitational acceleration. As the rover descended on its cables, it also deployed its landing gear. Pyros fired to separate the rear bogeys from the rover body 0.7 seconds after the rover separated.

The bogeys fell, pulling downward on the bent rockers and locking them into their final straight positions. Now, keep in mind that all of this is happening with no control from any human on Earth, because that of course could not possibly be done with the latency of the light speed travel time between here and there. Finally, just before touchdown, one more pyro fired to release the differential restraint, waiting until the very last moment, kept the wheels as coplanar as possible for touchdown, and would allow the landing gear to passively accommodate any surface roughness. One

thing the landing gear could not handle, however, would be the presence of a rock more than 66 centimeters tall positioned to spear the rover's belly pan. High-rise images, high-rise, the big camera on Mars Reconnaissance Orbiter, had shown few such rocks in the landing ellipse, but bad luck could win, and MSL had no active terrain hazard avoidance capability. Throughout, the descent stage should have continued to drop at a slow rate of 0.75 meters per second. It should then have taken 15.67 seconds for the rover's wheels to touch the ground. However, the actual time was 17.9 seconds, far longer than estimated. That is, the rover actually descended slower than planned at only 0.6 meters per second at the moment of touchdown. Moreover, the rover was still drifting horizontally at more than a tenth of a meter per second at the moment of touchdown,

more than twice as fast as expected. This slower than expected descent right at the moment of touchdown was a very serious error. Rob Manning, Rob Manning is the king of landing things on Mars, Rob Manning explains, we were to discover after MSL had landed on Mars that we had missed a crucial item. The long list of variable parameters had not included one that should be obvious, gravity. In the simulations, the EDL team used a fixed value for gravity that was rather generic for that part of Mars.

We failed to take into account that the shape of the surrounding terrain and hills might affect the actual gravity, and because we didn't try other values, we didn't notice just how sensitive the landing was to being slightly off with the value the team had chosen. The value for Mars gravity used in the simulation turned out to be slightly too high, very slightly, only 0.1%. But significant enough that MSL's slowest ever landing was even slower than we expected. Had the value for gravity been off by 0.1% in the other direction, Had the value for gravity been off by 0.1% in the other direction, the maximum design touchdown velocity could have been exceeded, potentially damaging the mobility system.

Fortunately, the error was in a safe direction, and the rover touched down on its wheels very gently at 05-17-57, or 431 seconds after entering the Martian atmosphere. At that moment, the rover computer stopped the descent of the descent stage and gave command of the descent stage to the descent stage thruster system computer. The rover commanded pyros within the bridle exit guide on the rover's top deck, get this, to fire guillotine-like blades that cut through the three bridle cables and the umbilical. Spring-loaded spools within the bridle exit guides retracted the cut ends of the cables attached to the rover. An attention cable that had unwound with the last few meters of the umbilical lifted the cut ends of the umbilical and bridle cables, dangling from the descent stage. The Curiosity rover was all by itself on the surface of Mars, but wasn't yet out of danger.

The descent stage hovered for about 0.7 seconds. To avoid dragging rocket exhaust across the rover, it needed to depart the rover either forward or backward, not sideways. Because the rover was landing to the north of the eventual science target, the descent stage had been commanded to depart whichever of those two directions was the most northerly, taking it away from the likely drive direction. The rover knew it had landed facing east-southeast, so the descent stage pitched backward and then burned the four canted engines at full throttle for six seconds,

sending the descent stage on a long parabolic arc away from the rover to a crash landing 650 meters away about 20 seconds later. Throughout powered descent, it had burned 270.4 kilograms of fuel, leaving 119 kilograms of usable hydrazine in the tanks during the crash. Back on Earth, this is the big finish. Back on Earth, engineers were waiting for three distinct signals to confirm that the landing had been successful and that the rover and descent stage were safely separated. Jody Davis announced the first at 05-3145 UTC when she noticed that the Mars lander engines have throttled down to half their former power, indicating that the descent stage was no longer supporting the weight of the rover.

Tango Delta nominal. Several seconds of quiet followed that comment because the landing would not be over safely until the descent stage had disconnected and flown safely away. David Way announced the second positive landing signal when he noticed that the rover inertial measurement unit was no longer reporting a changing position, RIMU stable. The rover was therefore not being dragged by a connection to the descent stage, nor was it sliding down a slope or tumbling off a cliff. The third announcement came from EDL communications engineer

Brian Schratz, who was monitoring the strength of the UHF radio signal between rover and orbiter, which would vary or, worse, disappear if the descent stage dragged the rover off the ground or landed atop the rover. Eight seconds after landing, he announced, landed atop the rover. Eight seconds after landing, he announced, UHF strong. The last two announcements collided with each other over the microphones. Adam Stelzner walked over to Alan Chen while pointing to Schratz, asking him to repeat himself. UHF strong, Schratz said again. Stelzner tapped Chen on the shoulder and gave him a thumbs-up signal. Touchdown confirmed, Chen said. Time to see where our curiosity will take us. The room erupted. And where were you when that happened?

Well, when all of that was happening, I was not anywhere close to that room. I was with the media in the von Karman Museum at JPL. There's a lot of people there. We were all packed into a very small space. There was a meme that circulated after this whole landing of premature celebration guy. In the mission control area, right after the announcement of Tango Delta nominal, one of like the 40 people in that room started doing this. And I was like, I was there in the media room and everybody else was like very concerned about what was happening in the rover. And I was like, Tango Delta nominal.

Tango Delta. Touchdown. Delta, touchdown, touchdown nominal, it landed. And so I was premature celebration girl in the media room where everybody else was like, what's going on? What's going on? And so that was a very fun moment, especially because I had done an informal poll of all of the media before everything was about to happen. I'd probably say that more than half of them

thought it wasn't gonna work. So it was, and I was the one reassuring them. I was like, you know, the engineers seemed pretty confident years in advance. And engineers, as a rule, are not confident people. They're usually like limiting your expectations of what can be achieved. But like a couple of years before landing, they were ready. The launch had been delayed by two years because the motors for the rover wheels and arm and everything had been delayed in production, but the landing system was ready. So the engineers were really super confident. So I figured it was probably going to work,

but I really wasn't ready to believe that it had worked until everything happened. And then I jumped up and down and celebrated, and then I hyperventilated, and I had to sit down and collect myself before I could, like, carry on doing my job. This reminds me of all the people on the Curiosity team, scientists and engineers, maybe the ones who weren't involved with the landing system, who, you know, I would talk to the next, the weeks following that wonderful landing, who said, the weeks following that wonderful landing, who said, yeah, it worked. Wow. You know, part of that is that it's not that people didn't expect it to work. They had to have something, they had to have a little bit of mental preparation for a failure, because there have been

a lot of Mars failures. And so they had to be ready to deal with the fact that it might not work, and they might have to move on with their lives after or they might not know what happened that would be the worst that there could be like just the signal vanishes and fortunately we had high rise in orbit so if something very bad had gone wrong we would have had a lot of clues about it very quickly but I think that you know people weren't even if they felt sanguine they weren't ready to talk about how excited they were in very strong terms until they knew for sure that the rover was on the surface and actually functional. Well, I know where I was, and maybe some of you were there too. Anybody at the convention center here in Pasadena for Planet Fest at that amazing, wonderful, memorable moment? Yeah, we got a few people smiling and raising their hands.

Wonderful, memorable moment. Yeah, we got a few people smiling and raising their hands. I was in the back because I was in charge of the AV stuff that day, and I was watching Bill Nye and Bruce Betts up on the stage narrating this. And then up on the screen, we were watching all those tense people in mission control, and we were jumping up and down with everybody else when that happened. One of the people who I believe was probably, I can safely assume, who was jumping up and down at that moment is our next guest on the show. He is the Mars Science Laboratory, that's Curiosity, project scientist. In other words, he leads all the science operations for that rover

that is helping us to learn so much about the Red Planet. And he earned his PhD right here at Caltech. Please join us in welcoming Ashwin Vasaveda. You heard, I've read the book. I now know almost everything there is to know about curiosity. Do you have a job for me? I have a job for Emily. Yeah, I guess you'd want to pick her up first. Do you remember your first thoughts when Emily told you, hey, I want to write this book about the mission and the spacecraft? I can't say I remember my very first thoughts, but there had

been three books that came out shortly after landing. They were great books, but there wasn't a book that when you work on it so long and you're so into the details and you know how thrilling every little detail is, as you've just proven, you know that it takes someone like Emily to capture that. That's really her trademark. Every time she writes a blog, it's detail-rich and exciting to read. And it's that mix of writing about this mission that was missing at that point. And so I'm thrilled that the book is out. Thank you, Asha.

Have you read it? Well, you know, Emily's style is, as we're all aware now, very detailed, Rich. So when you're asked to fact check it, you should be warned. There's probably like 10 facts presented. But yeah, it was a pleasure to read. And that's basically it. All we did was really make sure Emily was capturing everything accurately. There's a lot that the public doesn't have access to,

so she has done a great job of keeping up with everything. But when you know it's 2.673 meters per second, that's what we checked. So she did get most of it right? Oh, yeah. Or maybe all of it. I'm pretty sure it's quite accurate. No, she says no. Well, I don't think it's all right. However, I do know that there are things in it where I read very carefully things that engineers had written, and I wrote those numbers down, and then I sent them back to the engineers for fact-checking.

And they said, no, those numbers are actually not right. Those are the things we wrote before we landed, and it turns out it was actually this thing. So let me give you all the right numbers. So there are parts of this book that are going to be more accurate than what's actually published about the mission. Excellent. But then I've probably made my own mistakes. So, you know. I knew that this spacecraft, this mission had evolved over the planning that I guess you said in the book, we actually began around 2000. And that a lot of things, a lot of changes took place. One of the ones that you talked about, Emily, in the book is that, I guess originally it was designed, the thought was it would go much farther.

It was intended to drive a lot farther on Mars than the eventual design provided for. Well, they had a lot of ideas about what this thing might do. It might drive very far. It might have active terrain avoidance. It might not be a rover. It might be a lander with a deep drill. It could have been a lot of things. So that's how missions start. They have this really big space that they can work in. And then the scientists and engineers get together. The engineers say, you can't do that, but at least you can do this. And the scientists say, well, if we can't do that, then we can design the mission to do this particular thing. So it's an evolution over the course of a mission's development that you finally get what the

actual mission can be. There's a lot of blue sky thinking in the formulation of a mission. Yeah. And when NASA gives a place like JPL the charge to do a mission like this, it's not as thorough a description as you might think. It really is a mission statement, scientifically most of the time. And what NASA directed JPL to look into in the 2002-2003 timeframe was to design a mobile geochemical laboratory. And that's kind of it. So then it's left to the engineers to conceive what a geochemical laboratory on wheels

or that moves, doesn't have to be wheels, I guess, would look like. And so there's a lot of fun drawings that were done just before I started working on the project in 2004, when things kind of got more stable. But in the 2002, 2003 timeframe, there was two arms, one arm, multiple power sources,

a rover with a giant antenna so you could talk directly to Earth every day, all kinds of crazy ideas. And the sky crane, of course, the descent stage that Matt just described so well, that was still being invented during that time as well. I also read that there was originally thought that the mast, which is now at, you know, roughly eye level for a tall person, originally might have been much higher, like three and a half meters, something like that. I don't even remember all these different design things. I know for a while the mast had a whole scientific instrument on top of

its current head, and we got rid of that. Wow. You know, I'm going to go back to, you're talking about this sort of natural friction between scientists and engineers, Emily. It reminded me, I've got a good friend who used to be a ride design engineer for Disney at WDI. And people would come to him, the design people, the artists would come to him and say, we want to build this. They say, well, you can't build that because it'll cost a billion dollars and you'll kill everyone who goes on it. Does that sound like that? It's the same kind of tension. I'm laughing because of the cost a billion dollars part. Because when, you know, when NASA like originally conceived this thing, it was like, I don't know, $700 million. And JPL is like, yeah, we can build that. And then later on, it comes up to be $2.3 billion. And they're like, we built your mission for you. So yeah,

I mean, I think there's always these trades against what do you want to accomplish? And how much do you want to pay for it? And how much do you think you can accomplish? And how successful do you think you can be? And how long can it last? I mean, one of the reasons that this mission is so complicated is because it was supposed to survive a whole year, a whole Earth year, I think. Was it Earth year or Mars year? I forget now. Mars year. It's in the book.

Yeah. So about two Earth years. Yeah, that's right. Yeah. The previous rovers were much smaller and much simpler because they were only warranted to survive 90 days. And so this one needed to have two brains. It needed to have not only two like essential computers, but there are like three central computers to control different things.

And they all had to be able to talk to each other. So if one of this one broke and that one broke, then they would be able to crosswire them. And it was, I mean, it multiplies the complexity of the mission just to make it last longer. And you don't really think about the fact that, oh, I want to make this thing last longer, makes it so much bigger and more complex than you would have had to begin with. This was one of the most interesting parts of the book to me, the compromises that had to be made. And the complications. I mean, my God, if you read the book, you will. I thought I knew that this was a complex device, this spacecraft.

I didn't come close to understanding it. It was almost as if you took the entire, all the complication of a space shuttle, let's say, and crammed it into the size of a minivan. And just that issue that you were talking about, how everything had to be, what's the term? Crosstrap. Crosstrap, yeah. So that if one computer failed, the one that was left would still be able to run everything. Now, one of the things that I think is cool that I don't quite get into that much in this book is how the science instruments are kind of similar in that way, except they're not redundant.

But you have like a list of science objectives that you could accomplish with different instruments and that there's sort of a cross-trapping. Can you talk about like some of those tradeoffs you made with science instruments that way? Sure. Yeah, you're taking me way back now. This is fun. NASA goes through the process of independently selecting the payload, but they do so in a way that they do have this redundancy that accomplishes the goals you want to accomplish. And so for a long time, I remember we had made this chart that we used to present all the time and argue for our instruments, where we had, you know, science goals listed in one in columns and the instruments listed in another. And if an instrument had a lot of pluses that accomplished multiple science goals, that was a great thing.

But we also had multiple science goals accomplished by every instrument. So we had a lot of redundancy built in that way. And things are on the arm and things are on the mast. And we use that redundancy in interesting ways. We don't always have to drill a rock to learn about it. One step before that is we just place instruments on the arm and we can learn a certain amount just from that. And if we don't even want to drive up to a particular rock, we can take pictures of it from meters away or shoot it with our laser. pictures of it from meters away or shoot it with our laser. So there's a whole other,

there's sort of a whole family of ways we can use the rover to do the science we want to do. I have to ask another question here. How does the, do the people in mission ops talk about shooting rocks with the laser? Oh, they talk about zapping the rocks? Sure, what else would you do? Are there other like euphemisms? I just think it's so fun to have a laser on the spacecraft. There's a lot of pew, pew in the drill room as well. Peppering the book were a lot of really fun terms, like zapping sky crane. You explain, Emily, how that term came to be, how we refer to that landing system. Yeah, it had to do with the fact that when JPL called an external review for how, whether this whole process was even going to work, one of the engineers tapped for that external review happened to be a Sikorsky helicopter crane pilot. And he was like, oh, this is just like a sky crane,

which is the name of their helicopter. It's a heavy lift cargo helicopter that can move cargo around. And that's what it is. It's a heavy load on the tip of a long cable. And it worked. And the Sikorsky guy was like, yeah, that works. People can fly those. Here's another one of those fun terms. Why is MSL like a Dagwood sandwich? Or why was it?

It didn't end up that way. Yes, right. You have the rover, and you have the descent stage, and you have the aeroshell, and the heat shield, and the cruise. It's like this whole big stack of spacecraft that you just toss one part after another as you land it. And that's, you know, one of the things like most of the engineers who worked on this mission worked

on things that got utterly destroyed on the day of landing. And so like you have these pictures of like, especially the descent stage, which is just like this explosion mark on the surface. And the best part of that was the picture from the HAZ cams on the day of landing. I don't know, can you talk about seeing that, like the discussion in the mission operations about that HAZ cam view? Yeah, I mean, we got our first pictures back after landing, which were from these fisheye cameras that are on the front and back of the rover. And they had covers on them for landing, which were from these fisheye cameras that are on the front and back of the rover. And they had covers on them for landing because we knew that those rockets from the descent stage would pick up a lot of dust. Kick up stuff. Yeah, kick up stuff. And that actually

was true. They got quite dirty. And so our very first pictures were a little hard to tell what was going on. And I remember one of the engineers was looking and said, you know, look at that outline. That's Mount Sharp, this five kilometer high mountain that we wanted to land at. I said, no, you're crazy. There's no way. But he was right. Once we took the covers off, there was Mount Sharp. And in the other direction, there was a blob at the bottom of one of the pictures. And people were speculating that that was actually the explosion that was caused by the descent stage going off and crashing and raising a cloud of dust. And it's possible that's what it is. We can't really prove it, but it certainly captured something that seemed to go away.

I got one more of those terms that you used in the book, Emily, at least one more. And that was when MSL basically became a flying saucer flying over Mars. Yeah, I thought that was pretty cool. So this spacecraft, unlike any previous Mars lander, but like the Apollo capsules coming back from the moon, was actually guided on entry. It intentionally steered its way through the Martian atmosphere trying to find its very specific targeted landing site. steered its way through the Martian atmosphere trying to find its very specific targeted landing site. And so it's this thing, this clamshell thing with the heat shield and the aeroshell in the back, and it's like spinning itself. It's a robot in space that is saucer-shaped that is flying. It's a flying saucer invading another planet. That's what it is. With a ray gun. With a ray gun.

And big explosive tanks, as it turns out. I'm surprised, actually, that you didn't bring up what I think is one of the best terms on this spacecraft, which is the THWACK actuator. Oh, I know. I was going to get to it. The primary THWACK actuator. And the secondary THWACK actuator. Made me think of, I had like a coach in middle school who could have called his arm a primary thwack

actuator. But yeah, what's up with that? One of the biggest challenges we had on designing the mission for the science aspect, there was all these great challenges that we've already talked about a lot in terms of just getting 1,000 kilograms to the surface of Mars. Then you have to do the science, of course. And one of the things that we wanted to do that had never been done before is take actual samples of rock with a drill and then process that powder and carefully deliver it to instruments so we could run laboratories on the surface of Mars.

The challenge of being able to drill a rock, gather the powder, manipulate that powder, put it through a sieve, measure it basically in a little measuring cup, and then put it into an instrument. And being able to do that dozens and dozens of times without ever being able to have somebody get in there and release a clog or clean out something or whatever, that was a challenge. And some of the solutions were absolutely elegant that the engineers came up with. And some were rather brute force. And one of those was the thwack,

which is like if things just get hopelessly clogged, you just hit it. Which is what our coach used to do. Yeah, right. So we have a big spring that winds up, and that's the best way of clearing out the sieve that we use. It scares us. We don't hear it, fortunately.

I think it would scare us more if we heard it going off. Now I'm going back to that flying saucer stage because I was just, my mouth dropped when I read that there were weights on the spacecraft, big weights, 72, 75 kilogram tungsten weights, which were just there. Well, tell us why they were there and why you had to get rid of them. So as Emily mentioned, we turned this clamshell spacecraft that a lot of previous Mars missions had the same kind of looking capsule that goes in the atmosphere, but it just goes in straight and the heat shield burns off the energy as it goes in. We wanted to actually fly that spacecraft like a wing, basically. So you had

to tilt it. You had to have an angle of attack with the atmosphere and then kind of steer left and right. So you're doing these big banking turns to the atmosphere. So you had to go from having a perfectly balanced symmetrical spacecraft, so you didn't mess up the rocket and the cruise part of the mission, to having an off-balance saucer that would act like a wing. And so the way you do that when you're landing 4,000 pounds is you throw off a bunch of 75-kilogram blocks of tungsten, which I can't tell you the number of times that scientists were like, can we just put an instrument on it instead? All right, five instruments.

It's kind of hard to make an instrument that is as dense as a block of tungsten. So, oh, well. A lot of attention is paid early in the book to the steps that were taken, the concerns about planetary protection. And I'd love for both of you to talk a little bit about that because it became maybe a greater challenge than was originally intended. Well, and I think that part of that had to do with NASA's Planetary Protection Office. We're torn about how we feel about putting human-built things on Mars. We explore Mars in part

because we think it might once have had life, and who knows, there could be life there now. And the last thing we want to do is contaminate Mars with Earth life before we have a chance to discover Mars life on there. So we're very careful with our spacecraft. We sterilize them as much as we think we need to in order to prevent what's called forward contamination of Mars with Earth microbes. But then at the same time, we're also talking about looking for life on Mars and maybe sending humans to Mars. And if

you're ever going to send humans to Mars, I mean, that's game over for not contaminating Mars. You cannot sterilize a human. That's a dead human right there. Two words, poop potatoes. It's done. So we discover cool things, like maybe there's water running across the surface seasonally at some times of year in these particular locations.

Scientists are actually split on whether that's happening. We'd love to go explore that with a rover. Oh, but we can't because then we might contaminate the environment with our rover. And so we have to make these choices. JPL made a bunch of pragmatic choices. The NASA Planetary Protection Office disagreed with a couple of those choices. It was a sort of a struggle right up to the end. And the mission wound up getting classified slightly differently than it had originally been. Like, the NASA headquarters people could have chosen to say, no, you can't launch because you invalidated your planetary protection protocol. International Treaty says you can't launch. But fortunately, the spacecraft was headed to an equatorial location.

And near the equator on Mars, it's a lot hotter during the day. You don't expect any water anywhere close to the surface. So you don't really have this risk of contaminating near-surface watery environments. It'd be very different if Curiosity had been a near-polar ice-coring thing. Then you'd be very concerned because if you have a radioactive power source on something that then fails on the way, and you smash it, embed it into the surface where there's ice, then you have for many decades, a nice source of heat, a lot of water around, you can melt the water and any little bugs that happen to be there on the on the spacecraft that you sent to Mars could have a field day in that little environment on Mars. So fortunately, that wasn't the plan,

they're headed to the equator. It all worked out. And we've had a mission that's lasted many, many years. And I answered that question because I wasn't sure if Ashwin would feel like answering for headquarters. Ashwin, did this consideration have an effect on the science that Curiosity has been able to gather? Because you couldn't go to, even if one was nearby, one of those so-called recurring slope lineae that may or may not be liquid water on the surface of the planet. Sure. I mean, there's kind of two answers to that. One is that we're capable,

our payload is capable of looking for signs of habitable environments or even life to some extent in the past or in the present. We were able to accomplish our habitability goal in the past or the present. But after six years of working with the science team and thinking where we could best address the potential existence of habitable environments on Mars, we focused on the ancient a lot more than the present. We think that's when Mars was most likely to have such an environment. And so when you're going to rocks that are 3.5 billion years old and looking for what may have happened back then,

you're not so worried about things living today. And you can go to a place where, as Emily described, there's not likely to be anything living today where we're at near the equator. There's a lot of UV light. The temperatures are extreme, et cetera. So we're able to accomplish everything we want to do in these ancient environments without worrying about that. The other thing that's becoming slowly realized, I think,

by the planet protection community and by our mission itself is that once you're on Mars for five or six years, you get pretty sterilized for those same reasons. Mars is just a hostile place for life in the present. Maybe we'll turn the corner and there'll be a puddle of water someday, and we might have a chance of convincing the scientific community and NASA headquarters that it's worth driving over. Emily, you talk a lot about, we go back to how the mission evolved,

and things that were lost during the process. And a big thing that was lost, which also meant losing a Hollywood angle, was the change in the rover's main cameras, in mass cam. If you could describe that, and then Ashwin, I want to hear what you think of, you know, how did that affect the mission? Yeah, so it's a long story, and I actually think it's one of the better stories in the book, so I think I'm not going to give away too much of it because I'm going to let you all read it. But it was the case that this mission was originally proposed to have a pair of full-color, HD, zoomable, stereo cameras, and one of the members of the camera team was director James Cameron. And he was on the team

because these cameras were a thing that he could do his art with. Of course, every scientist in the room who's ever worked on a mission was like, but what about the data volume? I mean, there's a lot of pictures, but a lot of data would have been required to send back from Mars. But I don't know, I feel like NASA would have found the data volume for James Cameron to get HD movies from the surface of Mars, use those in IMAX theaters across the world, and so advertise NASA's Mars program. But there was a period on the mission

when the budget kept on growing, kept on growing. They kept on asking NASA for more money. There was an associate director of the science mission directorate, Alan Stern, who's best known as being the PI of the New Horizons mission, who is like, you can't take any more money out of the rest of NASA. It's all got to come from the Mars program, and it's got to come from within your mission as much as possible. And he cut science instruments. He cut the chem cam, the laser on the head. He cut the descent camera. He cost capped several instruments and he de-scoped the zoom and focus mechanism for

the color cameras on the rover. And after a lot of horse trading, many of those things came back, but the zoom capability did not come back. And what that meant was for the science to be done with these color cameras, they had to have both cameras zoomed in a bit more than they would have been at their widest zoomed out. And they are also of different focal lengths. So there's one that's zoomed that gets a wider view at lower resolution and one that gets a narrower view at higher resolution, which is why the rover has two different sized eyes and looks a little bit asymmetric. It looks

a little ugly. I always thought that compared to Spirit and Opportunity, Curiosity looked kind of homely. Until I actually got into the clean room and met the rover for the first time. And I was like, oh, I fell in love with it. So I didn't care about that anymore. But anyway, that's why it has two different sized eyes. And it doesn't get stereo color pictures, really. Jim Cameron can't make his color HD movie

from the surface of Mars, and he lost interest, and we lost a big potential for public outreach from the mission. So, Ashwin, how did this affect the science that you were able to get with MassCam? It affects a part of the science. I mean, the mass cams are the most incredible cameras we've ever flown in space. They're spectacular quality cameras, and the way that they're designed by Mail and Space Science Systems, who makes them in San Diego, are of such high standards that it really is stunning the work we can do with them. Their color, and, you know, we do have a telephoto and then a medium angle, so we have these two capabilities we can use for different purposes. But as Emily noted, the one thing we can't really do is the three-dimensional, you know, large stereo images are kind of hard to take.

We do them occasionally by sometimes moving the rover over a few meters to, you know, taking one big panorama over here and taking another one over there. And then you can do some long, we call it long baseline stereo, moving your eyes a little further apart. But otherwise, it's kind of difficult. And then, of course, geologists, you know, they really can't rely on that three-dimensional data to reproduce the world they're seeing on Mars in a way that they can interpret it like they would on Earth. You will learn when you read the book, if you don't know already, that Curiosity is absolutely festooned with cameras. I mean, there are cameras everywhere, hazcams, navcams, masscam, and a camera out on the end of that arm called MOLLE, which you can talk about a little bit. But I'm just wondering, I mean, you know what an Easter egg is when you talk about software applications and so

on? Mali has a calibration target. And there are some very interesting things on that calibration target, which is just, you know, attached to the rover so the camera can look at it now and then and basically calibrate everything else that it's looking at. There's a penny and very, very tiny letters in Greek, which you did not translate, Emily, in the book. That's because I did not get a reliable source on the record who would own up to what those letters meant. So because I did not have a reliable source on the record, I could not tell you. But there is information on Wikipedia about it. Any comment about that? And then, why a 1909 penny? So the principal investigator of the MOLLE camera is also at Mellon Space Science System in San Diego. His name's Ken Edgett. And he, I don't know exactly the story behind the

penny, but I know he was maybe, you know, collects coins or something. And he picked this very special 1909 penny. Even in 1909, it was a rare penny. And he decided that he wanted to fly it on Curiosity as a calibration target. Now you're asking, why 1909? And it's because we were supposed to launch in 2009. But by the time we had slipped to 2011, he couldn't go back and find a better penny. So we actually used that penny to calibrate the images we take of rocks with Molly by comparing them in some ways to that penny.

There's also a few other bells and whistles there, very fine lines that we can use to tell whether Molly's in focus, as well as a picture of a little creature called Joe the Martian that Ken Edgett created in a creative writing class when he was in grade school. And so he wrote some stories about Joe the Martian and kind of kept going after that. And he wanted to draw his little creation and send it to Mars. And Ken's a pretty fun guy, as you can probably tell. I don't know if it actually came up. A lot of these cameras on the spacecraft are from Malin Space Science Systems, which is not far from here, down towards San Diego. A company that is doing amazing things and is getting ready to put those Zoom cameras back on the 2020 rover. That's right.

They successfully proposed to the successor mission of Curiosity. It's currently called Mars 2020. I assume it will get a better name before it launches. rover. That's right. They successfully proposed to the successor mission of Curiosity called, it's currently called Mars 2020. I assume it will get a better name before it launches. But yeah, there is a Mastcam-Z camera being developed for that mission. That is the Zoom cameras with even better Zoom technology than had been proposed for Curiosity. And the Planetary Society is actually a part of that team. We're doing the education public outreach on that team. So I'm getting ready to do some very fun activities that I can't tell you about yet, but I will tease that we'll have some very fun education projects on that mission. Ashwin, any comment about those little Greek letters on the calibration?

You know, I didn't go here as a undergraduate, but the project manager of the camera system did. And so he put those on there and has something mysterious to do with one of the houses here at Caltech. All right. Fair enough for now. There are so many more. I was making notes like every few pages, adding them to the iPad because I was reading the e-book, that we are just not going to have time to get to. We'll try to cover a few more of those. But there is one

more person that we want to bring up here, because not only is she a Curiosity team member, but she represents something very important, and that is a new generation of planetary scientists who are working on missions like this. She is a JPL research scientist, deeply involved with Curiosity, but not just Curiosity, but its foremother, Opportunity and Spirit, the Mars Exploration Rovers. Please help us welcome Dr. Abigail or Abby Freeman. Hi, welcome Abby. Hello, thank you. Let's start with this. You got an interesting start in planetary scientists, at least I think it was your start. And it's another reason I wanted you to be part of this show, self-serving Planetary Society person that I am. Could you talk about something you did, I think, many years ago?

Absolutely, yeah. So I first became aware of planetary science and what it was like driving a rover on Mars when I was a student in high school, and I participated in the Planetary Society's Red Rover Goes to Mars program, which was a program where 16 of us from all over the world got to come to JPL when the Spirit and the Opportunity rovers landed. And through that, I learned that people can have careers driving rovers on other planets, and I thought it was the coolest thing ever. So I continued to explore that as a career possibility.

I never found anything I liked better. I think it's the best job on the planet, and so here I am at JPL, and I'm thrilled to be able to be a part both of the Opportunity mission that inspired me to pursue planetary science and then also now of Curiosity. And just out of Curiosity, pun intended, who ran that program? Why, I would be one Emily Lakdawalla. In fact, that was why I was hired at the Planetary Society in the first place, was to run this program that brought Abby. We have one other student astronaut in the audience today who's also at Caltech, That's Waylon Tan, who was there at the same time as Abby was. And we were all in mission operations when Spirit and Opportunity.

I think it was Opportunity's landing for all of you guys on Mars. And that was the best Easter egg, as far as I'm concerned, of any job I've ever had to be with the science team when their spacecraft landed. I remember when Opportunity landed and we got the first pictures that showed bedrock in the wall of the crater. I don't know if any of you in this room know who Matt Golombek is, but he was jumping up and down, screaming and running in circles around the room when he saw that bedrock on Mars. He was so excited. So yeah, that was a very special moment. And since he probably helped to pick that landing site, he must have been especially proud. He was very proud.

Yeah. So, Abby, what's your role on the mission now, the Curiosity mission? So my formal title is participating scientist. So I'm a member of the science team. You pulled from the wider science community to come enhance kind of the science return from the mission. For the last year and a half or so, I've specifically been a campaign lead for Curiosity's exploration of a feature on Mount Sharp called Vera Rubin Ridge. This was a feature that as a graduate student, I mapped using orbital data. So it's been so fun to be part of a mission, seeing what the rocks look like on the ground and figuring out the best measurements to take

to understand the story that they're telling us. So do you work for this guy that you're sitting next to? Absolutely. He's wonderful. One of the other utterly fascinating portions of the book is talking about how mission planning takes place. And it is frighteningly complicated because you have all these instruments and they can't all be run at the same time. And you have to budget the use of power. And it really is just mind boggling. I mean, Ashwin, you're a part of balancing all of that, right? Right. And not only is it challenging enough just to have a 500-person science team making decisions of what to do based on yesterday's data

and a very limited amount you can do with, you know, today, but we have to then integrate all the desires of this large science team with what the rover is actually capable of doing, which is determined and kind of managed by a team of about 150 engineers at JPL. a team of about 150 engineers at JPL. So it's a huge process, and we've operated probably, you know, 1,000 or so plans have now gone up to Mars over the 2,027 sols that we've been on the surface as of today. And so one of the things that we do now is, you know, we have all kinds of different levels of planning too.

There's the planning of the day, which we call tactical planning. Then there's plans you make a few weeks or even six months in advance, the strategic planning. And Abby's role as the campaign lead is really architecting this entire exploration we've been doing for the past year of this important feature on Mount Sharp called the Vera Rubin Ridge. So, you know, we are connected at the hip these days and talk hours and hours about strategy. Is it as intense as it was when the mission started, this planning process? It's eased up some, right? Well, the fact we're not living on Mars time anymore. That helps.

Yeah, right, when you're trying to stay in sync with the 24-and-a-half-hour day of Mars. But, you know, honestly, it hasn't eased up that much, which is a good thing in a way. I don't say that with regard to my personal life, but I certainly think that it would ease up if the power source was depleted or if the instruments are half broken, none of which is the case after five and a half years. It's spectacular, you know. I don't know if I would have wished this on myself, but I wish this for the mission, you know. You couldn't have asked for a healthier, more productive rover five and a half years from landing. Abby, as we said, you're also still involved with the remaining Mars Exploration Rover opportunity, which is still quite active and doing great science. I also am wondering about how the success of those rovers,

and even maybe going back to Pathfinder, Pathfinder Sojourner, how those helped Curiosity become a success. Yeah, absolutely. I mean, the success of the predecessor rovers, Pathfinder, Spirit, and Opportunity, really taught us, A, that we could successfully drive a rover on Mars, taught us about the sorts of types of science we could do with these rovers, and kind of gave us a feel for the pace of planning that was needed. You know, you can command only once or twice a day. So understanding how that all worked was something we learned with these predecessors. As I'm sure you'll see when you read Emily's book, curiosity is so complicated and there's so many knobs and dials you can turn. It's kind of like spirit and opportunity on steroids. There's just so many more decisions

that you have available to make every day and trades you can consider doing. So on the one hand, the predecessor rovers certainly have taught us a lot and kind of were a good skeleton for the baseline plan for how to run a rover. But with this bigger, more capable rover, there's just a whole new level of how you have to run it that we learned kind of on the fly as we did it. And I can't tell you how grueling Curiosity Mission Operations is. Like I just observed it for a few days here and there. And by the end of the day, I just, I could barely drive home. I was so exhausted and I wasn't even the one doing all the hard thinking. I mean, this is, hasn't really changed that much because you're compressing as you get more experience, you compress the timeline. And so it's, I think it's still,

my impression is that it's just as hard as it ever was. And we really want to run it to its limits. You know, this is a once-in-a-lifetime opportunity that the world has given us, NASA has given us, and we want to make sure that we spend every second of Curiosity's life on Mars doing the best science we can. So when we learn how to do something more efficiently and faster, that means we do twice as much the next day. We don't rest, you know? So it's great, though. Wouldn't have it any other way. Emily, a huge portion, a huge focus of this book are the science instruments on the rover, which we've barely talked about. And we won't be able to go into enormous detail,

which is a shame. I mean, I wish we had an extra hour just to talk about these instruments and how they've been developed and how they do their work. You'll have to read the book. It is absolutely fascinating. Let's talk about these two marvelous devices, not really, they're more than devices, that are inside the rover, the two that do chemical analysis on samples. Mention those for a second, and then I've got a little demonstration of just the kind of complexity that your colleagues up here were talking about. Well, there's two instruments. They're called SAM, which stands, everything is an acronym, it stands for sample analysis at Mars. And the other one is CHEMIN, which is just chemistry and mineralogy. kind of um phoned that one in i think but both of these instruments are designed to take in powdered rock and analyze

it to in chemin's case they figure out the mineralogy through something called x-ray diffraction and x-ray fluorescence which is an instrument that takes it's a size of a refrigerator on earth and they managed to build this machine that is the size of half a microwave right because because sam is like a microwave and maybe it's a toaster um that's inside the rover yeah so uh and that gets you that gets you what the minerals are made of which geologists will use to figure out the history of that rock on mars and then there's sam which is the most stupidly complex thing. Like, I can't understand how they convinced anybody to pay them to build this thing and stick it in a rover and then land it on Mars, because who could imagine that this thing would work? It's just ridiculous. It's a gas chromatograph mass spectrometer with a tunable

laser spectrometer and a quadrupole mass spectrometer all put into the size of a microwave. And it's got a turntable, it's got two ovens, and it's got helium tanks, and it's got like tubes that run this way and the other way. Let me jump in right there because I'm going to read some of the components of just one portion of SAM. And this is right out of the book. It's the gas processing system, which, as she said, is a spaghetti of tubing, valves, manifolds, heaters, pumps, and gas reservoirs. It includes two helium reservoirs. These contain a non-renewable supply of helium, which is used as carrier gas.

And then she talks about the volume of it. One low-pressure oxygen gas reservoir used for combustion experiments. One low-pressure oxygen gas reservoir used for combustion experiments, one low-pressure calibration gas reservoir, two turbo-molecular vacuum pumps, wide-range pumps to move gases through the system, 14 manifolds with 1 to 10 valves each, each one of those an independent valve that can steer gases through that spaghetti of tubing, two high-conductance valves, 52 microvalves, many transfer tubes, a lot of them wrapped with heaters, a hydrocarbon trap, a scrubber system that removes carbon dioxide, two getters that can remove all except some noble gases. And that's just part of the SAM collection of instruments.

My favorite detail about SAM is how proud the principal investigator is that he can program it in BASIC. And it works. It all works. Right, Ashwin? Yeah, it's amazing it does when you say it that way. I'll start just by saying, you know, we talked about how the previous Mars rover missions have contributed. And that is an amazing part of what NASA's strategy has been for a couple decades, to have a series of mission that each builds on each other technologically and scientifically. But the SAM laboratory is also very similar to laboratories or mass spectrometers that flew on Cassini, for example, and Galileo and a probe that went into Galileo's atmosphere.

So there's things we inherited from missions that had not been to Mars before as well. I can't let all this complexity go by without saying what it's found. Without sending the SAM instrument to Mars, we would not know that there's organic molecules on the surface of Mars. The building blocks of life are there. We would not know the dates. We were able to actually date in geologic time, in calendar time, the age of rocks on Mars and how long certain rocks have been exposed to the surface and therefore how signs of life that may be in those rocks would be degraded or not.

With the Kemen instrument, we not only can see that there's clay minerals, but we can look at the crystal structure of those clay minerals to figure out that some form in colder temperatures and some form in warmer temperatures when there's more weathering going on. So by seeing different kinds of clay minerals with height, we can actually see how the climate has changed over time on Mars. This is why we sent this $2 billion rover with these very complex laboratories. Abby, what's it like to have all of these instruments in this rolling laboratory checking out a region that you used to look at from high above?

It is so much fun. I mean, it's so satisfying to see something that you've been looking at at 25 centimeters per pixel for years. And now we're down there looking at it at microns per pixel with our microscope. And the answers are kind of revealing themselves about why we're seeing from orbit what we're seeing. And finally, kind of the puzzle pieces are clicking. And it's so awesome to have this toolkit available at our hands to be able to help us understand the story and tell the history of Mount Sharp and Mars kind of as a whole. For any of you, Ashwin, I'm so glad that you brought

up this legacy question again, because I think back all the way to the Viking landers, Viking 1 and 2, and I'm still in awe of what they were able to build into those earlier laboratories on Mars, including what, I think a grass chromatograph, Emily? Grass chromatograph, yeah. I mean, Ashwin knows more about it than I do. Well, they had the same, similar kind of instrument, something that you could build in 1970, of course. You know, they really went for it. It's amazing what was going on in the space program in the 70s, as many of you know. And in some ways, we're just, you know, slowly getting back to where what we did back then in sort of home run attempts to try to detect life on Mars.

We learned from that. And we learned that you have to ask the questions a lot more systematically and a lot more carefully and re-approach Mars in a very systematic way, mapping Mars, choosing good landing sites, building better and better payloads. And we're back to running those same experiments on Mars today with Curiosity, but understanding a lot more of how to interpret the data and where to look. We're getting very close to where we will start to take the questions that some of you may have who are here with us in the Athenaeum at Caltech. But before we do that, Emily, very close to the end of the book, you address science results in general because, like you said, that's the second book where you'll be able to go into detail. And there has been a perception, you said, from some people that they seem to be coming kind of slowly. And you say, really, that they seem to be coming kind of slowly, and you say, really,

that's not true. It's not true because this mission is so much more complicated than previous missions. You know, when you have the first mission to fly past the new kind of thing, like, say, Pluto, the pictures that you get, the very first pictures tell you a million times more than you ever knew about that world before. But when you're sending the, now I've lost count, sixth or something lander to the surface of Mars, and your science questions are much more sophisticated than what does it look like, then it takes you a lot longer to figure out the answers to your questions. And so this mission is, it took a lot longer to start getting science results. And even then, the first science results were like,

Chem Chem saw this, and Sam saw that, and Kemin saw this. And it was kind of a long litany of these papers that just had these facts without a lot of interpretation behind it. And really, it's only been in the last few years that I've started to see the scientists come up with much more considered explanations for the stories of what they were discovering in the rocks at the landing site. And of course, part of that is because, as I mentioned before, operations are so grueling that I can't imagine even trying to write a scientific paper under those circumstances.

And so it's just hard to get anything done. So it's sort of that you see these periods when the rover is down for some reason or another, it's Christmas time, or there's a drill problem they're working out. And all of a sudden, the scientists are like, yay, I can quit working on ops for a little bit and finally write that paper that I've been wanting to write forever. The last meeting I went to, the Lunar and Planetary Science Conference in March, the sophistication of the results that were being discussed there was just so much greater. And I think it's just going to get better and better as the years go on that we're, they're really, a science team is really beginning to dig deep into what the rover is telling us. And, and it's really a good picture is beginning to come into focus.

Abby, Ashwin, are we going to see people building their careers on this data for, well, for how long into the future? Yes. Yes, the rover has returned so much data, and there is so much in there. You know, there's what you can see right off the bat, the really exciting findings that are really obvious, and then there's levels upon levels upon levels as we start to dig in deeper and really get into the details. So yes, I think we've collected enough data to date to keep many PhD students happy for many years, but we're still going. So we're going to keep getting more data. So it's been really awesome. I just feel excited even to mention two ways that Curiosity is looking forward,

I just feel excited even to mention two ways that Curiosity is looking forward, not just for future graduate students and academics, but even future Mars exploration. Our whole goal that NASA gave us was to figure out if Mars ever presented a habitable environment for potential life. And we've determined that that is even greater than we ever imagined at Gale Crater, with lakes being there for a long time and groundwater for even longer after that. And that allows a mission like Mars 2020, the next rover, to confidently go and look for signs of life, to know that Mars presented the conditions. We still don't have any idea if life ever took hold there. But we know that the conditions were there, and we know sort of where to look.

And Mars 2020 can build on what we've done. And the second way that I find very exciting but often doesn't get mentioned is we're flying a little instrument that you can hold in your hand that measures the radiation environment on the surface of Mars, cosmic rays and solar particles that come off in solar storms. And we're the first mission to ever do that in Mars' surface where the particles come in through the atmosphere and they get changed in ways that make what you measure at the surface unique. And the reason that's important is because that's a real risk that astronauts will face when they go to Mars. And so the measurements that we take every single day are paving the way for astronauts to land there someday and know how to hide when the sun is getting ornery. Robots and humans, arm in arm. Let's go now to our audience here in the Athenaeum at Caltech. Raise your hand if you have a question for any of our panelists

about anything we've talked about today or anything else having to do with Curiosity. Thank you. A little sink point there. Okay. Right here, sir. And Richard will hold the microphone for you. Hi. Introduce yourself. Hi. My name is Ryan. Had a quick question. Emily, your dress is amazing. Did you print that yourself? So you can't see it on the radio, of course, but I'm wearing a skirt that I did, in fact, make myself. It features a 360-degree panorama captured by Curiosity at a site called Murray Buttes on Mars. I laid it out in Illustrator, printed the fabric on Spoonflower, sewed it up on my sewing machine. And the most important fact about it is that it has very deep pockets, which I've been using to store my water bottle throughout this evening.

has very deep pockets, which I've been using to store my water bottle throughout this evening. She is multi-talented. And Murray Butte, very close to the hearts of all of us at the Planetary Society because... They're named for Bruce Murray, former Caltech professor, founder of the Planetary Society, and one of the main reasons we have so many pictures of Mars, because he's the one who insisted that early Mars spacecraft, the Mariners, really needed to have a camera to show us the planets that we were exploring. Right over here. Hi. Hi, my name's Cecil. This might be a simple question, but I'm really interested in the THWACK. How, I know you said that you're glad that you couldn't hear it. How do you determine when a THWACK. I know you said that you're glad that you couldn't hear it. How do you determine

when a THWACK is needed? And how many THWACKs have you allowed for? Ashwin? That's a great question. We designed, and I say we in the most royal sense because I'm a scientist, not an engineer. So the engineers designed the system to, you know, we have all these sieves that the powder goes through and it also opens up in these amazing clever ways. So we can look at the insides and see when the screen is getting, you know, clogged up with some of the very fine stuff that we drill. So when it looks dirty, then we do a thwack. We always do the secondary thWACK, which is the sort of way,

and we shake a lot of things too. There's all kinds of little gizmos. But when we really need to get stuff off, we do a primary THWACK. We've probably done about 20 or so, I think, over the mission. There's another interesting detail where you build everything and then you build your spare copy that we still test at JPL. And the worst times sometimes are when something breaks on the one at JPL, and we're like, ooh, could that happen? And so we noticed that one of the screens that's a very fine sieve that we use to put powder through can start coming off on the edges, and we think maybe because we're hitting it so hard. So we've actually very carefully used that primary THWACK when we need to, so it won't keep that screen intact. The interview that I did about

this piece of the rover was, I think, my favorite interview on the mission. There are two engineers who are responsible for the Chimera mechanism, for explaining it and using it in mission operations. Their names are Louise Jandour and Cambria Hansen, two women engineers. like using it in mission operations. Their names are Louise Jandura and Cambria Hanson, two women engineers. And we spent hours talking about this piece of hardware. And even they, even the engineers who are responsible for this piece of hardware could not talk about it without a physical copy of it in their hands because it's so complicated. And so we had this interview and I was like writing things down and they were like twisting it this way. And then we opened this thing and then we opened that thing and then we turn it this way and we shake it and

then we turn it this way and we kind of rock it gently back and forth a few times and then and so I tried my best to explain that in the book but I really wanted a video of Cambria and Louise talking to me because that was just perfect it was my favorite interview right over here we got a question someone who's been waiting hi introduce. I'm Ken Elkert. I'm a member of the Planetary Society. I find it interesting, somewhat a parallelism between Mars and the Moon. As most people know, I think Viking 1 landed on the surface of Mars for the first time on the seventh anniversary of Apollo 11. That was when Neil Armstrong took his giant leap for mankind. If I'm not mistaken, I think that Curiosity landed on August 5th. That was Neil Armstrong's 82nd birthday. Oh, that's cool. I did not know that. So my question is, I know that the wheels on

Curiosity are getting chewed up. Any concern as to how much longer they might be lasting? And this is something Emily goes into as well in great detail in the book. Exhaustive detail. Very interesting. Very interesting story. Are we going to be able to keep rolling? We are. The wheels were something that scared us about a year into the mission when we noticed how banged up they were getting.

We knew they'd get a little scratched and dinged, but not to the extent that they were so early in the mission. And then kind of extrapolating that outward, we were really concerned we'd ever be able to finish our mission climbing this mountain. But a lot of careful work by the science team figured out what kinds of rocks were causing that damage. And we learned how to not drive on those particular rocks. And then the engineers at JPL did a lot of tests in what we call our Mars yard at JPL, figuring out exactly what mechanically was contributing to the damage. Because the mystery was that the rover was actually designed to support the weight of the rover on a pointy rock. So why would that be causing a puncture? And it turned out that one wheel had the ability

to drive the wheel in front of it into a rock. So not only was the weight pushing down, but the rover force itself, the mobility force was pushing even harder. So we've now designed a whole new way of driving through software. You know, we've beamed up to Mars new instructions for how to drive that prevent this damage from occurring. Let's do one more, maybe a couple. We had somebody right here. Hi. Hi. My name is Amina Jambo.

I'm a habitability scientist. And my question has to do with the problems surrounding contamination and how you guys foresee that influencing policy in the future, especially with Elon Musk, you know, kind of wanting to colonize Mars in the near future? Yeah, this is a great question, which is already being debated by people who are concerned about protecting Mars and other places. After all, we have people starting to send spacecraft all kinds of places, and they aren't all asking for permission. Where are we going with this? I think there's a couple of answers to that question.

One of them is that it's really important to have public conversations about our priorities when it comes to Mars exploration. Is it a bigger priority to put humans on there quickly, or is it a bigger priority to explore it more thoroughly first? And I think that you and a lot of other people should be speaking up and talking about how you feel about that particular question. The other thing is that the Mars 2020 mission is designed to be the first step in sample return. In particular, they are going to collect samples that will be stored in hermetically sealed containers, and they're going to go do that, they will be there before humans land. And so if nothing else, we will have those samples that were collected by the Mars 2020 rover mission that we don't currently have a plan to retrieve,

which is a little bit of a problem. But hopefully through public support, there will be future missions that are going to go there and do that. And so if some space cowboys go and drop humans on Mars and maybe don't do everything to NASA standards and maybe kill their astronauts on the way and they land and explode in little biological packages and throw things all over the surface, which is possible, people, we will have contaminated Mars a great deal if we do that, but at least we'll have the Mars 2020 samples in their little steel containers that were collected before Mars got contaminated.

But no, I mean, it's an important conversation. A lot of different people have a lot of different ideas about how we should expand into the solar system, and I think that we need to have public conversations about that. Abby, your thoughts about this? How important is it that we protect that planet, which is probably dead, but we won't know until we spend a lot more time there. Now, come on, Matt. It's not necessarily probably dead. It's only mostly dead. I'm being devil's advocate. I want Marvin the Martian to be, you know,

crawling in front of mass cam at some point. Yeah, I mean, I agree wholeheartedly with Emily about the importance of, you know, crawling in front of mass cam at some point. Yeah, I mean, I agree wholeheartedly with Emily about the importance of, you know, voicing public opinion for certain, especially from experts who study these sorts of things. I'm kind of in a camp where I agree planetary protection is extraordinarily important, you know, as a geologist and as someone who's interested in understanding pristine Mars. I think it's really crucial that we preserve the rocks that are there now in the form as best we can. However, I am also extremely, you know, strongly feel that planetary protection should not prohibit us from going to some of the most interesting places on Mars and, you know, eventually reaching our end goal of getting humans to Mars, which as Emily said, as soon as humans are there, planetary protection is out the window. So I think do the best you can for as long as you can,

but don't let it stop you from exploring is kind of my view of planetary protection. Actually, I have one more answer to this, which has to do with a Planetary Society policy paper, which there is actually a third way. There's an intermediate way, which is that you can send humans to Mars in a spacecraft, an orbiting station that then can tele humans to Mars in a spacecraft, an orbiting station, that then can teleoperate robots on the surface. And you can sterilize those robots. And we can't do that now because Mars is very far from Earth. And so you can't do this live control like, say, the Russians did with their Lunokhod rovers on the moon. But if we had humans in an orbiting spacecraft, you

could do that. You could take advantage of human intelligence, human capability. And I mean, I don't know about you guys, but I exist through computers these days. More and more, I'm in a virtual world. It's not going to be very long before people can really feel that they're experiencing the surface of another planet, even if they never actually touched down on it physically. And so we can explore Mars this way, but not only Mars. We can explore Venus this way. We can explore all kinds of hostile environments this way. And robotic exploration, I think, more and more is becoming human exploration because the human interface with the machines are getting closer and closer together. And so we may not actually need to face that choice quite as quickly.

Please. need to face that choice quite as quickly. Please. We are now officially running over time for this portion of the program, and we still have what's up ahead of us with Bruce Betts. I saw one other hand up. We'll go ahead and take that question. An extension on the wheel question. For the sinusoidal grousers on the 2020 wheels versus the corrugated ones, what was the primary engine behind that design, and how do you foresee that changing terrain scalability in soft terrain or more rocky terrain? Ashwin? Yeah, I'll answer it the best I can, admitting that I still work on the rover before Mars 2020 and not on 2020. the rover before Mars 2020 and not on 2020, they did change the wheel design. And you'll see that the wheels are kind of skinnier and they have these, as you mentioned,

these S-shaped treads instead of these angular diagonal kind of treads. And we realized that the treads on Curiosity that meet at angles create little stress points that contribute to the wheel cracking. And so when you just have these sinusoidal treads, you avoid that. The wheels on 2020 also are a little thicker aluminum than the Curiosity ones are. And apparently in the testing they're doing up in the Mars yard, they're just bulletproof. They really have solved the problem. Let's wrap this up. Ashwin, what's ahead for Curiosity? Ah, lots of good stuff. So we are exploring the second of four major geologic units on lower Mount Sharp. In our overly optimistic days before landing, we thought we'd blow through

these four geologic units in the first couple years on Mars. And here we are on the second one, you know, almost six years on the surface. But the reason for that is not necessarily because we're slow. It's because we've discovered way more than what the orbital data ever predicted might have been there on these lower units. The sort of other side of the coin with that is we still have these great units above us. So we're about to finish up with the Vera Rubin Ridge, which is the second one of those units that Abby's been leading us through. And then we'll hit what's called the clay bearingbearing unit, so a bunch of rocks that appear to have clay minerals when we look from the orbital data.

And clay minerals indicate a lot of water interacting with the rock at some point in the past. They're also a good place to potentially trap organic molecules, which would tell us more about the potential building blocks of life that Mars may have had in the past. And then above that, there's rocks that we call the sulfur-bearing unit, sulfate-bearing unit, which is another kind of mineral that might involve a little less water interacting with the rocks, creating those types of minerals and might indicate, you know, when we compare and contrast the clays with the sulfates,

we might be able to expand the story of seeing Mars climate warm and dry out as we go, or maybe cool and dry out as we go from the lower parts of the mountain to the higher parts of the mountain. So we think there's a whole lot left to discover, and we think the rover's still got a good number of years. It's hard to say exactly, but five, I think, is a good number. Abby, what's ahead for you after we get to know Vera Rubin? I think is a good number. Abby, what's ahead for you after we get to know Vera Rubin? Yeah, so as Ashwin and Emily have stated, operations takes a lot of time.

So for me, it's going to hunker down, write the papers, and disseminate to everyone kind of what we found and what it all means. So I'm actually really looking forward to taking the time to dig into the data we've collected over the last year or so. Emily, how long do we have to wait for that sequel? Well, if people didn't keep on giving me other things to do, it might be only another year. I'm sitting over here staring at my bosses over here in the corner, and they keep on giving me other assignments, which I enjoy.

So yeah, hopefully 2019, cross my fingers, it'll be out. Could be as fast as this time next year, probably won't be, but it'll get done. Because I dedicated the first book to my older daughter. So I have to have the second book done to dedicate it to my younger daughter. Both of whom are sitting right here in the front row with us at the Athenaeum. We have had a conversation tonight, a terrific conversation, with two members of the Curiosity team.

Please help us thank them, Abby Freeman and Ashwin Vasaveda. Thank you. And our guest of honor, the reason we are all together tonight, she is the senior editor for the Planetary Society and the author of the design and engineering of Curiosity, How the Mars Rover Performs Its Job. I have read it. I give it five stars. I recommend it to anybody who wants to dive deep into how we sent a laboratory to Mars, and it crawls around and tells us wonderful things about a different world, a fascinating world.

So please help me thank Emily Lakdawalla as well. Time now for What's Up on Planetary Radio. So we are joined, as always, by the chief scientist for the Planetary Society. Please welcome Dr. Bruce Betts. Thank you for coming, and I hope you enjoyed that conversation. My pleasure. I enjoyed it very much, and I've realized I want a new title, Primary Thwacker on Planetary Radio. No, no! No, I need to be the thwacker.

Please, maybe secondary thwacker, please. We need to talk about what's up in the night sky. Can we see Mars? We can indeed see Mars, but you have to wait until about 1 in the morning for it to rise in the east, looking kind of reddish and also not that far away as Saturn, looking kind of yellowish. We've got easier planets to see in the early evening. If you look over in the west soon after sunset, you'll see a really bright object. That's Venus. And then coming up in the middle of the evening in the east, another really bright star-like object, that's Jupiter. On Monday, April 30th, that evening, Jupiter will be hanging out next to the moon, looking quite lovely.

Oh, cool. Pretty close, obviously. About four degrees. Yeah. For those playing the home game. Nice. All right. What else you got? This week in space history, it was this week in 1990 that the Hubble Space Telescope was deployed. Wow. It's been up there a while.

That is amazing. And I know they just came out with some anniversary images as well. Another incredible thing that we've been able to do because we believe in exploring space. All right, now I need help from the audience. One, two, three. Random Space Facts. Yay, thank you. So the mass of the science instruments on Curiosity is approximately equal to just a little less than one Matt Kaplan. a little less than one Matt Kaplan. Is that in the book?

It's a standard measure, you know, in the English system. It is in my world. Yeah, I mean, that's why you asked me what I weigh earlier today. All right, let's get on to the really fun stuff that we've got for tonight. Do you have some trivia questions? Well, let's do the old question. We'll answer that one, and then we'll have some for these folks. All right, We asked you, what was the first astronomical object identified with a historical supernova explosion? How'd we do, Matt? Really great response. A lot of people who went after this one. But what's really interesting, because most of the time, you know, 90, 95% of

people who entered the contest get it right. Not so true this time. A lot of people went where I think you wanted them to go, but there were a few who called out apparently a supernova that was documented by Chinese astronomers in the year 185 AD, which was news to me. Had you heard of it? Yes, it only fairly recently got enough evidence that people kind of believe that, yeah, they probably did observe a supernova in 185. But the trick or the detail of the question was I was asking for the first object, nebula, that was tied to a historical supernova, and that was... The Crab Nebula. Dating to when Chinese and other astronomers saw a supernova in 1054 AD. It says here on the 4th of July, 1054. I don't really know if that's true,

but that's what came from our winner, chosen as always by Random.org, Kevin Nitka, I believe a first-time winner in Forked River, New Jersey, who indeed said it was a remnant of that supernova first observed in 1054. Kevin has won himself a Planetary Radio T-shirt, which a few people here in the audience might also win this evening, and a 200-point itelescope.net astronomy account. 200 points worth a couple hundred dollars

on that non-profit worldwide network of telescopes where you can do your own astronomy. Look at Mars, a backup curiosity, or you can donate it to a school or other non-profit organization. And just a couple of others to mention. Evan Sardo in Cheektowaga, New York, which was news to me that there's a Cheektowaga, New York, he said it could be seen, according to the Chinese astronomers, with the naked eye during the day. It was that bright, the supernova that led to the nebula, for 23 days during the day and at night for almost two years. He closes with, I want one.

That'll be the gif next time on Prime Trade Radio. Can we do that? We'll work on it. Yeah, there's no delivery. It might be 10,000 light years away. Torsten Zimmer in Germany said he also came up with the Crab Nebula. He said, though, however, flat earthers in 2018 called the observation a Chinese hoax and demanded that the controversy should be taught in every classroom.

Okay, he says, I made that up as far as I know. And then finally, from our poet laureate, Dave Fairchild in Shawnee, Kansas, here's his latest opus. By the way, he based this on that other supernova. Many, many years ago, 185 AD, a supernova flashed and was noted by Chinese. They wrote the book of later Han and put this guest star down as looking like a bamboo mat and gave it great renown. It lit the sky a full eight months, a stellar bag of tricks. Its nebula is known as RCW 86. Thank you, Dave. Thank you, Dave. Why don't we now, instead of going, we'll save the new question for the folks at home. Let's go to your questions you've got for people here.

All right. And I'm going to pull up some shirts. So wait for a microphone to get to you. And I'll ask a question, and then I will throw the shirt, and it probably will not reach you. If it's the wrong size, you may or may not be able to trade it in. Those are all the rules. The fine print will appear underneath. I don't know.

All right, so keeping the rover theme, what was the first successful rover on another world? Don't shout it out. Raise your hand if you think you know. First successful rover on another world right back here. What do you think it was? Was it Lunokhod? That is correct. It was Lunokhod 1 that beat the Apollo 15 lunar rover by a little more than half a year.

Round of applause for that winner. And a Planetary Society, Planetary Radio t-shirt. Congratulations. Next question. All right. What was the first successful Mars rover? And for bonus points, who was it named after? First successful Mars rover, who was it named after? No, what was, yeah, that's just bonus. Okay, and I don't need to repeat everything you say. I don't need to repeat everything you say. I don't need to repeat everything you say. Stop it.

to repeat everything you say. I don't need to repeat everything you say. Stop it. Okay. No guesses? Oh, way over there. Sorry. Oh, I don't know. Alright. Abby, go ahead. That was the Sojourner Rover named after Sojourner Truth. That is correct. The Sojourner Rover named after Sojourner Truth.

Name derived from a Planetary Society run contest. Oh! That's all right. It went to her boss, which she'd be smart to leave it with him probably. So, all right. How many cameras does Curiosity have?

Oh, man. Like I said, lots and lots. First, we take the people who are not employed by the project. And if none of them answer, then we'll go to people employed by the project. Go ahead. Wild guesses, folks. Way off there on the side. sir 17 i'm sorry what 17 17 is correct nice work

unfortunately this one's farther the short shirts don't throw very well oh nicely done better catch that could have gotten worse. You got one more? I always have one more. What two Planetary Society founders have Martian craters named after them? And as a side note, both craters are about 90 kilometers in diameter. There are only three founders, so you can't go too far wrong. I'd say Bruce Murray and Carl Sagan.

That is correct. All right. All right, one more. Who was the Curiosity Landing Site named after? Curiosity Landing Site. I will give you a hint. Famous L.A.-based science fiction writer who loved Mars right back there. Ray Bradbury. That is correct.

Nicely done. Congratulations. Congratulations to all of our winners. Now, Bruce, our question for the audience at home. All right, so don't shout out the answer if you know it. At least according to a NASA press kit, what country does the mound or mountain that Curiosity is exploring look like from orbit? What is Mount Sharp, named after Caltech professor Bob Sharp? What does that whole thing look like? And yes, I found it in an actual NASA press kit. Go to planetary.org slash radio contest. And you have until Wednesday, May 2nd at 8 a.m. Pacific time to get us this answer.

And you will, if you are chosen by random.org and have it right, win a Planetary Radio t-shirt and a 200-point itelescope.net account. I think we're done. All right, everybody, go out there, look up the night sky and think about if you wrote a 400-page book about your car and its activities, what would be in it? Thank you, and good night. Bruce Fetz is the chief scientist for the Planetary Society, who does join me every week here for Planetary Radio. We are done with this terrific tribute to Curiosity and its exploration of the red planet from Caltech, the Athenaeum at Caltech. And we will be back, of course, next week with another episode of Planetary Radio, which is produced by the Planetary Society and made possible by its Martian members.

Ad Astra and Ad Ares, everybody. Good night.