Planetary Radio • Jan 08, 2020

In the Clean Room With the Mars 2020 Rover

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On This Episode

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Michael Watkins

Director for Jet Propulsion Laboratory

Chris Chatellier

Mars 2020 assembly, test and launch operations (ATLO) spacecraft integration and test engineer

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Bruce Betts

Chief Scientist / LightSail Program Manager for The Planetary Society

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Mat Kaplan

Senior Communications Adviser and former Host of Planetary Radio for The Planetary Society

Put on your bunny suit! You’re invited to join Mat Kaplan and Emily Lakdawalla in the Jet Propulsion Lab clean room with the Mars 2020 rover. You’ll hear JPL Director Michael Watkins and some of the engineers who have built the robotic explorer that will collect samples for eventual return to Earth. The What’s Up space trivia contest asks you to look for rhymes among our solar system’s many moons.

Additional guests include:

  • Dave Gruel, Mars 2020 assembly, test and launch operations (ATLO) manager
  • Matt Wallace, Mars 2020 deputy project manager
  • Art Thompson, Mars 2020 ATLO deputy manager and former payload deputy manager
  • Ray Baker, Mars 2020 flight system manager
  • Jessica Samuels, Mars 2020 lead flight system systems engineer and sampling and caching phase lead
Mars 2020 in JPL Clean Room
Mars 2020 in JPL Clean Room The Mars 2020 rover as seen from the viewing gallery at NASA’s Jet Propulsion Laboratory in Pasadena, California.Image: Mat Kaplan / The Planetary Society
Mat Kaplan and Emily Lakdawalla in JPL clean room suits
Mat Kaplan and Emily Lakdawalla in JPL clean room suits Planetary Radio host Mat Kaplan and Planetary Society solar system specialist Emily Lakdawalla in clean room bunny suits as they prepare to view the Mars 2020 rover on 27 December 2019 during a media event held at NASA’s Jet Propulsion Laboratory in Pasadena, California.Image: Mat Kaplan / The Planetary Society
Emily Lakdawalla with Mars 2020
Emily Lakdawalla with Mars 2020 Planetary Society solar system specialist Emily Lakdawalla visits the Mars 2020 rover on 27 December 2019 during a media event held at NASA’s Jet Propulsion Laboratory in Pasadena, California.Image: Father & Sun Productions / The Planetary Society
Mat Kaplan selfie with Mars 2020
Mat Kaplan selfie with Mars 2020 Planetary Radio host Mat Kaplan captured this selfie with the Mars 2020 rover on 27 December 2019 during a media event held at NASA’s Jet Propulsion Laboratory in Pasadena, California.Image: Mat Kaplan / The Planetary Society
Mars 2020 SuperCam and Mastcam-Z
Mars 2020 SuperCam and Mastcam-Z A view of SuperCam and Mastcam-Z on the Mars 2020 rover.Image: Mat Kaplan / The Planetary Society
Mars 2020 wheels
Mars 2020 wheels The Mars 2020 rover features a new robust wheel design to better handle sharp, pointy terrain.Image: Mat Kaplan / The Planetary Society

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This week's question:

Two dwarf planets each have two moons that rhyme. Tell us the names of those dwarf planets and of their two pairs of rhymin’ moons. Feel free to respond in verse.

To submit your answer:

Complete the contest entry form at or write to us at [email protected] no later than Wednesday, January 15th at 8am Pacific Time. Be sure to include your name and mailing address.

Last week's question:

Your challenge: Create a joke that combines space and New Year’s Eve, Day or the new year in general. Any kind of joke or humorous riddle is fine, but keep it clean if you want to win!


The winner will be revealed next week.

Question from the December 18 space trivia contest:

What planet has the smallest angle between its orbital plane and the orbital plane of Earth? (Not including Earth!)


Uranus is the planet with the smallest angle between its orbital plane and the orbital plane of earth.


Mat K.: [00:00:00] Up close and personal with the Mars 2020 rover this week on Planetary Radio. Welcome. I'm Mat Kaplan of The Planetary Society with more of the human adventure across our solar system and beyond. A very special show this week as we go inside the giant clean room at the Jet Propulsion Lab to stand before the Mars 2020 rover. You'll hear from some of the engineers who have built it, from the leader of JPL and from our own Emily Lakdawalla, who joined me in the high bay, which is another name for that clean room. Wait 'til you hear the enthusiasm and confidence these experts have in this emissary to the red planet that will be joined there in early 2021 by spacecraft arriving from the European Space Agency, China and the United Arab Emirates. I hope you'll also stick around for another fun What's Up segment with Bruce Betts.

The [00:01:00] Downlink is back. Here are just a few of the great space stories you'll find in the latest edition, though its next Mars mission will probably be delayed beyond this year, India has confirmed plans to send another robotic lander and rover to the moon. The country's space agency officially announced the Chandrayaan-3 mission, which would likely launch no earlier than 2021. China's heavy-lift Long March 5 rocket successfully returned to flight for the first time since a launch failure in July 2017. That keeps two Chinese missions on track, a Mars orbiter and rover are scheduled to launch this summer, and the Chang'e-5 lunar sample return mission is expected to follow late in 2020. It also means China can proceed with plans to build a multi-module space station.

And NASA's Juno spacecraft recently completed its 24th close flyby of Jupiter. The [00:02:00] spacecraft is now in solar conjunction, meaning the sun is directly between Earth and Jupiter, which makes communication spotty. We'll be talking with Juno principal investigator, Scott Bolton, very soon. Much more awaits for you at Planetary Society editorial director, Jason Davis, post a new edition every Friday.

On the morning of Friday, December 27th, I boarded a shuttle bus at JPL for the short trip to the lab's spacecraft assembly facility. I've been in the giant clean room twice before and in the gallery high above its floor many times. It was in that gallery that this visit began. The narrow dark room was crowded with reporters and video cameras from around the world. Also there were JPL personnel, including Lab Director, Michael Watkins.

Michael W.: This is in fact our latest and greatest rover, and it will do great things on Mars, but not only is it a rover that's gonna be on Mars, it's [00:03:00] actually the first step in what we call the Mars sample return campaign. So the main purpose of this vehicle is actually go on to Mars, go to a- a fantastic environment, Jezero crater, and take samples, take rock and soil samples, seal them up in tubes so that another mission later can go back and retrieve those and bring them back to the Earth. We call that the Mars sample return campaign. We hope to launch the mission that will- that will bring them back in 2026.

Of course, many of our rovers have been exploring Mars. They're learning a lot about the habitable, ancient habitable environments on Mars, um, but when we get the samples back, we can do even more sophisticated scientific analysis of those- of those samples when we bring them back. Now this is a great chance, it's a rare chance, uh, to see this hardware on the floor and to get an opportunity to go- to go down onto the, uh, assembly and test, uh, floor there and take a look at once going on. We have a number of experts from the team for you to talk to you, experts in each part of the vehicle, the rover in the descent stage and the cruise stage.

To give you some of the ground [00:04:00] rules, to describe what you're seeing with some of the ground rules about what you have to do when you get down there, I'm gonna turn it over to Dave Gruel. Dave Gruel leads our assembly and test, uh, campaign for this mission. He's done it for several, uh, several Mars rovers in the past. He's highly experienced and he's gonna give you the rules of the road. So, Dave.

Dave G.: Yeah. So here are the good news. He's the good cop, I'm the bad cop. What you're gonna get a chance to do today is not afforded to very many people in the public, hardly at all. What we need to do is be very cautious of the vehicle, which is why there's stanchions that are out there so you can't get too close to anything. Um, the other thing that's very, very important to us on this mission is this is the first part of sample return, as, uh, uh, Dr. Watkins just mentioned. What we don't wanna do is get to Mars and find out in a sample that comes back that, hey, it's got my hair in it, hey, it's got my favorite cologne in it, things like that.

So all the rules that you received in terms of what you can and can't do on the floor, the things you can bring on the floor, the things you can't bring on the floor is all driven by our requirement to safeguard the science that this [00:05:00] mission is gonna do and the samples that we hope to bring back from Mars in the not too distant future. The team works on the floor regularly. When we work in critical hardware, we're not allowed to shower that morning. We can't put hair products in our hair, um, which is hard for me. I like my highlights and my styling, can't do that. Uh, there's only a certain, uh, type of, uh, deodorant you can wear. Uh, can't be any fragrance. And that's all to make sure that the science and the instruments, uh, they work they're designed. The samples we get back from Mars, they actually are giving us good data from Mars and not from things that we're bringing to it, uh, from- from the Earth.

There's an airlock, which is right outside of this building. It's just like an airlock you'd see in space. So we open the outer door, you can walk in there, you close that door, you can open the other door, then you can walk on the floor. We'll bring all your hardware in there, all your cameras, all your equipment. We'll have technicians who can wipe it down, make sure it's clean and ready to go on the floor. While they're doing that for you, we'll actually take you then to the gowning room so you can actually put the bunny suits on, just like people have here on the floor. Camera bags aren't [00:06:00] allowed. If your camera has a cloth strap on it, we're gonna ask you to take that off beforehand.

But then with all that stuff behind you, after you gown up, then you get to walk on the floor. And then what you get to see, in the right back there, that is the flight descent stage. Its job is to actually get the rover down to the surface of Mars. It's the jet pack vehicle. On the left hand side, that's the cruise stage. Its job is to basically get our spacecraft from the Earth to Mars. Um, and then the center, that's the star of the show, that's the rover. Um, looking incredibly flight-like. Um, basically, the only things that have not been installed yet are the sterile sample components. We put those in the vehicle very late in the processing flow in Florida, 'cause we wanna keep them as pristine as possible. Um, so those don't get installed until right before we actually find our way onto the top of the- the- the rocket itself.

Um, the only piece of flight hardware that's not here right now, that's our aeroshell. Its job is to protect us as we go through the Martian atmosphere. It's actually already down in Florida. We, uh, delivered it down in Florida, uh, [00:07:00] in early December. Uh, we got it unpacked, um, and [inaudible 00:07:03] processing activities, um, and it's ready down there waiting for the rest of the hardware to show up. The hardware we still have here will go down to Florida just around Valentine's Day. And once that happens, we're then on our glide scope towards launch. We finish processing the vehicle. We stack it and do its launch configuration, put it on top of the rocket and they press the red button, and then it's go time. July 17th is when the window opens.

Mat K.: JPL Director, Michael Watkins, and the Manager of Assembly Test and Launch for the Mars 2020 rover, Dave Gruel. Matt Wallace is the Mars 2020 Deputy Project Manager. He was also in the gallery that looked down over the rover. I had a question for him about the tubes that will store the samples collected by the rover 'til they can be returned to Earth.

I've heard that these [inaudible 00:07:50] may be the most sterile objects that humans have ever created, does that sound right?

Matt W.: Yeah. I don't think we can say the- the most sterile objects, but they're extremely clean. [00:08:00] Um, they're designed to be capable of being clean at very high temperatures, which eliminates essentially all that carbon products on the- on the surfaces of the tubes and, uh, so they're- they're certainly cleanest thing we've ever taken to Mars. Cleaner than viking in this particular case. We're searching for trace levels of chemicals, parts per million, really just very faint signatures, and we have to look, you know, deep down into the noise floor from billions of years ago on Mars, so these have to be extremely clean than they are.

Mat K.: Down the stairs, we went to that airlock area that Dave Gruel mentioned. Backpacks were stowed, equipment were swabbed, and we donned the bunny suits, face masks, gloves and booties that, one hopes, prevented even the tiniest bit of humanity from hitching a ride to Mars. You can see Emily and me and our stylish matching outfits, along with other images from our visit, on this week's Episode page at Finally, it [00:09:00] was into the airlock for a blast of air from what seemed like at least 10 directions. Good enough?

Speaker 5: Very good.

Mat K.: Okay.

crowd: [crosstalk 00:09:13].

Speaker 5: Hi there. [inaudible 00:09:16]? And [inaudible 00:09:20].

Mat K.: Okay?

Speaker 5: So series of questions. First of all, any makeup?

Speaker 7: No.

Mat K.: No.

Speaker 5: Okay? It's good?

Mat K.: Not today.

Speaker 8: We've got three different parts of the rover here. The cruise stage is right here. The rover's in the middle, and the descent stage is down there in the end. And we've got subject matter experts who can tell you about all of the different parts. Jia-Rui Cook, I work in the media office at JPL. So, welcome to our clean room. [laughs].

Mat K.: And there we were. Emily headed for the rover itself, where she narrated a video you should be able to see before long at

Emily L.: Huge amount of dust all over the place, um, and just lifting dust and covering the rover with it. [00:10:00] So as they get close to the surface, they're gonna turn on only the ones that are [inaudible 00:10:04] outwards so that the, uh, the dust gets blown away from where the rover is landing. On the very front of the spacecraft, you can see this, um, radar instrument that's gonna help it sense the surface. This spacecraft has something that Curiosity didn't, which is the ability to do Terrain Relative Navigation. It has a map onboard. It knows what the landing site looks like, what the topography is, where all the hills and bumps are. It also has a map of things that it does not want to land on. With this radar instrument, it's going to be able to feed information to its computer, um, and also with cameras that are mounted on the rover.

And the- the computer will figure out where the rover is with respect to the hazards that are in its landing ellipse and will actually be able to avoid some of the hazardous terrain. And so that allows it to land in a [inaudible 00:10:53] landing site than Curiosity was able to do, right inside a crater, right up against a del, uh, river delta.

Mat K.: [00:11:00] This is only my third time in here. It's your what?

Emily L.: Uh, this is I think my fourth time in this clean room. I'm excited to be here.

Mat K.: Excited is putting a [crosstalk 00:11:09].

Emily L.: [laughs].

Mat K.: Come on.

Emily L.: It's, actually, when you stop and think about the fact that we're standing here with spacecraft that are going to be on Mars, it's, uh, I could not be more excited. I mean, this is- this is amazing.

Mat K.: And how many years ago was it we were here doing the same with Curiosity?

Emily L.: That was in 2011, so that was eight years ago.

Mat K.: Yeah. Everybody here seems so confident, all the people that I've talked to, I bet you for pretty much the same thing.

Emily L.: Yeah. Well, at this point, the engineers better be comp... confident that this is gonna work. [laughs].

Mat K.: [laughs]. Mm-hmm [affirmative].

Emily L.: But yeah, they- they are. They've- they've done this before with a spacecraft that was built a very similar design. This rover's a little bit heavier than the last one was, but not a huge amount heavier. They've got a very similar descent stage. They just a couple extra bells and whistles on it to make it, uh, um, even safer for landing. So, uh, they're feeling very good, I think.

Mat K.: I honestly don't think [00:12:00] anybody here at JPL knows more of the ins and outs of Curiosity than you. How do you think it compares to this rover? I mean, I've been asking people, "What did you learn from Curiosity? What's different here?" Beginning with the wheels.

Emily L.: Well, yes, the wheels are certainly different. The wheels are, uh, uh, different design. They're thicker, skinned, they have different shaped treads, um, they are slightly narrower, actually. And so they'll be able to navigate the landscape just as well as Curiosity can with, hopefully, without all the holes in the wheels.

Mat K.: Yeah, right. Do you generally share the confidence that all these people who've been working on it for years, uh, that they have as well? I mean, we've done it before.

Emily L.: We've done it before and there's a lot of institutional memory here at JPL. You know, you don't wanna be overconfident, but I think that, um, these folks know what they're doing, these men and women are so experienced, so knowledgeable, and they have, uh, they have really good safeguards in place to make sure that if something goes wrong, they identify it and they fix it, and that's really the key. You know, anybody can [00:13:00] build something, but to build something that's going to work perfectly on its first try, with no repairs ever, and then work far beyond its planned mission, that's what these guys do best.

Mat K.: That is such an important point, because I don't think process, which they have come so close to perfecting here, gets the attention that it should.

Emily L.: Yeah, it's really assistance engineering is actually at the heart of it. So, you know, you think about spacecraft being built by engineers, and yes, the engineers are obviously very important, but, uh, management is just as important to make sure that something like this can come together and it can work.

Mat K.: All right. Let's talk science. Ignore sample return because we all know how high a priority that is, what are you most looking forward to from this rover?

Emily L.: This rover's gonna go to a different landing site, and every time we've gone to a different place on a different planet, we've learned things that we never had understood from all the previous places we've been. This one's gonna go to a really cool environment of river delta environment, and so we're gonna see how Mars made rocks in that landscape, we're gonna see how the weather and stuff was pertaining at the time, and we're gonna get [00:14:00] gorgeous pictures and I just can't wait to see the pictures from this machine with that fine, fine Mastcam-Z camera made by, uh, a team headed up by Jim Bell, the president of our board, so thank you, Jim, for the beautiful photos that we're about to get.

Mat K.: Emily, I'll see you in a little more than a year at Planet Fest, uh, for 7 Minutes of Terror, 7 More Minutes of Terror.

Emily L.: Absolutely. And then the terror that follows that of about a month as the scientists try to figure out whether their instruments [inaudible 00:14:27] surface. [laughs].

Mat K.: [laughs]. Thanks.

Emily L.: Thank you, Mat.

Mat K.: Planetary Society Solar System Specialist, Emily Lakdawalla. When we return, we'll talk with four of the engineers who have spent years preparing the Mars 2020 rover for its journey of exploration. One of them has been part of every successful Mars rover mission, beginning with Sojourner Pathfinder.

Kate H.: The Planetary Society is building the ultimate list of life goals for space fans, and we need your help. Hi, I'm Kate Howells, Community Engagement Leader for the [00:15:00] Society. What's on your list? The must-see objects in the night sky, the most awe-inspiring destinations, the experiences of a lifetime. Tell us about them at, we'll share them with your space soulmates around the world. That's Thanks.

Mat K.: Back to the spacecraft assembly facility at the Jet Propulsion Lab, stretching out before us in the huge clean room where the three major components of the spacecraft. All that separated us from them was a red ribbon strung between stanchions. At each station were two or three of Mars 2020 team members who have worked for all those years to assemble, test and launch this $2 billion explorer. Assembly, test and launch, that's ATL. My first stop was to talk with Christopher Chatellier, ATL Operations Spacecraft Integration and Test Engineer. Behind us here, the cruise stage, it has the job of [00:16:00] getting everything else to Mars.

Chris C.: It does. From Earth to Mars, this will be, uh, [inaudible 00:16:05]. It has two sets of thrusters that help make minor corrections to the trajectory that's set by the launch vehicle. It has, uh, a set of solar rays, it has a cooling system with the heat rejection system that helps radiate heat away from the spacecraft so it doesn't overheat. It has a telecom system to communicate back to Earth. It has a star scanner to find out where we are in space. It has sun sensors to- to make sure that we see... we know where the sun is rel... the orientation of the spacecraft relative to the sun. And it also provides the structural interface of the spacecraft to the launch vehicle, um, once we launch.

Mat K.: Which is a big deal in itself.

Chris C.: In fact, once the whole vehicle's stacked, the cruise stage is the way we pick the whole spacecraft up, uh, along the who... there's 12 points that have these, uh, red caps you see right here, and that's where we interface with it to- to pick up the cruise stage in the spacecraft.

Mat K.: What did you learn from Curiosity that might've affected this? Is it identical or have there been some improvements?

Chris C.: Um, so there's been minor improvements that were driven just by the, uh, [00:17:00] the heavier rover for Mars 2020. We do- we do one mission. There's- there's Mars Science Laboratory, there's Mars 2020, it's not an assembly line and so we built to the requirements of the mission. And so the cruise stage which is a built print design from Mars Science Laboratory was built for the Mars Science Laboratory rover. Mars 2020 got a little bit heavier. That drove a few changes as we tested the- the cruise stage, but it is mostly the same, yes.

Mat K.: Did you work on Curiosity?

Chris C.: I did not. So I've been here for just under five years and I've been working on Mars 2020 the whole time.

Mat K.: You must feel very fortunate.

Chris C.: Yeah, it's been- it's been very exciting. It's obviously fun to tell family and friends what we're working on, uh, and seen it this close to launch.

Mat K.: Where will you be during those, uh, seven minutes of, uh, terror this time around?

Chris C.: I don't know yet. It's still... so that will be in February of, uh, 2021. I haven't thought that far ahead. I'm still thinking about launch. [laughs].

Mat K.: All right. Best of luck. Best of success.

Chris C.: Thank you very much.

Mat K.: Thank you. Moving over to the rover itself, I struck up a conversation with Art Thompson. It was a lucky break. Art was primarily there to keep an eye on the other engineers and [00:18:00] spokespeople, but it turned out he had quite a story to tell. Art serves as ATL Operations Deputy Manager and used to be the Payload Deputy Manager for Mars 2020.

Art T.: This is a- a Curiosity class rover, so it's a little bit longer and it's heavier than the, uh, than Curiosity was. And we learned on Curiosity that the wheels, the- the design of the wheels on Curiosity were a little too soft. If you follow Curiosity, you'll notice that they- the wheels are actually getting torn up. So these are a complete redesign of the wheels, uh, made to take the heavier load and the very abrasive surface as we're driving over rocks and unknown surfaces, you know, as we turn in place on the surface, tends to be very hard on the wheels themselves. So this is a complete new design on the wheels. But the rocker bogey system actually has not changed since, uh, Sojourner rover. We had the same six wheels and the rocker bogey, with the differential going across the top. If you went back [00:19:00] and looked at Mar, uh, Sojourner, the mobility, uh, chassis would look very similar.

Mat K.: Seems amazing though that to scale up from that little, cute little Sojourner to this.

Art T.: Yeah.

Mat K.: The heaviest thing ever to land on- on the surface of Mars, if it ain't broke.

Art T.: [laughs]. Well, as far as the mobility is concerned, I agree. When we first, uh, designed Sojourner back in the '90s, uh, we were trying to decide between four wheels, six wheels and eight wheels, and we had a bunch of different concept vehicles that we- we built to test out the vehicle. We came up with the rocker bogey des... concept. We've just stuck with it ever since. We've been very happy with it.

Mat K.: You were around for Sojourner Pathfinder?

Art T.: I- I was. Uh, so I've actually been around for Sojourner, for Spirit and Opportunity, for Curiosity, and now, 2020.

Mat K.: Okay. This is totally off topic but-

Art T.: [laughs].

Mat K.: ... how did it feel to see Sojourner crawling around in that Mars habitat in the movie The Martian?

Art T.: Uh, you love it when they bring that back. To see the [00:20:00] vehicle, you go, well, that- that's definitely our- our vehicle. But you have to, as with all, uh, science fiction, you have to kind of, uh, suspend this belief. They drove her the wrong direction, although it really doesn't matter.

Mat K.: [laughs].

Art T.: 'Cause... but actually, these vehicles are very comfortable going forward or backward, so it's really arbitrary to call it forward or backward.

Mat K.: Well, we learned that with Spirit and Opportunity, right?

Art T.: Exactly. They- they like driving backwards as much as they like driving forward. The only advantage to going forward is we have more cameras on what we call the front of the vehicle, but we have hazard cameras on the back and we can rotate our RSM and we can do all the imaging to the back just as well as we can to the front. [crosstalk 00:20:38]...

Mat K.: RSM?

Art T.: The R... oh, I'm sorry, remote sensing mask.

Mat K.: Yeah.

Art T.: But the one thing that- that actually I always joke about, first off, the universal spacecraft bus, so you can go get an- an old spacecraft and bring it to a new spacecraft and plug it in and they work. That- that's always a fun thing, but the- the biggest concern would be on Sojourner, she used laser stripers [00:21:00] to mark the ground in front of her to just determine if it was safe to drive. Um, we don't do that. Actually, Pathfinder was the only v, uh, space or rover that needed those, so if- if you would've brought that into the hab on- on The Martian and then she got activated and started driving, well, she would be firing off these, uh, lasers-

Mat K.: [laughs].

Art T.: ... which would blind, uh, would blind, uh, uh...

Mat K.: Mark Watney.

Art T.: Yeah, Mark Watney, thank you.

Mat K.: [laughs].

Art T.: So, Mark Watney would've had a, uh, a little puppy running around, it would've blinded him.

Mat K.: [laughs].

Art T.: [laughs].

Mat K.: All right, now, on the other hand, Rob Manning has told me that the interface, the port that they used, that he used to control-

Art T.: Mm-hmm [affirmative].

Mat K.: ... uh, Pathfinder is really there.

Art T.: Oh, yeah. The... when they powered her up in The Martian and they actually used the same Unix interface screens that we- we used. So they did a pretty good job in res... doing their research.

Mat K.: Hopefully, I mean, with a lot of luck, maybe the 2020 rover will still be alive and kicking by the time humans arrive on Mars, whether they're [00:22:00] stranded there or not. Do you have the same kind of confidence in this spacecraft, in- in this rover that we've seen was, uh, was very well justified with Curiosity?

Art T.: Yes, we do. I think that the electrical integrity of the spacecraft is so high and the mechanical design, the lessons learned fr... on the newer vehicles, uh, we have every expectation that she'll way outlast her ex- expected mission, prime mission. And in fact, we're... I was hoping that we would have two vehicles still driving around when we did our entry, descent, landing so you could get images from the ground from two different locations on the surface as we're approaching. Unfortunately, opportunity just stopped operating about a year, year and a half ago or so. But, uh, it'd be good to- to have two driving around for a long period of time and- and enough time that we can get humans on the surface.

Mat K.: Well, I'm sure Curiosity will enjoy having company back on the surface [00:23:00] again, along with Insight, we shouldn't forget Insight, I suppose.

Art T.: Yes.

Mat K.: We- we covered the wheels, let's go up to the top. SuperCam.

Art T.: Okay. SuperCam is a- is a follow-on mission to the ChemCam instrument from MSL. Basically, it has, uh, the same lasers it had before, only improved, and we have a green Raman laser.

Mat K.: Mm-hmm [affirmative].

Art T.: So, basically, it can tect o... detect organic materials. That's, um, a vast improvement, plus there's actually a microphone on board as part of the SuperCam instrument.

Mat K.: Which we're very excited about 'cause we've been trying, at The Planetary Society, we've been trying to get a microphone to Mars for ages.

Art T.: Yes. And we want Jim Bell to be happy so we put the microphone on. [laughs].

Mat K.: [laughs]. Right.

Art T.: And speaking of Jim Bell, just below the SuperCam are the two Mastcam-Z or Z for zoom, and those are, uh, the follow-on to Mastcam from MSL. And so both lenses will zoom and they're- they're extremely high resolution. As in the past, Malin [00:24:00] and, uh, Jim Bell are gonna deliver some very beautiful cameras for us.

Mat K.: Yeah, Malin- Malin Space Science Systems, of course.

Art T.: Malin Space Science.

Mat K.: [inaudible 00:24:06] of those cameras. I also have been told that while you've been able to do pretty good job of faking video in the past, these cameras will actually send movies.

Art T.: Yeah, full- full video. Yes.

Mat K.: That's amazing.

Art T.: Yes.

Mat K.: Is there anything else that you wanna say about the guts of this, uh, this rover that, uh, are different from Curiosity?

Art T.: Uh, she's actually very similar to Curiosity, the electronics.

Mat K.: Mm-hmm [affirmative].

Art T.: I mean, we've learned some things and upgraded, but essentially, the compute elements, the RCEs, the PAMs, the power analog modules. If you looked at- at the electronics on Curiosity and the- the core electronics on this, they're very similar. So this is just the next generation Curiosity rover.

Mat K.: When will she be getting her power supply? When will they load in the plutonium?

Art T.: So the RTG, the MMRTG, multi-mission radioisotope thermoelectric generator, uh, will be integrated at Kennedy Space Center, it will never come here to [00:25:00] JPL. When we get back to Kennedy, and we're actually shipping the rover in early February, uh, in late M... April, we will bring the RTG out and- and integrate her for about 72 hours just to test to make sure everything's good, we'll then put it back away and, uh, wait 'til about 10 days before launch when we're actually on the launchpad, we will then integrate the RTG on the back. The rover will then be powered on and have to stay powered on through the end of mission. So we will not actually put the RTG on until 10 days before launch or flight.

Mat K.: Now is that partly because of the heat that's gonna be generated?

Art T.: Yes. Uh, it's mostly because of the heat, but also, we... well, we won't bring it to JPL because we are not equipped to handle that highly radioactive, uh, uh, an element. But at Kennedy, we're used to doing it there. The heat that's generated, and she's powered on, we cannot power her off. So right now, we do not have our control team. She's not powered on. You [00:26:00] see, our- our blue lights are not on.

Mat K.: Ah, yeah.

Art T.: So no one is monitoring her. Once the RTG is on and integrated, the spacecraft turns on and we have to have teams monitor her around the clock. And we don't wanna have to monitor around the clock right now for 10 months before launch.

Mat K.: Yeah, yeah.

Art T.: Eight months before launch.

Mat K.: Where will you be when, uh, she heads for the cape?

Art T.: So I'm going back with her. [crosstalk 00:26:23]...

Mat K.: Are you gonna fly on the C-17?

Art T.: Uh, I probably will not fly. Uh, the ATLO manager will be on the C-17. I will meet her back in Florida. And our team will be back there and we will basically do the- the final integration, uh, of the spacecraft itself. All the parts that we've taken off to get reworked, then we will, uh, configure her for launch and then we will integrate her on top of the atlas then push... put her out on the pad and launch her, that's what our... my team does.

Mat K.: And where will you be for launch?

Art T.: Uh, I'll be back in the control room. But I actually won't be on consul. I've, uh, I've been on consul for Pathfinder, [00:27:00] for, uh, Spirit and Opportunity and Curiosity, but I will not be on consul for this. I have a new team that will take her to launch, which I'll be standing behind them.

Mat K.: And you'll be watching.

Art T.: And cheering.

Mat K.: [laughs].

Art T.: And cheering.

Mat K.: For Curiosity, we were, of course, all at the Pasadena Convention Center with thousands of other people jumping up and down and cheering for you guys.

Art T.: My family- my family was there too.

Mat K.: Oh really?

Art T.: Yeah, absolutely.

Mat K.: Oh, that's great. All right. I hope they're with us again this time.

Art T.: They will be.

Mat K.: Best of success.

Art T.: Thank you.

Mat K.: The Mars 2020 rover and its cruise stage. Two down, just one big component to go. And it's the one that frightened me the most when its sister lowered Curiosity to the Martian surface nearly seven and a half years ago.

Ray B.: Yeah. My name is Ray Baker. I'm, uh, the Flight System Manager for Mars 2020.

Mat K.: Here is, for the second time, a sky crane-

Ray B.: Yes.

Mat K.: ... that's, uh, hopefully gonna be just as successful as the earlier one was with Curiosity. Are you pretty confident?

Ray B.: Very confident, yeah. [00:28:00] This is the descent stage. It is, uh, what I call a flying gas can. It has about 100 gallons of hydrazine propellant. It has eight Mars lander engines that produce about 700 pounds of thrust each. It's the power of EDL. It's... it, uh, provides all of the propulsive thrust to get us from, uh, 12,000 miles an hour at the entry interface, all the way down to about two miles per hour when we lower the rover the surface.

Mat K.: Some of our listeners remember that we made a previous visit to JPL to talk about those five antennas that you've got there, that radar system. Talk about that.

Ray B.: Yeah. So that radar gives us altitude and velocity when we're closer to the ground. It- it's what, uh, the rover uses to, uh, guide ourselves, uh, to- to that slow speed so that we can lower the rover safely to the surface. It is a heri... what we call a heritage system to Curiosity, so we had a lot of success on Curiosity with it. We're using it again here. In addition to this radar, we also got some new elements, including a Terrain Relative [00:29:00] Navigation system this time around. So Curiosity flew with its eyes closed, with no map, Mars 2020 has a camera that it will use for its eyes and it has an onboard map, so it will compare images to, uh, uh, high rise images from- from orbit and be able to shrink its- its uncertainty down to about 40 meters in position uncertainty.

Mat K.: This has sort of been the story of Mars exploration, right, or landing on Mars? These ellipses getting smaller and smaller and smaller, and now, 40 meters, that's amazing.

Ray B.: Well, that's our position uncertainty. Our- our ellipse is going to be about a seven-kilometer circle.

Mat K.: Ah.

Ray B.: Yeah, yeah. But it's much smaller. On- on, uh, Curiosity, we were about 20 x 10 kilometers. The- the TRN system, Terrain Relative Navigation, actually enables us to go to our landing site, Jezero crater, which is of great scientific interest. And so it's an enabling technology for us.

Mat K.: What else did you learn from Curiosity, from analyzing the results of that, the performance of the [00:30:00] spacecraft on that mission, that has gone into, uh, improving this one?

Ray B.: So Curiosity, it turns out, was- was right down the middle. It was a very nominal, very, very good day for us.

Mat K.: Mm-hmm [affirmative].

Ray B.: Uh, the system behaved exactly the way we though it would, uh, with very few, uh, exceptions. And so we didn't change much. We, uh, we made improvements by adding things like Terrain Relative Navigation, uh, but we spent a lot of time just trying to build what had worked before, and that's- that's what we call the heritage program for this- this system, so we could focus on the new parts and the new things and try to go to more challenging and more interesting places.

Mat K.: There is so much technology wrapped up in this, the radars, those pairs of engines, there's just so much, I mean, the- the things that cut the cable when you have successfully put the rover behind us here on the ground.

Ray B.: Yeah.

Mat K.: It just seems like it's maybe one of the most complex machines humans have ever made.

Ray B.: It's very complicated. Um, we do... we spend a lot of time [00:31:00] testing it, a lot of time simulating, uh, the landing, the entry, descent and landing, to ensure that the system is robust, reliable and that it's gonna work on landing day.

Mat K.: Where will you be for this seven minutes of terror? [laughs].

Ray B.: I will be here at JPL, uh, sweating bullets, uh-

Mat K.: [laughs].

Ray B.: ... uh, and of- of excitement, really. Just, I cannot wait, cannot wait to get this rover on the surface and, uh, have it do- do its job.

Mat K.: Just know that we'll be out there doing the same this time.

Ray B.: Thank you. Thank you very much.

Mat K.: Our time with the Mars 2020 rover was running short. I pushed my luck a bit further and was rewarded with one last conversation. It was with another JPL veteran who has been part of previous successes.

Jessica S.: My name is Jessica Samuels, and a couple different roles, uh, one, I started as the Lead Flight System, Systems Engineer for the project, uh, but I'm also the Sampling and Caching Phase Lead, uh, which means we work on both the flight system design of our sampling system, as well as how we wanna operate it, [00:32:00] preparing for the process that the team will use to collect the samples once we're on the surface.

Mat K.: I don't know how many times I have had Mars scientists, planetary scientists tell me sample return, sample return, sample return.

Jessica S.: Here it is.

Mat K.: You're one of the people making it happen.

Jessica S.: Here it is, yes. We're finally at the point where we are first leg of sample return. This is a very exciting time for I think the entire Mars scientific community. I know when I started here 18 year... 18 and a half years ago, I had teammates working on Mars sampler return, and to now actually be part of the team that is, you know, working on the sampling system, uh, designing it, testing it and ensuring its capability to acquire sample is... it's pretty outstanding.

Mat K.: Where are those super ultra clean bottles, those containers right now?

Jessica S.: Right now, they are still going through assembly and test, [00:33:00] uh, so we want to make sure that we don't put the super sterile sample tubes in until the last moment possible. Uh, we, you know, take great measures to preserve cleanliness through the entire assembly of the spacecraft but there are certain components that we want to make sure we, you know, are just waiting for the last minute to reduce the amount of additional exposure.

Mat K.: Because even this wonderful room, i- it's not clean enough, right?

Jessica S.: Uh, it's clean.

Mat K.: For- for those.

Jessica S.: It's clean for, um, for the external parts of the rover, for the internal parts of the rover that aren't necessarily interacting with the sample.

Mat K.: Mm-hmm [affirmative].

Jessica S.: But for th- those that we call sample intimate, uh, we want to make sure that, you know, once they go in there under a constant purge and being, uh, preserved.

Mat K.: At some point, if all goes well, those things are gonna be standing by with precious samples inside them. Have you been involved with what's gonna happen next? We just [00:34:00] got this announcement that the European Space Agency has committed to being a part of the return of these samples, how far along are we with the technology of getting that done?

Jessica S.: Honestly, my focus has been, you know, full bore on this project. Um, we definitely have a team here at JPL that is working the future mission and mission, um, you know, components, um, both working with the Europeans as well as the U.S. contributed, you know, in the- in the U.S. managed, uh, side. Until we land and collect our sample tubes, and I ensure that, you know, we all ensure that, you know, they are safely on the surface, my focus is gonna be here, and then we'll pick up with the teammates, um, in a few years.

Mat K.: Makes sense. I'm asking everybody, what did we learn from Curiosity that has affected the design of this new rover?

Jessica S.: Oh, many things. So the most notable, the wheels. We made them thicker, we changed the grousers to be able to withstand more of the, uh, the point loads that we get as we drive over [00:35:00] rocks. The other thing that we had to do was make sure that the accuracy and the placement of our robotic arm for these proximity science instruments that want to hover just a couple centimeters over the surface, um, that we can ensure safe placement. We enhanced the capability of our engineering cameras to be able to support that objective as well as our autonomous navigation. So now, we have color engineering cameras as well as the, you know, just additional data sampling, um, capability of those ca... of the cameras.

So one of the things that, you know, this mission is to acquire samples, and we need to cover a lot of Martian ground to acquire those samples, so we need to be able to drive quickly to those locations. So we enhanced our autonomous navigation algorithm, uh, we made it faster by processing the images while we're driving so that we can, uh, not have to pause while we create our stereo maps, and then decide what the right path is to- to drive. We can actually be processing the [00:36:00] images while we're also calculating what the path is, um, from the previous images that were acquired. Enhancing operability and enhancing science productivity were major themes of the development of this mission.

Mat K.: It went for a drive just a few days ago, didn't it?

Jessica S.: Yes, it did. We were... we took it off the [inaudible 00:36:17], we actually put it on- on the wheels, uh, we had, uh, blue, um, mats to help it from, uh, making sure we didn't build up any electrostatic charge while we were driving. Uh, but those mats, uh, covered ramps and it allowed us to articulate the mobility system under it some weight and drive over those- those features.

Mat K.: Now I already got one question from a listener about that kind of testing in 1G.

Jessica S.: Yes.

Mat K.: How does that compare to doing it on Mars in the [inaudible 00:36:49]?

Jessica S.: It's an over test here because Mars, you know, Mars is less so we obviously need to design our systems to withstand, you know, not only just the factor of safety for the Martian conditions, but we have to [00:37:00] design them to test them in Earth conditions. So same thing for the robotic arm, the gravity loading on the robotic arm when it's fully outstretched, you know, the- the motors need to be able to withstand that here on Earth as well as, uh, when it's operating on Mars.

Mat K.: How does your feeling right now, maybe a month, month and a half before this thing hedge for the cape and then Mars, how does this feeling compare to where we were with Curiosity at about the same point?

Jessica S.: Oh, I mean, I think everybody... you're always a little nervous at this stage, you know, because this is the last opportunity to really get in all the tests that you wanna get in, um, and you have to trust the- the tests that you have exhi... you know, gone through this, um, this far the right test, but it's exciting. From, uh, the stage of the spacecraft development, we're on track for our 2020 launch in July, so everything's coming together. I mean, we've been able to already run this rover through a lot of its paces and demonstrate that it's gonna be a successful mission.

Mat K.: And the other [00:38:00] question that I'm asking everybody, where will you be during those seven minutes of terror this time around?

Jessica S.: For landing, I will probably be where I was [inaudible 00:38:08] Curiosity, which is, uh, in the control room for the surface team. So once the entry, descent, landing team went through the seven minutes of terror, uh, we transferred the rains and transferred it to the surface control room. So I suspect I'll be in the surface control room again during landing.

Mat K.: Well, I hope that I will be, as we were for Curiosity with thousands of other people at the Pasadena Convention Center, cheering along with you when, uh, 2020 rover, soon to get a better name, uh, touches down on Mars.

Jessica S.: Yes. Well, I hope so. I mean, I- I really do have to say that the outpouring of the community support and excitement and, you know, Times Square, you know, let- let alone all the locations around Pasadena, Caltech, on lab or at the convention center, I know for my husband and, um, my family were at Caltech at the time and it- it feels great having the support of our community, um, and [00:39:00] the interest in what we do here. And hopefully, continue to inspire, you know, all the- the young people that are, you know, have interest in space and can see what we can build to continue to educate about our solar system.

Mat K.: I think you're accomplishing all of that. Best of success, even greater success with-

Jessica S.: Thank you.

Mat K.: ... 2020 than Curiosity. Thanks for all this.

Jessica S.: Thank you very much.

Mat K.: We are deeply grateful to NASA and the Jet Propulsion Lab for allowing us to spend these few minutes with the Mars 2020 rover and the handful of the men and women who have built it. We'll continue to cover the mission through its July launch, its perilous arrival at Mars, and as it begins its track across the surface of that planet.

Time for What's Up on Planetary Radio, and we're joined by the Chief Scientist of The Planetary Society, that's Bruce Betts, who's, uh, here to tell us about the night sky and, uh, get out as far as Uranus, at least, uh, on this trip. Welcome back.

Bruce B.: [laughs]. Thanks. Good to be back.

Mat K.: Dude, tell us about the night sky. [00:40:00] Venus is still looking absolutely gorgeous, really bright.

Bruce B.: Isn't it spectacular-

Mat K.: It is.

Bruce B.: ... in the evening sky in the west, not too long after sunset? And if you check it out in the next few days, if you look to its left and then progressing to its lower left, you'll see Fomalhaut, the, uh, only bright star in that region of the sky, but of course, Venus, much, much brighter. The morning is also turning out to be a bit of a party with Mars, not nearly as bright as Venus, but looking like a bright red star, is actually, uh, moving so that it is near the reddish star, Antares, which is, right now, a little bit brighter than Mars but two nice orange red [inaudible 00:40:41]. And then on the 20th of January, the crescent moon will join the gang.

And if you look to the lower left and have a good view to the horizon, you can check out bright Jupiter starting to make its climb into the morning sky.

Mat K.: I like that red on red.

Bruce B.: I do too. We move on to this week in space history. [00:41:00] It was 15 years ago, Mat, 15 years ago that the European Space Agency, Huygens probe, descended through the atmosphere of Saturn's moon, Titan, and landed on the surface.

Mat K.: I know. It must get tiring for some listeners to hear, but how could that possibly be so long ago? [laughs].

Bruce B.: Well, again, I'm thinking of starting to do these anniversaries in at least Mars years, if not Jupiter years-

Mat K.: [laughs].

Bruce B.: ... or Sa... even Saturnian years, so we feel much better about time passing slowly. It's all relative. It... I think that's how relativity works, but I'm not sure.

Mat K.: [laughs]. Ah, it's working for me.

Bruce B.: All right. We move on to Random Space Fact. So Eris, Eris' orbit goes from 37 AU, or Earth-Sun average distances, out to 97 AU from the sun. Pluto goes from about 30 to 49, so despite Eris going almost twice as far out as Pluto, [00:42:00] there are times when Eris is closer to the sun and closer to the Earth than Pluto. Of course, the next time that happens is a few hundred years from now, so I- I wouldn't worry about it.

Mat K.: What's that in Mars or Saturnian years?

Bruce B.: [laughs]. Well- well, in Eris years, uh-

Mat K.: [laughs].

Bruce B.: ... which is over 500 Earth years, it's, you know, it's- it's about one.

Mat K.: [laughs].

Bruce B.: Or magnitude one. We move on to the trivia contest and I asked you what planet has the smallest angle between its orbital plane and the orbital plane of the Earth, which is known as the ecliptic, so not including Earth, what's the answer? How did we do, man?

Mat K.: Almost everybody agreed on this one, and I think they agreed with what you were looking for. Among them, our winner, first time winner. He, uh, certainly seems to enjoy the show as you will hear, [inaudible 00:42:50] in Richmond Hill, Ontario. Here's his answer, "Uranus has the smallest ecliptic inclination with respect to Earth, [00:43:00] among all eight planets." Hah, we won't argue that. "My research shows most dwarf planets have wacky orbits, as I think you just gave evidence for. So I guess Uranus wins the prize among fairly large objects in the solar system. Bruce, prove me wrong please."

Bruce B.: [laughs]. Uh, no, 'cause that's right.

Mat K.: [laughs].

Bruce B.: Congratulations.

Mat K.: Yes, congratulations, [inaudible 00:43:24]. And, um, you're going to win the, uh, brand new Planetary Radio sticker and a Planetary Radio t-shirt. Those are what we're going to give away again in this next contest when we get to it in a minute or two. Uh, you can find them in the Chop Shop store, Planetary Society store, it's, we'll get you there though for everything that we, uh, sell from the Planetary Society. All goes to a good cause. Uh, I wanna add this, because [inaudible 00:43:52] did, Happy New Year to you guys and best wishes for a wonderful, joyful, healthy and prosperous 2020. I'm looking forward to another [00:44:00] 52 great episodes in 2020. Only 50 left now after this, [inaudible 00:44:06]. [laughs]. So if they go south, you- you know it's, uh, it's like a smaller number all the time.

Mark Smith, San Diego, California, nice town, I live there, you get different answers depending on how you interpret the question. Mark chose the minimum angle from the ecliptic, which is what you told him to do, there are several under two degrees, but Uranus is the closest at .77 degrees. We also got this from Joseph [inaudible 00:44:32] in Fanwood, New Jersey. He says it's the planet formerly known as Georgium Sidus, wisely renamed Uranus, that first name didn't bode well for a consistent naming of the planets. [laughs]. This means up at [inaudible 00:44:48], Johann Elert Bode. [laughs].

Bruce B.: Yeah, I went to college with him.

Mat K.: [laughs].

Bruce B.: Um, no. I assume it's the bode that came up with Bode's law, which isn't really a law [00:45:00] but kinda matches the distance between the different planets, but made him totally wrong. I...

Mat K.: No, I think you got it right because...

Bruce B.: Yeah, planet named George, I think it would've been awesome.

Mat K.: [laughs]. The Wikipedia said that, uh, it was Bode's law that helped, uh, place, uh, Uranus, uh, in its orbit. Uh, I guess it didn't help Uranus but it helped us determine what that orbit was. Uh, he added, the next discovered could've been Victorium or Louis Philippium from Louvre and the dwarf planet, Hooverium.

Bruce B.: [laughs].

Mat K.: I don't know, it struck me as pretty funny.

Bruce B.: Yeah, I think- I think it's- I think it's good that we didn't stick with, uh, naming planets after Mars.

Mat K.: [laughs]. We might get back to it.

Bruce B.: And apparently, everyone who wasn't in England bought that as well.

Mat K.: But as I said, we may get back to that before too long. Let's go on to another contest.

Bruce B.: This is for all of our- our poets out there. Two dwarf planets have moons that rhyme, so at each planet, dwarf planet, there are two moons of that dwarf planet, they [00:46:00] rhyme with each other. Name the dwarf planets, those two, and the two rhyming moons at each. You should end up with two dwarf planets and four moons of those planets. And hopefully, we'll get some poems or maybe people who argue that they don't rhyme. But my god, it's science. What the hell is wrong with you?

Mat K.: I- I appreciate the clarification. I think that was very helpful. And as I said, that's a Planetary Radio t-shirt and a Planetary Radio, uh, sticker, one of those brand new designs from Chop Shop, uh, waiting for the winner of this one, if you have the right answer and get chosen by We're done.

Bruce B.: All right, everybody, go out there, look up the night sky and think about, what kind of doctor was Dr. Pepper? Thank you and good night.

Mat K.: [laughs]. I know what kind of doctor he was but I think he was carbonatious.

Bruce B.: [laughs].

Mat K.: Best I could do in the spur of the moment. He's Bruce Betts, the Chief Scientist of The Planetary Society, who joins us every week here for What's Up.

[00:47:00] Planetary Radio is produced by The Planetary Society in Pasadena, California and is made possible by its Mars roving members. You can become one of us at and share the love. Please leave us a rating or review in Apple podcasts. Mark Hilverda is our Associate Producer, Josh Doyle composed our theme, which is arranged and performed by Peter Schlosser. Ad astra.