Planetary Radio • Sep 21, 2022

Countdown to DART: Will We Move an Asteroid?

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On This Episode

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Nancy Chabot

Planetary Chief Scientist at Johns Hopkins Applied Physics Lab, and Coordination Lead for DART

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Kenneth Farley

W.M. Keck Foundation Professor of Geochemistry for California Institute of Technology

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Bruce Betts

Chief Scientist / LightSail Program Manager for The Planetary Society

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Mat Kaplan

Planetary Radio Host and Producer for The Planetary Society

Additional guests include:

  • Simone Pirrotta, LICIACube Program Manager at the Italian Space Agency (ASI)
  • Giorgio Saccoccia, President of the Italian Space Agency (ASI)
  • Sunanda Sharma, Perseverance SHERLOC scientist at NASA JPL

We are less than a week from the DART spacecraft’s impact on asteroid moonlet Dimorphos as this episode is published. Mission Coordination Lead Nancy Chabot gives us a status update and a preview of what to expect during the September 26 encounter. Watching the smackdown from a few kilometers away will be LICIACube. Simone Pirrotta, program manager for the Italian Space Agency’s little cubesat, tells us about his high hopes. We’ll also visit NASA’s Jet Propulsion Lab to hear the exciting announcement of organics discovered and collected by the Perseverance rover on Mars. All this and a new What’s Up space trivia contest.

DART's first look at Didymos
DART's first look at Didymos This image of the light from asteroid Didymos and its orbiting moonlet Dimorphos is a composite of 243 images taken by the Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO) on July 27, 2022.Image: NASA JPL DART Navigation Team
LICIACube attached to DART
LICIACube attached to DART Engineers Alessandro di Paola (left) and Silvio Patruno from the company Argotech came to help install LICIACube on behalf of the Italian Space Agency. Here, they stand with the DART spacecraft and the fully installed box containing LICIACube (center) in a clean room at APL.Image: Johns Hopkins APL/Ed Whitman
What DART might see
What DART might see This infographic shows simulated images of what DART should see in its final moments.Image: NASA

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Trivia Contest

This Week’s Question:

What is the approximate diameter of the crater made by the Deep Impact spacecraft when it impacted comet Tempel-1? Use the estimate enabled by a later spacecraft that flew by.

This Week’s Prize:

A medallion created by The Planetary Society in 1989 to commemorate the Voyager mission’s Neptune encounter.

To submit your answer:

Complete the contest entry form at https://www.planetary.org/radiocontest or write to us at planetaryrad[email protected] no later than Wednesday, September 28 at 8am Pacific Time. Be sure to include your name and mailing address.

Last week's question:

How long from its launch will it take South Korea’s Danuri mission to reach the Moon?

Winner:

The winner will be revealed next week.

Question from the September 7, 2022 space trivia contest:

What are the names of the dog and sheep that will fly in the Artemis 1 Orion capsule? (Hint: They’re not real animals.)

Answer:

The dog and sheep that will fly in the Artemis 1 Orion capsule are Snoopy and Shaun the sheep.

Transcript

Mat Kaplan: Counting down as DART nears its destiny this week on Planetary Radio.

Mat Kaplan: Welcome. I'm Matt Kaplan of The Planetary Society with more of the human adventure across our solar system and beyond. The Double Asteroid Redirection Test spacecraft will meet its spectacular doom on September 26th when it slams into asteroid Dimorphos. With less than a week to go, we'll check in again with DART coordination lead Nancy Chabot. We'll also meet the program manager for LICIACube, the tiny Italian cube sat that will attempt to capture images of the impact and its aftermath. And in moments, we'll hear highlights of a September, 19 briefing at NASA's Jet Propulsion Lab that announced exciting finds by Perseverance, the Mars 2020 rover. As it rolls across the red planet, we inch closer to evidence of past life up there. Turns out the Artemis 1 Orion capsule has a lot more passengers than I knew about. We'll explain when Bruce and I answer the latest space trivia quiz.

Mat Kaplan: I'm in Tucson, Arizona as this week's show is published. NASA's Innovative Advanced Concepts program that's NIAC has once again invited me to host the live webcast of its annual symposium. It's something I love doing. I get to spend two and a half days talking with engineers, scientists, and other space nerds who've come up with scores of fascinating projects, solar sails, buildings grown from fungi, finding Earth-like worlds, novel ways to defend our planet and kilometer wide structures in space launched by a single rocket, so many more. It's heaven for this techno geek. You can catch the live stream on the NIAC website. We've got the link on this week's episode page @planetary.org/radio, or you can simply search for 2022 NIAC Symposium.

Mat Kaplan: Onto that JPL Media briefing. Past Planetary Radio guest, Ken Farley, is the project scientist for Perseverance. He spoke after we heard from JPL director Laurie Leshin and NASA associate administrator Thomas Zurbuchen. By the way, we learned last week that Dr. Zurbuchen will be retiring from NASA soon. All of us at The Planetary Society are grateful for his outstanding leadership of the Science Mission Directorate and we wish him well. Here's Ken Farley with an update on the Rover and some terrific news.

Ken Farley: I'm happy to say that we have made excellent progress towards achieving the goals that I just laid out. We've also managed to piece together quite a detailed history of Jezero Crater, a history that is surprising. It's not exactly what we expected. In the first year of the mission, we undertook what we called the crater floor campaign that's on the southeast part of this traverse. This is exploring the crater floor, the rocks that are below the delta. And what we found is not what we expected to find. Many of us expected to find out there in the middle of this crater that once held a lake, we expected to find sedimentary rocks deposited in that lake and instead what we found is igneous rocks. Rocks that were crystallized from a melt. That suggests a history that is more complicated than we expected. This crater not only held a lake at one point, but prior to that, likely prior to it, it also had active volcanism and possibly even a lava lake filling that crater so there's some complexity there that we hadn't actually expected.

Ken Farley: We acquired some excellent samples of those igneous rocks and this is an example of why diversity is important. Those igneous rocks will tell us a lot about the early history of a rocky planet, Mars, and in addition, one of the key things that in igneous rock return to earth will allow us to do is for the first time put a quantitative age on the surface of Mars. This is something that we just infer indirectly at present, so it'll be very important to get quantitative estimates of age on returned igneous rocks.

Ken Farley: After we finished the crater floor campaign, we drove very quickly in that arc around to where the rover is today at the delta front. The delta front is a scarp cliff about 40 meters high. You can see that we have driven back and forth studying this place. It's a really interesting place and the reason it's interesting is that the delta is a place where the sedimentary layers deposited in that lake are exposed in cross section so rather than just driving around on top of those sedimentary layers, we can actually drive up and see them one by one. This is from the area that you're going to hear a lot about. It's called Hogwaller Flat and you can see two of those sedimentary layers. The area in the background, the cliff forming layer, that's a sandstone and then in the material in the foreground that is lighter toned, that's a mudstone so these are sedimentary layers deposited in the lake that we have spent a considerable amount of time on.

Ken Farley: This specific area has probably the highest scientific value for exploration of the entire mission. This is the site that brought us to Jezero Crater. This is the place where we have the best chance to explore these ancient sedimentary rocks deposited in the lake and what you're going to hear is that we have discovered rocks that were deposited in a potentially habitable environment in that lake and we have been seeking potential bio-signatures. I want to be very careful to define potential bio-signature. This is something we've discussed a lot on the science team and I want to make sure everybody understands the concept of potential bio-signature. A potential bio-signature is something that may have been produced by life, but also could have been produced in the absence of life. Then key point about a potential bio-signature is it compels further investigation to draw a conclusion. This is the way science works. We don't always know the answer. We have hypotheses and the rocks that we have been investigating on the delta have the highest concentration of organic matter that we have yet found on the mission. And of course, organic molecules are the building blocks of life.

Ken Farley: This is all very interesting in that we have rocks that were deposited in a habitable environment in a lake which carry organic matter. We don't yet know the significance of these findings. These rocks are exactly the kind of rocks we came to investigate both with the rover and its scientific instruments and also to bring back to Earth so that they can be studied in terrestrial laboratory so time will tell what is in these rocks. Overall, I want to emphasize that the mission is proceeding extremely well. We are making very good progress at understanding the geologic history, finding some surprises in the history of the crater, and we are also making good progress in collecting this suite of samples for the Mars sample return effort. And what you're going to hear is that the suite of samples that we have collected so far is sufficiently good that we are now considering them putting down a subset of them on the surface of Mars as a target for the future missions to pick up and bring back to earth.

Mat Kaplan: Project scientists Ken Farley. To dig a little deeper, if you'll pardon the expression, let's hear from JPL's Sunanda Sharma. Sunanda works with Perseverance's SHERLOC instrument, that's the Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals.

Sunanda Sharma: And organics, as you heard from Ken, are commonly called the building blocks of life. All life as we know it is made up of organics. But importantly, organic matter can also be made up by processes that are chemical and they're not related to life so for instance, through water/rock interactions and it's also found in interstellar dust. By putting together the image and the spectral information that collects, SHERLOC can map where organics and minerals are in a rock, which tells us more about how the organic matter was formed, transported, preserved or concentrated. Organics tend to form clumps. We've seen this on earth and in Martian meteorites. And unless you can map, you miss some of that key information. This is the first instrument of its kind that's operating on Mars and it gives us very important information from rocks as they are found in place to support the selection of samples for the return to Earth.

Sunanda Sharma: In Wildcat Ridge, we detected signals that we think are from a class of organic matter called aromatics, which are stable molecules that are made up of carbon and hydrogen and sometimes other elements with ring structures. These signals were present at nearly every single point in every scan. They are also some of the brightest that we've seen thus far on the mission and they're about seven times brighter than what we saw at Thornton Gap, which is an abrasion patch on Skinner Ridge. The organic signals are also most strongly correlated to a mineral called sulfate that we saw in the rock. This correlation suggests that when the lake was evaporating, both sulfates and organics were deposited, preserved and concentrated in this area. While the detection of this class of organics alone does not mean that life was definitively there, this set of observations does start to look like some things that we've seen here on Earth.

Sunanda Sharma: On earth sulfate deposits are known to preserve organics and can harbor signs of life, which are called bio-signatures. This makes these samples and this set of observations, some of the most intriguing that we've done so far in the mission and it fulfills some of the excitement that the team had when we were approaching the delta front. To put it simply, if this is a treasure hunt for potential signs of life on another planet, organic matter is a clue and we're getting stronger and stronger clues as we're moving through our Delta Campaign. I personally find these results so moving because it feels like we're in the right place with the right tools at a very pivotal moment. Mars 2020 is giving us a better understanding than we've ever had of the Martian surface to select samples for return and then Mars sample returns stands maybe the best chance ever of answering a very profound question. Are we alone in the universe?

Mat Kaplan: There was much more in the briefing than we have time to share, but I can't resist including my question for the panel. Like most reporters, I was on the phone, you'll hear Ken Farley mention SAM on Perseverance's sister, Curiosity. Sam is the powerful Sample Analysis at Mars laboratory built into that other rover. It was replaced on Perseverance by the complex robotic systems that manage collected samples.

Mat Kaplan: Hi everyone. Congratulations on the collection of these very exciting samples. Part of my question's already been answered, but I'm still curious as we wait for them to return to Earth, do you ever wish, and I'm certainly not suggesting this would be possible, that Curiosity could drive over to Jezero and add its capabilities? I imagine that has to run through some of your minds.

Ken Farley: Yeah, if only rovers could drive that far. Yeah. Well I guess the one thing that I would pick up on is something that Sunanda said, and I'll just say it a little bit differently. You have two very different kinds of capabilities for characterizing both the chemical composition and the organic composition in the rocks. There's the SHERLOC instrument which makes a map. It is not as sensitive as the SAM instrument on Curiosity. This is a wonderful combination that you could bring together where the SHERLOC instrument could provide spatial resolution and really detailed mapping, and then we could take advantage of the kinds of capabilities that exist on SAM to penetrate deeper and get not only lower detection limits for certain kinds of molecules, but we could actually learn a little bit more about which molecules are present. That's a thing that I would do if I could bring the two rovers together.

Sunanda Sharma: Yeah, I completely agree. That would be what I would want to do as well so we could get a couple of different views because that's what I would do on Earth. When we bring these samples back to earth if and when that happens, that's what I would do. I would put together the capabilities that SAM has on curiosity and the things that we could do with SHERLOC, but at much higher space spatial resolution as David was saying, and figure out what's going on in these rocks. That would be my top dream too.

Mat Kaplan: Sunanda Sharma and Ken Farley at a NASA JPL media briefing about the latest news from the Perseverance Rover on Mars.

Mat Kaplan: Onto DART and our latest visit with planetary scientist, Nancy Chabot. As I said, Nancy is the coordination lead for the DART mission. She's also deeply involved with the Japanese space agency's, Martian Moon's Explorer Mission and the joint European Space Agency, Japanese Space Agency, BepiColombo mission to Mercury. Nancy's a fellow of the Meteorical Society and will become that group's president next year. Incidentally, she got her Bachelor's from Rice University 32 years after John F. Kennedy delivered his moon speech there, the one we heard a bit of last week. She earned her PhD at the University of Arizona where I am attending the NIAC Symposium.

Mat Kaplan: Nancy, welcome back to Planetary Radio. Oh my gosh, I have the DART website open just so that I can refer to the countdown timer, which is now telling me there are 11 days, five hours, 54 minutes and 32 seconds before the great smack down. Pretty darn exciting.

Nancy Chabot: And it really is, definitely, it's exciting. We are counting down the days here at Johns Hopkins Applied Physics Lab where I am right now and be like, "Oh, who's counting?" And it's like, "Yeah, we're counting."

Mat Kaplan: And of course by the time people hear this show, which is several days from now, you'll be even closer. You'll be you, it'll be less than a week. I know that in addition to what your team will be doing that there'll be a lot of people gathered at the Applied Physics Lab and my boss, the science guy, is going to be there as you count down those final seconds. I wish I could be there like I was for the New Horizons encounter with Arrokoth. Can you believe that was nearly four years ago and you and I were, even back then, talking about what was to come with DART?

Nancy Chabot: Yeah, it's so exciting that we're going from something that we've been talking about for so long and that the team here at APL built this spacecraft during a global pandemic, had been working on this project for years, and we're days away from this big event. Very happy that NASA is going to share this with the world in real time as this event happens and that we can host that at APL and that it's going to be broadcast live on the internet and on NASA TV worldwide.

Mat Kaplan: I am expecting a gigantic audience and we'll talk a little bit later about other ways for people to participate in that. What is the current status? How is the spacecraft doing?

Nancy Chabot: The spacecraft for DART is doing wonderfully. Everything is nominal, which is a lovely word in space science and any sort of mission operations. And so things are going really well and everything is on track for September, 26th at 7:14 PM Eastern daylight time, which is when the impact occurs. LICIACube, which was just deployed this last weekend, and that's fabulous, and so we're really happy to have that milestone reached. Sometimes when I say everything's going nominal, it might seem like, oh, we're not really doing anything. Oh no, I would stress also, the team is very busy. This 10 month cruise period that we're coming up to the end to, there's been over 200,000 images taken to help really understand the spacecraft, characterize how it operates in space, calibrate that camera, and be ready for this big event, and so mission operations in particular at APL is still very busy getting ready for this event, but everything is on track and we are counting down the days.

Mat Kaplan: Just a note to the audience, you're going to hear a little difference in the audio quality from Nancy because we ran into some technical difficulties. She has now switched to her phone and to a very appropriate location. Where are you now, Nancy, at APL?

Nancy Chabot: I'm in the Science Operations Center. We refer to this as the SOC. This is where a lot of the people on the science team get together where we'll be doing the data analysis and looking at those first images and the models and figuring out where the DART spacecraft hit, what this all means for planetary defense. Right now it was conveniently empty, so I could take this call in here, but it's not going to be that case for very much longer.

Mat Kaplan: No, I bet it won't. All right. Well let's pick up, I saw an image of Didymos taken by your spacecraft, by DART. I suspect that was not an easy image to get from, I think it was 20 million miles or was it kilometers, away? How did that happen?

Nancy Chabot: Yeah, so we've always been trying to use the camera on board called DRACO, the Didymos Reconnaissance and Asteroid Camera for Optical Navigation. It's similar to the camera that flew on the New Horizons mission that took spectacular images of Pluto and so it's a really capable design for a camera built here at APL by the team and everything. But still, Didymos and Dimorphos are far away and they're pretty small and not very bright. We always expected to try to have our first detection about a month out, so about 30 days out, but really the camera is working so well we were able to detect it even earlier than that, and it's just a little point of light, but seeing that little point of light that is DART's destiny in the camera and knowing that everything's in sight and in its sights is really exciting.

Mat Kaplan: That point of light, I guess a tiny portion of that point of light is contributed by your target, Dimorphos, but you can't pick these two apart yet, can you?

Nancy Chabot: Oh no, you absolutely cannot separate Didymos from Dimorphos in any of these images. And in fact, that's one of the main challenges of the DART mission is targeting such a small spacecraft in space at high speed when you've never seen that asteroid before. And even with this amazing DRACO telescopic camera that we have on board the spacecraft, we won't be able to distinguish Didymos from Dimorphos until within the last hour of the mission. This is going to be a very tense and very exciting time because this has to be done autonomously and the spacecraft analyzes the images on board, identifies which one's Didymos, which one's Dimorphos, sees Dimorphos the first time and adjusts the thrusters to ensure that you stay on an intercept course with Dimorphos and that's all done autonomously with this system that's called SmartNav that was developed by the team here at APL trying to solve this problem of how do you hit a small asteroid in space at high speed when you've never seen it before?

Nancy Chabot: It's a really capable algorithm, but it's also one of the main challenges and one of the main technologies that we need to develop for planetary defense and that we're testing out with this mission.

Mat Kaplan: What an adventure. At this point, we're still days to go. Is the spacecraft still under control from Earth and are there more trajectory corrections ahead under the control of mere human beings?

Nancy Chabot: Us mere human beings do have control of the spacecraft here in the Mission Operations Center at APL. Yeah, there's images being taken every day still. Looking at the Didymos system, taking images of stars for optical navigation, this activity will continue for the next days. The autonomous portion will take over it four hours out. Until then, still very much operating the spacecraft on normal behavior, that four hours out is when the SmartNav system kicks in.

Mat Kaplan: Wow! What can we expect to see during those last four hours or the last hour?

Nancy Chabot: You're coming in really fast to something that's really small, so even four hours out, it's just still a single point of light, but it's within that last hour that it's really going to get exciting. And that's one of the big things will be within the last hour, closer to the top of the hour than the bottom, most likely. That's when it'll separate into two dots of light, one that's slightly bigger than another one, and you'll see Dimorphos. But then after that, you'll see that it starts to get larger and larger in the field of view, the camera, the images are coming back to Earth one per second. They're the same images that the autonomous system on board SmartNav is using, but they're also transmitted back to Earth real time. There's no transmitting back to Earth after the collision, so very important to get those images down when they happen.

Nancy Chabot: Those images will come back one per second and very slowly you'll see zooming in on Dimorphos, zooming in on Dimorphos, and it's really within the last two minutes that you can start to see what this asteroid that we've never seen before looks like. What does Dimorphos look like? And it will start to see out the shape, will be the first thing, and then you'll start to see the geologic features on it. Dimorphos will fill the whole entire image, fill up the view. You'll be like basically zooming in, crashing right into that surface, seeing things that are down to tens of centimeters in size so things that you could like hold in your hand practically.

Mat Kaplan: Good Lord! You are far from being old enough to remember this, but I was a little kid, I remember the Ranger spacecraft approaching the moon and taking pictures on their way in and then of course being blown to smithereens. It sounds like you're part of that legacy.

Nancy Chabot: I think it's going to be very similar to that and I think when you look at those, sometimes people are like, "Well, you really know anything the night of." And I'm like, "Oh, I think it's going to be a pretty spectacular and definitive way for the final moments of the DART spacecraft to see this surface of this body that you're seeing for the first time zooming in on you", so it is very much like those early lunar exploration days.

Mat Kaplan: This is all a great lead in to where I want to go next with this. You already talked about the successful release of LICIACube, that Italian Space Agency or OSI CubeSat, and I think I told you that I'll be sharing a brief conversation that I had a couple of weeks ago at Kennedy Space Center with the program manager for LICIACube, Simone Pirrotta, what are your hopes for what that little companion spacecraft will be able to do?

Nancy Chabot: Oh, we're so delighted that LICIACube is flying now independently of DART. I was going to say as part of DART, but they literally are not part of the DART spacecraft anymore, part of the overall mission and our overall team obviously, for this combined project. LICIACube is going to bear direct witness to DART's collision. They are going to be capturing images of DART's collision. They make their closest fly by three minutes later and capture the effects that happen, the ejecta, the pulverized rocky material that's thrown off during DART's, high speed collision, how that evolves, what that looks like. LICIACube stores all their data on board and then they'll send it back in the days and weeks and months that follow. It's going to be great to see all of that come in. LICIACube already, is quite an accomplishment. I think everybody in Italy in particular should be very proud of operating this spacecraft in deep space for Italy for the first time.

Mat Kaplan: I remember also looking back again a few years, the last time we smacked something into a small body, deep impact, which we were actually covering live, had an audience with us, kind of like what you're going to be doing at APL on the 26th. There was a camera that was able to observe that, but there was this huge flash and so much debris it really wasn't possible to see much. You folks have got to have considered this since you know that you don't have much else as a precedent to study.

Nancy Chabot: Oh, absolutely. We learned so much from that mission. LICIACube, when they do their imaging, their closest approach distance will be about 50 kilometers away. They really will be a nice, safe distance such that they'll be able to watch the plume evolve as you see from there. It should fit nicely into their field of view and so I don't think that will just be so much ejecta that the whole frame is filled with it or anything like that. We'll be able to get out the shape and the dimensions of how the ejecta evolves, which will be very exciting.

Nancy Chabot: But also I think what's interesting is that LICIACube needs to be safe because they store all their data on board and so this is a compromise as well because they have to make it through this whole thing and capture it and then send the data back afterwards. So it's a good compromise. Certainly, we've learned a lot from the missions that have come before us, but a small asteroid crashing something like this so fast into a small asteroid is also going to be new, and so we're looking forward to unexpected things.

Mat Kaplan: Where will you be when this climactic moment comes?

Nancy Chabot: Oh, I'll be here at Johns Hopkins Applied Physics Lab along with a lot of the team watching the whole moment unfold, living in the moment, enjoying this accomplishment that we've been leading up to for years. I think I'll take a moment to be there and enjoy that, but then we're going to get to work. Over here on the science side, this is also in some ways just the start. We've been waiting to not just execute this test, but to analyze it and to see what it means and that's where a lot of us on the science team and on the science side will appreciate what an accomplishment it is and what a challenge it is to autonomously hit a small asteroid in space that you've never seen before. But I guarantee people on the team also are going to start pointing at those images right away and when you like, where did DART hit? What does that feature look like? And it's going to be so exciting for the weeks even afterwards.

Mat Kaplan: This is such an important point. It's exactly where I was going to go because people may be thinking, wow, you spend years working on a mission like this and all those other missions, I don't know, Casini, the Mars Rovers, Voyager that go on for years and yours ends in an instant, but it's not at all the end of the mission, there's so much more to be done and a lot of observation that will be done what, by some of Earth's most powerful telescopes, to see if you were able to nudge this rock.

Nancy Chabot: Yeah, I think right now we're really focused on talking about the DART spacecraft and LICIACube because those are the first immediate things that happened, but we want to know how much we deflected this asteroid and we're not going to learn that from DART. The DART spacecraft is going to take those spectacular images as it comes in and then that's it. LICIACube just does a fly by as well, so it's going to witness the collision and capture that and the ejecta, but then it won't stay around.

Nancy Chabot: Instead, the telescopes here on the Earth are going to have to make that measurement, which is great because they're really good at doing this. They discovered that system decades ago and they've been watching it over years and [inaudible 00:26:52] takes 11 hours and 55 minutes to do one orbit around right now for Dimorphos to go around Didymos. It's exciting actually that telescopes around the world have embraced the unique experiment that is DART. We've got telescopes across the country here in the United States and across the world, in fact on all seven continents, even some in space, that are going to be turning their gaze towards the Didymos system to see if there's any brightening during ejecta, see how that ejecta of evolves over the days after dart's impact and then also to measure this period change, which is one of the fundamental measurements that we need to make in order to see how much we deflected Dimorphos around Didymos.

Mat Kaplan: Simply thrilling, not just in itself but for what it represents as humanity learns maybe how to protect itself from the next big rock that actually has our name on it that's coming our way. Let's tell people how they can also participate by watching and maybe even joining in with friends and family to do this.

Nancy Chabot: Yeah, we definitely are encouraging people to tune in because this is going to be accessible on the internet and on NASA TV, NASA, YouTube, and a whole variety of channels. We've put some resources up on the website, on the DART website, dart.jhuapl.edu, and you can host a watch party so there's some ideas for decorations or games or all sorts of videos that you can play and really tune in and invite everybody to be a part of this historic moment and to watch it as it happens.

Mat Kaplan: You can bet that I will be one of those virtual participants. I'll just say again Nancy, I wish I could be there with you at JHU APL, but I know Bill and I will represent The Planetary Society well. Best of success with this incredibly exciting effort. I hope you're able to get some rest between now and the time that we see this spacecraft meet its destiny at Dimorphos.

Nancy Chabot: Oh yeah, thanks. It is an exciting time, but I'll try to get some sleep as will the team. We're all very busy but also just really excited that after years and years, this moment is finally upon us.

Mat Kaplan: Thanks Nancy.

Nancy Chabot: Thank you.

Mat Kaplan: Go DART and go LICIACube. You may have heard last week's interview at the Kennedy Space Center with Italian Space Agency President Giorgio Saccoccia. When we come back, I'll share a special portion of that conversation that I saved for this week.

Bill Nye: Greetings Bill Nye here, CEO of The Planetary Society. We need your help as we launch a new and exciting project. It's a new subscription style program for kids. We call it the Planetary Academy and it's getting underway with a kick starter campaign. The Planetary Academy is a special learning and membership opportunity for kids ages five to nine. Young Explorers will receive four adventure packs each year that have been developed by our experts. We're creating the first adventure packs right now. Academy members will learn all about our solar system throughout of this world activities and surprises, preparing them to blast off to exciting destinations. After this first successful year, we'll expand the Academy to a full three year program that explorers and their families can renew annually. Will you help us kickstart the Planetary Academy by backing our project? Visit planetary.org/academy today to learn more and get behind this exciting new opportunity. That's planetary.org/academy. Thanks.

Mat Kaplan: Welcome back. Here's that small portion of my conversation with Italian Space Agency President, Giorgio Saccoccia that I decided to keep for this week's show. I think you'll understand why in a few moments.

Mat Kaplan: You said that you had a colleague here that you wanted to bring out to join us.

Giorgio Saccoccia: Yes, Simone, who is here is the program manager of LICIACube and the nice thing of LICIACube is that it is very well associated also to ArgoMoon what is playing on SLS because they are both witness something that will happen in space and I'm sure Simone will have a lot to tell you about LICIACube and ArgoMoon as well.

Mat Kaplan: Welcome.

Simone Pirrotta: Thank you. My name is Simone Pirrotta, I'm the project manager of LICIACube. Yeah, we are hoping this new season of interplanetary CubeSat. We have start mentioning that ArgoMoon and LICIACube will be the first European CubeSat operating in deep space. ArgoMoon in near deep space but LICIACube will be very far, will be a DART companion and it'll be released in two weeks from DART to collect the very important pictures of the impact effect on the Didymos surface.

Simone Pirrotta: Yeah, they have in common a general architecture. They have the same size like 6U CubeSat with similar architecture and a couple of optical payloads. What is very attractive on their design is that they are capable to identify targets and to keep it pointing during this very challenging flybys. You're probably aware that LICIACube will pass through the DART impact with a very high relative velocity so the capability of maintaining the pointing during this approaching phase is very crucial and this is what we are working on together with our colleagues of APL and NASA. It be capable to identify the impact than possibly the [inaudible 00:32:33] on the surface, but for sure the plume of material that will be released, which is very interesting for the confirmation of the energy that is transferred to the target and also to have give scientific information about the composition of the asteroid and some other important features of this interesting interstellar body.

Mat Kaplan: Perhaps it's obvious DART will not be able to observe its own impact, it will be in tiny pieces, even if it could, it wouldn't be able to report on them. So many of us are looking forward to getting those results back from LICIACube.

Simone Pirrotta: We know, we know so that we have very frequent meetings with the APL and NASA colleagues because we are preparing the phase of the release and the analysis, very [inaudible 00:33:19] and quick analysis of the images and they release both for the outreach purposes but also for the scientific side. As I mentioned, we will be able to identify the impact, [inaudible 00:33:33] impact to also capture images of the not observed side of the asteroid because DART is, it is already identified, it has already identified asteroid at this point in towards, but you can see just one side.

Mat Kaplan: Yeah, it's just a pixel or two still, right? It will stay that way until it's very close, just before impact.

Simone Pirrotta: Yeah, it will, the DRACO camera on board of DART will be able to image DART in the very last part of the approaching phase while LICIA will maneuver in order to be a little bit out of the plane so we'll have a good illumination of the sun in order to imaging the plume ejecta and also the not visible side of the Dimorphos. This will allow a very interesting reconstruction of the shape of the asteroid, which is part of the unknown information which will contribute to.

Mat Kaplan: We wish you the greatest of success. This is such an exciting mission between these two spacecraft. We cannot wait for, I think it's September 26th?

Simone Pirrotta: Right. We will be released 15 days before the impact. September 26th, the impact will happen and in a couple of days we will be able to provide the scientific community and all the people interested with very, we hope, fascinating images of this event.

Mat Kaplan: Thank you very much. I'm glad that Giorgio brought you out.

Simone Pirrotta: I'm very happy too and we are excited for ArgoMoon that will be launched tomorrow.

Mat Kaplan: Yes.

Simone Pirrotta: Hopefully it'll be a testing of the similar technologies that we have on board. I am part of the, I'm also deputy project manager for ArgoMoon, so that's why I'm here and if there will result in a good success, we will have much more confidence in LICIACube's performances.

Mat Kaplan: Also a pioneering effort from Italy and the Italian Space Agency. Giorgio, I want go back to you for a moment if I can, because of what this represents. I was in Italy, specifically Frascati, in 2015 for the Planetary Defense Conference. In fact, we did a live show in front of an audience at the headquarters of ESA. Italy has had tremendous involvement in the effort to protect Earth from near earth asteroids, comets and so on. It's a big concern of ours at The Planetary Society. I guess you could say that LICIACube is a portion of that effort. Can you say something else about why Italy is treating this as such a high priority?

Giorgio Saccoccia: Well, it's part of the approach of using space and considering space as part of the sustainable future our planet. We need to protect not only the planet, but also the environment of the planet, around the planet. So we need the instruments, we need the right approach to preserve the surface of the planet for what can arrive from space natural or artificially generated.

Giorgio Saccoccia: For this reason, yes, I agree with you certainly LICIACube and DART are part of this overall scenario, but there are other important instruments that need to be developed. I can mention one where Italy is particularly involved, which is a special type of telescope, specifically designed and developed to monitor near hurt objects, is called Flyeye. It's a composite lens telescope that we have developed through the European Space Station, I mean the first prototype say, an intention now is to develop a number of recurring that will be deployed in different part of the herd to contribute to the monitoring of our environment. I repeat is something that we can't avoid to do because it's not only question to go to space, but to do it in a sustainable and careful way and also to protect our herd from what happened up there.

Mat Kaplan: Italian Space Agency President, Giorgio Saccoccia and LICIACube program manager Simone Pirrotta. We'll check in again with Nancy Chabot soon after the DART spacecraft impacts Dimorphos. It's worth repeating, go DART.

Mat Kaplan: Time for what's up on Planetary Radio. So here's the chief scientist of The Planetary Society, Bruce Betts has joined us once again. I welcome you and as I mentioned at the top of the show, I am out of town as people hear this show, if they hear it early on. I'm at the NIAC Symposium hosting the webcast, and I note to you there are at least two, I thought there were more, there are at least two presentations from NIAC Fellows about solar or light sails, not our light sail, but light sails in general. And I thought that was very encouraging and I bet we, the society, maybe you in particular, have something to do with this renewed interest.

Bruce Betts: I think, that's me in particular, although I have presented to some of the people who were talking, our mission, I mean it's part of what Light Sail 2 was or Light Sail Program, the goal was to elevate the visibility and prove the viability of solar sailing, particularly in small spacecraft and I'm excited that I think we've done it. We've got multiple NASA missions that are ready to go, including one on the pad right now with the SLS and NEA Scout, more in the future and people thinking wild and crazy thoughts like the ones being presented at NIAC of future unusual possibilities of using physics in creative ways.

Mat Kaplan: And we're still planning to talk to Les Johnson, he's the leader of that NEA Scout project. We're just delaying it hopefully until the SLS actually takes off and that CubeSat gets to unfurl its sail. Fingers crossed for that. What's up there?

Bruce Betts: I look at Jupiter. Jupiter on September 26th, is in opposition? So it's on the opposite side of the Earth from the sun. Percentage wise, it doesn't vary that much over the year, but it is about the brightest it gets, which is really, really bright, brighter than any star, except the sun. And it will rise around sunset and set around sunrise. When you see it off in the east in the early evening, if you look higher above it away, you'll see a yellowish, much dimmer, but still bright star, that is actually Saturn. And Mars coming up now in the late evening and it will be getting brighter and brighter as it approaches it's opposition. That'll be a few weeks away.

Mat Kaplan: Does Jupiter ever appear brighter than Venus in our sky?

Bruce Betts: No.

Mat Kaplan: Okay, moving on.

Bruce Betts: They both vary, particularly Venus because of where it is. And we also see different phases in Venus so it's brightness varies, but it's always brighter than Jupiter, which also varies.

Mat Kaplan: Sorry, Jupiter. I tried.

Bruce Betts: Well, it's Jupiter's fault for being out at five AU instead of closer. Although, gravitationally I'm glad that it's not closer.

Mat Kaplan: Yeah, I'm just fine with that.

Bruce Betts: Okay. All right. We're good. We're satisfied with the solar system position. So let's go on to this week in space history. 1846 is a biggie. Neptune was discovered in this week by Johan Godfried Galle, G-A-L-L-E, based upon predictions by Le Verrier, my French is even worse. Kind of big, it's a planet. I don't know if they knew that. And for you, Matt, three weeks in a row, I've had something for you. I don't know if you're a big fan or not, 60 years ago the Jetsons premiered.

Mat Kaplan: So 62. Yeah, right. Oh yeah.

Bruce Betts: Accurate portrayal of space and more importantly, robot dogs that sound like Scooby would sound years later.

Mat Kaplan: His boy Elroy ... I was a huge fan. I was a bigger fan of the Jetsons than the Flintstones for obvious reasons.

Bruce Betts: Oh yeah.

Mat Kaplan: I mean, they had cool, they had flying cars and lived up in the sky. It was amazing. And a trip to the moon was basically, you could go there to buy your groceries I think.

Bruce Betts: Yeah, that's not actually realistic, but ...

Mat Kaplan: Well, I got to say this, There was a great one where the building superintendent is excited. He wants to show George this amazing machine he's been working on. It's an old car. It's a car with big fins because after all 1962, and it just belts all kinds of smoke and smog and it's like George has disgusted and runs away and I thought, oh my, wouldn't that be wonderful ... 60 years later?

Bruce Betts: We'll find that episode for you.

Mat Kaplan: Yeah. Thank you.

Bruce Betts: It's time to move on to random space facts. Daughter Judy, random space fact. Yeah, that was better. You've been hearing about DART mission. Here's a little random space fact for you that's not so random because it's about DART mission. Dimorphos has about 10 million times the mass of the DART spacecraft that will slam into it, but it will slam into it at over six kilometers per second, giving it a significant amount of momentum and energy to make a bit of a change in it. I was impressed by that.

Mat Kaplan: Me too. This is going to be so spectacular. I just love this.

Bruce Betts: Well, yeah, I mean slamming things into other things at high speed.

Mat Kaplan: I know, I know. Reminds me of toys I had in childhood.

Bruce Betts: Welcome to Matt's childhood memories show.

Mat Kaplan: Really, maybe we should do a whole episode sometime.

Bruce Betts: I'll suggest that as an interview after you retire from being the host. Okay, I need to move on. Onto a happy subject. I asked you to name a dog and a sheep flying on Artemis 1. How did we do?

Mat Kaplan: Here is a poem from Margaret Cross, I assume in Florida, you'll hear why in a moment aboard. Aboard the SLS, two critters want to play, a canine friend of NASA and a sheep from ESA. Snoopy is the beagle, he'll be flying like a comet and beside him, Willie Sean, friend of Wallace and Gromit. Like them I long for launch day, perhaps next they'll send a gator. I give tours out here at KSC, a NASA communicator. Good work, Margaret, nice contribution. Yeah.

Bruce Betts: Very nice. Anne, correct Snoopy and Shaun The Sheep.

Mat Kaplan: Congratulations to everybody who got it right. As I said last week, huge response. Everybody I think who submitted, got it right. And what a fun one. People loved this. Here's the winner, first time winner. In fact, I think she's an early listener as well. How would I say has not been listening long? Diane Brezzanne in New Jersey who said, "Yeah, Snoopy and Shaun". Of course, Shaun The Sheep. She adds, I discovered the Planetary Radio podcast last year. I've been listening faithfully to each new podcast, binge listening from your first ever show. I'm finally up to the year 2011, enjoying the old with the new. Well, that means you can enjoy Bruce and me.

Bruce Betts: She probably meant the guests, but whatever.

Mat Kaplan: I think so. Diane, congratulations. You have won are Artemis 1 prize extravaganza.

Bruce Betts: Dun, dun, dun.

Mat Kaplan: It's an Artemis baseball cap, a mission pin, a really nice mission pin, a rubber Orion capsule and my press pass lanyard, which I'm sure will be useful for many things around the kitchen.

Bruce Betts: Comes complete with Matt's Sweat.

Mat Kaplan: Probably considering it was worn in central Florida, Florida coast. Timothy Myers in California, Pabul Kamesh in Belarus proving the great minds think alike wherever they are. They both submitted one giant leap for lamb-kind. Barry Olson in Alberta, so no cats? What's wrong with cats? On second thought, cat litter may be a problem in zero-G. It ain't just the litter, Barry.

Bruce Betts: Yeah, don't want to meet a cat floating around in zero-G. But I will. I should remind people these are stuffed animals.

Mat Kaplan: Zero gravity indicators, right?

Bruce Betts: Snoopy at least will be performing a critical function, which is okay, not critical, but looks cool, flying on camera when they get in the micro gravity as opposed to not.

Mat Kaplan: Robert Laporta in Connecticut reminds us that Snoopy has been flying since Apollo 10. That was the Snoopy command module. We also heard from a bunch of people about the time that Snoopy spent on the space shuttle. I think it was STS-30, I think. Joe Calaputra, New Jersey. Sparky would be proud and Wallace and Gromit can give pointers on where to land. Sparky was Charles Schultz's nickname, the father of Peanuts, of course, and therefore Snoopy and Wallace and Gromit, did you see the one where they go to the moon?

Bruce Betts: Yeah.

Mat Kaplan: I think because Wallace loves cheese.

Bruce Betts: Exactly, in the moon, cheese, yeah. It lacks realism, but it's very entertaining. That at least is a joke. I'm disturbed when they throw the ball up and it doesn't come back down.

Mat Kaplan: It's made of flubber. PlanRad poet laureate, David Fairchild, surprised me with word that one of Sparky's pen nibs is also going to fly on Artemis 1. By the way, I highly recommend the Charles Schultz Peanuts Museum and ice skating rink in Santa Rosa, California. It's a fun place.

Bruce Betts: Oh my gosh, that's amazing.

Mat Kaplan: You knew about this.

Bruce Betts: No.

Mat Kaplan: Charles, Sparky was a huge ice hockey fan. He used to love to play ice hockey.

Bruce Betts: I would love that. And yeah, Snoopy's been going, doing space for a long time. He's also the representative of safety. They give out Snoopy pins for people who demonstrate a particular safety in their mission and maybe they'll fly your headphone, some day.

Mat Kaplan: I'd like that. I'd rather they take me and I'll leave my headphones behind. Related to that though, Gene Lewin in Washington informed us that the Girl Scout space science badges that are on board will go to a bunch of lucky Girl Scouts. And here's a poem from Gene that mentions other passengers. A Shropshire Lamb by name of Shaun, on Artemis he'll ride along, with Snoopy once a World War ace will travel to the realm of space. Traveling in Lego style two crew mates join named Kate and Kyle and Phantoms from the DLR passenger Helga and Zohar, together this eclectic troop in a distant retrograded loop.

Bruce Betts: Nice way to work in retrograded.

Mat Kaplan: Yeah. And the phantoms, of course, those are the two mannequins. And did you know that there are little Lego mini figures on Artemis 1 inside the Orion capsule? They stole another idea from The Planetary Society.

Bruce Betts: Yeah, no, I knew that they've been getting around since they flew in two dimensional form with us on Mars Exploration rovers on our DVD that we flew with NASA. But they also are hanging out at Jupiter on Juno. They've got some Lego mini figures on there as well.

Mat Kaplan: Oh, I didn't know that. I got one only one more. Paul Bergal in New York. The only countdown I'm not looking forward to ending is the countdown to Matt's retirement. Since the mission was scrubbed, maybe we can convince NASA to throw in a Lego planetary radio announcer figurine that would be a fitting sendoff. Well, once again, that's fine with me, Paul. Thank you. But I'd rather go myself.

Bruce Betts: Yeah, probably easier to get. Yeah. Okay. We'll work on that Matt.

Mat Kaplan: I hear there's no life support provided in Artemis 1 as Orion Capsule, so maybe I should reconsider.

Bruce Betts: Yeah, you should probably should wait on Artemis 1. Maybe you'll, anyway, but a Matt mini figure is a lovely idea. We had many figures produced for the Mars Exploration Rovers through our partnership with Lego, named them through a contest Bev Starling and Sandy Moon Dust, I can see just Matt Kaplan being the next in line.

Mat Kaplan: I'd be happy to join that group. You got a new one for us?

Bruce Betts: I do, I do. And this is throwback to Deep Impact, which slams something in at high speed. But to a comment, what is the approximate diameter of the crater that Deep Impact made when it impacted Comet Temple one. So it's approximate, but little tip for those hearing it on the radio. There's a later spacecraft that flew by that got the best estimate, use that. Go to planetary.org/radio contest.

Mat Kaplan: Very cool. You have until the 28th, That would be September 28th, a Wednesday at 8:00 AM Pacific time. How about this? Because we had a lot of interest in this when I mentioned it. One of those voyager Neptune and encounter medallions that The Planetary Society had made, struck, I guess is the right term, will be, we'll go to the winner.

Bruce Betts: Are you going to sweat on it?

Mat Kaplan: No.

Bruce Betts: Makes it more valuable.

Mat Kaplan: Yeah, sure it does. Yeah. A little DNA. We're done. Can you get us out of here? This has been extraordinarily long, but I had a good time.

Bruce Betts: I did as well. And maybe you'll actually trim it up a little bit. All right everybody go out there, look in the night sky and think about what you would name the asteroid that you slammed a spacecraft into. Thank you and goodnight.

Mat Kaplan: [inaudible 00:52:10]

Mat Kaplan: Planetary Radio is produced by The Planetary Society in Pasadena, California. And it's made possible by its impactful members. You can add to our momentum at planetary.org/join. Mark Hilverda and Ray Paoletta are our associate producers. Josh Doyle, composed our theme, which is arranged and performed by Pieter Schlosser. Ad astra.