Planetary Radio • May 10, 2023
The case for saving VERITAS
On This Episode
Professor of Astronomy at Mount Holyoke College, Deputy Principal Investigator for NASA’s VERITAS mission
Chief Scientist / LightSail Program Manager for The Planetary Society
Planetary Radio Host and Producer for The Planetary Society
NASA's VERITAS mission to Venus is currently on an indefinite hold. Darby Dyar, Deputy Principal Investigator for the mission, joins Planetary Radio to share the human story behind the spacecraft. She provides an insightful overview of the mission's background, its intended scientific contributions, and how listeners can help advocate for the mission. Then Bruce Betts guides us through upcoming night sky events and looks forward to asteroid Apophis' close flyby of Earth in 2029.
- VERITAS, NASA’s Venus mapper
- Why we need VERITAS
- The Planetary Society, American Geophysical Union, and Prominent Academic Institutions Call on Congress to Save VERITAS Mission to Venus
- Digital Day of Action 2023 - Prep Rally
- What happened with Psyche? A first-hand account from JPL Director Laurie Leshin
- Planetary Science Decadal Survey: After the Red Planet, an Ice Giant
- The Night Sky
- The Downlink
This Week’s Question:
What will the OSIRIS-REx mission be renamed when it starts its new mission to the asteroid Apophis after it drops off its asteroid Bennu sample at Earth?
This Week’s Prize:
RedSky Core Rule Book from Solar Studios.
To submit your answer:
Complete the contest entry form at https://www.planetary.org/radiocontest or write to us at [email protected] no later than Wednesday, May 17 at 8am Pacific Time. Be sure to include your name and mailing address.
Question from the April 26, 2023 space trivia contest:
Put the following five launches or public releases in chronological order from oldest to youngest: Mars Curiosity rover, Planetary Radio, Minecraft, Mars Odyssey, and iPhones.
Mars Odyssey, Planetary Radio, iPhone, Minecraft, Mars Curiosity Rover.
Last week's question:
What's the official name or the official designation for NASA's toilet on the International Space Station?
To be revealed in next week’s show.
Sarah Al-Ahmed: Making the case for saving VERITAS this week on Planetary Radio. I'm Sarah Al-Ahmed of The Planetary Society with more of the human adventure across our solar system and beyond. This week, we have a very special guest, Darby Dyar, the Deputy Principal Investigator on NASA's VERITAS mission to Venus, which is now on an indefinite hold. Darby will share the story behind the spacecraft, the foundational science that it hopes to achieve, and how you can help save the mission. Then, we'll kick it over to Bruce Betts for What's Up? He'll let you know what to spot in the upcoming night sky, take a look back at this week in space history, and we'll wrap up with our space trivia contest. But first, it's time for some space news. Environmental groups are suing the United States Federal Aviation Administration over SpaceX's Starship launch. The lawsuit argues that the FAA failed to fully assess the environmental impacts of the Starship launches from Boca Chica, Texas. It cites as an example the April 20th launch that scattered debris over Boca Chica State Park. The launch created plumes of material that spread 10 kilometers or 6 miles and caused a 3.5 acre wildfire. SpaceX says that it's taking measures to prevent similar debris in future launches. Our Chief of Space Policy, Casey Dreier, discussed this turn of events with environmental expert, Eric Roche, in our most recent space policy edition of Planetary Radio, which came out on May 5th. If you are a fan of the beloved Voyager spacecrafts, we've got some great news. Voyager 2's lifespan has been extended thanks to engineering ingenuity. The spacecraft launched in 1977 and is now in interstellar space. It has very limited battery power remaining and was facing possible shutdown, but mission engineers found a way to reroute power to science instruments from a non-essential voltage regulator. This could potentially extend the spacecraft's lifespan by three years to 2026. Meanwhile, back on Earth, plutonium, which powers missions like Voyager, is in short supply. Missions that travel far from the sun need nuclear power rather than solar power to operate, but the particular isotope that these generators use, which is plutonium-238, is very difficult to produce. Only about 1.5 kilograms or 3.3 pounds of plutonium-238 is produced in the United States each year, and this won't be enough to power all of the planetary science missions planned for the next decade. NASA is developing more efficient power technologies, but the agency has had to scale back on these efforts due to budget cuts. It's a conundrum, and what happens when you combine a global pandemic growing competition from the private sector and a never-before-seen mission? In the case of NASA's Psyche mission, you get a delay. When Psyche missed its launch date in 2022, it set off a chain reaction of delays and cost overruns on other missions led by the Jet Propulsion Laboratory, including the indefinite hold on the VERITAS mission, which we'll be discussing shortly. Laurie Leshin, who took over as JPL director around the time that this was all happening, shared her insights with us on the myriad causes that contributed to the situation and what she's trying to do to right the ship. You can read that interview and get more information on all of these stories in the May 5th edition of The Planetary Society's weekly newsletter, The Downlink. You can read it or subscribe to have it sent to your inbox for free every Friday at planetary.org/downlink. Now, you may have noticed that in recent decades, there's been an absence of NASA emissions to Venus. Earth's enigmatic neighbor is shrouded in thick clouds and scorching temperatures, and despite its relative proximity to Earth, there's a lot of fundamental questions about Venus that remain unanswered. We need to know more about its geologic history, its atmospheric composition, and whether it once harbored water or even life. The lack of missions to this world has hindered scientific progress, leaving us with a limited understanding of the planet's evolution and potential habitability. That's where NASA's VERITAS mission comes in. VERITAS stands for the Venus Emissivity, Radio science, InSAR, Topography, And Spectroscopy mission. It was designed to address these gaps in our knowledge by mapping Venus's surface and collecting data on its geology, topography, and atmosphere. The mission aimed to help scientists unravel the planet's mysteries and compare its geological processes to those on Earth. Unfortunately, in November 2022, NASA announced that the VERITAS mission would be put on hold. This delay not only sets humanity back in the timeline for gathering crucial information about Venus, but it's also having devastating impacts on the VERITAS team and its international partners. That's why in April, The Planetary Society teamed up with the American Geophysical Union and several prominent academic institutions to call on the US Congress to save the VERITAS mission. Our guest this week is Dr. Darby Dyar, the Deputy Principal Investigator on the VERITAS mission. She's a professor of astronomy at Mount Holyoke College in Massachusetts, USA. Darby specializes in planetary science with a focus on understanding the distribution of elements throughout our solar system. She's published over 260 scientific papers and won numerous awards for contributions to her field. Darby has spent time studying the moon, Mars, and asteroids, but Venus, among all of these beautiful worlds, is a target that she's had her sights on for decades. Hi, Darby. Thanks for joining me on Planetary Radio.
Darby Dyar: Oh, so happy to be here.
Sarah Al-Ahmed: The United States has not been back to Venus with a big mission since Magellan in the 1990s, and I was so pleased when NASA announced it, I think it was two years ago now, that we were going to be having two big major missions go out to Venus. It feels like now is the perfect time to do that, and then we had this beautiful moment where the Decadal Survey doubled down on those priorities, told us that going to Venus was something that we should be doing. So I was on a Venus hype train right up until the moment that I found out that VERITAS was on an indefinite hold. A lot of people when they hear a space mission is delayed, they can shrug it off, but this is more than about a spacecraft. This is a human story that I feel like you are uniquely situated to tell. So how did you find out that the VERITAS mission was going to be on this indefinite hold?
Darby Dyar: Well, let me backtrack and go back to the beginning. I started graduate school in the fall of 1980, and at that time, the US had a big mission plan to Venus called Venus Orbital Imaging Radar. It was a bonanza mission, Christmas tree, many different cool Venus Instruments, and so the first course I took in graduate school was about Venus. I, at that point, bought the Venus t-shirt also and became emotionally involved in Venus. Soon thereafter, I experienced my first political disappointment of my career as a scientist, which is that Ronald Reagan got elected and VOIR was canceled. At that point, I decided, "Okay. I'm going to do my thesis on lunar samples, and maybe I'll work on meteorites for a while, and maybe the pendulum will swing back, and someday I'll get to work on Venus again." So, in the meantime, I did all of those things. I was part of the Curiosity Rover Science Team. We built part of the rover at Mount Holyoke College, but all of that time in my heart, I carried VERITAS. So the story goes 12 years ago, we started working on this, at least the precursor to this mission, and we've been working on it really hard ever since. So, as you said, to find out two years ago that we got selected was a pivotal moment in my career. So, fast-forward, 18 months after that, I was actually at a conference in Houston at the Lunar and Planetary Institute about lunar samples, and I got a phone call from the PI, Sue Smrekar, who said, "Call me." I was like, "Okay." So I stepped out in the hallway and called Sue, and she said, "Darby, we're in trouble. They are going to put us on indefinite hold or maybe even cancel us." So there I stood in the hallway with tears streaming down my cheeks. I was speechless. We were completely blindsided. I didn't know what to say. You hear in books about people working on something for a decade and finally having it happen, and so I always thought that that was our fairy tale, and to have the rug pulled out from under us after a decade of working on this thing was heartbreaking is the only word I can use.
Sarah Al-Ahmed: Yeah, and not only have you been working on this for so long. I know that this was going to be the cherry on the sundae of your career. You were hoping this was going to be your last big mission before you retired, right?
Darby Dyar: Well, and it will be my last big mission before I retire because I just turned 65. So, at this point...
Sarah Al-Ahmed: Congratulations.
Darby Dyar: Thank you. We're not even going to launch until... Right now, headquarters is telling us that without action from Congress, we will launch before 2031. So, in 2031, boy, do the math, I'm going to be old. So, yes, I will go out on this mission, and I have personally come up with some new strategies for how we're going to interpret orbital data from the spectrometer on VERITAS, and so darn it, I'm going to hang in here on this mission because I want to see my algorithms and my ideas come to fruition and make the first composition map of the surface of Venus. So I'm going to hang in there, but no, it's heartbreaking. I was planning to retire to my house on the coast of Maine and watch the fishing boats go by. I guess I'll be watching the fishing boats go by and watching a screen that has Venus images on it. So it is what it is.
Sarah Al-Ahmed: Yeah. I think something that's also really important for people to understand about this is that this mission was postponed or put on an indefinite hold for no fault of its own. Your team was on budget, you were on time, but I'm sure as everyone is well aware, we've been through this really difficult period the last few years. The COVID pandemic had all of these knock-on effects, and that wasn't the only reason why other missions at NASA were delayed, but primarily, the Psyche mission got delayed a little bit, and that caused this knock-on effect. It caused this delay to VERITAS, and your team did absolutely nothing wrong. That feels a little unprecedented.
Darby Dyar: Yeah. In my life. I try to always say, "What could I have done differently to affect a better outcome?" In this situation, there's nothing that anyone on the VERITAS team could have done to affect a better outcome, and that's another part of this that is really hard to accept. The other thing is that it's been a gradual trickle of information from headquarters. Initially, they told us, "Okay. Because of the Psyche issues and because of budget issues, we're going to stand you down." Then, the next thing we knew a couple months later, it was like, "Oh, yes, and also, we aren't going to stand you up until Mars sample return is on budget and Europa Clipper is in good shape. Oh, by the way, we also want you to deliver this piece of equipment to India." So, over a period of months, headquarters kept adding additional heartbreaking conditions to this, so that was very difficult. As a scientist, you always want a clear explanation, and had they been able to give us that, I think maybe it would've been easier to accept this. It's just unclear to us the fact that two years ago, we had $811 million in the budget, and now we have $1.5 million times 5 years. So there's no paper trail, no accounting of exactly where that money went, and that just... They're not trying to make it hard on us, but it just makes it that much more difficult emotionally to deal with.
Sarah Al-Ahmed: Yeah, and that money doesn't just go to actually building the spacecraft, it goes to retaining the teams that build and work on this spacecraft. I'm sure this has had a deep impact on everybody who was a part of this team.
Darby Dyar: Well, of course, because another thing that was handled poorly was that when we found out, when I was sobbing in the hallways in Houston, the foreign partners who were contributing $90 million to this mission were also told at the same time, and they are in a difficult bind because the European Space Agency is committed to a follow on Venus mission called EnVision. By pushing VERITAS back, NASA is forcing those partners to do two missions at the same time, which they cannot do. So what's ended up happening is that the foreign partners are going ahead on schedule because they all have their money, but we're in this really awkward situation where imagine building something to go on a spacecraft and not having anyone in the US to talk to about the spacecraft. It's a very, very difficult situation for our foreign partners, and those people, of course, are my friends, so it's doubly difficult for me.
Sarah Al-Ahmed: Did you have enough information that they can work from, or is it going to be a situation where they might alter some things on accident because of lack of information that will later impact the spacecraft when you actually have to finish everything?
Darby Dyar: Well, of course, yes, we're terrified of that. Anytime you push a mission back, you induce risk because certain components that you might already have purchased become less useful as Dan Cosan. NASA did give us a small amount of money to stand down, and we've spent most of that money in the stand-down period trying to do the best we possibly can to interface with the foreign partners and make sure that they have the information that they need. So, as a team, we're trying really, really hard to make sure that our colleagues, and friends, and partners in Europe are going to be as little inconvenienced by this delay as possible, but it's hard.
Sarah Al-Ahmed: There's also an extra thing on this, which is that not all of these things are built just by the space agency. They have outside contracts that you have signed. There are some consequences when you try to pull out of these contracts. As I was learning about what was happening with your international partners, I realized they're not pulling out of those contracts. They're going full steam ahead. So it's going to be a very interesting situation if they find themselves in a space where that mission gets ultimately canceled.
Darby Dyar: Absolutely. NASA will lose a lot of good faith. I mean, it's already awkward for me as a US citizen to hang out with my friends in Europe now because I'm terrified that we're going to let them down, and NASA has been unable to give any of those foreign agencies a guarantee that this mission will go. So we teeter between being worried about being canceled and being worried about only delayed. It's a tough period for us on the team.
Sarah Al-Ahmed: Thanks for sharing that with us. I know it's a very emotional subject, but they're...
Darby Dyar: I've got tears in my eyes.
Sarah Al-Ahmed: Yeah, but there is hope. I don't want to make it sound like this is absolutely going to be canceled because you have the support of all of us here at The Planetary Society. We are going to try everything we can to try to get the mission the funding that it needs because it's important. We haven't even begun to touch, really, on what the spacecraft is going to do, so I think we should let everyone know. We need to make the case so everyone knows why they should give their time to advocacy for this because the things we could learn from VERITAS are mind-blowing and it's unique. There are many missions about to go to Venus, but what this spacecraft does is pivotal in the structure of all that we're trying to learn. Why don't we go into this from the very beginning? What are the main mission objectives for VERITAS?
Darby Dyar: In planetary science, it's a typical progression that when you start to explore a body, one of the first things you do is do a topography map because regardless of whether you're going to do some kind of orbital measurement in which you need to know where the high mountains are or whether you're going to take pictures or do any other kinds of measurements, you need a topographic map. Quickly following on that, in most planetary bodies will come some kind of camera, so you can figure out what the surface looks like in whatever wavelength range you're able to make the measurements. Because we haven't been to Venus in 30 years, the data we have on Venus are nothing short of pathetic. Let's put it that way. We have better topographic data on Pluto, which isn't even a planet, than we do on Venus. We don't know the rock type on Venus. We have a few chemical analyses from a handful of sites that look like basalt, but that's like saying, "I'm going to walk out in my backyard and analyze the outcrop back there, and then I'm going to extrapolate that to all of Earth." That's just ridiculous. So VERITAS was really designed as the fundamental mission to take us to Venus and get us ready for whatever kind of exploration comes next, and the two fundamental measurements that we really need to make on Venus are what is the topography? We need to get the topography better than Pluto, and as good as Mars, we need to get good topography data on Venus. Then, secondly, we need to get some hint of what the rock type is. So those are the two big measurements, and we're going to cover the entire planet with these measurements many times over. So all of these data lay the groundwork for anything that can come after us, including potentially a Venus lander, which was proposed by the recent Decadal Survey as one of their possible flagship missions. We'd love to know more about what the atmospheric composition is so we can do orbital measurements even better. So those are the two fundamental measurements that we're making. Really, the two big instruments that we have, the radar, which will make topographic measurements, and the spectrometer, which will take specter of the surface.
Sarah Al-Ahmed: I think what's really cool about the radar in particular is that these kinds of synthetic aperture radars have only been used on Venus once in the Magellan mission, and I had a really great time talking with Robbie Herrick and Scott Hensley more recently about their paper, Recent Vulcanism on Venus. That detection was made with that synthetic aperture back 30 years ago, and I can't even imagine with the new resolution on this instrument how much more information we could get about the surface of this world. What's the resolution on this thing?
Darby Dyar: Topography is 5.9 meters vertical resolution, 250 meters horizontal. The SAR imaging will be 30 meters resolution. In certain places, we'll have targeted data sets where the SAR imaging will be 15 meters. We'll be able to look at surface deformation of 1.5 centimeters of vertical. So imagine what we're going to see with the radar alone. It is mind-boggling.
Sarah Al-Ahmed: I know too that it's not an instrument necessarily, but you're also going to be getting gravitational information about this planet as well as you're orbiting, right?
Darby Dyar: Right. So another of the big mysteries that persevered ever since Magellan is the whole question of how does Venus resurface, and how does Venus lose its heat? In order to answer those two questions, we need to understand the thickness of the crust and where heat is flowing out of the planet. As part of that, we will also determine the size of the core in its state, whether it's liquid or solid, from these gravity measurements. So, again, it's fundamental measurements. In any science, it seems that fundamental measurements should come first before you do all the other exciting things, but they are the foundation on which all subsequent Venus research must rest.
Sarah Al-Ahmed: I'm hoping that by learning more about the internal structure of this world, we can learn a little bit more about its magnetic field In that situation. Having a planet like Venus with such a thick atmosphere, but no internal dynamo is so fascinating to me, and it also leads to more fundamental questions. We don't even know whether or not plate tectonics are a thing or what role that would play on Venus. There are so many fundamental mysteries about this world, and it's right next door.
Darby Dyar: Not only is it right next door, but of course, you have to recognize that Venus is similar to so many of the hundreds and soon, thousands of exoplanets that we're discovering. If we don't understand what Venus is doing, we can't hope to understand what's actually happening on exoplanets. I think Venus is the key to following the water in our solar system. If you're familiar with the Mars program as I am, you know that for many years, the slogan for the whole Mars program was "Follow the water and find the life." That was what we were doing. But in the last five years, it's become obvious to everyone involved that Mars only had liquid water for 300 million years compared with Venus' liquid water which was, by some estimates, as much as 3 billion years. So if you're going to look for life elsewhere in the solar system, Venus seems to me now the logical place to be looking for it. So Venus is so important in the light of that habitability discussion because if indeed there was liquid water and if indeed there were to have been life developed during those 3 billion years, then that's a pretty good scenario for all those other Venus-like exoplanets that we're finding, and to me... I don't know. I always say as a professor that the most profound question you can ask in almost any class at college is, "Are we alone?" I think Venus might hold the keys to answering that question.
Sarah Al-Ahmed: I think you might be right. I mean, honestly, I've been steeped in planetary science and astrophysics my whole life. It was what I wanted to learn about. I always want to learn more about particularly the worlds than our solar system because they're so close at hand. But when I learned that Venus had potentially water on it for not just the hundreds of millions of years, but billions of years, maybe even 3 billion years, I was stunned. We're dedicating so much time to Mars and rightfully so. It's a fascinating world that deserves all of that research, but could there have been life on Venus? The conditions seem so much more good for it. I was stunned.
Darby Dyar: It should have struck me... I had the same epiphany myself about a decade ago. It should have dawned on me because when I teach planetary science, I always talk about how a solar system heats up as the star heats up and the heat wave moves out through the planets. So it stands to reason that yes, Venus is both close to Earth in terms of orbital and distance from the sun, which means it's compositionally similar. Yet, it's closer to the sun, which means it heated up earlier. So we now think that Venus was probably warm enough to have liquid water before Earth. So once you start putting together those very simple conclusions, you realize, "Oh my gosh, this is a place where we have to go," and I too love the Mars program. I am part of the Mars program. I think Mars is a really fascinating place, and it deserves all the, as you say, all the interest that people are giving it, but it may not be the place where we answer this fundamental question.
Sarah Al-Ahmed: What I'm wondering is what this mission can actually tell us about that history of habitability and how this world has changed over time. What are the measurements that we're going to be taking that will help us determine that?
Darby Dyar: Let's talk a little bit about plate tectonics for a minute. So Earth is the only planet that we know of that has plate tectonics on it currently. Yet, there are tantalizing hints on the surface of Venus that perhaps there are trench-like structures around the fringes of these large volcanic structures called corona. There are many scientists who have put forth compelling arguments to suggest that the trenches around the corona could be the nascent plate tectonics smoking gun on Venus. If that's the case, then plate tectonics is not unique to Earth. Why is that important? It's important because although we think about plate tectonics in terms of recycling crust, it's also recycling water, and plate tectonics has a very valuable role on Earth in helping to affect and influence our hydrologic cycle. So if there is plate tectonics on Venus, then that could have, both in the past and in the future, play a very important role in regulating how water is extracted from the planet. So that's a key question. So another thing that we'd really like to know that's related to plate tectonics, of course, is, is there active vulcanism? Now, if you heard the episode where you talked to Robbie and Scott, you know that we recently found in 30-year-old Magellan data evidence for pretty obvious volcanic eruption that suggests that volcanism was going on 30 years ago on Venus and presumably is still going on today. How will VERITAS deal with this? VERITAS has a lot of cool ways that we can do this. First of all, it can see the ground moving. Second of all, we can see the glow of a volcanic eruption. When there's heat and light being given off by an eruption, you can see that from orbit. The other thing that happens in an eruption, of course, is that gases are given off and VERITAS has spectral bands that can detect gases being given off. So VERITAS has many different ways of detecting change, not to mention radar pictures, which will presumably show the same kinds of changes that were detected by the previous paper, i.e. a volcanic vent opening up or the texture of a flow changing as it moves away from a vent. Those sorts of things.
Sarah Al-Ahmed: I know that a major challenge for that team when they were trying to figure out whether or not this volcanic activity was happening was mostly just that as they were going around this planet, they were getting different angles of vision on these locations. So it's difficult to see if there's actually been changes over time. Have you been connecting with that team to see if you can use similar technologies to actually see differences between your orbits in this data?
Darby Dyar: So they had three cycles of data acquisition on Magellan. We're going to have many, many more. So we will have many more opportunities and better viewing angles than they had with Magellan, so we will be able to see things in a much more straightforward way rather than doing all the modeling that had to be done with the Magellan data because of the limited angles of look that were available for that mission.
Sarah Al-Ahmed: With the higher resolution, I'm sure it will be much easier to tell if that's a difference in the light versus an actual difference in the topography. Forgive me if I'm incorrect about this because I'm not a geologist, but I remember reading that you can actually tell more about the water content of a world from the volatiles that are actually expelled from volcanoes.
Darby Dyar: Absolutely. Yes. I mean, VERITAS will look for water vapor. That's the predominant gas that we're looking for to help us detect eruptions. Although with respect to understanding the volatile budget, if you will, of Venus, I have to give kudos to our sister mission, DAVINCI, which is going to have an atmospheric probe that's essentially going to look at noble gases and gas composition as a function of altitude in the atmosphere. EnVision will give us complimentary and yet, different kinds of information about what's in the atmosphere now. So VERITAS is going to look for changes and unusual locations of water vapor in the atmosphere because we have the advantage of being global, whereas DAVINCI will go through in one place, and punch through, and make those measurements. So we're going to have these two great measurements that are going to give us different types of information that will answer the same kinds of questions.
Sarah Al-Ahmed: We'll be right back with the rest of my interview with Darby Dyar after this short break.
Rae Paoletta: Want to see humans on Mars by the mid 2030s? You can join the people working hard to get us there at the Humans to Mars Summit, once again, offered by our friends, Explore Mars. Humans to Mars happens May 16th through the 18th in the beautiful Washington DC headquarters of the National Academy of Sciences. You can learn more and register at exploremars.org. Planetary Society members, enter our discount code for substantial savings. It's Planetary Society Mars 2023, and say hi to Matt Kaplan if you attend. There's also a lot that we don't understand about just the basic chemical makeup of the surface of this world, and thankfully, you've got spectroscopy to help you out with that, but how much do we actually know about what's going on with the surface of Venus and its composition, and how much more could we learn through this mission?
Darby Dyar: Oh, of course. I'm a spectroscopist, so this is my baby. So let's begin with the fact that it's pretty obvious that much of the surface of Venus is covered with flows. They look like basaltic flows. We're confident from previous missions from the Soviet Union in the '60s and '70s that we have an idea that those are probably basalt, which should surprise no one since basalt is the predominant rock type in terrestrial bodies in the solar system. However, there are these very enigmatic terrains on Venus called tessera, and the tessera are these intensely-deformed, high-standing, topographically high-standing terrains, and there are multiple hypotheses for what formed them. One side says, "Oh, maybe those are remnants of some old giant basaltic lake where somehow the cooling crust coagulated in," one of my colleagues calls, "pond scum." So imagine pond scum on a basaltic lake. So one side says that the tessera are composed of basaltic composition rocks, and they're old, and broken up, and eroded, and they've been impacted. Another side says, "Oh, no. Those are actually old continents that still persevere." Therefore, by analogy with Earth, must be granitic, and if they are granitic, then on Earth, granites form in the presence of water, so all of these things tie together. Understanding the rock type to a geologist like me is the most important measurement we could be making.
Sarah Al-Ahmed: Which parts of the surface of Venus are older or younger, and what can that tell us about the way that the planet evolved over time?
Darby Dyar: So, without return samples, of course, we have very little way of understanding age, except through impacts, and the impact record on Venus is tricky to interpret for a couple of reasons. First of all, the thick atmosphere means that a lot of the little impactors don't make it through. They end up burning up. So we don't have quite the same distribution of crater populations that we do on other terrestrial bodies in our solar system. So that's part of the problem. However, we do know that if you look, and this was known as far back as the Magellan mission, if you look at the distribution of craters that we do see, they're actually quite rare on the surface of Venus and quite randomly distributed, which suggested both to the Magellan scientist and to most modern scientists that much of the surface of Venus, especially those basaltic flows, is all the same age or comparable age. When we say the same age to a geologist, that maybe doesn't mean the same as what it means to a five-year-old. It means it's within a couple dozen million years of the same age. So the surface is probably much the same age, but we also see impacts on those tessera. In fact, because they're so poorly exposed, it's difficult to say whether they really are older. Most of the information that we have about the tessera's age comes from the fact that the basalts seem to flow up into them, but not be able to flow over them, which tells us that the basalt came after the tessera, but how much longer after? We actually don't know.
Sarah Al-Ahmed: In order to actually send anything there to get a sample, it's going to have to survive the surface, and just doing that functionally is very difficult, but I can't even imagine trying to do that without a good topographical map of the whole planet. How do you even avoid landing on rocks?
Darby Dyar: Yes, that's exactly... I mean, the DAVINCI mission is bravely descending in an area of tessera, and lucky for them or cleverly by them, they did not guarantee that their probe would last after it landed, but we're hoping to get some insights into that from the DAVINCI imagery as they descend. But unfortunately, their spectroscope only has two channels as opposed to the six channels that we have on VERITAS. So I fear that we won't maybe get as much compositional information from the DAVINCI mission as I would want. But on the other hand, they're getting amazing data on the atmosphere, so. You can't have everything in one mission. That's why you have multiple missions going to Venus.
Sarah Al-Ahmed: Exactly. I'm wondering. Part of this is because we want to learn about the history of life in our solar system. We want to know if Venus was habitable at some point, and this mission is going to be doing things like looking for water content and all those other things, but you're going to need other missions like DAVINCI to literally test, like taste the flavor of the atmosphere, and see if there's things like maybe life. I know it's still a little contentious, this idea that there might be some kind of phosphine creating life in the atmosphere, but there's so much mystery here to be had, and you need all these missions working in coordination to really answer these questions. Otherwise, what if we get some kind of measurement and we can't interpret it because we don't have fundamental data? I think missing out on VERITAS is really going to impact these other missions.
Darby Dyar: We have 30 years of no missions to make up for.
Sarah Al-Ahmed: Yeah.
Darby Dyar: So you think about how many missions have gone to Mars or the moon in that period of time. We have a lot of catching up to do. I suspect we will ask more questions than we will answer, but man, are we going to answer a lot of questions?
Sarah Al-Ahmed: It's funny because I get a little frustrated about it. "Why are there so many missions to this, that, and the other thing?" Then, there's whole worlds like Venus, and Neptune, and Uranus that just don't have the dedicated missions that they need. Then, I just have to scale it back a little bit and remember that we're just at the beginning of this age of exploration. We haven't been back to the moon in 50 plus years, but we only just sent people to the moon 50 years ago. We're just starting out, and I have to be patient. That being said, delaying missions like this could have consequences on their own. What are the impacts if, say, we send this mission in 10 or 20 years instead of now?
Darby Dyar: Oh, so many consequences. The first one is the potential for obsolescence of some of our components. We started designing it 12 years ago. Obviously, every time we resubmitted it, we updated the technology that we were going to use, but the longer we push this off, the harder it's going to be to catch up in terms of components. Before we were told to stand down, we were already wheeling, and dealing, and making deals on components. It's unclear now, if we get pushed back by an additional three years, whether the components that we thought we wanted, which we couldn't, of course, pay for now, are going to be what we want. So there's a huge risk of obsolescence when you push back. There's also the risk of losing people. I'm a good example. Well, I'm an academic, so I'll never retire, but the same cannot be said of the professional staff who probably will retire, and that's another part of the heartbreak that seems to be the theme of my remarks here. The heartbreak of this mission is that we had just brought on a team of incredible engineers and support people at JPL. Really top-notch people excited about the mission, supportive of the science, wonderful people to work with, and then almost as soon as the ink was dry on their contracts, we had to let them go, and it's unclear because JPL has so many different commitments whether we'll get any of those people back. So obsolescence of technology, loss of senior people who understand the mission, and as I said, retirements. People like me and Scott Hensley who have been around a long time, we risk us retiring. So that's part of it. Then, the last part is that anytime you postpone a mission, things cost more. So we put in a budget, and like anything, if you budgeted for something, and then said, "Oh, no. You're going to have to wait 10 years before you can buy that thing," you quickly realize that you didn't have enough money, so every year that they push VERITAS back is going to cost more money. Of course, the delay also interferes with this beautiful progression that we had. VERITAS gets the fundamental data, makes the fundamental maps. Then, DAVINCI goes in with its eyes open to where it's going to go based on VERITAS's topographic data and spectroscopic data. Then, EnVision comes along from the European Space Agency. They look in more detail at some of the areas that we've flagged as being interested. There was supposed to be a nice long gap, like a 10-year gap between VERITAS and EnVision so that we could do change detection quite easily. So all of those things got thrown out the window when the VERITAS mission got stood down with this nebulous startup date of no sooner than 2031.
Sarah Al-Ahmed: Interesting too to me is that we're just at this beginning of understanding the broader populations of planets outside of our solar system, and you touched on this a little bit earlier, that a lot of the planets we're finding outside of our solar system are Venus-like in size. I think it's almost 50% of them are about Venus in size. Is that correct?
Darby Dyar: Yes, that's correct. Although you got to remember that that number is... You have to take it with a little bit of a grain of salt because there's an observational bias. The way we observe exoplanets mostly is by watching them pass in front of their stars. Obviously, the closer something is, the more often it passes in front of the star, and so there is a little bit of an observational bias there, but yes, that's true that of the exoplanets that have been discovered, close to half of them are Venus size.
Sarah Al-Ahmed: That's a little startling when you think of it in the context of using the transit method. The bigger a planet is, the easier it's going to be to find. So finding anything of Venus' size is necessarily more difficult. So the fact that half of them are Venus in size speaks to the fact that they're probably common, very common, and we're just beginning to analyze the atmospheres of exoplanets with JWST. I hate the idea that not understanding more about Venus could impact our understanding of the broader populations of exoplanets. That seems like it could impact our understanding for years to come.
Darby Dyar: Exactly, and to me, what's really fascinating about looking at exoplanets is in our solar system, we currently have this paradigm of the habitable zone, which currently is centered on where Earth is in terms of Earth distances from the sun, but few people take that analogy far enough to realize that the habitable zone is mobile, and it's a function of time. So when you think about our solar system, sure, the habitable zone is where it is now. But when you start looking at the observations that have been made for exoplanets, we don't know how old those stars are, and so we don't know exactly where those Venus-like exoplanets are in terms of their own habitable zones. So it's fascinating to think about the concept of habitability as being different in every solar system that forms because of the rate at which the star heats up.
Sarah Al-Ahmed: That also impacts the way that we think of our planet in the context of our solar system. I think of Venus as this beautiful case study or cautionary tale, if you will, about what happens to habitable planets when things go wrong. There is conceivably a history where that planet could have had life, could have had oceans, and been very Earth-like, but something went wrong, and now, it's a face-melting hellscape with acid clouds, and we do not want that to happen to Earth. I'm not saying that delaying a mission like VERITAS could impact and turn Earth into Venus in the short-term, but we want to understand more about how planets change over time so we can protect ourselves and look for habitable worlds elsewhere.
Darby Dyar: It all goes back to the two recurring themes in this conversation, heartbreak and fundamental. Fundamental data, to me, are the key to understanding not just global. As a geologist, I always think about global processes, but universal processes, which is how I think about as an astronomer. So understanding the fundamentals of how planet habitability changes over time is such an important question in astronomy. It's critical that we get moving on this as soon as possible by studying Venus and understanding what it has to tell us.
Sarah Al-Ahmed: When we're looking for life in the universe, people come back to this idea of the Drake equation that helps us calculate how long intelligent creatures could be around, how many of them are out there, and we always think of what the actual species are doing themselves, how that could impact their longevity, and whether or not we discover them, but there's this great mystery to how long planets remain habitable. We don't really know, and knowing that a planet like Venus could have changed, that could be a huge piece in this mystery. Maybe it's not the alien's fault.
Darby Dyar: Well, eventually, our sun is going to continue to heat up, and eventually, Earth will become a hot enough place that our atmosphere will boil off, and then it will no longer be a very nice place for whatever kind of life forms exist, but I don't think that's going to happen tomorrow, luckily. I have a side anecdote about this. So when my daughter was five years old, she started, for weeks on end, crying herself to sleep every night, and we couldn't figure out what the problem was. Finally, she told me tearfully one evening that she was worried that our star was going to explode and that the Earth would burn up while she was sleeping.
Sarah Al-Ahmed: Oh.
Darby Dyar: In order to convince my daughter that this wasn't going to happen soon, I had to bring home a textbook and read it to her where it says yes, in 6 billion years, the Earth will burn up because our star is going to explode. Only then was she able to get to bed at night and not worry. So I don't think that's going to happen to Earth anytime soon, but it is interesting to see the progression of chemistry that happens when the atmosphere starts to heat up, and the sun starts to heat up, and the environment changes. From that, we will get fundamental data which will inform how we lessen and mitigate the climate change things that are happening on Earth.
Sarah Al-Ahmed: Exactly. Happily, this is not the end of the tale. While the situation is a little...
Darby Dyar: Dire.
Sarah Al-Ahmed: Darby Dyar. Sorry to make that joke. We still have a chance to change this, and we've been working very hard in our advocacy efforts at The Planetary Society to try to support this mission, and I'm really happy to share that over a thousand people in the United States written their congress people to try to advocate for this mission because we believe it's important. So what are you hoping would be the outcome? What can Congress do to save this mission?
Darby Dyar: First of all, let me say on behalf of the team, many of whom are unable to lobby because they are federal employees. But on behalf of those who can speak, I want to say that we are so grateful to everyone, especially including The Planetary Society, for reaching out and helping us advocate for this mission. It's one thing to be a heartbroken scientist, but to know that you're a heartbroken scientist supported by a community of people who believe in science is incredibly inspiring, and it really made all the difference in this battle. I personally went to Washington and visited over 105 congressional offices myself. I wore out some shoe leather in the process of doing that and was aided in that by Jack Kiraly of The Planetary Society, and it was really inspiring on those visits to find out that most of the congressional people support NASA. People are really interested in Venus, excited about what NASA is doing, understand on both sides of the aisle that scientific exploration and fundamental science of the sort to be done by VERITAS is something that everyone wants to do. So that's been quite heartwarming to know that, to know that we're supported by people. However, the battle isn't over. We went to those congressional offices and asked for some specific authorization language in support of launching VERITAS in 2029. So I won't have quite as much white hair by the time it launches myself. If we launch VERITAS in 2029, we'll still beat EnVision and DAVINCI to Venus, and we'll be able to support them in ways that are useful. So launching VERITAS in 2029 is the goal of our public relations campaign, and if people want to sign on to this petition, all they have to do is go to The Planetary Society website, planetary.org/action, and you can sign onto the petition. I thought it was pretty cool. You just put your name and address in it, figure out who your Congress people are, and it writes to them for you. It's a really good tool you guys have, so.
Sarah Al-Ahmed: Oh, I'm so glad. I love anytime I go in there, I have to activate myself to take the next step of action. Then, I get in there, and one minute later, it's already done.
Darby Dyar: Yep, yep.
Sarah Al-Ahmed: I love how easy that is. Also, I want to say that if you live outside of the United States, you can also support this mission. I know we're talking about this in a very US-centric, NASA-centric way, but there are many international partners working on this, and you can help out by going online and sharing the #SaveVERITAS. Every little bit helps, and hopefully, if we get enough people talking about this mission, we can get enough mobilization to save it.
Darby Dyar: I wake up every morning thinking about this and hoping that the authorization language will come out to get us launched in 2029. I'm hoping that it will happen. I've waited my whole career for it, and I can't wait for this mission to get off the ground.
Sarah Al-Ahmed: I still have hope in my heart. I think we can do it. Together at The Planetary Society, we have helped save countless missions, and it's not just about us as an organization, it's about the true love that people have for space exploration, how they know that it brings out the best in us and helps us collaborate with people across the world. These things are important, and it's easy to mobilize people to do it because there's no downside. It's just pure awesome science and love of where we are in the cosmos. I love that.
Darby Dyar: I'm with you. I have to say that I'm a scientist. I didn't even know who my local congressperson was. I'm embarrassed to say I had to look it up. I am focused on science as only a quintessential geeky person can be, and so it's been very illuminating to me to understand that actually, science is enabled by a whole group of people who aren't scientists, but still are as excited as I am about what we're doing. I find that incredibly inspiring. It's great to know that there's a fleet of people standing behind us wanting us to get this mission to Venus.
Sarah Al-Ahmed: Absolutely, and I always feel that way whenever I gather with Planetary Society people. We're not just an organization of scientists. It's literally people of all ages, all walks of life who just love space, and they should. It's awesome and always, always inspiring to meet them, and even more inspiring to see them take action, and through that, learn more about how they can take steps to support the things that they love. Just like you, many people I talked to during our Digital Day of Action last month told me that this was the first time they'd ever done anything like that, writing their congressperson, and it's easier than you might think. So, hopefully, it helps empower people not just to support this mission, but to support the things that are important in their lives to them.
Darby Dyar: It's certainly easier than what I was doing, which was cold calling, walking by myself into a congressional office and saying, "Hi. I'm Darby Dyar. I'm a Venus scientist. I want to talk to you about this mission, VERITAS, which has been put on indefinite hold." That was very hard for me to do 105 times, but I did it because I believe in this mission, and the response, as I said, was amazing. So everybody wants NASA to do well, and they want space exploration to happen, and they want the human condition to be illuminated as only it can be by thinking about it from an extraterrestrial perspective. So we feel so supported by The Planetary Society and are really grateful for the petition and the ability to make our problems known and hopefully, our inspiring science also known so that other people can get as excited as we are.
Sarah Al-Ahmed: No matter what the outcome is, whether or not we manage to save VERITAS or not, I want to thank you and the rest of the team for putting so much thought and effort into this beautiful mission. Whether or not it flies now or we have to wait another 10 or 20 years and rebuild the thing, it will happen, and it's going to be amazing.
Darby Dyar: We'll get there, and God willing, I'll be on the mission.
Sarah Al-Ahmed: Yes. Well, thank you so much, Darby, for joining us, and sharing your very human story, and letting everybody know why they should get behind this mission because I know I'm very passionate about this, and I think a lot of other people just became huge VERITAS fans.
Darby Dyar: Go VERITAS.
Sarah Al-Ahmed: My conversation with Darby Dyar is a poignant reminder of the dedication and tireless efforts that thousands of people invest in every space mission. It's easy to overlook the human element behind each instrument and piece of bent metal, but these spacecraft carry the dreams and aspirations that drive scientists and engineers to push the boundaries of human knowledge. The Planetary Society's members have a remarkable history of working together to save space missions over the last four decades. I'm so grateful for every person who's helped support our campaign to save this mission, and I really hope that by working together, we can put VERITAS on that list. Now, before I start ugly crying about spacecraft, let's check in with Bruce Betts, the Chief Scientist of The Planetary Society, for What's Up? Hey, Bruce.
Bruce Betts: Hi, Sarah.
Sarah Al-Ahmed: What do we have to look forward to in the night sky this week, Bruce?
Bruce Betts: Oh, there's good stuff. You just keep mentioning Venus. Well, not even that low on the west after sunset. Super bright. We've got Mars significantly above. Well, above Venus. We've got some interesting things coming up in the evening sky. Mars is in line with the twin stars of Gemini, Pollux and Castor, on May 15th, making a neat, even roughly, evenly spaced line, and Venus is down below them. On May 23rd, the crescent moon is near the star Pollux, our friend in Gemini, and between reddish Mars above and super bright Venus below. So you got a nice, top going down, Mars, crescent moon, Venus with Castor and Pollux hanging out in Gemini. That's the 23rd. Then, we go to the pre-dawn sky. You got Saturn up getting pretty high looking yellowish. Jupiter, our friend Jupiter, the second brightest star-like object in the night sky is starting to come up. It's really low though, but if you can see it on May 17th, the crescent moon is hanging out very close to it in the pre-dawn east on the May 17th, but again, you'll need a nice view low to the horizon and just not long before dawn. We move on to this week in space history. It was the last mission of the US Mercury program was this week in 1963. Gordon Cooper flew in Faith 7 with 22 orbits around the Earth before splashing down. Lots other good stuff happen, but I'm excited to get us along to the...
Sarah Al-Ahmed: This must be exciting. What have we got this week?
Bruce Betts: Well, what's exciting is this week, shortly after this episode comes out, actually, right around then, there is an Apophis workshop. T-minus six years for the asteroid Apophis until it flies by on April 13th, 2029 closer than geostationary satellites. That's about a 300-meter asteroid. We've talked about it before. We'll talk about it again. I want to point out that it will be traveling, if you're one of the places that can see it, which is parts of Europe, Africa, Western Asia, at that time, it will be moving along, clipping along at a little more than one lunar diameter per minute.
Sarah Al-Ahmed: Wow.
Bruce Betts: One lunar diameter per minute. It's supposed to be roughly magnitude three at its brightest. That would be easily visible from a dark site, reasonably visible from a suburban site, and could be challenging from a bright city site, but with binoculars, you can pick it up. So anyway, get ready. Six years to go. Apophis. It will not hit us then. It will not hit us in 2036. It will not hit us for at least a hundred years, probably more, but it is the closest flyby of an asteroid this size in recorded history, so a lot to learn. We'll come back to that in the trivia contest in a little bit.
Sarah Al-Ahmed: It's funny because we're all about making sure that asteroids and comets don't get too close to Earth, but this is one of those moments where I'm actually really excited for an asteroid to fly by, in a way, that's visible for people to see because I think it's going to spark all kinds of interesting conversations and hopefully, a renewed interest in planetary defense because people are not... They do not understand. This is about to be the only thing people are going to talk about six years from now.
Bruce Betts: You heard it here on Planetary Radio. We move on to the trivia contest. I said the following five things are still going or working. Put them in chronological order from oldest to youngest with spacecraft starting with their launch data and for others, the first public release. So we had Mars Curiosity Rover, Planetary Radio, Minecraft, Mars Odyssey, and iPhones, and we do.
Sarah Al-Ahmed: A lot of people got this right, although people suggested some things that I did not see coming with this one. So I'll get into that in a moment, but the answer goes in this order. First, we have Mars Odyssey in 2001, then Planetary Radio, our favorite, in 2002.
Bruce Betts: Yay.
Sarah Al-Ahmed: The iPhone. This was an interesting one. iPhone came out in 2007. Then, Minecraft. That was 2011, and then literally, just a few days after Minecraft launched, the Mars Curiosity Rover launched. So people got those two a little bit back and forth, but that is the correct order.
Bruce Betts: Did they go into... Anyway, Minecraft has a more complicated history, I believe, but go ahead.
Sarah Al-Ahmed: Well, that's true. Yeah. I was actually one of the first testers on Minecraft back in the day on Reddit.
Bruce Betts: What?
Sarah Al-Ahmed: Yeah, back when Notch was just posting stuff on Reddit asking randos to help out with Minecraft Alpha.
Bruce Betts: You were a Minecraft Alpha rando? Congratulations.
Sarah Al-Ahmed: Yeah. I love that game. My little sister is very passionate about Minecraft, but our winner this week is Aquiel Gado from Los Angeles, California, USA. I love this because we always ask people how to pronounce their names when they send in their trivia answers, and this week, this person wrote in, "Aquiel as in the Star Trek episode." I had to think about it for a second, and then it is. It's an episode in Next Generation. My question is this, was Aquiel named for the episode, or is this just a crazy awesome happenstance?
Bruce Betts: You'll have to ask Aquiel.
Sarah Al-Ahmed: Right? You'll have to write in and let us know when I let you know that you won the prize.
Bruce Betts: Well, that's pretty cool.
Sarah Al-Ahmed: But John Guiton from Samford Valley, Australia wrote in to ask us whether or not you were talking about Apple's iPhone or Cisco Systems' iPhone. Apparently, both products, and they had a very similar name.
Bruce Betts: Did they come out at similar times?
Sarah Al-Ahmed: They did. Although, there's the testing phase of Cisco Systems' iPhone. I think it rolled out a few years earlier for testing, but then officially came out a few months before Apple's iPhone, and it's very different. This iPhone was one that you could use to call people around the world on Skype and things like that.
Bruce Betts: Oh, yes. No. I apologize. I was unaware of that one. I meant Apple iPhone, but I would accept any answer that was backed up by justification.
Sarah Al-Ahmed: Right? I had no idea, but the more you know. This was another thing that I didn't know. So the prize for this week is a Planetary Society beanie. What I didn't know is that our friends in Canada don't always call this type of hat a beanie, and I did confuse a few people out there. So just in case anybody is wondering what a beanie is, it's a type of really comfy hat that you pull over your head and over your ears. In some places in Canada, I believe they call it a toque.
Bruce Betts: Toque?
Sarah Al-Ahmed: Fool of a Took. Another really cool thing that happened this week is every once in a while, people will send me some cool stuff to the office because they're fans of Planetary Radio or they want us to check out their new book, that kind of thing. This time, I went to my desk, and I was very happy to see that a company called Solar Studios sent me the Collector's Edition of their Core Rule Book for their new Redsky RPG. I know that this happened because I started rolling dice for Planetary Radio instead of using the random number generator, but I'm very grateful that they sent that to me because now I have two copies, one of which I can give away on this show. So if anybody out there is a fan of tabletop roleplay games for people, who are fans of Dungeons and Dragons, Redsky is a magically science fiction setting that's based off of the fifth edition Dungeons and Dragons world. So the whole thing takes place on this cool WorldShip in space. I haven't messed around with it too much, but our trivia winner this week is going to win my new Core Rule Book extra copy.
Bruce Betts: Yes. We have other roleplaying royalty in terms of people creating things that listen to this show. I'll give a shout-out to Bruce Cordell who was one of the designers of D&D as well as several other RPG games, and he's a regular listener.
Sarah Al-Ahmed: That's so awesome. I love that. Now, that we're talking more about gaming, people are coming out of the woodwork. All right. So what is our trivia question this week?
Bruce Betts: Oh, yeah. We should do another one. What will the OSIRIS-REx mission be renamed when it starts its new mission to the asteroid Apophis after it drops off its asteroid Bennu sample at Earth? What will they rename OSIRIS-Rex to? Go to planetary.org/radiocontest.
Sarah Al-Ahmed: You have until May 17th at 8:00 AM Pacific time to get us your answer. Lucky winner will win a copy of this Redsky Core Rule Book, and I tell you, I am so excited that OSIRIS-REx is going to Apophis. This is going to be so cool.
Bruce Betts: Oh, it's very cool. Very, very cool. They'll arrive very, very shortly after closest approach, but we'll be able to assess some of the changes. That's great, and they're bringing rocks back from Bennu in just a few months. Here they come.
Sarah Al-Ahmed: I love that we have so many samples from asteroids now. I mean, it's not so many samples. It's only a few asteroids, but...
Bruce Betts: There are so many.
Sarah Al-Ahmed: It feels like so many.
Bruce Betts: If you count meteorites, but otherwise, I think we're only up to two so far. It will be three.
Sarah Al-Ahmed: It will be three. So, right now, we have two?
Bruce Betts: We have very, very tiny amount from Itokawa, and then more from Ryugu. We're looking forward to piles, piles of rocks, I tell you, from Bennu. Well, maybe not piles, but enough to do a lot of great science.
Sarah Al-Ahmed: I mean, after the sample, the way that container tried to close, but it couldn't because it literally had too much stuff in its little robot mouth, that was awesome. I'm expecting a lot of cool rocks.
Bruce Betts: Its robot mouth. I like that. I like that very much, and I'm just going to tell everyone to go out there, look out the night sky, and think about robot mouths because I know I am now, and I'm a little disturbed, but thank you, and goodnight.
Sarah Al-Ahmed: We've reached the end of this week's episode of Planetary Radio, but we'll be back next week with more of the passion, beauty, and joy of space exploration. Planetary Radio is produced by The Planetary Society in Pasadena, California and is made possible by our dedicated members and space advocates. You can join us as we continue to support missions like VERITAS at planetary.org/join. Mark Hilverda and Rae Paoletta are our associate producers. Andrew Lucas is our audio editor. Josh Doyle composed our theme, which is arranged and performed by Pieter Schlosser. Until next week, ad astra.