Planetary Radio: Space Exploration, Astronomy and Science - Juice mission liftoff: A new era of icy moon exploration begins

Episode Date: April 26, 2023

Join us as we celebrate the successful launch of the European Space Agency's Juice mission! Our special guest, project scientist Olivier Witasse, shares the thrilling details about the launch and the next steps for this groundbreaking mission to explore Jupiter’s icy moons. We'll also recap the inspiring events of last week's Planetary Society Digital Day of Action, where space enthusiasts and advocates united to make an impact on the future of space exploration. Don't miss our resident astronomer, Bruce Betts, as he guides us through the upcoming night sky in What's Up.Discover more at: https://www.planetary.org/planetary-radio/2023-juice-mission-liftoffSee omnystudio.com/listener for privacy information.

JUICE launches to Jupiter. This week on Planetary Radio. I'm Sarah El-Ahmed of the Planetary Society, with more of the human adventure across our solar system and beyond. If you like the suspense of rocket launches, last week was a blast. We're celebrating the successful launch of the European Space Agency's JUICE mission with project scientist Olivier Vitas. He'll tell us about the launch and the next steps for the mission as it makes its way to Jupiter and its icy moons. We'll also take a look back at last week's Planetary Society Digital Day of Action, where space lovers and advocates joined forces to make an impact on the future of space exploration. And as always, we'll turn to our resident astronomer, Bruce Betts, for what's up and

a guide to this week's night sky. We've got to start our space news this week with the Starship. No way of sugarcoating this one. SpaceX's Starship exploded during its first orbital test launch. What can we say? Space is hard. The company's Super Heavy booster and Starship spacecraft blasted off on April 20th from the Starbase launch facility in Boca Chica, Texas. It self-destructed several minutes after taking off in what SpaceX described as a rapid, unscheduled disassembly.

The Starship is the most powerful rocket ever tested. It might take a couple of attempts to get it right, and even though the rocket exploded, the test still represents a step forward in the company's ambition to send humans to the Moon and Mars aboard Starship. And here's a fun one. China has selected an asteroid for a deflection test. At the recent Biennial Planetary Defense Conference, a representative of the mission announced that the Near-Earth Object 2019 VL5 will be the target

of a dual-spacecraft asteroid deflection and observation test, which is planned to launch in 2025. Much like NASA's DART mission that purposefully crashed into an asteroid last year, the new Chinese spacecraft will smash into a roughly 30-meter or 100-foot asteroid to attempt to alter its velocity. Another spacecraft will observe the impact and evaluate its effect on the asteroid. The more planetary defense missions we have, the better. We'd also like to send a huge congratulations to Planetary Society board member Brittany Schmidt. As a planetary scientist, Brittany does research in Antarctica, where conditions are analogous to frozen deserts on worlds like Mars.

Time magazine named her one of the 100 most influential people of 2023 because of her research on an enormous glacier that's melting due to climate change. Congratulations, Brittany, and thanks for fighting the good fight for planet Earth. You can learn more about these and other stories in the April 21st edition of The Downlink, our weekly newsletter. You can read it or subscribe to have it sent to your inbox for free every Friday at planetary.org slash downlink. On Tuesday, April 18th, the Planetary Society held its Digital Day of Action. Here's Casey Dreyer, our Chief of Space Policy, and Jack Kearley, our Director of Government Relations, with the details.

Thanks for joining me, Casey and Jack. Great to be here, Sarah. Great to be here. This past week, on April 18th, we held our Digital Day of Action here at the Planetary Society. I had a great time doing it. But Casey, you've been the main organizer of this event since its inception, really. What is our Day of Action, and why are these events so important to what we do as an organization? Our Day of Action started as the in-person opportunity to go and advocate directly to members of Congress and their staff in Washington, D.C. And we had really gotten into a nice groove with those. We were getting hundreds of people showing up, really positive experiences in Washington, D.C. And then, of course, COVID hit, so we couldn't do those in person. And the last few years, we've done what I call a virtual day of action,

where we had organized the same level of meetings, person-to-person, via computer, doing the same type of activity. This year, 2023, we're back. We have an in-person day of action, but it's in September. But we still wanted to retain an opportunity for people to participate in an advocacy opportunity, a day of action from wherever they live. We heard a lot of feedback from our members that either financially or physically or any other number of reasons that it's very difficult to get to Washington, D.C., which I totally understand. It's across the country for me. And we wanted to retain an option for this. And so we called this our first digital day of action. It's a slightly lower lift commitment. We're not doing we're not organizing one to one meetings, but we're asking people to all act together. So we had a number of

very specific letters to Congress that people could sign. Jack and I gave a prep rally, which is his term, which I really love. And we talked about why advocacy works, what advocacy we're trying to do. We had special guests from the Veritas mission talking about the potential that they can do at Venus if they get this mission back on track. And of course, special words from our president, Bethany Ellman, a professional planetary scientist and PI for her own planetary mission. It was a really great opportunity and really the first of what I see now as kind of a one-two day of action punch every year.

Starting next year, we kind of reverse these. In the fall of next year, we'll do our next digital day of action where anyone can participate. And we go back to spring in-person day of actions next year. So it's just we're expanding the opportunities for people to participate. And Jack, you've participated in our in-person day of action many times before as a volunteer. This is your first time doing this as an employee of the Planetary Society and your first digital version of this. What was your experience like during the event this year? It's a lot of firsts all around. Yeah. So for many years, I did the in-person day of action.

Now, I had the benefit of downtown DC was only about four or five Metro stops away. Still a bit of a harrowing adventure if you've ever taken the DC Metro. But it was a fantastic exercise in showing just how great our community is. And, you know, we did it in our member community, quick plug for the member community, if you're not already in it. And it was a great opportunity for people from all over the world to come together to celebrate space exploration and to advance our goals as an organization. The Day of Action historically has been a very U.S.-centric event, and this one incorporated some opportunities for our international partners and our members all around the globe to take part in advocating for VERITAS and Mars Sample Return and all the other missions that we have that are priorities for us. We always try to find opportunities for our

international partners to participate. And we've taken specific actions either in support of HERA and the European Space Agency or or Canadian space policy. So this is an extension we're really trying to work this in so everybody has a chance to participate together, which is the societal aspect of the planetary society. And that brings up a great question, which was one that you had to address during the PrEP rally. We have members all around the world who want to get into space advocacy, but our day of action focuses primarily on NASA advocating for their budget and their missions. Why is that such an effective way

for us to be using our advocacy time to advance space science and exploration? Well, there's a couple of practical reasons, right? The majority of our members are in the United States. NASA is the largest space program, and through its international partnerships, NASA is the largest space program, and through its international partnerships, it really sets the agenda for a lot of other nations. NASA also has, through the particulars of the U.S. democratic system, a lot of very direct opportunities for citizens to weigh in, whether through the representatives or to NASA itself. The system is designed for very direct public input. designed for very direct public input. It's a bit more complicated and a few steps removed in a lot of other parliamentary systems in the US or the European Space Agency, which is itself comprised of various space agencies representing their various national interests. So it's very direct in that sense. But one thing I always like to say to our members, and we've done this in the past,

if you see opportunities for rallying members of your country or members of your, you know, if you're an ESA and you see an opportunity within ESA for public input, let us know. And this is the real value of, you know, Jack and I are just two people focusing on U.S. space policy primarily. But when we see opportunities other places and we trust our members will bring those to us, we can act on those. And we have in the past. And I feel like it's a lot easier for our members to communicate that to us now, because now we have our member community app. I loved seeing everyone in that community getting engaged in our day of action. It was no longer just spaced out across social media. It was all in one place together with all of us celebrating. How many

people actually joined in during our member community event? I think we had 130 active people watching. So cool. And that's pretty good for advocacy. And I'd say one thing when Jack and I are very happy, we hit our goal during the day of action of more than 1000 individual actions supporting Veritas, which is, I think, very, very good for a Venus mission that is still in the early development stages that is a relatively modest mission in terms of size and scope. It's just the, it punches above its weight. We're just very excited to see so much traction happening with this. And this is on top of the letter to Congress that we have other, like the American Geophysical Union signing on, other top universities around the country. And, you know, we're really getting the word out. And this is something that we've

actively been really putting a lot of time in that I should say Jack in particular has been putting a lot of time in wearing out his shoes on Capitol Hill. How's that been, Jack? I know you've been going literally office by office trying to talk to people. Yeah, and I'll be I'll be doing the same thing this coming Friday. So I guess past Friday, when this episode airs, I'm going to be on Capitol Hill again with another member of the science team from Veritas. It's been a fantastic experience. We've gotten a lot of warm reception from folks on Capitol Hill because they understand the importance of following through on the decadal priorities.

As part of the Planetary Science Decadal Survey, Veritas is one of the many missions that are expressly endorsed in that document. And then outside of that, this is the first U.S.-led mission to Venus since Magellan, which decommissioned in 1994. So there is a national prestige element to this, as well as the scientific benefit that we're going to get. So the welcome that we've received has been warm, and we are just pressing the pavement, making sure that the message is heard. There's a lot of competing interests in Washington right now. If you turn on the news, you can see some of them. So we're just making sure that planetary science in it being really a very aspirational part of what the federal government does and something that

basically every member of Congress can agree to, that this is an opportunity for cohesion on Capitol Hill to support a very important mission that's going to be bringing back very important science. I think one of my favorite things about the Day of Action is that we're giving people an easy place to start when they want to learn how to advocate for what matters to them. No one wants to argue against us exploring space. That's a good feel-good opportunity. But I've heard many times from people that participate in this event that this was their beginning point. This was their happy way to get into advocacy. And it taught them how to do more in the future.

Have you guys heard that same sentiment? Yeah, we have. Absolutely. And that's by design. And it's always really encouraging to hear that. My goal here at the Society has always been to lower the activation energy of turning space fans into space advocates. And the whole system can be very intimidating. And particularly if you're walking through the

halls of Congress, which is this ornate 19th century building, and you're wearing a suit, and you're saying, you know, who am I to be doing this or telling anybody anything? But the point is, you are you. The system is designed to listen to you. And when we schedule your meetings, we give a ton of training online and in person, lots of background. You're walking in very prepared. And we've heard that from a lot of people who just come in. They say they felt super confident. They're going in with other people. So they have a team supporting them. And then at the end of the day, a lot of people, you know, they just feel better about the democratic system that we have, which is just a great bonus, really, that we feel more confident about our whole representative democracy. And it's a really

wonderful way to engage in that system. And we do try very hard to say, if you're doing this for the first time, congratulations, welcome, come on in, the water is warm. And I will say in the initial feedback that we've gotten from the folks that participated in the Digital Day of Action, two-thirds of them, this was their first Day of Action event. So obviously, this is digital, and people could join from anywhere and people did from all over the globe. And we are really looking forward to on September 18th, 17th is the training day, 18th is the day on the hill.

We really look forward to welcoming any number of new space advocates to our ranks. Can we plug that, Sarah? Can we plug the registration for the Day of Action, which is live now? You can register for it, planetary.org slash dayofaction. There, I did the plug. Yeah, you can absolutely sign up for our Day of Action later on in September at planetary.org slash dayofaction. Or if you're sad that you missed our Day of Action, our digital Day of Action this last week, there is still time. All of our assets for advocating for these missions are still available on our website. So you can go check out all of our advocacy actions

at planetary.org slash action. That's it. Always an opportunity to be an advocate for space. And this year in particular, marathon, not a sprint. You know, we need to keep up that pressure and there's a number of exciting missions. We really need to get their funding for this year. And really looking forward to securing that with your help and the help of the members of the Planetary Society. Well, thanks for joining me, Casey and Jack. I'm so grateful that we do events like this. And I can see it working.

Every moment we all band together to try to advocate for what we care about, it always makes the world a better place. So thanks for being that happy starting place for so many people to get into space advocacy. Thanks, Sarah. And I have to say it works for us, too. It just maybe speak for Jack here, but just seeing all the people engage and take action and give that feedback, very heartwarming, very inspirational for us. It really energizes us to get out there and keep doing

this every day. So I just want to give thanks to everybody who participated and everyone who listening to this will be so inspired, will participate in the future when they take actions online or join us in September. I'll just thank you in advance because it's very inspiring to see you all do this. I'm going to ditto that. It was very heartwarming to see so many people coming together from across the entire planet to advocate and support the space program. So thank you, thank you, thank you. And I look forward to seeing as many of you as possible in September. The European Space Agency's Jupiter Icy Moons Explorer mission, or JUICE, launched from French Guiana on April 14. This begins the mission's eight-year journey to Jupiter, where it will study the moons Europa, Callisto, and Ganymede.

En route to the Jovian system, the spacecraft will perform the first-ever Earth-Moon Dual Gravity Assist flybys in August 2024, followed by a Venus flyby and then two more Earth flybys before reaching Jupiter in 2031. Jupiter's three largest icy moons, Europa, Ganymede, and Callisto, may host liquid water oceans beneath their icy crusts. This has prompted decades of speculation about these moons, how they formed and evolved over time, how they interact with Jupiter, and about the potential for life on these worlds. ESA's JUICE mission aims to investigate their habitability and expand our understanding of potentially life-harboring locations in the universe. Dr. Olivier Vitas is a planetary scientist and a project scientist for the JUICE mission.

He joined the European Space Agency in 2003 and has worked on a number of missions, including the Huygens probe to Titan, Venus Express, Chandrayaan-1, Mars Express, and the ExoMars Trace Gas Orbiter. That's an impressive resume. In 2015, he joined the JUICE mission team and turned his sights to Jupiter. Hi, Olivier. Hi, hello, Sarah. How are you doing? I'm doing really well, and it's been a really exciting week. I want to congratulate you and everyone on your team for the successful launch of the JUICE mission.

Yeah, thank you very much. It was a big week last week and that's the start of the new phase and the start of the journey to Jupiter. How are you and the rest of the team feeling? Did you celebrate afterwards? Yes, of course, of course. We had a few celebrations. I was in our operation center in Germany. So people were split between our operation center in Germany and, of course, the main site in Kourou in French Guiana. So on both sides, there were a lot of celebrations. And in the operation center now, people are working very hard for the first phase of the mission.

So I can relax a little bit from my side, but there are people who are still working very hard for the first phase of the mission. So I can relax a little bit from my side, but there are people who are still working very hard on this project. I know that you guys had about a one-second launch window in order to achieve the correct orbit. What's the status of the mission? Is everything on track right now? As you have seen, we launched with one day delay. There was some bad weather and lightning activity at the time of the launch on the 13th of April. So we postponed to the 14th. It launched on time. I mean, we had one second to launch, so we did it. And then the launch sequence went absolutely perfectly. All the parameters were nominal. I mean, everything was on schedule. So the separation, the injection to space, I mean,

it could have been better than that. It's good to hear. The James Webb telescope, you know, the injection was perfect. There was a lot of discussion about that. So for JUICE, it's the same. So we don't need any correction maneuver in the next week. So that's good. Then after the separation, there was the first, the acquisition of the first signal from JUICE. Here, there was a little bit of delay, so people got a bit nervous, but then it went well. And the deployment of the solar panels happened a little bit earlier than expected. So all in all, it went very, very well. That's perfect, because I know just like the James Webb Space Telescope, making sure that you do the perfect launch and that you don't have to use that fuel means that you

can do a whole lot more when you get to your target, which is perfect because you're going to need that fuel to get this mission into orbit around Ganymede at some point. Now we need a lot of fuel. In fact, more than half of the spacecraft mass is fuel because we have a lot of maneuvers. We have a few maneuvers during the cruise phase. Then we have a big maneuver when we arrive at Jupiter. Another major upsized maneuver when we arrive at Ganymede to enter an orbiter on Ganymede. And in between, we have 34 flybys of the moons of Jupiter where every time we do a flyby, we need a little bit of fuel to correct if needed. So we need a lot of propellant, so it's good that the launch was perfect. Then we can keep a little bit of margins for the future

milestones. And for people who are just now learning about this JUICE mission, what is this mission going to do and why is it so important? Everything is in the title. JUICE means Jupiter Ice-Sea Moons Explorer. So that means we'll explore Jupiter and the ice-sea moons, which are Europa, Callisto and Ganymede. And one of the big questions for our mission is to understand whether there are habitable places within the icy moons of Jupiter around a planet like Jupiter. The main question is to explore the liquid water, because when we talk about habitability, the first thing to check is the presence of liquid water.

And there is liquid water inside the AC moon. It's kind of strange to think about it, but underneath the surface of Europa, Ganymede, and maybe Callisto, there is more liquid water than on Earth. And Juice will explore that. And because we want to understand habitable places around Jupiter, we will explore Jupiter as well. So the atmosphere, the magnetosphere, and also the full system. So the other moons, Io, very interesting moon, the dust, and how everything is connected to each other.

For example, how the moons are connected to Jupiter via the gravitational force. As a result, there is tides on the surfaces of the moon. So we'll explore that. And they're also linked to Jupiter via the magnetic field line. So there is a lot of magnetic things to discuss, to explore. So it's a very rich mission and very broad. And yeah, we are very excited by it.

And this is the first dedicated Jupiter mission by the European Space Agency, right? What kind of sparked the creation of this mission? Yeah, so that's the first time we go to Jupiter. So that's a very challenging mission. It's one of our biggest missions in ESA, at least in the solar system exploration as a follow-up of the Rosetta mission, for example, this kind of big mission. So a lot of challenges. First, we have to have a mission which lasts 10 to 15 years. So there is a lifetime. We go to Jupiter, which is a very hard radiation environment, very difficult to resist for the electronics, the spacecraft, the instrument. We go there where it's cold around Jupiter while doing the cruise to Jupiter we go via Venus. Venus it's a warm environment so we

have to design a spacecraft which can work in the cold environment, in the warm environment. Plus we'll do a lot of very sensitive measurement of electric and magnetic field. That's one of the measurements very useful to detect the liquid water underneath the surfaces. And then we need to have a very clean spacecraft from the electromagnetic point of view. We don't want to measure what is coming out of the spacecraft. So the design was extremely challenging for this and because we are far from the sun, little power, little solar illumination, that means we had to embark huge solar panels. So if you see how the spacecraft looks like, you see the big solar panel with a cross-shaped 85 square meters of solar panels, so huge. So we need to find the right solar panels which can work in the cold environment with low illumination

conditions in the radiation environment. So all in all, it's a very challenging mission. Yeah. With NASA's Juno mission, they put it on an orbit that took it very far away from Jupiter and then back in. And the readings of the radiation coming off this thing are unreal. So how is the spacecraft grappling with that level of radiation? That's one of the big issues of any mission to Jupiter. So how is the spacecraft grappling with that level of radiation? That's one of the big issues of any mission to Jupiter. So that means you have to check what you can do. That depends on your science objective. For example, the Juno science objective are to study Jupiter in detail, the interior, the atmosphere, the gravity field, the magnetic field. So they have a polar orbit, and they go very, very close to Jupiter.

And then they go very, very far, not to be in the radiation belt all the time. So they design the trajectory depending on their science goal. For JUICE, we are mainly interested in the icy moon. So we need to orbit in the equatorial plane of Jupiter. So different orbit than Juno, because Juno is a polar orbit. JUICE is an equatorial orbit, because we want to fly by the moon. So we need to stay in this equatorial plane, where there is a lot of radiation environment. So we need to stay at a reasonable distance from Jupiter.

So that's why we don't go to Io, because Io is very close. We go only twice to Europa, because also Europa is very interesting, but relatively close. And we focus on Ganymede, because it's at a reasonable distance from Jupiter. Ganymede is a very unique moon, very very interesting, so we met Ganymede as our prime target. So the first thing to cope with the radiation environment is to make sure that your trajectory is fine with that, so not too close to Jupiter for example. And then in the design of the spacecraft, we protect the very sensitive electronics of the instrument and the spacecraft inside the satellite, in the core, in the middle of the satellite, in what we call volt. So we have two big cavities in which we put all the sensitive elements of juice.

So such they are protected from the radiation environment. And we have more than 100 of shielding a bit everywhere in the spacecraft to shield the particular sensitive area. And on the solar panels, which are outside the spacecraft, we put a layer of cover glass to protect again from the radiation environment. So you see, we have thought a lot about the design and that was the main requirement is to protect the spacecraft as much as possible from the radiation environment. And you need to keep all those scientific instruments able to do their job. And there's a lot of them on the spacecraft.

What are the most important instruments on board JUICE to help it do its mission? Well, we have 10 instruments and they have been selected at the same time, of course, and each of them to achieve specific objectives of the mission. And they have been selected such that they can work also together to address all the big questions of JUICE. So there is no one instrument particularly more important than the other. They are all very important because they have selected all together to fit the science objective of the JUICE mission.

We have three big packages. So we have the remote sensing instruments, so the eyes of JUICE, so all the cameras, spectrometers. So we have four of them because we want to take images and to study the geology of the moons and the atmosphere of Jupiter. And then we have spectrometers covering radio, near infrared, visible and UV for the atmospheres and for the surface. So that's how JUICE will see everything around the spacecraft. Then we have a package which is called Geophysics. That's a very interesting one because that's the first time we fly this kind of instrument to the moons of Jupiter. Here we have a radar to study the first 10 kilometers

of the crust, so to penetrate the ice. So we will see the first 10 kilometers, how is the structure, so that's the first time we will do that. And we have also a laser altimeter, which is very, very interesting because we measure the topography of the Moon. So we send laser shots and then from that we can see the topography. So if you have small hills, craters and so on. But what is very interesting is we will come back to this same point many, many times and we will see the tides of the Moon. So how the height of the Moon changes with time.

And that is a way to study the interior and the liquid water. We have a radio science experiment to study the gravity field. And then we have what we can call the nose of the spacecraft, it's an in-situ measurement of particles, electric field, magnetic field, radio wave, to study in situ what is around the spacecraft in terms of particles and in particular for the magnetosphere. And that's a world to detect subsurface oceans. Each of them are very useful and they will be all providing a small piece of the puzzle. I'm really excited to see what it can tell us about whether or not there actually are in fact subsurface oceans on these bodies.

And the way that particularly Ganymede interacts with the magnetic field of Jupiter is so wacky that I cannot wait to learn more about this. And as I was learning more about these instruments, I learned, too, that there's an experiment, which is called the Planetary Radio Interferometry and Doppler Experiment, or PRIDE. And, you know, as the host of Planetary Radio, that made me very happy. Yeah, this one I did mention because it's not an instrument. It's an investigation. So there is no hardware on the spacecraft.

They will use the communication system of the spacecraft. So how we transmit data to the Earth. They will listen to big radio telescopes everywhere around the Earth. And then they will do a special measurement to detect the speed of the spacecraft, and more importantly, the position of the spacecraft in the plane of the sky. And then we'll get very interesting information, for example, on the positioning of the moons in the Jupiter system, so their orbits, and that's an interesting topic for JUICE as well. Yeah, it'd be very useful to be able to verify the positions and movements of these spacecraft from afar from Earth.

I've been so excited about this for so long. Jupiter has, what, 92 moons, I think, at this point. But these ones have the potential for subsurface oceans and, therefore, the potential for being habitable. JUICE isn't going to be directly detecting life, but what can it teach us about the potential for habitability on these moons? Well, first it's to really confirm that there is liquid water. We are pretty sure there is liquid water at Europa, relatively sure that there is liquid water on Ganymede. Callisto, there is a question mark, so Callisto is also quite

interesting. And the first thing when you want to discuss habitability is to really understand the properties of liquid water. So because we don't know where it is, so at which depth, we have some ideas, of course, some indication. But for example, the subsurface ocean at Ganymede could be at 100 kilometers underneath the surface, but it can be 110, 20, 120, 150. So we need to know. It's important. We don't know exactly the depth of those oceans. So is it 100 kilometers, 50, 80? We need to know because we want to know the amount of water that you have there.

And also the composition. We know they are salty because we detect them with the magnetometer. So we know they are salty. That's an interesting piece of physics and detection, by the way. But we don't know how much salt do they have there. And the composition is quite important to characterize liquid water. Is it an interesting water for life, et cetera? We'll also be studying the radiation environment because it's good to know the radiation environment. I mean, on Earth, we are happy to have the magnetic field. Then we have less radiation coming from the Sun. So what is the case at Europa when there is no internal magnetic field

and Europa is close to Jupiter? What is the case at Ganymede, which is a bit further away, I mean much further away, with an internal magnetic field? That's the only Moon to generate its own magnetic field, so very, very special. So what is the role of this magnetic field does that help to protect not at all how this interaction between the magnetic field of Ganymede and the magnetic field of Jupiter and what is the case at Callisto the moon which is the much further away for in for with the Galilean moons so in principle it's better for the radiation environment at Callisto but at the same time the moon is far from Jupiter, so the tidal activity is very weak.

The moon has probably not evolved since its formation. When you look at the surface of Callisto, it's plenty of craters. So that means the surface is very young. Probably there is not much geological activity. So is there a liquid water underneath the surface or not? That's an interesting question. And the finding, either yes or no, will be interesting. And then you can compare the three moons.

So Europa, which is active with the possible geysers, very interesting ocean, but close to Jupiter. Then you have on the other hand, you have Callisto, which is dead. We don't know if there is an ocean. In principle, it's not very interesting for habitability and life, but who knows. And then you have Ganymede in between. So a big question mark. So that will be very interesting to know more about the three moons and then to compare them and to understand better the question of habitability and whether around Jupiter,

there is interesting place to study life. And then to study life, we need another mission. Yeah. Well, thankfully, you know, we have NASA's Europa Clipper mission coming up for Europa. But you make a great point, which is that Europa doesn't have a global magnetic field. And that might be necessary. I mean, depending on the thickness of the ice. That's really fascinating. I'm really excited, too, about the potential that we might be getting pictures of geysers on these worlds. We do have evidence that that might be happening on Europa, but who knows about Ganymede? Those images might be mind-blowing.

Exactly. We will see. Even at Europa, the situation is not very clear for the geysers. So we'll see a little bit with Zeus, mainly with Europa Clipper. We are very happy that there will be two spacecraft in the Jupiter system at the same time. By the way, we already started to collaborate with the two science teams, so that's great. Then, yes, maybe there will be some activity that we detect at Ganymede. We will see. It's very, very exciting. We'll be right back with the rest of my interview with Olivier Vitas after a short message. Hi, it's Casey Dreyer. I'm the Chief of Space Policy here at the Planetary Society. And I just want to take a moment to thank you for being part of the world's largest

and most influential nonprofit space organization. Together, we are on a remarkable journey to make a better future for humankind through space science and exploration. Your support in the United States enables our team, my team, to work to make sure every U.S. representative and senator in our Congress understands why space exploration is a critical part of U.S. national policy, from workforce technology to science to even international relations. Each year, we urge Congress to maintain robust funding for NASA's ongoing missions,

guaranteeing that they stay on course and achieve their scientific goals. Now look, there are 81 new faces in Congress and several returning members that are joining space-related committees for the first time. All of these could influence NASA's future endeavors. And already, they have begun to discuss next year's NASA budget. The time to act is right now. So in addition to writing Congress yourself, which you can do if you live in the United States, there's something you can do to bolster our advocacy work. And anyone can do this anywhere in the world. And that's to make a donation. Thanks to the generosity of a fellow

Planetary Society member, your gift today will be matched up to $75,000. This ensures our advocacy efforts will continue to thrive. Now, to make your contribution, you can visit planetary.org slash take action. On behalf of everyone at the Planetary Society, thank you for your support in helping us champion the future exploration of space. JUICE is arriving in 2031, right? Am I remembering correctly that Europa Clipper is arriving in like 2030?

Yeah, yeah. They're a few months before us if they launch next year. So that means there will be an overlap of maybe two, three, four years between the two missions. So that's great. Yeah, that's absolutely great. And that's so exciting. Something that I learned recently when I was learning more about recent results from Juno is that Ganymede's magnetic field is actually creating an interaction with Jupiter's magnetic field that is causing aurora that trail behind this moon. Is there

anything that we can do to study those aurora and this interaction with JUICE? So in fact, there are two types of aurora. So the one at Ganymede, due to the magnetic field of Ganymede, we have imaged that with the Hubble Space Telescope and with other ground-based observations, observatories. Those aurorae on Ganymede, you can use them to study the interaction between the magnetic field of Ganymede and the magnetic field of Jupiter, but also you can use them to study the liquid water ocean underneath the Ganymede surface. And that's a very interesting piece of physics. It's because the oval on Ganymede, so we have the ovals like on Earth, this oval oscillates with

time. So there is a small oscillation of this of this aurorae. And the level of these oscillations depends if there is a liquid water on the ocean underneath the surface. Because the ocean includes salt and then this ocean generates electric currents and those currents disturb the magnetic field around Ganymede. It's quite complex. We call that an induced magnetic field. And then this induced magnetic field competes with the magnetic field of Jupiter. That's kind of physics of the magnetic field. And that means the aurorae that are generated because of the magnetic field of Ganymede, they could see the presence of this

liquid water ocean. So to study this light, you can get something on the interior of Ganymede. So it's quite interesting. But then because Ganymede is connected to Jupiter with the magnetic field line, so there is a kind of invisible connection between Jupiter and the moon. And the charged particles, they can travel via this magnetic field line

because the charged particles, they like the magnetic field. they follow the magnetic field line. And then those particles can impact the atmosphere of Jupiter around the poles of Jupiter because the connection to this field line occurs at the pole. So when you look at the poles and the aurorae of Jupiter, you not only see the normal aurorae at Jupiter, but you see also the aurorae due to the moons. We call that the footprint of the moon. So you see that for Io, for Europa, for Ganymede, maybe Callisto, here the situation is less clear. So you see the situation is quite complex, but at the end it will be quite interesting to study.

You said there's a spectrometer on board. What can that teach us about the potential for habitability here? Are there certain elements the spacecraft might be looking for? Yes, so we have a near-infrared visible spectrometer, which is a very useful instrument to measure the composition of what you observe. Because you take images, and then at the same time with the spectrum in the visible infrared, you get the composition. So if you look at the surface of the moon, you can get information on the composition. For example, different ices, different molecules, organics. And there are many molecules we have not identified. For example, on the surface of Europa, this orange pattern on the surface, it's not very clear what it is.

And it can be organic molecules. So if we detect molecules which are interesting as a biomarker or that interesting molecule as a building block for life, that will be important to identify, to detect. So we'll do that at Europa,

Ganymede and Callisto. And then we'll see what we get. With the spectrometer, you can also study the thin atmosphere of the moons. We call that exosphere. It's a very small atmosphere composed of water vapor, oxygen, a bit of CO2.

And then if you study the atmosphere, it's also interesting because what is in the atmosphere is partly due to what is on the surface because there is some interaction between the atmosphere and the surface. So that's, yes, the spectrometers that will be used for this. How thick are the atmospheres on these moons? They must be fairly

tenuous. Yeah, it's very tenuous. I mean, it's only up to the minus six atmosphere, so it's almost nothing. I mean, they go very high in altitude, but the density is pretty small. At Europa, it might be a bit denser because of the possible plumes or geysers and with our two flybys of Europa we have a mass spectrometer that it will detect the molecules that are present in the atmosphere. So also we'll have here a direct detection of molecules. So we have the remote spectrometer that will look at the light from which you can get the composition but there will also be an in-situ spectrometer with which you really detect what kind of molecules do you have in the atmosphere. And with the gravitational readings on these worlds, I know we'll be able to know more about the liquid water ocean underneath,

but will we be able to get enough information to make, say, diagrams of the different layers within these moons, how thick the ice is, or if they have cores, for example? Yeah, so here particularly, we will do that at Ganymede. Not so much at Europa because we are only with two flybys, it will be a bit difficult, but partly at Callisto because at Callisto we have 21 flybys, so it's a lot. But yeah, Ganymede, because at the end of the mission, we'll be orbiting Ganymede for nine months, one year. With our gravity experiment from an experiment called Radio Science, we will get the gravity field coefficient of the Moon. And from that, you can get the entire structure of the Moon. So we'll do a real tomography.

What do we know about the interior? Because we think that there is a first icy shell, so the ice, then there is liquid water, then there is probably another layer of ice, and then the mantle may be made of rocks, and then the iron core, because if there is a magnetic field

there must be an iron core. But that's more or less all what we know. But with JUICE, with the radio science experiment, together with the laser altimeter, and also partly a little bit with the camera, we have a lot of investigations that can complement each other. It's quite nice.

We will get, in principle, the entire structure of Ganymede. And that, to understand the habitability of a body, like a moon, a planet, it's very important to know the entire structure. I love the idea, too, that this altimeter will allow us to probably make a global map of Ganymede and actually see all the different peaks and layers, the topography of this world in a way that we've never been able to see before. That's going to be really exciting.

The laser altimeter, it's a great tool. I mean, when we got the first data at Mars from the NASA Molar Laser Altimeter, everybody was completely crazy about that. So we'll do the same at Ganymede. The images can be used also to image the surface in stereo. So we can get a 3D view thanks to the images. I mean, when you look at that at Mars, it's also quite fantastic. So we'll do the same at Ganymede.

The radar will get also quite interesting information on the subsurface, but also on the surface. So yes, if we put all the data together, it will be very, very exciting. I can just imagine a future where people are, you know, in virtual reality, in stereo staring down at this world. I always love those experiences. They're so fun. Yeah, indeed, indeed. I hope we will make it. Is there anything that you think, you know, you would be surprised to learn from this mission once it reaches these moons? In fact, this is what we like also in planetary exploration. So we built a mission, we designed a mission to address many, many questions.

So we want to do that. We want to learn that. But in addition, there is always surprises. What is also quite interesting is which surprises will come. So, you know, just need to wait. Yeah, we have no idea. Is there anything that you personally are really interested to learn more about? So in terms of planetary science, it's just the dream because you have everything. Plus, what is quite interesting for me is also the study of oceans underneath a surface. And I think that will trigger a lot of new studies in comparison with our own ocean.

And at the moment, planetary science and oceanography are completely decoupled. I mean, it's completely two different communities. I mean, we have the scientists on Earth. they study the ocean, and there are many interesting stuff, the dynamics, the soil, the current, the link to the global warming, the climate, the clouds, etc. But then we'll be studying the oceans at Ganymede, Europa, and maybe Callisto. And that will trigger a lot of studies, because how can we have an ocean between two layers of ice, and at Europa between one layer of ice and a layer of rocks? What's happening inside? Do we have hydrothermal activity at Europa? The dynamics, the pressure, the temperature? And then I'm pretty sure we'll come back to the people doing oceanography on Earth to understand more,

and they will also ask what do we learn here? So that's, I think it's a very interesting aspect of the mission. So I will see more and more connection between geophysics at the Earth and geophysics in the outer planet. So I think that's quite interesting. And I look forward to it already. Yeah. And I think we've seen this happen with past missions, particularly to Mars, where we had to call in geologists and be like, what is going on with this rock on Mars? And it's created a whole new field of science where people are doing the geology of other worlds. So who knows how many people might inadvertently find their way into exo-oceanography

because of this mission. That's really cool. Yes. And then there is another link, which is also very interesting for us, which is the link with our solar system and other solar systems. Because we will be studying Jupiter as a small solar system.

So as you said, we have 90 moons. Maybe there are more. So many, many moons orbiting Jupiter, a big planet, The dust rings also. If you learn more about Jupiter, we could learn more about our own solar system, how it was formed, how it evolved. It's very important. We've learned a few years ago that the image of the solar system that we see now,

it's not the same as the one when it was formed. The planet, in particular, the giant planet, they migrate. So now we see them where they are. But in the past, they were closer to the sun and then they went back further away. So it's quite interesting to study the evolution of the solar system. So studying Jupiter as a small solar system can help also understanding that.

And the same for the extra solar system that we discover very regularly. And with James Webb, there will be a lot of new data. Because Jupiter, you have everything. You have big moons, water, big planets. What we know about we will use, we will apply that to other systems. So there is also the link between planetary science and exoplanetary science. So it's very rich.

Yeah, my focus when I was going in undergrad was exoplanet detection. So the fact that we're now in a phase of research where we're going to be getting enough data on these moons that then we can compare it to the spectra of exoplanets light years away, the fact that we can even look at the atmospheres or, you know, analyze the surface composition of these things with JWST is still blowing my mind. I'm still not able to grapple with that power. Yeah, no, indeed, indeed, indeed. And maybe we will find the water world.

I mean, if we can call water world those moons around a giant planet, not only around Jupiter, but also Saturn, Uranus and Neptune, maybe there are many more water worlds everywhere. Yeah, but it might be possible that worlds like Earth, where there's water on the surface that isn't obscured by ice, might be far more rare. If we're looking at our solar system as an example, there are many, many ocean worlds, but only one Earth. Understanding the surface composition of these moons a little better could not tell us that these worlds far away have subsurface oceans, but could at least help us indicate. We're going to have some weird secrets hidden underneath that ice.

Well, this is all very exciting, and I cannot wait for these results to come out. How is this mission going to be sharing all the science data with the rest of the world? Here, this is a standard procedure. So when we take the data with juice, of course, we download all the images, data, etc. to Earth. Then we give that to the scientists who have built the instrument. They have a few months to understand how the instrument works, if they need to do correction, or we call that calibration. They can do some data processing to make sure that the data can be correctly interpreted, because we don't want to say mistakes with the data set. And then we will put that into the public archive, so accessible to all the scientific community, but to everybody. So after a few months, after we receive the data

on Earth, the data will be publicly available. So everybody can check what we have done at Jupiter. Yeah. Between that and Europa Clipper collaborating together, we're going to have such a better understanding of how these moons operate. And I want to know the answer. I want to know for sure whether or not there are subsurface oceans on these moons, because so frequently we talk about these subsurface oceans, but it's still very speculative. We aren't 100% sure. And I want that assurance so we can say that there might be. So in 10 years from now, we'll know, I think. Yeah, that's really exciting.

We've been thinking about this for ages. I mean, even since Voyager flew by Jupiter. So I'm so happy that we have this mission to finally help us definitively answer these questions. Well, thanks so much for sharing this mission with us, Olivier, and good luck to you and all of your team in these next phases of the mission. It's going to take a while to get there, but we're all going to have to be patient, and I'm sure that's the worst for your team. I think we have been working on the last 15 years, so we can wait a little bit more.

Thanks, Olivier. Thank you, Sarah. This is a moment in space history that deserves to be marked. We're embarking on a new era of icy moon discovery with the launch of JUICE and the upcoming Europa Clipper mission. Europa Ganymede and Callisto have captured the imaginations of scientists and science fiction writers for ages, and there's no wonder why. These worlds represent untapped reservoirs of knowledge that could reshape our understanding of habitability in the cosmos. It's hard to say

how rare worlds like Earth truly are with their liquid water oceans and abundant life, but icy moons are everywhere. These are the beginnings of a deeper understanding of our place in space, and who knows how many icy worlds have creatures thriving in their oceans under a vault of ice. Only time and science will tell. Now let's check in with Bruce Betts, the chief scientist of the Planetary Society, for What's Up. Hey, Bruce.

Hi, Sarah. Now, what a week. I mean, Day of Action was cool. Starship exploded, you know. Yeah, I don't know how to follow that, other than telling people what's up in the night sky. Oh, don't forget hybrid solar eclipse and a weird meteor shower. All were a party. It's true.

But we've got more. We've got Venus. Our buddy is just hanging out. Always is. I just keep saying it because it keeps being there over in the west after sunset mars moving over moving gradually towards venus up higher in the sky looking reddish a lot dimmer and then in the pre-dawn saturn's getting higher and higher in the east the night of the fifth through the sixth and above average meteor Eta Aquarids, will be partying.

Here's the good news, bad news. If you're in the northern hemisphere, hey, you get to see most things, but this one's going to be tougher. Southern hemisphere, this isn't a better position for you to see it. Unfortunately, there's going to be a nearly full moon, and so it'll be tougher to see, but that's the evening of the 5th, 6th, a few days before or after. Pretty good meteor shower, especially southern hemispheres. So go out and check that out. And, yeah, it's pretty chill other than that. Yeah, the only time I'm ever sad that a full moon is out is during a meteor shower.

We move on to this week in space history. The first image of earth from the surface of the moon by human built robotic spacecraft was taken by surveyor three on April 30th, 1967. And it's not very spectacular, but compared to like now, but it's pretty substantial when it's the first time you do that. It was a few months earlier. They got the first images from orbit as well.

All right, we move on to random space fact. What do you got this week, Bruce? I've got something that requires a brain, sorry, which is the speed of sound, commonly called Mach 1. The speed of sound at the Mars surface is about a little over 70% of Mach 1 at the surface of the Earth. So on the surface of the Earth, it's 340 meters per second or about 781 miles per hour. 340 meters per second goes down to 244 meters per second and 546 miles per hour. So you've got, because it's dependent on things like what the atmosphere is made of and

temperature. And of course, both those numbers vary depending on your altitude and depending on the temperature, but ballpark bottom line is you hit supersonic at a lower speed, which is something when people think about, which people occasionally do. And I was involved in at some point. Mars airplanes, it's a whole different

world because you go supersonic at a slower speed, which requires a different design. I hadn't even considered what that would mean for airplanes someday. Like I thought about it in the context of what that means for Martian microphones. I mean, that also is why sound, it's related to the differences in sound and frequency shifts and things like that. Yeah, that's really cool. All right, let us move on to the trivia question, because usually we ask you one. And in this case, I ask, what was painted on the front of Yuri Gagarin's flight helmet, and why? How'd we do, Sarah? When you posed this question, I knew part of the answer, but it got weirder and weirder the more I read about it. And every answer that people

sent in gave even more pieces to this puzzle. So it was really cool. Yeah. I mean, the too long don't read version of this is that the Soviet Union wanted Yuri to be clearly labeled as a member of their nation when he was doing this. But the real tea here is that about a year before Yuri Gagarin went on this wild flight into space for the first time, there was a US U-2 pilot named Gary Powers that the Soviet Union shot out of the sky while he was doing surveillance. So everyone was like on high guard in the situation. And they were worried that if Yuri went off target and landed back in the Soviet Union, or even in another nation, he might be seen as an invader or a spy or something. So an engineer about half an hour before he went up on his historic flight.

Yeah, that's where it gets funny. Yeah, half an hour before. This is crazy. This guy spray painted CCCP, which is, of course, the Soviet Union's version of USSR on his helmet, just in case he landed back in the USSR, they wouldn't think that he was invading them from space. Yeah, that's why I asked because I thought the story was fascinating. I knew he had that on his helmet. I didn't realize it had been such a last minute addition or why.

Right? Half an hour before. So who talked to us? Who won? Oh, yeah. You know, it was hard to pick on this one because so many people had like partial answers, that kind of thing. But in the end, our winner is Miranda Weaver from New Hampshire, USA. And Miranda, you're going to be getting a cool prize. It's our Yuri's Night gift set.

So lots of stickers and patches and cool little fake tattoos of Yuri's face. Although I don't think that any of these images actually have the CCCP written on the helmet in them. I think they kind of internationalized his image. Lost over them? Yeah. Yeah. No, you read his speech before he flew and it was not internationalized at the time. Spicy.

I'm going to have to do that because this story was really cool to learn about. I mean, I doubt he wrote it. Yeah. And I loved too, all the comments we got on this. Some people were talking about their experiences, going to see statues of Yuri Gagarin, that kind of thing. But Pavel Kumesha, who lives in Belarus, wrote in and said, since childhood, as a resident of the former USSR, he'd seen countless images of Yuri Gagarin and other Soviet cosmonauts with the CCCP on the helmets. But, you know, at that point, it was already standardized. And so, this was actually the beginning of that practice. And now we all know why. That's really cool.

Look how much we learn. Right? We learn today. We got some other really good comments too uh mark dunning in florida usa wrote in and i like this one i'm going to share this with our t-shirt team said howdy t-shirt request dart punching an asteroid in the face for the dinosaurs i totally buy it that works yeah we could add it to our, you know, kick asteroid line. I like that. And then this one too, I wanted to share because Hyunwoo Chang from South Korea wrote in to say, Hi there, I've been enjoying Planetary Radio for over two years now and keep up the good work. And I just want to say thank you because this is the first person to write me from South Korea for Planetary Radio.

So that was awesome. Cool. No, we love the international listenership. Oh, yeah. It makes me so happy just hearing from people all around the world. Being on this side of it and just seeing how much participation and love there is from people all around this planet. It just it makes me so happy. Softly gooey.

So gooey. But all right, Bruce, what's our next trivia question? You're going to stump them this time? No. What's our next trivia question? You're going to stump them this time? No, but I am going to deliver something in a format that has never before been used with the trivia question. This is a put things in order question. I'm going to give you five things. You're going to put them in chronological order. Following five things are all still going or still working.

Put them in chronological order from oldest to youngest. If it's a spacecraft, start with their launch date and for others the first public release all right get your notepads out here are your five things the mars curiosity rover planetary radio minecraft mars odyssey radio, Minecraft, Mars Odyssey, and iPhones. Go to planetary.org slash radio contest and give us the five in chronological order from oldest to youngest. And you've got a week to answer this one. You have to turn in your answer by May 3rd at 8 a.m. Pacific time, and the winner will get a Planetary Society beanie. I love these kinds of questions because I feel like, particularly with historical events that we learn about in classes and school, whenever someone puts all these things in context in their order, especially when they're disconnected, right?

A historical event plus a TV show or something, it always blows my mind because there's so many things that happen in such close proximity that are so distant in my brain. So it's always awesome. Distant in your brain. Hmm. How far distant can things get in your brain? I mean, there's an empirical answer to this, but it wouldn't reflect how far apart they actually feel in my mind. Oh, I see.

It was a figurative thing. Okay. Yeah. About like two centimeters, maybe. All right. I think this needs to end. All right, everybody. Go out there and look up in the night sky and think about a wet

dog nose on the back of your arm, because that's what I have right now. Thank you, and good night. We've reached the end of this week's episode of Planetary Radio, but we'll be back next week with Matt Kaplan's adventures at the Planetary Defense Conference. Planetary Radio is produced by the Planetary Society in Pasadena, California, and is made possible by our curious members. You can join us as we continue to daydream about crabs in the oceans of Europa at planetary.org.

Mark Helverta and Ray Paoletta are our associate producers. Andrew Lucas is our audio editor. Josh Doyle composed our theme, which was arranged and performed by Peter Schlosser. And until next week, Ad Astra.