From the Mojave to Phobos: PlanetVac rides with MMX

Sarah Al-Ahmed: A Japanese spacecraft is about to set off on a journey to bring home a piece of a Martian moon, 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. Japan's Martian Moons eXploration Mission, or MMX, is scheduled to launch next week on its journey to Phobos and Deimos, the two small moons of Mars. If all goes well, it will bring the first ever sample from the Martian system back to Earth, straight from the surface of Phobos. The Planetary Society's public outreach astronomer, Asa Stahl, joins me to explain why these small little moons are such a big mystery and what those samples could reveal. Then Kris Zacny, vice president and senior research scientist at Honeybee Robotics, returns to the show to talk about PlanetVac, a sampler that Planetary Society members helped get off the ground more than a decade ago. Its descendant will soon be on its way to Phobos.

In What's Up, Bruce Betts, our chief scientist, looks back at PlanetVac's history with the society from its first prototype test to a rocket launch in the Mojave Desert. If you love Planetary Radio and want to stay informed by the latest space discoveries, make sure you hit the subscribe button on your favorite podcasting platform. By subscribing, you'll never miss an episode filled with new and awe-inspiring wisdom of the cosmos and our place within it.

Mars is one of the most explored worlds in our solar system, but its two moons, Phobos and Deimos are still keeping some of their biggest secrets. The Japanese Aerospace Exploration Agency, or JAXA, is about to launch its Martian Moons eXploration Mission to change that. For those of us in the United States, that's set for Monday, October 19th, 2026. But for our friends in Japan, because of the time zone difference, it's the next day, Tuesday, October 20th. MMX is a true international effort with contributions from NASA, the French Space Agency, CNES, the German Aerospace Center, DLR, and the European Space Agency. To help us understand what this mission is setting out to do and why it matters, I'm joined by Dr. Asa Stahl, The Planetary Society's public outreach astronomer. Hey, Asa.

Asa Stahl: Hey, how's it going?

Sarah Al-Ahmed: Oh, man, I am so excited for this mission. We've been looking forward to this for so long, but finally we're going to get to go out to the Martian moons. Are you excited?

Asa Stahl: Yes. I mean, it's so weird that we haven't been there already. I think it's the kind of thing where whenever I tell someone about this mission, they're like, "What? For real?" And that it doesn't get that much press. It's not as big in the news. Maybe it will be now that it's launching and getting there, but I think this one kind of snuck up on a lot of people.

Sarah Al-Ahmed: I think too that people assume we understand what's going on with those moons, right? We've had so many spacecraft in the area that people would assume that we know more, but actually it's a lot more complicated than that. So first off, this mission is actually launching next Tuesday. It's a little complicated. It's October 20th if you're on Japan time, but October 19th if you're in the United States. But for anyone who might be looking forward to this mission, might be looking forward to this launch, what is this mission actually going to do?

Asa Stahl: It is going to bring back the first ever samples from Phobos, which is one of the two moons of Mars. You can kind of picture it like a potato the size of Manhattan or so covered in craters. It'll in general perform detailed remote measurements of both Phobos and Deimos, and in doing so, hopefully teach us a bit about maybe giant impacts, maybe how asteroids get captured. We don't know what we're going to find, but it promises to teach us something about how planets form and the ancient history of the solar system. So it'll be a few years to get there, orbit Mars, well, orbit Mars, but in doing so, it's going to orbit Mars in a way that also circles Phobos as a sort of quasi-moon of Phobos, just like we've had some quasi-moons of Earth discussed on this show before.

It won't land on Deimos, but it will touch down on Phobos, a rover, and then bring back some samples through a couple different mechanisms to Earth, hopefully in 2031. So the upside of all these sample-return missions is that we get back samples and we're able to do amazing science with them. It's the most impactful mission you can have is a sample-return mission. The downside is you have to be patient.

Sarah Al-Ahmed: Yeah. But also, I mean, how amazing is it that we're attempting to go out to the Martian system and actually bring something back? I mean, that is massively complex, let alone trying to land a rover and all this other gear on these tiny little moons. That's got to be really complex.

Asa Stahl: Yeah, it's a uniquely tricky situation because Phobos only orbits about 6,000 kilometers above the surface of Mars. That is closer than any other moon to its planet in the solar system. So you have this funky situation where you're playing with Mars' gravitational field in a way that you wouldn't be otherwise, but then also Phobos itself is quite small. Like I said, it's about as long in each of three axes as Manhattan is, but irregularly shaped. It's either a rubble pile or something pretty porous but coherent. So you can imagine that you're trying to land on it and then bring back a sample, operate on it. You don't want to bounce off of it. It's almost like The Little Prince moon from that book. I don't know what it's called.

Sarah Al-Ahmed: That's so funny. So we've got these two weird potato-looking moons, and essentially we're going out not just to test out our technology to learn more about these moons, but it is. It's a big mystery how these moons even formed. How can this be such a big mystery all this time later, especially considering how much we've studied Mars?

Asa Stahl: Yeah, it is a bit surprising and it always goes to show you how much we don't know. So we have a few different ideas. We have lots of different ideas really about how Phobos and Deimos formed. One idea is that they're asteroids from further out in the solar system that were then captured by Mars' gravity, likely shortly after Mars formed and Mars is thought to have formed very, very early on after the Sun. There's things kind of pro and against that idea. One is that Phobos and Deimos have these irregular shapes and their chemical makeup seem from a distance to be aligned with things that are farther out like in the asteroid belt or closer to Jupiter. But on the other hand, they also orbit Mars in pretty circular, normal, pro-grade orbits. They orbit in the same direction that Mars spins. You would think that if they were just randomly captured asteroids, they would maybe have wonkier orbits.

It might turn out that the kinds of asteroids that are more easily captured by Mars could end up orbiting in that more neat fashion, particularly because if they got captured at the right time and the right way, they would get circularized by what we call the solar nebula, the gas and dust that was still kind of diffusing the solar system more very early on in its history. So that's one big option. On the other hand, maybe we have a giant impact type situation, which is always my favorite just because I love explosions and I love that history of the moon. Maybe something about the size of Vesta or Ceres smashed into Mars and then that formed a disc of debris and then out of that disc of debris formed Phobos and Deimos. That's an option too.

And then there's other kind of weirder secret third things. So for example, you could have an asteroid that gets captured, but as it's getting captured, it gets fragmented by a tidal influence of Mars and sort of disrupted. And then those fragments form a disc and out of that disc, moons form. And then another one that I think has less going on for it but is still a possibility is that we have a ring moon cycle. So probably the coolest thing about Phobos is that it is dying. It is living in fear, I guess, because it is spiraling inward toward Mars at about two centimeters per year or a couple meters per century. So within tens of millions of years, maybe 50 million years, it will either crash into Mars or break up into a ring. There's one hypothesis that it's just on a cycle of that where every some number of millions of years it disintegrates into a ring and then gradually that ring coalesces back into a moon and back and forth and back and forth, a fraction of it reforming into a moon every time.

Now to explain why we see it in that process of becoming disrupted now, but there's other reasons that would maybe point against it. One of the things that MMX will do is actually look for signs of a faint ring around Mars that would be too faint for us to detect from afar, and that would support that hypothesis. And then the last thing I'll mention is that maybe Phobos and Deimos just co-accreted with Mars at the same time. They all form together. That's less studied, but also worth noting. So at the end of the day, we don't know what these moons are. We don't know whether they are asteroids or were former asteroids. We don't know whether they're fragments of asteroids that were reprocessed. We don't know that if they were chunks of Mars that got blown off. We don't know, so that's why we got to go.

Sarah Al-Ahmed: Okay. So we're going to go to Mars. We're going to go to these moons, maybe learn a little bit about what their origin is, but why do we even care? Is this something that just planetary scientists are personally curious about or does this have some kind of bearing on our larger understanding of how our solar system formed?

Asa Stahl: It has pretty profound implications. So we were talking about the different ways that Phobos and Deimos might have formed, and it turns out that could mean quite a few different things for the solar system writ large. So for one, we know that the Moon very likely formed from a giant impact with Earth. So if Phobos also formed from a giant impact, then we would be able to see how the predicted signatures of an impact actually show up the way we think and then help us see and identify others in the solar system, which I think would be pretty incredible because it's always cool whenever we can look at a different world and be like, "Oh, that exploded off of something," and also, I mean, just tells us more about where things came from and how, some of the most dramatic moments in our history.

And then also specifically with Mars, some think that if Phobos did form from a giant impact, it was the impact that formed the Borealis Basin, which is what makes Mars' northern third, the smooth lowland, and then the rest in ancient highland. This is a very longstanding mystery of why that is the case on Mars, and so this could explain that. And then if it's not a giant impact, if it's asteroid capture, then that helps us understand how that works and that's something that has led to various moons of Jupiter and Saturn and Neptune, and in general, just helps us understand how easily material from the outer solar system comes into the inner solar system, which then connects to the question of how Earth got its water and the building blocks of life. There's a lot that we can get out of it either way that ties into how we got here and how life formed.

Sarah Al-Ahmed: I have heard some ideas that potentially we could use Phobos as a staging position for future missions. What would that gain us?

Asa Stahl: I think the idea is similar to that of anything like a quasi-moon or lunar gateway would be around the moon is if you have this thing that's in a higher gravity, well, it's easy for you to get to from the moon of Earth, for example, then you can stage things on it, you can build things on it more easily in certain ways. And then from there, maybe take trips down to Mars. People have thought about this with quasi-moons too, that they're naturally going to be orbiting the planet that you're maybe interested in studying or appearing to orbit, circling it, and so that makes it maybe easier as a sort of middle point. They don't have to jump all the way in and out of these gravity wells all at once, but you can break up the journey into pieces.

Sarah Al-Ahmed: You said something interesting that I want to come back to, which is that the spectra of these objects suggests that it might be more like asteroid material. Why is there any question there? How could the spectra be misleading?

Asa Stahl: This is the kind of technical question that only Planetary Radio will ask, and I love it. So depending on where a world forms in the early solar system, it will include different materials in different ways, and a lot of that's based on just how close you are to the sun, so the temperature that you're going to be at. You're going to have ices far out from the Sun that you wouldn't have if you were close into the Sun. So you can look for signs of these sorts of things, and then it gets complicated because we have the effects of space weathering, for example, so the solar wind, high energy particles bombarding things, micrometeorites bombarding things, temperature swings. Phobos goes from really, really, really cold to just Chicago cold on a somewhat frequent basis. All these things can transform the surface and a little bit beneath the surface in ways that then could make it harder to just remotely tell what's going on.

However, MMX does carry the MEGANE spectrometer which has been contributed by NASA. That is predicted to be able to distinguish between the asteroid capture versus giant impact scenario in the majority of imagined cases. There are some where it wouldn't quite be able to do it, and that's what we have sample return for. But by looking at the chemical makeup of the moon and seeing whether it aligns better with something that formed closer to the Sun like Mars versus something that formed farther away, like an asteroid near to Jupiter, for example, you can pin down hopefully the origin.

Sarah Al-Ahmed: How are they actually going to be doing this sampling?

Asa Stahl: Well, it's something that's very near and dear to The Planetary Society's heart because they're going to do two things, and one of them, The Planetary Society's members and supporters help make happen. So we've got C-sampler and P-sampler. C-sampler is a coring device and P-sampler is a derivative of PlanetVac. PlanetVac is much more than what it sounds like, because it sounds kind of like a dust buster. It is potentially a way to revolutionize how we collect samples on other worlds. This is something, as we've been saying, that is extremely scientifically impactful to be able to do that. Bringing back samples from the moon taught us a great deal about its history. Bring back samples from asteroids, taught us about what asteroids are made of and how they could maybe have organics on them and other things that could help seed life. So if we can do that more easily than something like a robotic arm, which has a lot of parts and is mechanically complex and power hungry and tend to be expensive, then that would be fantastic.

PlanetVac does this by blowing almost pure nitrogen gas. It puffs out gas in such a way that it lifts material off the surface of wherever it's landed up into itself and then back into a collection chamber. It's a very smart design. It has essentially one moving part, which is the valve and could be much more versatile in the kinds of places it works. Planetary Society, our members and supporters funded multiple tests of PlanetVac along its development throughout the 2010s that ultimately helped to book a ride on MMX. Previously, it landed on the Moon on Firefly's Blue Ghost Mission 1 and successfully operated with flying colors, but it's never done science on the sample that it's collected. That didn't happen on the Firefly mission. That was just a technology demonstration. So this would be the first time where not only does it do science, boy, is it going to do science. This is kind of the holy grail right here.

Sarah Al-Ahmed: It's going to be so cool seeing this thing that's just been a plastic 3D-printed model around the office actually up there, seeing it on the moon. That video just brought so much joy to my heart, but thinking of it out there on a moon around another world, it's really fun to think that we all contributed to that, but also just that this technology exists at all that could massively help us in our sampling efforts.

Asa Stahl: Yeah, it is definitely, I think, an empowering and inspiring thing to think about that regular people were able to help make this happen, and then here it is on another world and soon to be on yet another world. It's incredible.

Sarah Al-Ahmed: Yeah. We'll hear from Kris Zacny from Honeybee Robotics in a moment, but the first time I met him in person actually was at the Honeybee Robotics facility when we went to go see their PlanetVac model, and they actually had it set up to do the entire process but with Nerds candy. So I finally got to see it in person. That was really fun. Much more delicious than Phobos regolith though, I'm sure.

Asa Stahl: Now you're going to have to give me a call when they can do the Nerds gummies because that would be very impressive.

Sarah Al-Ahmed: That would be impressive. Very sticky though. But it's an interesting thought. We're going to be bringing back material from this moon, which is going to tell us more about the moon as well, but there is a possibility that we might get some kind of bonus information about Mars as well on this process. How does that work?

Asa Stahl: Yes. This is a nice little Easter egg, or rather maybe 30 of them, I believe, is the estimate. So the idea is that some material from Mars may have been ejected by asteroid impacts that would then have landed on Phobos, regardless of how Phobos originally formed. And then that means samples from MMX could contain some bits of Mars in it.

For about 10 grams of Phobos sample, we would expect maybe a couple dozen grains of Mars material, and that is something that'd be quite new to us on Earth because though we have meteorites on Earth that originally came from Mars that are blasted off Mars and then landed here, those tend to be skewed toward younger Mars materials, really strong rocks that are more coherent because they have to be able to get blasted off by a really energetic impact that were more common in the early solar system and then survive this long arduous trip all the way to Earth and reenter its atmosphere and make it intact to the ground, whereas something only needs to be blasted off with a little bit of energy by comparison and make a much shorter trip to land on Phobos from Mars. So we could get more weak and fragile different materials that could tell us different things about Mars. Until we have Mars sample return, which fingers crossed, this is what we're going to get.

Sarah Al-Ahmed: Well, I'll just have to tide us over in the meantime, right? But another thing I really like about this mission is that they're attempting several really new things here on these small objects with not a whole lot of gravitation, and one of them is that they're going to be dropping this little Idefix rover on there. A tiny rover on a moon going around Mars is wild and I'm sure very difficult to accomplish. What is this rover going to be doing while it's there?

Asa Stahl: I love imagining these rovers on these worlds.

Sarah Al-Ahmed: So cute.

Asa Stahl: Yeah, I do not think they get enough play. It is cute, but it's also... I don't know. It's daring and adventurous that the gravity on these things is practically nothing. The rover will weigh a tiny fraction of what it would weigh on Earth and they have to take that into account. When it lands, like we said before, we have to make sure that MMX doesn't just bounce off. I believe Kris Zacny, when he comes on, will also be able to speak to this quite well, that they had to design PlanetVac in certain ways to avoid similar challenges. But this rover, it's joint collaboration between German and French origin, and it's based on MASCOT, which was the rover on Hayabusa2 that deployed on Ryugu.

Its goal is to last for about a hundred days or at least a hundred days on the surface of Phobos, which would be quite a long time. It's going to carry a spectrometer, a radiometer, essentially test the properties of the material on Phobos' surface, that regolith, what's its texture, what sort of minerals make it up, and also a temperature. So this will provide a really useful ground truth to the measurements being made from a distance that they can then calibrate against.

Sarah Al-Ahmed: I love that we're now in the phase where we're sending cool technologies partly funded by the public with companies collaborating with NASA, with multiple space agencies around the world, all working to send sampling and rovers to the moons of Mars. This feels like a really cool big moment that almost nobody knows is about to happen, and I hope it blows their minds when they realize that this is happening. I've been waiting for this mission for so long, and I hope it brings a lot of people joy because this took a lot of people a long time working together to make it happen.

Asa Stahl: Yeah, it's definitely the end of a journey and the beginning of a new one.

Sarah Al-Ahmed: Well, I guess the beginning of a journey that's going to take a longtime. We've got to wait until 2031. Asa, how are we going to do it? How are we going to wait that long?

Asa Stahl: Well, we've got a couple new missions between here and then that we have to look forward to. I think we'll be keeping busy. Maybe there'll be a couple of trajectory maneuvers we can pay attention to as well.

Sarah Al-Ahmed: Who knows? Well, thanks for joining us to talk about this mission, and I know we're all going to be watching that live stream together next week. So if anybody has any questions about this mission or if you have a particular amount of joy you'd like us to share with the Honeybee Robotics team, just let us know. But thanks for joining, Asa.

As Asa mentioned, one of the tools MMX is going to use to collect its sample has a special connection to The Planetary Society. It's called PlanetVac, and our members and supporters helped bring it to life years before it had a ride to the Martian Moons. Back in 2018, as PlanetVac got ready for a rocket test flight in the Mojave Desert, the society rallied supporters the only way that felt right, with a completely serious, extremely professional infomercial. Here's a blast from the past.

Audio: Speaker 1: The following is brought to you by PlanetVac.

Audio: Bruce Betts: If you're like me, you know one of the most challenging tasks in space exploration is the coveted sample-return mission, but it's not easy. Luckily for you, now there's PlanetVac.

Audio: Speaker 2: Ooh, PlanetVac.

Audio: Bruce Betts: PlanetVac, created and tested by Honeybee Robotics in partnership with The Planetary Society. PlanetVac is a low-cost, quick, and reliable solution to your planetary sample-return needs.

MUSIC: It's PlanetVac. PlanetVac.

Audio: Bruce Betts: PlanetVac.

Sarah Al-Ahmed: I just love that little piece of Planetary Society history. You can hear how much fun our team had making that, but both our team and PlanetVac have come a long way since then. The little sampler went from a vacuum chamber test to a rocket in the Mojave Desert and then all the way to the moon. In March 2025, PlanetVac rode aboard Blue Ghost, a lunar lander built by Firefly Aerospace. It was sent to the moon through NASA's Commercial Lunar Payload Services program or CLPS. Blue Ghost actually touched down in Mare Crisium, a vast lava plain on the Moon's near side becoming the first fully successful commercial moon landing. Once it was there, PlanetVac got to work, collecting lunar regolith with a puff of gas.

Next week, its descendant is going to launch for Phobos. Here to tell the story is Dr. Kris Zacny, vice president and senior research scientist at Honeybee Robotics. Kris has been working on PlanetVac since its earliest days, and he joined me at Planetary Society HQ to talk about the long road from those first tests to the Moon and now onto Mars. Hey, Kris. Welcome back.

Kris Zacny: Thank you. Thanks for having me here.

Sarah Al-Ahmed: It was wonderful seeing you recently at Honeybee Robotics over in Altadena. I loved seeing your facility.

Kris Zacny: I must say it's been a very rewarding growth. We came to Pasadena in 2010 and the primary purpose was to be closer to JPL, the premier robotic exploration institution in the world. We were originally from New York City and first office was on Elizabeth Street in Little Italy and then Midtown Manhattan. But being the only robotics/aerospace institution on the island is tough, is really tough, pulling talent and companies that think alike. The growth has been very difficult. So I moved west with our chief engineer, Gale Paulsen, and we decided to start this little office in 2010. When I arrived, I wanted to be as close to JPL as possible. So I pulled out a map of Pasadena, I put a pin where JPL is, and then I drew this circle, five-minute circle. I called it circle of pain. If you further way than five minutes, it's unlikely that you're going to come and see us for lunch or it's very unlikely we're going to go and see you for lunch.

So we narrowed down location very close to JPL, which was just over a mile from JPL, and we started our office and it was super rewarding. We didn't really know much how to run a business, but we learned very quickly. So this enabled growth. We were fortunate enough that many of our proposals got funded, so we decided to hire more people. With more people, we wrote more proposals, which got funded, and we are slowly growing, growing, growing. Eventually in 2017, Honeybee was acquired by private company called Ensign-Bickford, and this helped with a fresh cash injection, the growth, and we moved to a new location up the street in Altadena. We took over a building that used to be one of these smaller Walmarts. So sometimes if you come to Honeybee and you say, "Hey, let's go to Walmart." No, we're not going to Walmart. We're going to one of our buildings.

Sarah Al-Ahmed: It did have one of those vibes.

Kris Zacny: Yes, it's a very nice building. So we got, renovated it and we very quickly grew to hundred people. And then as we were growing, the parent company didn't know what to do with us because we were kind of an oddball within this conglomerate and Blue Origin was growing even faster. It kind of made sense that we would be part of Blue family. In 2022, we were acquired by Blue Origin, and at that point we grew even faster. So now we are 200 people and our growth or number of people that we have is primarily limited by the number of parking spots that we have. So anyway, it's been a lot of fun.

Sarah Al-Ahmed: We'll be right back with the rest of our look forward to MMX and PlanetVac after the short break.

Speaker 3: What if a salty frozen lake in British Columbia holds the key to searching for life in other worlds? That's just one of the questions Dr. Jacob Buffo and his team have been working to answer, thanks to generous supporters like you. Dr. Buffo is a recipient of The Planetary Society's STEP grants. That's our Science and Technology Empowered by the Public program, which funds groundbreaking research driven by your support. They've been studying salty lakes with chemistry like ancient Mars, chemistry that may still exist in the hidden oceans of distant icy moons.

Now it's time for the next phase. With your help, the team will build artificial intelligence tools that let future spacecraft help find the most promising places to look for signs of past or present life and be able to do it all on their own as needed, even without waiting for instructions from Earth. They'll test it right here on Earth at Mono Lake in California and the Great Salt Lake in Utah. Since 1980, The Planetary Society's members and donors have supported science and technology projects crucial to future space exploration. Visit planetary.org/step, that's S-T-E-P, today. Your support will help fund the next phase of Dr. Buffo and his team's work. Thank you.

Sarah Al-Ahmed: It's wild seeing a company that was small started in New York above a piano shop, I believe. Now you're putting things on the moon. You're building Mars rovers, and we're just this close to sending something to a Martian moon. That's got to be just so satisfying seeing this thing that you've worked on for so long make it to this point.

Kris Zacny: Yeah. The PlanetVac for Blue Ghost or pneumatic sampler, but that's essentially PlanetVac that we call on Martian Moons eXploration, it has a special place in my heart and special place in many people's hearts that have contributed to the mission. It took a village to get to this point, but the story starts back when I was still a grad student at Cal and Go Bears.

Sarah Al-Ahmed: Go Bears.

Kris Zacny: I was working on my PhD on extraterrestrial drilling and mining. As a grad student, he obviously tried to figure out the crazy ways of doing things, and that's when the idea of using gas came to be primarily based out of the work that I was doing on a drilling on Mars. What happened was my drilling setup was inside a vacuum chamber, Martian vacuum chamber. When I start drilling in icy soil and ice, ice turned into vapor. Ice essentially didn't turn into liquid, turned straight into vapor. I could see the cuttings, drill cuttings being blown out of the hole at the very, very high speed. So this was very first inspiration that gas is actually very powerful and could provide some drilling fluids and the mining approaches.

So then as a grad student, I was privileged enough to have a couple of undergraduates working with me. And then we combined into a very nice team and we came up with many methods of using gas to mine the moon. One of these methods looks sort of like a walking stick, where astronaut would walk around and press the button on top where you hold the walking stick. And then the gas would rush down into the bottom of the walking stick and regolith would rush up into the container. So we found bending over to pick up regolith, you could have just walked around and pressed the button and you would get a sample inside the container.

So then when I joined Honeybee Robotics, I learned about this program called Small Business Innovative Research or SBIR. I wrote a proposal and I was essentially fortunate enough that this proposal was funded. This is how my relationship started with NASA Kennedy, that Rob Mueller, who is at NASA Kennedy, he's a technologist and the founder of Swamp Works, he reviewed my proposal and he thought the idea is pretty crazy, but he said that that's what SBIR phase ones are supposed to do. They're supposed to pick on crazy ideas and see if they work. So he decided to select this, and since then he was a great supporter of this technology. Then phase one turned into phase two and phase two led into many different ideas and so on. And the phase two ended, ended with a design of a Mars sample-return mission using pneumatic system from a surface of Mars.

That's when Planetary Society came and they said, "You know what, ideas are fine, but let's try to demonstrate this." So using the funding from members of The Planetary Society and Planetary Society itself, during summer with the help of bunch of interns, we built a mock-up of a lander, mock-up of a Mars ascent vehicle. The lander had three legs and each of these legs had PlanetVac and the pneumatic tank. We put everything inside a big vacuum chamber. We have 11 foot vacuum chamber. Inside the chamber, we dropped the lander on a bed of soil, then pneumatic sampling acquired soil into the rocket, which was right in the middle of a lander. And then guess what? Yes, this rocket was actually launched inside a vacuum chamber and hit the top of a vacuum chamber. So if you look at the rocket, the tip of the rocket is blunt because it hit the top of the chamber many, many times.

Sarah Al-Ahmed: Many, many times.

Kris Zacny: Many times. This is the first time in the history of humankind when rocket was actually launched inside the vacuum chamber.

Sarah Al-Ahmed: This was in 2013, yeah?

Kris Zacny: It was in 2014. This demo, it was a big deal because all of a sudden it made something, turned something from PowerPoint into a real tangible thing. Everyone could look, touch and goes, "Oh, my goodness, it could actually work." This really helped to get additional funding from tech flights. So NASA has another program that's funding relatively low-technology-readiness level technologies and help them through the valley of death into the higher tier or tier five of six. So we received some of that funding to demonstrate PlanetVac on the Masten lander in Mojave.

That's when Planetary Society came again. And together with NASA and Planetary Society, we developed a PlanetVac for Masten Lander. In fact, Masten lander had four legs, four footpads. Guess what? Each of its footpads was PlanetVac. We took off and the Masten lander took off, went up, went down, landed in a bed of soil, acquire sample, took off again and landed back on a concrete platform. This was again demonstration that technology could potentially work on a real rocket, the real lander and the atmospheric conditions at 1G. So our conditions were extreme to some extent because moon is so much easier.

And then the flight came in. We were selected by NASA to fly on a Blue Ghost lander, really a dream come true and we went to the moon. We went to the moon. Initially we are supposed to do all the mission operations here in Altadena in our mission control room, but as you recall, there were big fires. In fact, the fire started where I live and fire ended where I work. So within 12 hours I could have lost my home and the business and the reverse happened. My home survived and Honeybee survived. So I was the luckiest person on this planet. But what this meant is that we couldn't do mission operations in our facilities. At that point, NASA stepped in and asked friends at Firefly if we could actually fly to Austin and sit in a mission control room in Austin and do mission operations. Firefly said, "Sure, come on over. We're happy to help." So we flew over and we set up groups of people for mission operations. So every person's supposed to sit at a console for 12 hours.

Sarah Al-Ahmed: It's a long time.

Kris Zacny: It's a long time. And then 12 hours on, 12 hours off. We landed at night. It was like, I think, 2:00 AM. And then the robotic arm that was deploying us, I think, was deployed something sometime in the morning. And then first operation was sometime in the afternoon. And guess what? Our approach to operations went out of the window. No one, no one left the seat. No one left the seat.

Sarah Al-Ahmed: Who would want to?

Kris Zacny: Who would want to? You don't want to miss the action. So we were sitting put in our seats and there were many other instruments. So we are taking turn who is going to go next, right? So Firefly folks would tell us, right, "PlanetVac, you're next," or "LISTER, you're next, or "Some other instrument, you're next." So we didn't want to miss that and no one wanted to sleep. No one wanted to sleep. So people were put in the seats. They would doze off in the seats waiting for our turn.

Sarah Al-Ahmed: Just when to get shaken awake.

Kris Zacny: And then we were given go ahead, and go ahead and send a command to the moon to send a puff of gas into the PlanetVac and acquire a sample. We had a camera. The camera was inside our sampling chamber and we took bunch of pictures of a sampling chamber, which was pristine. It was absolutely clean. What we wanted is for this sampling chamber to be dirty because then you would know you got something. So we sent a command and then we waited. We waited. We waited. We waited. We waited for a picture to come back from the surface of the moon. These incidents in your life where you know exactly where you were and what happened, they define essentially your life and this was one of those. We were very stressed out.

Sarah Al-Ahmed: I'm sure. I mean, the previous two landers that had attempted to make it to the moon both didn't make it. One, I guess, technically made a soft landing but tipped over. So knowing it was there all-

Kris Zacny: Yeah, we we're on its two-

Sarah Al-Ahmed: That's got to be so terrifying.

Kris Zacny: It was very terrifying. What was also terrifying is the pneumatic mining system was never tested on a moon. This was the very first time that somebody would use pneumatic mining to do mining on the moon for this matter of planetary bodies in this way. So it was like Edmund Hillary climbing Mount Everest. You don't know if it's possible to climb Mount Everest, right? And he did it and then everyone else realized it is possible to do this. So for us it was very, very stressful and we are eagerly awaiting for a picture because you can imagine if a picture came in and there was nothing inside, that would have been pretty embarrassing. And then everyone would say, "Guys, this is crazy idea. You should have used scoop and the robotic arm like everyone else." Finally, we saw the data coming down. It was a big file. It was a file of our image. And then we opened the image and no one was breathing. And then what we saw was dirty screen.

Sarah Al-Ahmed: Success.

Kris Zacny: I've never been so happy seeing camera lens to be dirty. Okay. At that point, we knew, "All right. It worked. It worked." And then we did more tests, more tests. What we realized after analyzing data, after analyzing pictures and videos... By the way, Firefly took a video of us taking a sample so we could see the PlanetVac blowing gas and blowing regolith to the side. We did some analysis and what we realized is that PlanetVac was not actually really touching the surface. It was off the surface, only like the tip was barely touching, everything was off. So it's to some extent borderline magic that without touching the surface, we managed to scoop regolith. There was another surprise. The camera that was watching us got kind of dirty during landing. It was like watching something from the fog. When we fired gas, this gas essentially cleaned up the camera lens, blew away all the fines from the camera and they made the picture pristine clear. And not only our camera looking down, but also cameras around the rocket engine. So the good thing about using PlanetVac, it has a cleaning effect on all the cameras.

Sarah Al-Ahmed: I mean, that's really useful because even if you don't use PlanetVac as a technology, just using this kind of pneumatic system could be a good way to clear off all the cameras after landing. We're going to need that in the future.

Kris Zacny: Yeah, absolutely. So it was a great mission. And then Maria Banks, who was a program scientist on a mission, came over. She asked how we doing and she was super happy to see us succeed. And then she asked, "Well, we still have few other missions." I said, "Maria, we are supposed to run a PlanetVac couple of more times," but I said, "Maria, it's time for other instruments to take a turn. If there is a time at the end, we can still send a puff or two, but it's time for other people, other principal investigators to push the button, deploy the instruments and have as much fun as we had." What's amazing, this mission had, I don't know, like seven to 10 instruments and actually all of them worked.

Sarah Al-Ahmed: That's amazing.

Kris Zacny: All of them worked and there's nothing better to see every single instrument succeed. The mission was a really dream come true mission.

Sarah Al-Ahmed: Yeah. We were all watching and cheering the entire time. I'm definitely going to be sharing that video of what happened when PlanetVac worked on the surface. That video is so cool.

Kris Zacny: Yeah.

Sarah Al-Ahmed: Did PlanetVac not touch the surface because of the orientation of the spacecraft?

Kris Zacny: Yeah. So what happened is it's typical a four-legged table problem. You go to a restaurant and whenever table has four legs, it tends to be wobbly, right? And then you lean down and you stick a piece of cardboard or napkin to stabilize it. So that's exactly what happened on the moon, that we landed on the side of the crater rim. PlanetVac was close to one of the legs, but lifted off the ground. So that's a reason why it couldn't reach and it couldn't be flat on the surface. But despite that, the technology was robust enough to actually do all the sampling. So I can tell you our engineers at Honeybee, they essentially were coming out with extreme scenarios like, "What if we land that way? What if we roll 20 degrees to the left? What if we roll 20 degrees to the right?" And then they would go straight into that test mode. They would put the PlanetVac for its paces.

So I would say the credit to all the team that came out with all the crazy ideas that we could be deployed or we could potentially fail and proving every single time that it could work. At one stage, the amount of tests we've done was over a hundred. We would have meetings and the team would go, "Oh, we only acquired 20 grams," or "We only acquired 50 grams." There was arguments, "We should do this, we should do that." I said, "Guys, have you ever done a test where we acquired nothing?" And there was a silence. There was a silence in the room. And then somebody said, "No, we always got something." I go, "All right. You guys are brilliant. Okay. You guys are brilliant, because at the end of the day, acquiring something is better than obviously acquiring nothing."

Sarah Al-Ahmed: Well, I'm sure, as with all scientists, we're all our worst critics, right?

Kris Zacny: Yeah.

Sarah Al-Ahmed: So you want to make the optimal design that's going to make sure you get exactly what you want, but the fact that it worked every single time bodes really well. The fact that we've seen it work on the Moon, also very great. I've also seen personally it work on many Nerd candies. That was really fun at the office. But now you guys are going to be entering a scenario where you're going to the Martian moon, Phobos, and the gravity on Phobos is so much less. How do you account for that when you're using a pneumatic system? Wouldn't you potentially thrust yourself off of the moon?

Kris Zacny: At the end of the day, MMX is a sample-return machine. So we really had to change our approach to sampling and try to solve all these problems. So one of them that you mentioned is the gravity is really small. I don't remember the exact gravity, but I can tell you, I weigh 200 pounds and on Phobos, I would weigh two ounces. Okay? That's what I remember. Phobos is size of Manhattan and it's relatively small moon. So we were worried. We were worried that... At the end of the day, gas is like a rocket, right? It blows gas at the certain thrust and the impulse and last thing we want is for the lander to hop or move.

So again, what people, our team decided to do is, well, the best way to counteract thrust is with anti-thrust. So we have a couple of nozzles pointed straight up. So as we blowing straight down to stir up a regolith and create these micro tornadoes for vacuum cleaning process, we also have couple of nozzles pointed straight up. This momentum of gas going up, so to some extent, cancels out momentum of gas going down and makes us to some extent neutral in terms of momentum and the thrust. So this helped that particular problem.

Then we had another problem. This is a sample-return mission, right? These samples will be coming back home in 2031 and they're going to land in Australia and taken to Japan, to the lab, and then distributed to bunch of other labs, including JSC curation facility for us to analyze. It's really important to make sure that we do not bring any bugs with us to Mars and only to rediscover microbes, right? So the cleaning process has been second to one. We had to go into ultra-clean room. It's a 1K clean room. Everyone was dressed up in bunny suits. The only thing you could see is eyes and behind glasses, but it was super, super clean. Every single thing had to be clean. It had to be rinsed. It had to be verified that it's clean. It had to be bagged for shipping. You had to have all the covers to make sure that a system remains clean.

And then there is a so-called tiny witness plate in our sample canister. The purpose of this witness plate is to witness any potential contamination that PlanetVac could have acquired during integration and test during launch and even post-launch when the spacecraft is outgassing. So when the sample comes back, we're going to grab the sample and we're going to grab this disc, this witness plate, and we're going to analyze to see what things hitched the ride to Phobos and back. So this was a bit of a departure from PlanetVac, which it doesn't necessarily have to be extremely clean, even though it was assembled in a clean room, not the same quality of clean room as a pneumatic sampler, but nevertheless, still a clean room.

So anyway, we're waiting on launch. The launch is October 19th, October 20th in Japan. Just recently, actually, I did went to the launch site and Masaki Fujimoto-san, who is a director general of ISAS, which is a planetary division of JAXA, decided to come as well, and Sato-san, who was leading development of a C-sampler or core sampler, which is another beautiful engineering feat sampling system on MMX. We went to see the spacecraft, all stacked. It consists of three parts. It has legs. It has this thing that's going to bring samples back and it has propulsion module. So that was a really beautiful view.

The spacecraft is huge. It's a humongous spacecraft. It's really, really big. The legs are like three meters long and it has four legs. And then we saw the rocket and rocket is all ready. It's all ready to accept the fairing with the spacecraft. I mean, it was quite a sight. For myself and Masaki Fujimoto-san, it was also a bit emotional because Masaki-san has been working and the Sato-san has been working on it for a long, long time. It's essentially somebody's career. So everyone was super happy to see things coming together. We are very ecstatic about the launch and the mission operations 2029. It's going to be a lot of fun.

Sarah Al-Ahmed: Are you going to be there to see the launch in Japan?

Kris Zacny: So I'm going to miss the launch.

Sarah Al-Ahmed: Oh, no.

Kris Zacny: My wife said, "Another international trip and the divorce papers are coming your way." So I'm going to miss it. Also, as you know, very often the launch gets slipped because of the weather and all of those. But I'm going to be cheering. I'm going to be watching and I'm going to be in a mission control when we're going to do the sampling and the operations. That's something I'm not going to miss. It's once in a lifetime. Hopefully, I'll make my way to Australia when a sample canister is going to come back with the rest of the samples.

Sarah Al-Ahmed: I was just speaking with someone the other day who went to see a canister come down from Hayabusa, the first one in Woomera, Australia and what that experience was like. It sounded very thrilling and I hope you get that experience because after all of the work you've done, the fact that this started as a dream back during your Berkeley days and now has arced all the way to a Martian moon, that's got to be so satisfying. When that comes down, I hope you're there to see it.

Kris Zacny: Yeah, I hope so. Again, it took a village. It took so many people at NASA, Planetary Society. In Honeybee, we had so many people rolling on and off the project during different phases of a project. It really took a village and each of those folks is absolutely critical to the success. So there's going to be a lot of folks cheering for this mission and a lot of happy faces when the sample comes back.

Sarah Al-Ahmed: And all of The Planetary Society members included. We are so excited that we could be a part of this and the questions that we're going to be able to answer is just so exciting and PlanetVac gets to be part of that legacy forever. So I'm really glad to get to talk to you about this and I'm going to be cheering your team on that whole time during the launch.

Kris Zacny: Go MMX.

Sarah Al-Ahmed: Go MMX. Thank you so much, Kris.

Kris Zacny: Cool. Thank you.

Sarah Al-Ahmed: Before we head into What's Up, I want to send a little love to the entire MMX team at JAXA and at every partner agency and company around the world. This took a lot of effort and I cannot wait to see it launch successfully. There's a phrase on the MMX mission poster that I cannot stop thinking about. "See you in five years. Until then, take care of Earth." I love that. A spacecraft headed all the way to the moons of Mars, asking us to look after our own planet while it's gone. So from all of us here at The Planetary Society, itterasshai, MMX. Go well and come back safe. We'll be here and we'll see you in five years. And now it's time for What's Up with Dr. Bruce Betts, our chief scientist here at The Planetary Society. Hey, Bruce.

Bruce Betts: Hey, Sarah.

Sarah Al-Ahmed: PlanetVac. PlanetVac.

Bruce Betts: PlanetVac.

Sarah Al-Ahmed: I'm so glad we got to pull the audio from that. That infomercial was-

Bruce Betts: Oh, you did get it.

Sarah Al-Ahmed: I did.

Bruce Betts: That's great.

Sarah Al-Ahmed: I did get it, and it is so funny because I want to say that was one of the first things that our coworkers shared with me when I came on at The Planetary Society as an example of our more wacky stuff. I loved that.

Bruce Betts: Yeah, it's a good time. We had a few of those doing the PlanetVac.

Sarah Al-Ahmed: PlanetVac. Well, PlanetVac, it goes back further than our involvement in it, but I am curious, how did The Planetary Society originally get involved in this? We heard a little bit about how Kris thought about this, but I don't know, what were you thinking when this first came across your desk?

Bruce Betts: I was thinking, "Hmm." And then I thought that in silence for a while and I'm hesitant on anything to begin with. And then when we started working with them and they're really good people and do great work, I was much more comfortable with exploring this. And then it was neat. It was fun. Learned a lot in a realm of things that I wasn't that familiar with, drilling on extraterrestrial planets and in some cases or in this case, figuring out how to collect samples, however you do it. So we got involved in this thing in 2012, 2013 where we supported them. They needed funding for a test in a Mars simulated atmosphere in a big vacuum chamber. So I think that's a good time. So they had a big vacuum chamber that was the size of an analogy that most people won't recognize anymore, but a phone booth and did the experiment to see if it worked in a Mars atmosphere and as a whole system.

So that's what they'd done pieces here and there, but they never put together a mock-up even of a full system test. So that's really what that did. The point of that was then to get it to the next stage where they could get additional funding to take it to the next stage. And then we came back a few years later in 2018 and we had these great tests in 2013 with fun sampling and picked up a bunch of dirt. They learned a lot about how to design the details. And then things happened, things happened. 2018, they had funding for significant portions of a flight on a Xodiac rocket, which is a hovering rocket in this case that basically tests can your instrument survive being shaken around by a rocket blasting right near it and then do its job. But they didn't have full funding, so they couldn't quite make it.

So we were able to get together funding with members and donors supporting it. And then we got to go out and watch and have a flight of this rocket with a prototype of PlanetVac that then landed. It went up and hovered for 30 seconds or so with the big rocket blazing. And then it came down on simulated Mars soil dirt and did a successful sampling. They got three times what they had hoped is a minimum of what they'd collect and it was groovy.

Sarah Al-Ahmed: It would've been so cool to be there for that test. I've seen the videos, but you're out there, you're dealing with regular simulant, you're dealing with a rocket. Also, I love this fact, Pendleton Ward, who was the creator of Adventure Time was there that day. How did that happen?

Bruce Betts: He was interested in what we did and made a contact. I don't remember who contacted whom, but Pendleton was into it and even created a little animation. He was, of course, the creator of Adventure Time and other animated things. So it was fun. He made a little animation tied to PlanetVac, and he was out there that day with a colleague and had a good time.

Sarah Al-Ahmed: Man, so cool to know that all these tests are now going to amount to something literally on Mars. I mean, on Phobos, but in the Martian system.

Bruce Betts: And bringing it back to Earth.

Sarah Al-Ahmed: Yeah, and bringing it back to Earth. I mean, we might not get full Mars sample return, but we're going to get Phobos sample return and that's sick.

Bruce Betts: That means very good for those not familiar with the inverse terminology. I don't understand. But what I do understand is PlanetVac's cool and Phobos is cool as we talked about a couple shows ago, and this is exciting. We're very excited and very pleased and so glad that our donors and members stepped up when we needed it. They needed a little infusion here and a little infusion there so that basically when they did something like once they had the Zodiac test that was successful, they then could really have something more that they could show of, "Look, this thing works and we can take it to the next level when they proposed it on a missions." That's how they flew it to the Moon, collected samples just like it was supposed to, and now off to Phobos with MMX.

Sarah Al-Ahmed: Seriously. Good luck MMX.

Bruce Betts: All right. Onto Random Space Fact Rewind. Ceres. Ceres.

Sarah Al-Ahmed: Ceres.

Bruce Betts: Has more than a quarter of the mass in the asteroid belt. Millions of asteroids. Ceres is the biggest object there. Dwarf planet nowadays in classification. Fascinating as we learn from Dawn spacecraft orbiting there, all sorts of weird stuff going on that you wouldn't expect in an object that size just hanging out in the asteroid belt, but it's more than a quarter of the mass of the asteroid belt in that object. And then you take the next two or three biggest and you really comparatively small stuff and lots of it in the asteroid belt. But it's still really, really spread out for those of you watching science fiction where people go through asteroid fields where they're a few meters apart.

Sarah Al-Ahmed: Yeah, that's always my biggest pet peeve whenever I see something like that. I'm like, "If these asteroids are too close together, maybe make it a planetary ring or something instead if this is your intention."

Bruce Betts: Yeah, exactly. Then you can at least get a ballpark of that, but you stick it in an asteroid, random asteroid fields that can happen. But Ceres, cool. Learn more.

Sarah Al-Ahmed: I remember that moment when they first got the data from Dawn back about Occator Crater and that shiny thing in the middle back when it was still a mystery. Now we know it's salts, but at the time it was like, "Why is that so shiny?" Really cool.

Bruce Betts: It's so bright compared to everything around it. But salts, that becomes interesting on its own.

Sarah Al-Ahmed: Yeah. Ceres deserves to be counted among the cooler worlds. Whenever people get upset with me that Pluto is a dwarf planet, I'm like, "You are not mad that Ceres is no longer a planet." And that is a cool world, so priorities.

Bruce Betts: Ceres has gone through more name changes than most anything else in category.

Sarah Al-Ahmed: Right.

Bruce Betts: It started out as a planet and in the early 1800s, discovered in 1801, I believe, and then ended up... Some people thought it was a comet, and so then an asteroid dwarf planet. It's a party. But you know, it doesn't matter what you call it. It's really cool, whatever you call it, whatever you call Pluto, and so at some point, the important thing is to explore these worlds and learn cool stuff.

Sarah Al-Ahmed: Well said, bro. Well said.

Bruce Betts: Thank you. Thank you very much. All right, everybody. Go out there and look up the night sky and think about ice. Just think about ice. Thank you. Good night.

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 space science and exploration. If you love the show, you can get Planetary Radio T-shirts at planetary.org/shop, along with lots of other cool spacey merchandise. Help others discover the passion, beauty, and joy of space science and exploration by leaving a review or rating on platforms like Apple Podcasts and Spotify. Your feedback not only brightens our day, but helps other curious minds find their place in space through Planetary Radio. You can also send us your space thoughts, questions, and poetry at our email, [email protected], or if you're a Planetary Society member, leave a comment in the Planetary Radio space and our online member community app.

Planetary Radio is produced by The Planetary Society in Pasadena, California, and is made possible by our members. Some of you helped fund PlanetVac's very first tests, and next week its descendant launches to the moons of Mars. Imagine what we'll build next. You can join us at planetary.org/join. Rae Paoletta is our producer. Kate Howells and Mark Hilverda are our associate producers. Casey Dreier is the host of our monthly Space Policy Edition, and Mat Kaplan hosts our monthly Book Club Edition. Andrew Lucas is our audio producer. Josh Doyle composed our theme, which is arranged and performed by Pieter Schlosser. My name is Sarah Al-Ahmed, the host and executive producer of Planetary Radio. We'll all be cheering on MMX next week. Ad astra.