Planetary Radio: Space Exploration, Astronomy and Science - A Comet’s Legacy, and a Helicopter is Ready for Mars

Episode Date: September 4, 2019

First we return to JPL for an update on the Mars Helicopter that has just been attached to the belly of the 2020 Mars Rover. Then it’s across the pond for a review of the amazing science coming from the Rosetta mission that spent years exploring comet 67P/Churyumov-Gerasimenko. We wrap things up with another What’s Up view across the solar system and beyond. Learn more about this week’s guests and topics at:  http://www.planetary.org/multimedia/planetary-radio/show/2019/0904-2019-balaram-helicopter-rubin-tubiana-rosetta.htmlSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

A comet's rich legacy and a helicopter that's ready for Mars, this week on Planetary Radio. Welcome, I'm Matt Kaplan of the Planetary Society, with more of the human adventure across our solar system and beyond. We've got it all this week, beginning with a status report on the Mars helicopter that has now been mated to the 2020 rover at JPL. Then we'll meet two of the happy scientists who will be working with data and images from the Rosetta comet mission for many years to come. They'll give us a peek at just a fraction of that great science, and we'll finish with another What's Up segment, courtesy of Bruce Betts. Most of you probably remember my conversation with Mimi Ong in our July 31st episode. The first flying machine to head for another world was still going through final testing. Now the little helicopter has been attached to the belly of that new rover.

Mimi wasn't available to give us an update, so we turned to Mars Helicopter Chief Engineer J. Bob Ballaram. Bob is Principal Member of Technical Staff at the Jet Propulsion Lab near Pasadena, California, where he works with the Mobility and Robotic Systems section. Bob, thank you for coming on to Planetary Radio to give us just a quick update on the Mars helicopter project, which our audience is so enthusiastic about. Me too, actually. Where is it now? Last week, we did both a mechanical and an electrical integration procedure with the rover. So mechanically, it consisted of the rover being flipped upside down so that we had access to the belly area, the belly pan area. And prior to that, the Mars helicopter had already been integrated with its delivery system. This is

the system that actually lowers the helicopter onto the ground in a safe manner from the underside of the rover. We also electrically mated with our base station, which is the piece of the helicopter system that stays with the rover. And that's our primary interface to the rest of the rover system. So that electrical interface consists of battery charging lines and serial communication lines that allows us to look at status and so forth during cruise and before we get deployed, mating of our onboard battery to the base station charging circuits. We did a food electrical checkout. And then we also charged up the battery, which hadn't been charged in a couple, three weeks. We charged it up back to a safe level. So that keeps us going till the next charge point. So that was all accomplished and everything looked good. And then

after that, the rover is going through its preparation for environmental testing. And we will be participating in those environment tests, I believe it's through October. There's a vibration test. There's a system thermal test. During that system thermal test, we will also be going through a deployment checkout again. So that's what's upcoming. A lot of us have been following along, watching the action in the high bay there at JPL. It looks like not only is the helicopter now integrated with the rover, but the rover is pretty much finished and very close to being ready for those environmental tests. Oh, yes, I believe it.

I can't directly speak for the rover team as a whole, but that's my understanding, too, that they're all ready to go into environments right now. You have provided a good reminder of just how complex some things can be, in fact, almost always are, that otherwise might be guessed at being pretty simple. The integration of the helicopter and all of these connections that have to be made successfully for battery charging with your base station and so on. Nothing really is simple or easy when it comes to space exploration, is it? I think it's a matter of being extremely thorough and, you know, looking through all the possibilities before attempting a particular operation. Many times you only get one chance. You don't want to jeopardize anything by making a mistake. It's

not something you'd run off to your hardware store and pick up a spare part if you make a mistake. So there's a lot of procedure write-up, there's a lot of scrutiny, there's a lot of peer review to make sure that we haven't forgotten anything. And then it's a very deliberate process with not only actually the main procedure being run, but there are folks from our quality assurance groups who are there to remind us and make sure that we don't forget anything and scrutinize every step. That's the way in which essentially the things get done to the best of our ability, because human beings are still the weak link in the chain. But we try to minimize as much as possible, you know, the possibility of doing something wrong. In the case of electrical

integration procedure, I mean, there's a lot of safe to mate checking where you make sure that the, you know, the various things that are going to connect up. Before you connect them, you take them out to a breakout box and you verify that resistances and measurements and what's supposed to be open is open and what's supposed to be closed is closed. And you do all of those combinatorics and you verify that it meets your expectations. And then after that is when you actually like connect up, you know, two cables. You don't just connect up the cables and then find out afterwards that somewhere along the line something got miswired. Yeah, that could obviously be a disaster. So you're going to be busy through the testing period and maybe have some things to do right up until launch. But then what happens during that long trip to Mars?

What do you, Mimi, and the rest of the Mars helicopter team, what will you be doing during that period as you wait for entry, descent, and landing? So right now we are getting our entire operations tools in place. There are operations related to once we are on Mars, how do we select a good site from where we would conduct our experiments. So there's certain requirements on our drop zone being nice and level so that we get the safest possible drop and then we have this little landing pad area where we will, you know, do all our flight operations. Tools that we need to make sure that we find that place quickly and

it's safe to drop off and how do you make the assessment. So that's one set of tools. Then there's another set of tools which are all related to, you know, how do we fly the system? We get downlink telemetry. How do we quickly process it? How do we give the helicopter operations team enough situational awareness as to what the helicopter has done? How do we then take the data and then, you know, also like run simulations going forward to make sure that the upcoming flight is good? And it's not just flying. It's also like things like heater set points and battery state of charge and how well is the solar panel doing.

So there's a whole set of operations tools and processes where lots of boxes which need to be connected, some of which which are people type processes and others which are like more automated tools. So all of that toolkit has to be in place because once we launch, we'll actually be going into more of a training up the ops team and practicing together with the rover team, a lot of the operations. So these are called operational readiness tests, which will probably be about a year from now.

So right now, all the focus is on getting all the tools in place. We have built the hardware, but now it's all the operational side that we have to focus on. So plenty to keep you busy. Here's something that only just occurred to me. We all know that the rovers on Mars have all had drivers, not that they have a steering wheel in front of them. Is the Mars helicopter going to have someone or a team of people called pilots? I don't think we quite have that designation. someone or a team of people called pilots? I don't think we quite have that designation.

I think since it's quite autonomous, you know, we have an operations team that will decide what the next waypoint in the sky would be and what the sequence of those waypoints would be. So to the extent that those waypoints get selected and visualized by our ground ops team, that's the extent of driving, but there's nothing more than that. It's basically just making sure we get the right X, Y, Z, and sort of heading types of lists that are safe and do what we intended to do. And then we'll, of course, have a number of operations things that are related to when do we wake up the helicopter, what temperatures do we set for the batteries, the set points for the thermostats. So there's a lot of housekeeping kinds of things that need to be done and what kind of priorities we give for the data we return.

We have a limited bandwidth overall in terms of data. Most of the data that we get will probably be just left on the helicopter because we just can't send it all back. So prioritizing those thumbnails, those kinds of things. It's going to be quite a big team trying to run it for those 30 days of operations. So only part of it is really driving. I don't want to even call it that. As we heard from Mimi, I mean, you're pioneers at this. Nobody has ever done anything like this before on a different world. So I'm sure there'll be a learning process as well. Yeah. In fact, just as much as, you know, the building of the hardware and the software was a learning process. We also learned along the way, how do we test such an animal that's never been built before? But the third

leg, which is yet to come, is how do we operate such autonomous agents on another planet where it's not quite a spacecraft, which is in a sort of a steady state environment like an orbit or interplanetary cruise where things are very predictable. Nor is it like a rover where it's almost quasi-static and you can always have the luxury of sitting and thinking if something goes wrong. And you can always have the luxury of sitting and thinking if something goes wrong. So here we are learning how to operate something that's in a much more dynamic environment and also in a much more uncertain environment. So that's kind of one of the big benefits that we will get by actually doing the real operations that we could never really get that full experience by just simulations or by a test program. simulations or by a test program. So learning how to operate such a vehicle, also learning how to operate such a vehicle in the vicinity of our mothership, you know, so that's going to be the other, a lot of safety related things. I think overall, it'll be a pathfinding in that sense that, you know, any future mission that has this kind of mother-daughter relationship between a big, say, rover asset and a helicopter or a future deployable system.

We'll learn how to operate that too. And then, of course, future bigger helicopters, we hope that with the success here, we'll likely scale up and be sending what I would call science helicopters in the 20, 30 kilogram class with one to two kilograms of science payloads, if not more.

This all will be pathfinding for that. And that's why we are doing this as a technology demonstration is to learn all of this. And elsewhere, too. I mean, we talked with Mimi about how you were staying in touch with the Dragonfly folks at APL who are going to send a flying machine to Saturn's moon Titan. Let me finish with this, since I read that you are also an EDL, an entry, descent, and landing guy. Are you going to be any less anxious when the 2020 rover carrying your helicopter approaches Mars

than you were when Curiosity arrived almost eight years ago? Amazing to think it's been that long. They had their seven minutes of terror. I think we'll call it our seven seconds of terror with the landing, perhaps. Yeah. But my guidance and navigation control lead, he wants to break the record for the number of landings on Mars. So he's hoping to do that with his helicopter. So assuming we're successful and we don't crash, he's looking to break the landing record on Mars because he thinks that over 30 days he might get a lot more landings on Mars than anybody else.

There's both a part of it that makes us anxious, but I think there's part of it that new ground, new means of mobility, the whole aerial dimension. It's kind of slightly exciting to think that the last time somebody first did a powered control flight on a planet was on Earth, you know, with the Wright brothers. So in some sense, it has that sort of feel to it. I think the team is both simultaneously excited and nervous at the same time. And I think that's the right place to be. I couldn't agree more. It is quite an adventure. I wish you and Mimi and the rest of the Mars helicopter team, well, the whole 2020 rover team, the greatest of success.

We sure look forward to checking back in with you folks when that helicopter is on its own, on and above the surface of Mars. Thanks so much, Bob. Thank you. You're welcome. Bob Ballaram, chief engineer for the Mars helicopter project at JPL. The 2020 rover is slated to leave for the Red Planet in July of next year. Planetary radio fans probably know better than to think that the end of a spacecraft's life means the end of its contributions to knowledge of our solar system and the universe. The European Space Agency's Rosetta finished its pioneering work at Comet 67P nearly three years ago in September of 2016.

As you're about to hear from my next guest, the science continues to amaze with more surprises surely in store. Martin Rubin is a researcher in the University of Bern's Department of Space Research and Planetary Sciences and serves on Rosetta's mass spectrometer team. His colleague Cecilia Tubiana is a research scientist at the Max Planck Institute for Solar System Research in Germany, and is part of Rosetta's camera team. Together, they contributed an article to the June solstice edition of the Planetary Society's magazine that you can read for free on our website, planetary.org. That's where we started our recent conversation. Martin and Cecilia, thank you so much for joining us on Planetary Radio,

and thank you for contributing this wonderful article to the Planetary Report, Rosetta's Ancient Comet, ESA Mission Unlocks the Secrets of Icy Relics. Thank you for joining me today. Thank you. Thanks. Of course, you are looking at some of the results coming back from Rosetta after its exploration of Churyumov-Gerasimenko, or 67P, as I will call it from here on out, just so that I don't run into the pronunciation difficulties. It is clearly, and you say this right at the top of the article, it was a tremendous technical success. But you do open the article by saying it's the science that Rosetta has delivered that is really its greatest success. And I couldn't agree more. Really, the science coming back from this mission,

it's going to keep folks like you and the rest of the Rosetta team busy for a long time, isn't it? Martin? Yes, absolutely. We are still doing science investigations, and we keep on working on all the data that we've collected over the course of these two years. You know, the instrument was running 24-7 pretty much, and there's so much data that nobody actually has looked into. So that will keep us busy for quite some time.

So is it possible that there are still big or even small surprises left in that data that just hasn't been seen yet? I think so. There are still a few surprises. Actually, we are still detecting new species in the ices of this comet. Actually, we measured the composition of the coma, for instance, and we're still finding molecules and we're still looking for traces of other species that might be present that nobody has seen before. And hopefully we can get into a little bit of that. Cecilia, you were part, are part of the camera team for Rosetta.

Anyone who takes a look at this article, which is easily seen at planetary.org, you can find the entire spring edition of the Planetary Report there. Anybody can take a look at it for free. And of course, Planetary Society members receive the printed copy of the magazine. It's hard to get over how spectacular the images are that have been returned by Rosetta. Have all of those, we may not have looked at all the scientific data yet, but have all of the images been examined? No, definitely not. So a large majority of images have been looked at and analyzed, but I'm pretty sure that some has not yet been looked at. So

there are so many images. So OSIRIS has acquired 80,000 images during these two and a half years. And I very much expect that some of this has not been looked at yet. That is quite amazing. And what a legacy for this mission, for this spacecraft. You had over two years, just over two years at the comet. And of course, science was underway even before you reached the comet. There really is nothing like being able to stick with an object over time, is there? Particularly in this case, right, Martin? Yes, absolutely. We encountered the comet when it was well beyond the three astronomical units from the Sun,

so more than three times the distance from Sun to Earth. And then we followed it to its closest point to the Sun, which is just outside of the Earth's orbit. And then we moved out together with the comet again. And so we encountered very, very different regimes in this activity, meaning how much gas is coming out of this object. And we could really follow this through an important portion of its orbit. Yes. We talk about this a lot with the Cassini mission because it had so much time at Saturn. Certainly very true at Rosetta because as you said, you were able to track it right through its highest point of activity as it approached and then departed from the sun.

Yes. And also if we go back to other comet missions, one very prominent example is the Chotto mission, which passed by Comet Alley. And the flyby speed at that time, it was huge. It was almost 70 kilometers per second. So actually the data collected there, it was maybe over 10, 20, 30 minutes at max for the whole encounter. And now here we have two years of data. And also with technology that has improved since. So actually, there was a big leap,

a big leap done in cometary science, I would argue. Absolutely. Cecilia, with so much left to learn, I mean, you even say in the article that it is really no more than an overview of some of the biggest findings so far from the Rosetta mission. But can we now say with confidence that Comet 67P is a remnant of our solar system's formation four and a half billion years ago? Well, comets are remnants from the solar system formation. Then how much they have evolved, this depends how much they have been in the close vicinity of the Sun. Definitely, 67P has come in the vicinity, I mean, in the last few orbits.

So it has evolved. That's clear. Sure, the results that have been provided by the different instruments show that 67P is a remnant from the formation of the solar system. What was most surprising about what we've learned about the comet so far to each of you? Martin? I mean, there's lots of spectacular discoveries. I mean, the first, well, maybe I'm taking this away now from Cecilia, but, you know, already the first pictures of the comet, I mean, it was astounding that the shape, the way it looked was so different from what was expected originally. And then, of course, all these theories

come along on how these objects form, you know, is it the gentle collision between two cometesimals and now looking at other comets and their nuclei, it seems that this is quite a common shape. So we are looking at the result of a process that seems to be quite common. And really, the Rosetta mission brought this very much to our attention. About that shape, can you remember when someone first referred to this comet as looking like a rubber ducky? Oh, well, this was as soon as we had, so as soon as the spacecraft was close enough to the comet that we could see its shape. So at the beginning, while the spacecraft was approaching, it was just a dot. And then these dots start to be a flickering dot. So it was clear that

the object was far from being spherical. And then the space track got a bit closer. And then it was clear that it was something that we definitely did not expect. And when we could see these two lobes, it was immediately called the duck shape. And you mentioned in the article that not only was that entertaining, it caught on with the public, but it was useful because if somebody referred to, let's say, the neck of the duck, people knew where to look. Yes, exactly. I mean, it's sometimes difficult to point to features on an object when you are just talking to it. But having this peculiar shape,

it's easy for everyone to identify the head, which is the small part, the body, which is a big part, and the neck, which is the connection between the two. So this really helped in also in talking, in describing, in discussing. It is a fantastic looking object, quite striking, and certainly much more diverse, the surface, than I was expecting. I mean, did this diversity surprise the two of you and members of the team, or was it pretty much what you expected? I think it was quite a surprise. You know, very early on in the mission,

we were actually looking for a smooth spot for the lander, so that the lander would certainly have a safe landing. And look at this object, there is no smooth spot, you know, large enough that we were absolutely sure that we would not hit some boulders or something else on the surface. So it was a big surprise to everybody. And in the end, there was, of course, some risk involved for the lander. But this basically shows very much how surprising or how unexpected the object was. Cecilia, one of the images in the article also shows the comet from two sides, basically the two poles of the comet, and they are quite different.

Can you talk about that? Yes. These images, I think the ones you're referring to, show the northern and the southern hemisphere. Yes. And these are really different. So the northern hemisphere looks much more dust-covered, much smoother.

And it has these big pits and these big cliffs and features. When the Southern Hemisphere was then imaged at the same resolution, so we could really compare the images from the North and the Southern Hemisphere, we could really see how the Southern Hemisphere instead is much more rocky. It resembles like our mountains. You don't really see this dust cover, which is typical of the northern hemisphere. And this was one of the very big differences that we have immediately noticed with the southern hemisphere could be really image at high resolution.

Martin, anything to add? It's actually interesting to look at the seasons on both hemispheres. So we have a very short but intense summer in the south that's during the passage close to the sun. But then for the remainder of the orbit, more than five years, it's actually the northern hemisphere, which is better illuminated, but farther away from the sun. So both hemispheres witness much different seasons. This is also seen in the outgassing, in the activity of this comet. And so actually these

objects, they lose mass. Of course, all the gas or the coma, as we call it, this atmosphere that's lost into space, this is all ice sublimating from this object. And as this happens, these objects get smaller and smaller. They lose mass. And it's actually very different in the north and in the south. This comet loses much more mass from the southern hemisphere than from the northern hemisphere. I'm so glad that you brought this up, because I wanted to talk about the material that the comet lost as it was being observed by Rosetta.

How much mass was the comet actually losing to space as it was heated by the sun? And of course, that varied over time, I suppose, as it approached the Sun and then receded from it. Yes. The closer it got to the Sun, the more material it lost. And I think the estimate is on the order of per mil of its own mass that it lost during these two years that Rosetta accompanied the comet. That basically tells you there's a limited number of orbits that this comet will do before it will disintegrate. Do we have any idea how long 67P might continue? I think this is actually quite difficult to say. Maybe Cecilia has some more information, but it's probably not just the mass loss that is an issue but also

and that's another very interesting result is actually we've seen that this comet is spinning up so at the spin rate is going up it's so to say the comet days get shorter and shorter when we encountered the comet one rotation lost 12 hours and 24 minutes and at the closest point to the sun we were down to 12 hours so the comet is spinning up and at some point it might just be that the two lobes are pulled apart because of the rotation and the associated the push in both directions of the two lobes so it could just tear itself apart. Yes, that's a possibility. Yes, and that is most likely the cause of the disruption of this comet rather than the loss of material due to activity. The breaking apart due to the increasing spin rate

is a bigger effect than the material loss. And I think, Cecilia, you actually see cracks in the material loss. And I think Cecilia you actually see cracks in the in the neck region. Yes there is a crack that has been seen expanding. One of the very big aspects or important aspects of the fact that Rosetta was in the vicinity of the comet for a long time is that we had the possibility to observe different parts of the surface at different times. And so the same part at different times, sorry. So we could see how the surface was evolving with time.

And one of these parts was the neck, the neck of the comet. And one of the cracks had definitely increased its size between the two observations, showing that the comet is really evolving. An amazingly dynamic object, changing literally before our eyes or before Rosetta's eyes. Let's switch to the interior of the comet. What have we learned about its interior, its structure? There were actually dedicated instruments to look at, so to say, to look at the interior of the comet by sending radar waves between the lander and the orbiter.

And actually, their result shows that the comet inside is actually quite homogeneous. So there are no extensive or big voids inside this object, at least the part that they were able to sound through or to analyze. And so it seems to be quite homogeneous. Another interesting feature is actually it's a very low density. So the gravity was determined of the object. And then from the camera, you get the shape. And if you have, so to say, the volume and its mass the camera you get the shape and if you have so to say the volume

and its mass you can derive a density and the density is something you know like half what you would get for a density of pure ice so actually its density is very low and its porosity on the other hand is very high so there are there's lots of empty volume, but it's, at least on large scale, it's quite homogeneous. We've heard comments sometimes described, and perhaps not as accurately as we thought, as dirty snowballs. It sounds like 67P doesn't really quite fit that. There is still ongoing discussion. Actually, it's an important topic, actually, that we are still investigating, we're still debating and not everybody

agrees with each other, is actually how much, let's say, ice and how much refractory material is in this comet. What is the proportion of ice and refractory material? So whether you talk about a dirty snowball or a snowy dirtball

or however you want to call it, that's still quite a debate, yes. It's an important quantity. It's important to know this. Martin has given a good view of where we are now, of course. Rosetta has acquired a lot of data which could help in understanding this, but it's still an open question and more studies need to be done to arrive to really a solid conclusion on which is the amount of ice and dust which is in the comet. talk about the ice or the water in this comet, even if there isn't, maybe there may not be as much as what was expected. Has Rosetta given us a better idea of where this comet and perhaps most or all comets get their water from? Yeah, it's also a difficult question because we have measurements of several different comets and in some quantities they tend to differ

and in others they are quite similar. An important measurement that we wanted to do was to measure the deuterium to hydrogen ratio in the water. That was one of the top goals. And the idea here is that you look for these isotopic signatures of different elements, and in this case of hydrogen in the water, and you compare it to, for instance, to Earth, to the Earth's water, because that will give you some hints on whether that type of comet

or this type of comet could be the source for the water on Earth if the isotope ratios are the same. It's not a proof, but it would allow the possibility that comets... One more piece of evidence, at least, yeah. Yes. But this comet, the D over H, as we call it, ratio, it didn't match. But there are comets where it matched. There was some confusion.

Originally, it was thought that the different families of comets, there are Oercloud comets, and then there are the Kuiper belt objects, like this Jupiter family comet 67P. And we saw, originally it was thought that this D over H depends on from which family these comets come. But basically that theory has been overturned, especially after Rosetta, because the elevated D over H in 67P just didn't match.

That's one measurement. And then one can also go and compare these D over H ratios in different molecules to observations that have been done far away from our solar system in the interstellar medium or around protostars. And then you can start to compare our results with with these objects and this indicates or some indication that actually the water in this object predates the formation of the solar system this means that the water has formed and it has stayed it stayed frozen at least part of it stayed frozen

throughout the formation and then the evolution of this object. In other words, some of this water perhaps, much of it perhaps, came from elsewhere across the galaxy. Or basically, yeah, I would argue that the comet is still made up of the same material like our solar system, the whole solar system is made from, but it just has not experienced hot temperatures, any melting or sublimation and recondensation processes in the inner solar system. And actually some of the quantities, some of these isotopic signatures that we see,

they differ from other objects in the solar system. This also gives some indication that this early solar system or where the comets formed, it was quite heterogeneous. It was not the same everywhere and not all the comets ended up with the same quantities of different molecules or isotopes. Cecilia, while this is fascinating in itself, it also brings me back to a recurring theme we talk about on this show. And that is that every time we look at a new object up close in our solar system and increasingly beyond, we learn again that they are all unique, that it is a very heterogeneous universe as we look around. Do you see that as well? Sure. In certain aspects, that's clear. And in certain others, no. For instance,

when we saw 67P for the first time, we thought that this shape was a very unique shape. However, now that more objects have been observed, you can see the latest object, which was observed by New Horizons, also shows a very bilobate object, which is different, of course, from 67P, but is not that different. I would say, yes, objects are unique, but are maybe not so unique as we were thinking before. Yes, of course, you were talking about Ultima Thule, that Kuiper Belt object that New Horizons passed at the beginning of this year. Let's go back to talking about the composition of 67P and those most promising and perhaps interesting of compounds, the organics.

Were there a lot of organics found in the comet? Quite a lot of organics. And we looked for them in the volatile phase, meaning the gases. Actually also in what we call refractory, the dust mass spectrometer measured the composition of this dust, mostly dry dust. It also contained almost 50% of organics. So organics, there's a lot of organics in this object. I think it's also very prominent in camera images of this dark, the dark surface that is often attributed to some organic residue,

I would call it, that basically turns this object into such a dark, you see this dark nucleus and Cecilio may be able to tell you a little bit more about this, but these images that were done by the camera, they had to be enhanced quite dramatically to make all these features visible.

Yeah, the images of this comet look very dark. So the comet in the images looks very dark. All the bright patches that we see are due to ice. But overall, I mean, the nucleus is very dark. Its albedo, it's about 6% on average, which means that it's really a dark object. It's like charcoal. Yeah, or darker. I mean, that just makes me marvel even more at the success of the cameras on Rosetta.

marvel even more at the success of the cameras on Rosetta, because not only was this a dark object, but for so much of Rosetta's encounter, there just wasn't much light hitting the comet, right? Well, part of the comet was always illuminated. So the trick is to expose the image as long, so long enough to be able to actually detect the reflected light from the surface. So the comet is reflecting sunlight. Of course, the further the comet is from the sun, the less sunlight is reflected. Of course, also the further the camera is from the comet, the longer you need to expose the image in order to see something. It just makes me even more impressed with the performance of Rosetta's cameras, along with all those other instruments. And those instruments, moving on here to another topic that

you briefly address in the article, and that was monitoring the magnetic field or magnetic activity around the comet. Was that what was expected? When this comet formed, the magnetic field of our forming solar system, actually at the location where the comet formed, imprinted itself in the material. in the material so that you have like a magnet that the comet, if the comet is actually something like a magnet, because its magnetic field of the object was co-aligned with the outside magnetic field. It sort of gets frozen in place, the magnetic field, right? Yes, exactly. And so the idea then was with the lander and with the orbiter to do measurements of the magnetic field as the lander descended towards the comet. And to see whether there is any difference, of course, between the two magnetometers because of an intrinsic magnetic field of the comet. So it doesn't look that this object has any frozen in, let's say, magnetic field, at least not at the landing site, but basically also no global magnetic field.

So this was really a question that required a lander with a magnetometer to land on this comet. There is in the article, though, some discussion of some other magnetic qualities that were found at the comet. Something about a different kind of field or, in a sense, the lack of a magnetic field? Yes, exactly. We know that the solar wind, as it gets more active and you have seen on the first picture the activity of the comet, you see all these gases coming out of the nucleus. They basically push away from the object, they push away this solar wind and its magnetic field. And so if you get close enough to this object, then you are in a region where you are inside this bubble where the comet blows away everything that's coming in terms of particles that's coming from the sun. And so you enter this region where no solar wind magnetic field is. It's called a diamagnetic cavity.

It has been observed at Comet Alley already, but here, because of our prolonged stay, we actually flew inside this region and out many, many hundreds of times, actually. And we were able to study what happens at this interaction where the cometary gases dominate versus where you have also solar wind particles and the associated magnetic field. Again, absolutely fascinating. Cecilia, I've already said that there are so many wonderful images in this article and far more that can be explored by anyone, and we will provide links to some of these photo archives from the Rosetta mission on this week's show page that people can get to from planetary.org slash radio.

But just considering the ones that you included in the article, one of the most fascinating for me is not a view of the overall comet, but of a tiny, tiny area. It's a shot of the comet's dust particles under a microscope. And I thought I knew a lot about this mission, but I did not realize that among the instruments on Rosetta is an atomic force microscope, one that could actually look at the smallest things that can be seen. Yes, there were several instruments on Rosetta and there were two in particular which could look at these small particles. So one is Midas and the other is Cosima. I think the image you are referring to is the one that was taken by CosA, which shows how it's working is that COSIMA had an aperture and the particles

were entering inside the instrument and sticking on the target. In this image, you can see how we have different types of particles. So the COSIMA team has characterized them in four types according to the properties once they have sticked on the target. So you can see that there was this type A particle which stayed, which looked like it stays more compact, while the others are more, they got like more destroyed when they have impacted on the target. And so this was then used to characterize which are the properties of the dust, which is making up these particles. So we are learning more about Comet 67P at every scale, from the microscopic to being able to examine this entire beautiful object in one image. You know, you close the article by mentioning that NASA is considering a sample return mission for this comet, 67P.

I bet that's a mission the two of you would love to see. Well, I think by now, actually, NASA selected the competitor. So it's not going to be this comet, but hopefully we'll get another chance at the comet at the sample return mission. I think especially for the dust community, this is, of course, something that has to be done. I think it's a little bit more difficult to bring back some of the highly volatiles because this would require a very, very low temperature for the return trip and also the atmospheric entry and the quick pickup. And so I think technically that's a very, very challenging one. But already in the dust, or maybe some of the organics we talked before,

this would be very interesting. If they're not very volatile, then we could bring them back. We've seen a lot of very interesting organics, including glycine, which is actually the simple most amino acid. Finding this on a comet that's certainly devoid of any life, I think this is quite fascinating. Thank you for the correction. First of all, I'd forgotten that the comet sample return mission that basically was eliminated because of the selection of the Dragonfly mission to Titan, I'd forgotten that that was the one that

would have gone to 67P. Cecilia, what about your feelings? What would you like to see happen next in our efforts to understand comets and therefore our own solar system? I think that Rosetta has definitely increased our understanding of comets and our understanding of the in a way of the solar system however it has opened a lot of questions and left and also left many questions still unanswered so definitely Rosetta is not an ending point on the on the study of comets but but it's a starting point. So having more missions or new missions studying comets is definitely important. And as Martin was saying, having a sample return mission which

brings back volatiles is very, it's very complicated. Still, at least having a sample return mission that brings dust, that would help to answer to some more questions compared to what Rosetta has answered so far. There are pros and cons of going back to the same object. Given that all these comets are to some extent similar, but on the other hand, differ vastly one from another. And actually, the sample of objects we have visited, I will be very much in favor of going to another object that we haven't had a spacecraft close by before.

Or potentially, you know, the next time when Comet Halley is returning, we could consider actually doing another visit at Halley. Wouldn't that be something, to have a mission like Rosetta at that most famous of comets that could stay with it as it makes its journey around the Sun? Yes, that would be great. Technically, it's extremely difficult, because Halley is moving opposite to the planets. So to say, it's moving in a counter direction of all the planets. So actually, getting on its orbit is pretty much impossible, unfortunately. I have no doubt, though, that with the amazing

success of missions like Rosetta, somebody out there could figure this out. Let's hope so, yes. In the meantime, though, it sounds like both of you expect to remain very busy working with this data, much of which, as you said, is yet to be examined from the Rosetta mission. Oh, yeah, definitely. In these years, there's no doubt that also for the images, for instance, I mean, many images have been analyzed and big discoveries have been done, but there are still many more details that have to be understood or which could be understood. understood or which could be understood. And definitely the data that Rosetta has provided are the best data about the comet for the

next decade, at least. This will be the subject of studies of the next generations, I think. Actually, we're putting a lot of effort in putting together or archiving all this data. And to make it available to the community, there are research projects. There's actually a data analysis program by NASA where you can apply and you can use the data archive to do your own science investigations. So it's not that the data is just with us, but actually it's publicly available. And I think that's also the goal, to make this available for a whole lot of scientists to look. Everybody brings a little bit of a different turn, a different twist,

and has a different experience. And actually bringing this all together is very much to the benefit of the mission. Exciting science. I wish you both the greatest of success as you continue to work with this data from Rosetta and learn about its origin and perhaps our own origin as well. Yes, very much. I mean, we're really looking into this. Again, the organics, you know, that's yet another question. We figured out that that type comet is maybe not the major supplier of water on Earth. On the other hand, it could be a significant supplier to the terrestrial atmosphere. atmosphere. Through impacts, parts of the atmosphere might be of cometary origin, but then also a lot of these organics arrive on Earth. Maybe a little bit of comet is in all of us. I like that. Cecilia, you sound like you do too. Yes, sure.

Well, thank you both once again, both for joining us today on Planetary Radio, but also for this excellent overview of the Rosetta mission and the science that continues to pour from it. And I do wish you the greatest of successes as your work with this data continues. Congratulations to you and the entire Rosetta team. It's hard to believe that it has been three years since the end of this mission, but in so many ways, it seems to live on. Yes, it's living on. And it's really, as you just mentioned, it's the work of a big team, and it needed a lot of expertise in different fields. And I think Cecilia and I were just lucky that we could give this interview, but

it's actually on behalf of a big team. Thanks for having us. Yeah, thanks to give us the possibility also to show to more people how successful Rosetta has been and how much more can be understood from the wealth of data that Rosetta has collected. And as Martin was saying, the data are not only for the science teams, but are really for everyone. So really everyone is welcome to go to the archive and look at the data, and even just look for the fun of looking at how a comet is

or just to also to analyze the data and to give his or her own view or opinion on what Rosetta has seen. Again, we will provide links to that data, images and other science from Rosetta on this week's show page. Planetary.org slash radio is where you will find it. You are both most welcome. It has been a pleasure. And, of course, this is why we do this show, so that we can talk to folks like you and share in the excitement and discoveries that you're making. excitement and discoveries that you're making. My guests today have been Martin Rubin, who is a researcher in the University of Bern's Department of Space Research and Planetary Sciences, and he serves on the Rosetta mission's mass spectrometer team, and Cecilia Tubiana,

who is a research scientist at the Max Planck Institute for Solar System Research in Germany and is part of Rosetta's camera team. Time for What's Up on Planetary Radio. Bruce Betts is the chief scientist of the Planetary Society. He is back to tell us about the night sky and maybe take us through a few other things. I had a bunch of people here. It was sort of a fundraising thing and two telescopes out and of course it clouded over moments after we took the telescopes out. So we course it clouded over moments after we took the telescopes out. So we didn't get a chance to look at beautiful Jupiter, but I know it's still up there. That's a well-known scientific effect of pull out the telescopes and it will cloud over,

or just take me to your observatory and it will have a similar effect. Bruce's law. Okay. Yeah, exactly. So yeah, Jupiter looking lovely when you don't have clouds or fog over in the southwest in the early evening, brightest star-like object up there and to its upper left, kind of over to the left, more to the south, the Saturn looking yellowish would have been lovely through your telescopes. And it's hanging out just a little above the Sagittarius. And I'll once again encourage you to look for the teapot shape of Sagittarius if you haven't before. We move on to this week in space history.

1977, Voyager 1 launch. Still working. I keep saying it's several weeks now. I've been saying we've got to get Ed Stone back on the show for an update, but I'll get to it. Still working. I keep saying it's several weeks now. I've been saying we've got to get Ed Stone back on the show for an update, but I'll get to it. I promise. 2016, a little more recently, Osiris-Rex launched, but also very successful hanging out at Asteroid Venue right now. And of course, I like to mention for you every year, 1966, a great year, Star Trek debuted. year, 1966, a great year, Star Trek debuted. 53rd anniversary of that show.

And who's still with us? The Shat. Shatner himself. The Shat. We move on to Random Space Fact. Was that your rendition of the Star Trek theme? Yeah. Was that your rendition of the Star Trek theme? Yeah. Yeah, fortunately you didn't pass that audition when you auditioned for Gene in 66.

Yeah, no, my sons are the singers of the family, obviously. And they're very good. Moving on. If Shondrayan 2, which is in lunar orbit right now, lands successfully in the next few days, so keep an eye on the news, including planetary.org, it would make India the fourth country to soft land on the moon after works out. It's going to happen Friday afternoon Pacific time. And I would love to think there'll be some kind of live coverage coming from the Indian Space Agency, ISRO. But I haven't heard about that. We'll have to check it out. We'll find out. But in any case, kind of exciting. Yeah, very.

Speaking of exciting, we go on to the trivia contest. I asked you, what was the first spacecraft to take a picture of the Earth from the vicinity of the moon? How'd we do, Matt? I will answer with a poem, a little limerick, not from the poet Laurie at this time, who is taking a break, but from David or Dave Douthat, whose name I have been mispronouncing when he comes up here. Charlestown, West Virginia. Way back in 1966, something new was in the mix. NASA sent a probe to space, took a photo of Earth's smiling face. While it was orbiting around old Luna, the probe was Lunar Orbiter Una. Lunar Orbiter One, right? Yes, Lunar Orbiter Una. Lunar Orbiter One, right?

Yes, Lunar Orbiter One, that is correct. Here is our winner, Chris Godey or Getty of Delphos, Ohio. He said, sure, yeah, it was Lunar Orbiter One, which was sent out there to sort of scout the surface for the Apollo astronauts and the Surveyor Landers, right? Yep. Gave us all sorts of groovy pictures of the moon. Well, there were a bunch of people, first of all, who were surprised that this was actually done with film. Good old-fashioned film that was shot

by Lunar Orbiter, developed, and then finally scanned in an analog fashion. Yeah, that's why the original versions you see stripes from the scanning process. You're old enough, aren't you, to remember the old photo booths, pre-digital, that actually there was one that was like a see-through, a transparent one at the old Museum of Science and Industry in LA. And you could see the film being dipped into, simulated actually, because you couldn't, they couldn't put light on it,

but see the film being dipped into these various solutions to develop the film. It was just fascinating. But it was only a couple of people, including Norman Kassoon in the UK, regular listener, who reminded us that the camera to do this came from Eastman Kodak and was actually developed by the National Reconnaissance Office in the U.S. to be flown on spy satellites. Boy, I miss Kodak. I miss Eastman Kodak.

What a great company. I know they're still around, but they're a shadow of their former selves. They were such a great company. I know they're still around, but they're a shadow of their former selves. They were such a great company. Yes, yes. I used Kodak film for a very, very long time. When you did your stuff with big, big, big telescopes, were they still shooting film, or was it already digital by then? By then, it was digital. The astronomical community led the way with that, or at least were one of the entities.

The astronomical community led the way with that, or at least were one of the entities. So they were doing digital CCD detectors before they were in the commercial market by a few years. I mentioned it only because I know Kodak used to treat scientists well because, you know, film was needed for all kinds of things, including astronomy. And that was just one of the great things about the company. I will. I got one more for you. And that was just one of the great things about the company. I got one more for you. It's nothing to do with the contest, really.

But it's from George Sonier in Louisville, Kentucky, who has been listening. He's one of these crazy people who's been listening to old planetary recordings started back when the show started, 2002. Would you stop calling him crazy? He says, I got to tell you, compared to those old recordings, you and Bruce sure have slowed down in your old age. But then George remembered that he's been listening to the old episodes at one and a half times speed. Well, I guess the new ones are exciting enough he doesn't need to do that. No, I guess not. There must be some people out there who like to listen to us at 10 times speed, just to get it over with. I'm being so cruel today, including to us.

You're so cruel to the show. Take us to another cruel contest. Take you to a cruel contest to a cruel world. Name the last three Venus orbiters. Go to planetary.org slash radio contest. By the way, I neglected to say that our winner, Chris, this week is getting some of the stuff that somebody is going to get next week as well. He got a priceless Planetary Society kick asteroid, rubber asteroid, which we're not awarding this time. We're replacing that with a Planetary Radio t-shirt. The latest and greatest design. It's back. A 200-point itelescope.net astronomy account, that great astronomy service,

which is now working with this new image processing system. It's integrated into iTelescope. And I've seen some of the before and after shots that amateurs have been getting, and it's really very impressive. And both to the current winner and the person that will win in two weeks, a copy, maybe a signed copy of Bruce's Super Cool Space Facts, a fun, fact-filled space book for kids. Big day for you, right? It's officially out as we speak. It is. Big day. Very exciting. It's out and available on Amazon. And it's published by Rockridge Press. You can win one if you get picked. I think we're done. All right, everybody, go out there, look up in the night sky, and think about your favorite wind direction. Thank you, and good night.

He's Bruce Betts, the chief scientist of the Planetary Society. He blows in like a Nor'easter every week here for What's Up. By the way, the deadline for this week's contest is Wednesday, September 11th, at 8 a.m. Pacific time. Planetary Radio is produced by the Planetary Society in Pasadena, California and is made possible by its sail-powered members. Mark Hilverde is our associate producer. Josh Doyle composed our theme, which was arranged and performed by Peter Schlosser. I'm Matt Kaplan, at Astra.