Planetary Radio: Space Exploration, Astronomy and Science - The Coming Descent to Asteroid Bennu

Episode Date: January 22, 2020

After a year of circling close to near-Earth asteroid Bennu, the OSIRIS REx spacecraft is almost ready to dip down and collect a surface sample for return to labs on our home planet. Principal Investigator Dante Lauretta prepares us for this exciting event and shares the great science already accomplished. Editorial Director Jason Davis stops by with a report on the successful test by SpaceX of its Crew Dragon escape system. Are we finally about to see astronauts using it to reach the International Space Station? Learn more and enter the weekly What’s Up space trivia contest at https://www.planetary.org/multimedia/planetary-radio/show/2020/0122-2020-dante-lauretta-osiris-rex.htmlSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

The coming perilous descent to asteroid Bennu, 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. Dante Loretta is back. The principal investigator for the OSIRIS-REx mission will tell us about the site selected on Bennu for a daring descent and sample collection. SpaceX just successfully demonstrated that its Crew Dragon capsule can get itself clear of a troubled rocket. We'll ask Planetary Society Editorial Director

Jason Davis if the next step is putting humans inside, later you can join what's nearly a space poetry festival as we enjoy another What's Up with Bruce Betts. Remember me inviting you last week to check out my monthly Planetary Radio newsletter? The January edition is now available and you can easily subscribe by visiting planetary.org slash radio news. That's planetary.org slash radio news to add to your already sublime PlanRad experience. Our conversation with Jason Davis is just ahead after we tease you with some of the space headlines in his latest edition of The Down Lake. We'll start with a headline from the Juno mission. On Christmas Day, the spacecraft imaged a section of the big planet's moon Ganymede on its 24th orbit.

We'll have to ask Principal Investigator Scott Bolton about this. He'll be joining us on next week's show. You can learn more about and see more of our solar system's biggest satellite at planetary.org. NASA welcomed 11 brand-new astronauts in a graduation ceremony. The six women among them include a geologist and a biologist. They're two Canadians. It's safe to assume some of them will be riding either the SpaceX Crew Dragon or Boeing CST-100 Starliner into orbit before long. NASA's Mars 2020 rover is one step closer to getting its new name. 155 semifinalists have been reduced to just nine

nominations. I was honored to serve as one of the evaluators who reviewed some of the names and justifications submitted by kids. And we are barely a week away from the end of the Spitzer Space Telescope. The infrared observer has been making momentous discoveries since 2003. These included five of those seven Earth-sized exoplanets found around the star Trappist-1. Planetary Radio will also soon welcome leaders of this very successful astronomy mission. There's more to read in the Downlink, and you can reach it each week at planetary.org slash downlink. Here is its creator, Jason Davis. Jason, how significant is this successful test by SpaceX of the Crew Dragon capsule? Pretty significant. This actually checks off

their last milestone of the initial commercial crew awards that date back many years. I'd have to look up the exact date, but this was the last big milestone on their checklist that they had to successfully prove that the spacecraft could abort in the event of an emergency in flight. This essentially was the last thing they had to tick off before NASA can finally look at all the data and say, you know what, you all are ready to take astronauts to the International Space Station. So I imagine they're still looking at that data, although everything certainly looked like it was great in real time. great in real time. But if all goes well, does it look like we may be seeing American astronauts on a Crew Dragon spaceship before too long? It does, yeah. In the press conference after the test that had representatives from both SpaceX and NASA, terms that were getting thrown around were second

quarter of this year. I believe someone said April. It is actually looking promising, barring any other setback that comes up along the way. But they did say the initial look at the data checked out and, you know, all the parachutes seemed to work perfectly. The ship was recovered quickly and, you know, is on its way back to shore now. By all indications, I know we've said this so many times, it really does look like this might happen this year. I caught the last portion of that press briefing with Jim Bridenstine, the NASA administrator, sitting right next to Elon Musk. And Bridenstine looked like a pretty happy guy. He did.

He is just the latest administrator who has had to deal with some setbacks, I guess the other being Charlie Bolden. deal with some setbacks, I guess the other being Charlie Bolden. As promising as commercial crew and commercial cargo have turned out to be in some respects, getting private companies to ship crew and cargo to the International Space Station, there have been lots of setbacks. So it seems like they'll take a step forward and then they'll have two steps backwards. You know, just some that come to mind would be SpaceX did a successful uncrewed test of their Crew Dragon spacecraft to the station. That all went well and everybody was in great spirits saying, yeah, it looks like we're on the way. And then the thing blew up during a test of the thrusters at Cape Canaveral. Every step forward they take, they take a couple back.

Jim Bridenstine has expressed a lot of frustration with them before. a couple back. Jim Bridenstine's expressed a lot of frustration with them before, but also he's clearly happy now that it seems like this final milestone is out of the way and they can get serious about setting a date for the real test flight. So, of course, you've also made me think of Boeing's ups and downs with their CST-100, the so-called Starliner, where they had that problem. I mean, they called it a successful mission, but they didn't reach the ISS. I don't want to put you on the spot, but does that look like it may delay their readiness to carry humans up there? They have not said yet whether or not it will require another test flight. This was when Boeing tried to do its uncrewed demonstration flight,

and there was a problem where the thrusters didn't fire properly to raise them to the station's altitude to actually complete the docking. Spacecraft came back to Earth okay, and it turned out to be a relatively minor glitch in computer code that caused that thruster firing not to happen correctly. But they are still considering whether Boeing will have to redo that flight or whether the data they got from that test flight will be enough. So we'll stay tuned on that one. But, you know, possibly SpaceX and or Boeing could make this happen this year. I don't want to say that there's a new space race underway here, but it will be interesting to see which of these new spacecraft makes it up there with astronauts first.

Jason, I'm sure we'll be checking back with you to talk about this as it continues to develop. Thanks. Definitely. Thank you, Matt. OSIRIS-REx. You don't hear it spelled out very often. It's actually a pretty cool acronym. Origins Spectral Interpretation Resource Identification Security Regolith Explorer. Why security? Because asteroid Bennu may in the next century be on a collision course with Earth. That's just one reason we need to learn more about these relics of our solar system's origin.

Principal investigator Dante Loretta can tell you many more. Actually, he's about to. And there has been big news from the mission since our last conversation with Dante. He is a professor of planetary science and cosmochemistry at the University of Arizona's Lunar and Planetary Laboratory. He's also the driving force behind Extranaut, the game of solar system exploration. And there's news on that front, too.

Dante joined me a couple of days ago from his Arizona office. Dante, what a pleasure to get you back on the radio show. It has been a year since we last talked. And not by coincidence, it has also been, what, just over a year since you went into orbit around Bennu. And now it has just been a few weeks, well, December 12th, that you made this momentous announcement of where OSIRIS-REx will be descending down to this asteroid to grab that first precious sample. Congratulations, first of all, on all of this. Thank you, Matt.

It's always great to share our adventure with the Planetary Radio audience, and I can't believe it's been a year since we last visited. I bet it's gone very fast. It's been a very busy year for you guys, one with a lot of surprises, right? This asteroid was not what you expected to find exactly. Yeah, Bennu is certainly challenging us on OSIRIS-REx. It's a great asteroid, I can say, from the scientific perspective, it's everything we hoped it would be,

and more specifically meaning we targeted an asteroid we hoped was composed primarily of hydrated, that is water-bearing minerals, and we're seeing lots of evidence for abundant carbon on the surface. This is the material that we are after. Bennu is definitely going to tell us about the precursor molecules for the origin of life and why Earth is a habitable world and how it probably got its water and where our oceans came from. But operationally, we certainly have our work cut out for us.

And the same thing happened with Hayabusa 2. In fact, a lot of people have remarked on how similar these two asteroids are and how incredibly challenging. I mean, more challenging, aren't they? Isn't Bennu more challenging than you expected it to be as you were approaching? Bennu is more challenging. I mean, we really got fooled by our assessment and interpretation of the astronomical data we used to characterize the asteroid. That's not to say we didn't do a really great job.

Some of the things we absolutely nailed. We got the shape of this object. We got its rotation state, its pole orientation, overall its composition, as I mentioned. But what we really didn't get right was the average grain size of the surface. We looked at data from the Spitzer Space Telescope, and we looked at data from the planetary radio systems at Arecibo and Goldstone. We looked at data from the planetary radio systems at Arecibo and Goldstone, and everything was suggesting a very smooth surface with your average grains on the order of a centimeter or so. And as we've all seen with the phenomenal images coming back from OSIRIS-REx, that is not what we are up against. No, it's amazing to look at.

It's amazing to look at. I mean, it's spectacular, but not what you'd probably want to drop a spacecraft down onto to pick up a sample. I will tell listeners, if you have not seen them, you really must see the images. Now, we'll put a link up to your website, Dante, which has probably the most appropriate name for any mission I've ever seen, asteroidmission.org. Couldn't be easier or more appropriate. Not only will they be able to see still images of pretty much the entire asteroid, but also these fantastic simulated 3D flyovers of these candidates that you looked at for making this first collection. Tell us about the one that you've chosen. Yeah, so first let's talk about that data set, because it really is unprecedented,

and it led us to the site selection. So you referred to those simulated flyovers. The way we produced those is we took altimetry data from the OSIRIS-REx laser altimeter instrument, which was provided by our partners at the Canadian Space Agency. And when we were in orbit, or what we call our orbit B phase, where we averaged about a kilometer from the center of mass, about 700 meters from the surface of the asteroid, we mapped the entire surface of Bennu at five centimeter spatial resolution and about a few centimeter vertical precision.

The entire surface of the asteroid is understood at that level. And then during our detailed survey campaign, we used our polycam instrument that we built here at the University of Arizona. And we also imaged the surface of the asteroid at five centimeter per pixel resolution. The overlay of those two data sets produce that amazing global shape model of the asteroid that you've probably seen rotating. And then as we're selecting the sample sites, we were doing targeted high resolution imaging over four areas of interest that we named after birds that are native to Egypt. And just as an aside, all of the features on Bennu will be named after birds

or bird-like creatures from mythology. And we're working with the International Astronomical Union to finalize our first set of candidate names. We mapped those four sites at 1.5 centimeters per pixel and then overlaid that on top of the laser altimeter data. So we were looking at in the south, the Sandpiper site, near the equator, the Kingfisher and the Os So we were looking at in the south, the Sandpiper site, near the equator, the Kingfisher and the Osprey sites, and in the north, the Nightingale site. Each one of them had their pros and cons scientifically and operationally. From the operation perspective, the equatorial sites are more accessible. It's easier to get the spacecraft to match the rotational velocity of the asteroid there but the scientific objectives are best met by the high latitude sites both the sandpiper and

the nightingale site because we're interested in water bearing minerals and we're interested in organics they stay cooler those higher latitude sites and those compounds we think are better preserved there and so then it came down to Sandpiper looks like an older site. The surface has been exposed to the space environment for a longer period of time. Nightingale looks like a really fresh, small crater. And it seems to have exposed this subsurface region of fine grain material that looks very rich in organic material and very rich in hydrated minerals. And at the end of the day, I'm excited. I didn't think it was going to be the case, but science got to be the deciding factor, and Nightingale came out on top. Oh, great. I know it's always on every mission,

it is a challenge balancing science versus the safety of the spacecraft. It's exciting and courageous to hear that science may have slightly tipped the balance, at least a little bit in this case. When you say that the northern latitudes or the polar latitudes on the asteroid are somewhat better protected or stay cooler, is that because Bennu is spinning on its axis much like a planet and just doesn't get as much sunlight toward the poles? Yeah, that's exactly right. Bennu is rotating once every 4.3 hours. The equator goes from 400 Kelvin down to 200 Kelvin every 4.3 hours, so an extreme thermal cycle is experienced there. The rotation axis is almost exactly 180 degrees, and the reason I don't

say zero degrees is because it actually is a retrograde rotator. So in the solar system, coordinate system, its north pole is pointing south. So it's kind of spinning backwards from our perspective. That means that the higher you go away from the equator, the cooler it gets. You're just getting less direct solar radiation and your peak temperature drops all the way down to about that 200 degrees right at the pole. So you have a really nice temperature gradient. We are limited. We can't sample right at the poles from an operational perspective, but we could get down to about 60 degrees north or south, and Nightingale is right at that limit at 55 degrees. Okay, so Nightingale it is. And yet, Bennu was still throwing up big challenges. I mean, I read that your target area is only about, what, one-tenth of what you had hoped to find to drop Osiris-Rex down onto. Talk about challenges. How have you adapted to this unexpected reduction in your target?

Yeah, not only what we hope to find, but what we designed the spacecraft to do. So we really built a navigation system, which was using a guidance navigation and control LIDAR system to target regions on the order of 25 meters in radius. That was a hard requirement to set because we were going to a new world, we didn't know exactly what we were up against, and so we looked to the only object that a spacecraft had visited that was comparable and that was the asteroid Itokawa that the first Hayabusa mission had visited. And that had this beautiful region that they named the Muses C that was about 50 meters in diameter. And we were using Itokawa as what we thought was the worst case design scenario,

because Bennu was bigger, it looked smoother, it was, you know, we thought finer grained. And then we get to this asteroid, and its surface is dominated by boulders, one up to 100 meters in diameter, and then lots and lots of them that are 10 meters, 5 meters, and 2 meters and below. Now, as we started to look at these regions of interest, we got to go from a 25 meter radius down to about a 5 meter radius. And as we know, area scales as the square of your radius, so we're looking at a substantial increase in the navigation precision that's required on the vehicle. So we had to basically abandon the LIDAR system. You know, we're NASA mission. We're always got our belt and suspenders when we get out to these things. We had put a backup guidance system on the spacecraft called natural feature tracking.

So what this system does, we're going to take all of the data that we've collected over the past year. We're enhancing that. In fact, tomorrow on January 22nd, we'll have our first low altitude pass over the Nightingale site to collect the final data set to build a catalog of features. And these are features, maybe boulders, but more, you know, albedo variations, things that would be easy to recognize in an image, regardless of the angle that you're viewing it at. So we have to build a three-dimensional model of a patch of the surface, and then a albedo model, or what we would call a photometric model, so that you can predict, depending on how you're observing it, how it's going to appear to the camera. And we need hundreds of these all the way from the

time of orbit departure down to the final closure with the asteroid surface. The spacecraft will be taking images all the way through the final sequence. It'll be looking for features that are in its catalog and correlating on those and using that information to update its own knowledge of where it is relative to the asteroid surface and particularly to the sample site. So that change in technology is what is allowing us to go from that 25-meter requirement down to the 5-meter guidance accuracy that Bennu is levying on us. Is there a parallel in this new approach, speaking literally, to what the Mars 2020

rover is expected to do in about a year we've talked on this show about how it will for the first time be using its knowledge of the terrain of its target thanks to images taken by the Mars Reconnaissance Orbiter sounds like you're going to be doing the same thing except that OSIRIS-REx had to collect its own image database. That's right. Yeah, Mars 2020 will be doing terrain relative navigation. So it has one chance to fire thrusters during its EDL sequence. So it's going to come in, it's going to do a very similar kind of calculation. It's going to see where it is and what it sees in its field of view. It's going to determine the six degree state. So it's position and velocity in three axes. And then it's going to make a decision. Do I continue on the nominal path or it can do

one burn laterally to kind of push it away from a hazard? The big difference with OSIRIS-REx is that we're not a one way trip, right? So the spacecraft, if it's at the final approach to the surface, in fact, at the five meter crossing, it will do an assessment against an onboard hazard map, just like Mars 2020 does. But if it predicts that it's going to come down on an area we've identified as a hazard, it can just say, okay, timeout, fire thrusters back away from the asteroid surface. Let's reset and try this again. Mars 2020 is going to the surface no matter what. They don't have the option of going back into orbit around Mars. So we do have that safety net.

This is a much different energy regime than a Mars EDL, right? We're coming in at 10 centimeters per second. In fact, just two weeks ago, we did a real-time Walcock simulation of the tag day. So we watched what it's going to be like for six hours from orbit departure, you know, pre-orbit departure, all the way down to contact with the asteroid surface. And on the big screen, we had the simulation of where the spacecraft is relative to the asteroid surface. And it's literally like a baby crawling down to the surface of the asteroid to go pick up that sample. It's really slow and gentle. And so an abort maneuver is not a penalty in terms of fuel. It really is a matter of time because it takes us a while to reset and then reestablish the trajectory to go in for

another sample attempt. So no seven minutes of terror here. Yeah, it's more like four and a half hours are we there yet? But also like Mars 2020, your spacecraft I assume, even with this extra time, it's making this descent pretty much on its own using its own judgment based on this programming that you'll have done or do you have more ability to sort of manually say, oh no, we don't like that, OSIRIS-REx, back off? Yeah, once we program the sequence, it's on its own from orbit departure

through contact with the surface and the back away burn. And then we reestablish contact with the spacecraft. We should maintain a link through that whole process. The only time we may lose the ability to communicate is right at the point of contact because the spacecraft may tip over and the antenna link may drop. That's an expected event. It's going to be frightening and nail-biting because that's when all kinds of things can happen. That's the biggest uncertainty in the whole program is what happens when we hit the asteroid surface. And then as soon as we fire backaway thrusters, we should very quickly reestablish contact with the vehicle. But, yeah, it's a smart little spacecraft. It's going to have to make its own decisions as it's heading down to the asteroid surface on whether it wants to continue in and get the sample or live to fight another day.

another day. I can only imagine the anxiety of designing the algorithm that's going to decide what is too hazardous and what is just right. I mean, is there a concern sort of on the opposite end of that spectrum of what if the algorithm is too careful? What if it decides, the spacecraft decides to avoid a touchdown that actually might have been okay. That's, you've really hit the nail on the head there, Matt. That is the debate that we are wrestling with internally, where we have tunable parameters. How much risk do you want to accept? It comes down to kind of a probabilistic calculation. What is the likelihood that you are actually going to make contact with a hazardous location on the asteroid surface? The requirement that we levied was that the spacecraft has a 99%

chance of remaining safe during sampling, but proving that it's 99% is not an easy task. And are we really willing to accept that 1% risk of the spacecraft suffering damage to the point where we'll be unable to return the sample? More from Dante Loretta is coming right up. I know you're a fan of space because you're listening to Planetary Radio right now. But if you want to take that extra step to be not just a fan, but an advocate, I hope you'll join me, Casey Dreyer, the chief advocate here at the Planetary Society, at our annual Day of Action this February 9th and 10th in Washington, D.C. That's when members from across the country come to D.C. and meet with members of Congress face-to-face and advocate for space.

To learn more, go to planetary.org slash dayofaction. We're back with Dante Loretta, principal investigator for the OSIRIS-REx asteroid sample return mission. You're a co-investigator on the Hayabusa 2 mission. Did that spacecraft's sample collection success very recently, did it give you and your team more confidence? Yeah, it's a great honor to be part of the Hayabusa 2 mission. I've been huge fans of their program since the first Hayabusa, and we really reached out as agencies, NASA to JAXA, and established this great collaboration. I have members from the Hayabusa2 team on my team as well, so it's kind of been this nice cross-pollination between the two different groups. And they've been fantastic, and we have learned a lot from

their experience. After their first successful sample acquisition touchdown, I actually brought a contingent of my team from project management, from the spacecraft, from the sample collection mechanism. And we went to Japan and we had a two-day summit where we went through all of their lessons learned. lessons learned. We showed them. At that point, we had 50 possible sample sites on the asteroid surface. We kind of went through all of the different areas of Bennu that we were looking at. And I wanted their opinion, especially Tsutasan, who's the project manager over there, because he's been living the same thing. And so his insight was really valuable. And of course, they were very gracious hosts. It was a great international cross-cultural experience. And we gave a press conference over there as well to express our gratitude for all of the support that they provided to us. That is absolutely wonderful to hear. You mentioned the sample collection mechanisms, quite different between Hayabusa 2 and yours.

You've done this before, but would you review for us once again how exactly, once you get down to the surface, you're going to be able to pick up those precious bits? Absolutely. So OSIRIS-REx is going after a large bulk sample, and that's one of the distinctions between us and the Hayabusa 2 system. That requires us to remain in contact with the asteroid surface for a longer period of time because our strategy is basically what I would call a reverse vacuum cleaner. So we have the TAGSAM, which is the touch-and-go sample acquisition mechanism, and that's a three-meter-long robotic arm, and at the end of that arm is a large air filter, essentially. I always like to say it would look right at home on the carburetor of a 57 Chevy. Same basic technology, right? Never thought of that, but I know what you mean. I've seen it. Yeah, you're pushing air through a filter and you're trying to catch the dust.

We have built it big enough so that it can pick up particles as large as two centimeters across, so a nice big sample for those of us who are analytical chemists, that's a lot of material and it can pick up hundreds and hundreds of particles like that. So we place that air filter onto the surface of the asteroid. Obviously it requires particles to be two centimeters or smaller for the device to work, which is what drove the site selection campaign. And then there's no air at the asteroid. It's an airless body. So we've brought three different bottles of high-purity nitrogen gas. And as soon as we sense contact with the asteroid surface, we open up one of those bottles, and we blow that nitrogen down into the regolith of the asteroid, basically fluidizing it. It's going to expand up back into the vacuum of space, and our air filter is waiting there

to catch that regolith entrained in that expanding gas plume. And if everything goes exactly perfect, we're going to pack that filter full of Bennu regolith, and that's going to be as much as a couple of kilograms of sample. The science requirement is 60 grams. We're confident Nightingale gives us the best chance of meeting that requirement. Fantastic. And another reason, of course, that we're very happy to see this sample collection mechanism headed someplace around the solar system is its similarity to the one that we call PlanetVac that we've worked with that company Honeybee Robotics on, which might be headed to the moon in the coming years. So we have even more reason to wish you the greatest of success with this.

Let's say that everything has gone well. You've dropped down to Nightingale and maybe someplace else as well, and you've picked up that rather large sample. What happens when, in 2023, these samples get back to Earth? I mean, what are the priorities once these reach the labs that will be telling us so much more about this asteroid that dates back to the start of the solar system? This is an area where we are actively developing the plans right now and establishing the new hypotheses that have come to light because of our understanding of Bennu. There's clearly some

things that we want to understand right away. We're wrestling with the age of Bennu's surface. You know, one of the big surprises was how many large impact craters there are still apparent on the surface of this asteroid. When we run our cratering models for Bennu being in the main asteroid belt, we're getting numbers like a billion years. We thought that the surface would be much younger because it's definitely a pile of rubble. We thought that it would be getting overturned and modified as it does close approaches to

the Earth and the other planets of the inner solar system. But it looks like this shape, this very quintessential spinning top shape that Bennu and Yugu both have, seems to maybe date from the formation of the asteroid, which, according to our models, was from a disruption of a much larger asteroid about a billion years ago in the main asteroid belt. So the first thing I want to know is how old is that surface? And in order to do that, what's happening when the materials at the surface of the asteroids is getting exposed to cosmic rays, and those cosmic rays initiate nuclear reactions and they create unstable isotopes that will be emitting gamma rays.

So we want to get a sample as quickly as possible within days of being on Earth into a gamma ray counting facility. And we just started a conversation with a group up in Canada. They run a facility called the Snow Lab. They're buried two kilometers deep in an old mine called Sudbury because that gets rid of all the cosmic ray background at the surface of the Earth. And we just want to put this thing in their gamma ray counters and count and see what is coming off of it and that'll give us an indication of the age

of the asteroid the asteroid surface in particular uh the other thing we want to know is this look like anything like meteorites that we have on earth some of the things i'm seeing on this asteroid i can tell you right now we don't have any of that in our meteorite collections so you know we're hoping to get the diversity of materials we see on the surface of Bennu in there. And you're basically starting a catalog. How many different types of rocks did we pick up? And now we got a plan for each one of those because each one of those needs its own detailed geologic and geochemical investigation to understand the story that's recorded in there. So a lot of it's going to be triage, like, okay, what do we got? And now how many different investigations are required to understand the diversity of material and the history that's recorded in here. We're going to

want to know its bulk composition. We're going to want to do radioisotope age dating. Of course, the organic molecules are a key part of our investigation. We want a full organic inventory. In particular, we're interested in understanding, did asteroids like Bennu contribute organic molecules that led to the origin of life on Earth? One of the key compounds that we target are the amino acids. And we do study amino acids in carbonaceous chondrite meteorites, but we avoid certain compounds because they're totally contaminated by biology immediately upon arrival on the surface of the Earth.

So I've encouraged the organic analysis team to figure out how can we go after all 20 amino acids that are used to build proteins for life on Earth, things especially that we could never measure before in our meteorites because of contamination. So those are some of the high-level objectives. Of course, there's going to be labs all over the world. That's one of the great things about sample return, and NASA in particular, is that this material is available to any laboratory anywhere on Earth that's qualified to make the analysis that they're interested in.

Do you expect that, like those those now aging samples from the moon, some of which have been kept pristine from the time they were brought back by the Apollo astronauts, that these samples from OSIRIS-REx are going to be delivering science for maybe decades to come? Absolutely. Sample return is the gift that keeps on giving. And one of the things we'll be doing very quickly after Earth return is putting a subset of the sample into hermetically sealed containers for exactly the same reason they did that with the Apollo drill core. Because we're smart, but the people 40 or 50 years from now are going to be even smarter. They're going to have better instruments. They're going to know more about asteroids.

are going to be even smarter. They're going to have better instruments. They're going to know more about asteroids and they're going to have ideas and measurements that they need to make that are not even conceived of right now. So we're planning for analyses in 2023, but we're also planning for analyses in 2135. And I didn't pick that number randomly. 2135 is the year of Bennu's close approach to the Earth. And that interaction between the asteroid and the Earth's gravity field will determine whether or not Bennu is returning on an impact trajectory or not. So people are going to be really interested in this asteroid over 100 years from now. And so in the 22nd century, which I would love to think one of us will be around to witness, but doubtful, we will influence this rock and it could become one of those that will threaten our planet. It's a good part of why you chose Bennu, right, as a target for this mission.

Yeah, Bennu is the asteroid that has the highest probability of impacting the Earth within the next 200 years. As a result, it's a really great object for us to be studying, because we may have to deal with it as a species within a 150-year time frame. And I know that sounds like a long time for you and me, but on a species survival timeline, that's nothing, right? So the data that we are collecting right now and that sample that we are returning will be really valuable to the people of the future if they need to solve that problem. And also what it's doing is we're seeing Bennu is now becoming the case study for asteroid mitigation, impact mitigation studies. If you've looked at all these different groups that are out there trying to understand different technologies and approaches to deflecting a potentially hazardous asteroid,

because of the great job we've done characterizing Bennu, they have everything they need in their simulations to really say, okay, what if we had to deflect this asteroid? What could we really do about it? Let's talk a little bit for at least a couple of minutes before we turn to other topics about what you have already learned about Bennu. You've touched on this. You've already found organics. And just finding this amazingly rich surface, unexpected surface, which, by the way, it occurs to me that this is more evidence of why it is so important for us to get up close

and personal with asteroids, right? Yeah. So one of the things we haven't talked about, which was also one of the biggest surprises of arriving at the asteroids, was the particle ejection. Exactly. That's where I was hoping we'd go. Yeah. So within a week of getting into orbit around this asteroid, we started downlinking optical navigation images. So we use a different set of cameras called the tag cams to do navigation. It's a very wide field of view, like 40 degrees. So it gets the asteroid and it gets stars in the same field of view. And the navigation team uses that information to figure out where the spacecraft is and where it's going.

And in one of those, we saw what looked like an eruption from the asteroid surface. There was just hundreds of particles that were being ejected into space. And you can imagine the immediate response was for spacecraft safety. It's like, is this a hazard to the vehicle? Do we need to fire thrusters and get away from this object until we can understand what's going on? So a whole safety assessment was triggered. We had to do some quick orbit determination on the particles. Some of them are completely ejected away from Bennu and are now part of the interplanetary dust population. Other ones are actually bound in orbit around the asteroid. So Bennu, as we're seeing, has this constant population of mini satellites. These things are on the order of half a centimeter, maybe up to as big as 10 centimeters, so softball size.

And they persist in orbit for maybe a day, maybe a week or so, and then they end up re-impacting with the surface. So this is a completely unexpected phenomena. Bennu is now part of a rare class of asteroids we call active asteroids, those that we see either exhibiting comet-like activity or ejecting dust through some other mechanism. So that's been really fascinating. The science that's resulted from that is phenomenal because one of the challenging things that we really want to measure is the gravity field of the asteroid. And when you characterize the precision of a gravity field measurement, you say, what is the degree and order of the field? And it's a spherical harmonic expansion technique that's used to characterize the field in this way.

Our requirement was to get down to fourth degree, and we were going to struggle to do that. We were actually getting worried we weren't going to be able to achieve that level of precision because of the challenge of operating the spacecraft that close to the asteroid. And then we got these particles in orbit. Some of them are skimming the surface within meters. Some of them are actually bouncing off the surface and going back into orbit, or hitting the surface and launching new particles into orbit. And so we have phenomenal gravity field probes by watching these things zip around this asteroid. And we're solving the gravity field toes by watching these things zip around this asteroid, and we're solving the

gravity field to eighth degree now. So well beyond what we were required to do because of this fortuitous phenomena that nobody predicted. Well, I shouldn't say nobody. Some people actually did predict it, and they've reminded me of that, that at least Bennu would be an active object, and in part because that was one of the rationales for selecting it, was that it might be volatile rich and therefore might exhibit some low-level cometary activity. But is it possible that asteroid Bennu is a little bit comet? I would say yes and no. And the reason I say no is because we don't think that ice is involved here.

And that's what dominates comet dust production is. You've got ice that's sublimating and it's entraining dust particles and then lifting them off the surface of the comet. And we've looked, you know, we have two fantastic spectrometers, OVIRS and OTIS on the vehicle, and there's no sign of ice anywhere on this body. But what we do have is we have a lot of water bearing minerals. Normally the water is actually in the hydroxyl molecule or the OH molecule inside the crystal structure. But if you stress mechanically these kinds of rocks, you will transform that OH out of the crystal structure and into a water molecule. And then that may get hot enough and give you a little

bit of vapor pressure and be lifting the dust off the surface. So that is a viable candidate for what we're seeing there. The other option that's looking pretty promising is micrometeoroid impacts onto the surface. You know, Bennu is in the inner solar system. We all love to go out in the night sky and watch shooting stars. Bennu's getting hit by those same kinds of dust particles, and some of those come in fast enough that they could produce the events that we're seeing. So my guess is that there's a combination of those factors in play here. You've got a water-rich surface.

It's not going to take much to heat that up and maybe drive off particles. And then the micrometeoroids might be adding that little kick of energy to kind of jumpstart the process. So even with the unexpected challenges that it presents, is Bennu looking as exciting or even more exciting as your choice for this spacecraft as you were hoping it would be years ago before the launch? Matt, I can honestly say the past year has been the most exciting time of my life, without a doubt. I mean, as you can imagine, it's a great honor to be leading an expedition like this. And Bennu is paying off because the science is amazing. We're learning so much about near-Earth asteroids, about organic material in the inner solar system, water-bearing materials. And we're just getting started because the real action happens when the sample is back on Earth. So yeah, it's a place we needed to go, I think, as a species. It's going to be of interest for many reasons in the future. We talked about the impact hazard. If you wanted to mine asteroids for rocket fuel, Bennu is your number one choice right now. There's a lot of water on this asteroid

that you could process and turn into propellant for use in future space exploration. So yeah, it's an area of the solar system that we need to understand. And it's been really exciting to see all of the surprises and challenges. And even though we operationally are up against a bigger problem than we envisioned, the team kind of relishes that. It's just what they do, and they're incredibly good at what they do, and they're going to solve this problem. I have no doubt that we're going to get a sample off this asteroid. Can't wait. Looking forward to it, Dante. Before I let you go, I saw on your Twitter feed that in the midst of running a mission, you're still teaching at the University of Arizona, and a new semester began just a week or two ago. At least one class you're teaching has a fascinating title, Gameful Learning. What's that about?

Yeah, I think one of the reasons, and maybe the best reason, that we as taxpayers invest in programs of exploration like this is to inspire the next generation and to lift them up to go after big things. You may remember way back in 2013, NASA made the decision to cancel the education and public outreach program on OSIRIS-REx, for better or for worse. That was really upsetting to me personally, because I was particularly excited about the educational opportunities that this mission provides. And I decided to pursue other means to get the word out and to really work with the next generation of explorers. And I designed a couple of board games that focus on space exploration themes and started to understand the value of gameplay in primary education and how kids can learn through these kinds of activities. One of the

organizations that's very important to me are the Boys and Girls Clubs of America. It's a place that I went to as a kid. It was very important to me to have that stable presence in my life. So I reached out to our local Boys and Girls Clubs in Tucson, and I said, hey, we would like to come and do an after-school science program in your clubhouses. And of course, they were really excited about that. And over time, I formalized it. I started to get undergraduate students who wanted to help, who were excited about working with kids. And so I asked them, hey, what could we do to get more of your peers interested in this program? And they said, teach a class on this. So I reached out to a colleague at the College of Education, Dr. Corey Knox, who's an educational researcher. And I said, let's try to formalize this. I'm working with these kids. I'm designing these board games. I'm not an educational researcher. How do I know if this program is effective or not? That's exactly what they do over in the College of Education.

they do over in the College of Education. So we've kind of joined forces and we put together a course. It's a service learning class. So the students go to the Boys and Girls Clubs one night a week. We're in two different clubhouses locally here in Tucson. And they play science-themed board games. And not just my board games. They play all kinds of different science-themed board games. There's been an explosion of games about biology, games about physics, about math, about chemistry, about ecology. And so I have a big collection of science games. The students take them into the clubhouses every week. They build phenomenal bonds of friendship with the younger kids. from a lot of backgrounds where they would be the first generation to go to college if they decided to pursue higher education. I was the same way. I was a first generation college student when I was their age. And we're talking everything from second graders really to high school kids. I had no idea how you went to college. How did you pay for college? How did you apply for college? Having a friend who's in college that's a few years ahead of you at the University of Arizona

is a phenomenal resource for these kids so they ask all kinds of questions you know about school but about what is your life like as a college student how do you cover the expenses of going to college how can I go to college and at the end of the semester we do a big field trip here to the University of Arizona we either come to the Osiris-Rex Operations Center, which has been a real treat for the kids. Last semester, we went to the brand new Honors Village on campus so they could see where the honors students live and work. We've also done campus tours, etc. So we're in our third year of running this program, and it's been phenomenally successful. The education research has been fascinating, and we're actually getting ready to publish some of that work as well to demonstrate the effectiveness of this program.

One of the greatest experiences I had in college was a service learning class where we could pick the science experiments we wanted to bring out to a local elementary school in an area, an underprivileged area of town, and excite kids with science, just the way that you and your students are doing with these games and the other activities that are going on. And I can tell you, I saw it in the kids' faces. It is a thrilling and very rewarding thing to do. And so I thank you for putting that together. About those games, listeners who've been with us for a while remember the original Extronaut, followed now by Constellations.

I'm much more familiar with Extronaut. But I guess you are about to unveil a second version, a 2.0 version of Extronaut? We also had a third game called Downlink, the game of planetary discovery. And that's a more advanced game. As a gamer, I wanted something that was very strategic and in-depth. And that's a more advanced game. As a gamer, I wanted something that was very strategic and in-depth. So that one came out last year. But you're right. We are now getting ready to launch a Kickstarter for Extranaut 2.0. And really, this is showing my growth as a game designer. Extranaut was really my first foray into the world of board game design.

And it's a good game. It does well. It's reviewed well. But it does have some design flaws, quite honestly, and things that you just wanted to fix and make better and also just to enhance the content that's in it. For example, one of the things that we did with Extranaut 2.0, we're super excited about the Dragonfly mission. That's New Frontiers 4 to explore Titan, the moon of saturn uh so we put rotorcraft into the game as well so you can design rotorcraft mission to that's great any target that has an atmosphere in the solar system uh and then we've also put a lot more actions into the game and we've streamlined how the actions come into play the actions are where the strategy lies it's

how you interact with the other players. We recognize that we're in a changing world. I put a couple natural disasters into the game. If you're launching out of Cape Canaveral, you have to worry about hurricanes hitting. If you're launching out of Vandenberg, you have to worry about wildfires. So you're kind of realizing that climate change is impacting everything that we're doing as a species on this planet and they show up in the game and can really uh foil your attempt to get off the launch pad a lot more politics in there as well and uh definitely streaming the gameplay so that it comes in within one hour there are episodes of extra not that i've played where it can kind of drag on a little bit and you're just waiting for a card to show up so we've improved the game mechanics so that almost every time in a game, you're done in an hour, which is about the right time.

And then finally, we added two more launch sites so the game now can accommodate six players. Oh, great. Stay tuned, listeners, because you may be hearing more about Extranaut 2.0 and this Kickstarter campaign in the coming days. Before I let you go, Dante, what is Extranaut beyond? So one of the things we're also trying to do is reach out to people around the world to get them involved in space exploration. You know, we're seeing a lot of new space activity. The cost of spaceflight is dropping. If there's one thing that I know how to do, it's how to design a spacecraft mission. So we're working in this new space kind of mode. We're looking for lower

cost space missions. We're targeting targets from Venus to the asteroid belt. And we're really building in all of our educational experience. So we're working with countries in Africa, Latin America, and Asia to try to get them interested in sponsoring an educational mission of exploration. These can range from $15 to $40 million if you want to do an orbiter or a flyby. If you want to land something that's more expensive, so that's going to be something like $100 million. And so we're really excited. There's a couple different entities that are interested in this. And so we really hope that we can grow the space exploration community and start to reach out to other nations and get their whole population involved in the joy, excitement, and thrill of discovery.

Part of this growing democratization of planetary science and space exploration, more very exciting stuff. Dante, I got just one more question for you. For that, we'll go down to the bottom of the OSIRIS-REx website, asteroidmission.org, and it says, in remembrance of Michael J. Drake, could you remind us of why this website and, to a degree, this mission are dedicated to your former colleague? Yeah, thank you, Matt. Mike was an incredibly important person in my life and in the development of OSIRIS-REx. I've been on this program now. I'm actually two weeks away from my 16-year anniversary on this mission. Sixt 16 years ago, I was a young, bright-eyed assistant professor at the University of Arizona, just in awe that I had actually gotten a job at the Lunar and Planetary Laboratory and was joining some of the biggest names in planetary science, including Dr. Mike

Drake, who was the director of the laboratory. So I was in my office, and the phone rang in 2004, and it was Mike on the phone. And, you know, my first thought was, oh, man, the boss is calling. Did I screw something up or what? Am I in trouble? But Mike was like, hey, working with Lockheed Martin, we're developing an asteroid sample return mission. And I would like you to be the deputy principal investigator on this program. And that was stunning.

I was like, that's amazing. It was a risk because I had not achieved tenure yet. And there's a lot of things you got to do. And as we all know, these mission proposals are high stakes. The odds of winning are low. A lot of teams go into these competitions and only one comes out with a flight opportunity. But it was too exciting to pass up. And Mike and I worked together for seven years, writing and rewriting and submitting and resubmitting proposals to NASA until we finally won the new Frontiers 3 mission opportunity in 2011. It was May of that year that we got the call from NASA announcing the selection, and it was September that Mike passed away. So he really was only the PI on the program for four months. It was a huge blow emotionally to me and to the team. And I knew I had to step up.

One of the most difficult conversations I ever had with Mike was at the end when things weren't looking good. And I was nervous and I was quite honestly scared. I was like, I don't know that I can do this. And he said, you can do it and you have to do it. So take this team, carry the mission forward and make us all proud. And so we do, everything we do is in honor of Mike Drake for believing in me, for believing in this mission, for the passion and the dedication he put forward in convincing NASA to fly this program. He would be having such a great time right now. It really brings tears to my eyes to think that he's not here to see all of this data from Bennu.

Thank you for that, Dante. Thank you for this entire conversation. It's a great place for us to end it. But I very much look forward to our next conversation as we steadily progress toward that time. Well, this summer, right? You're shooting for August for that first attempt? August 25th is the tag date right now. If everything goes according to plan, we will be contacting the Service of Bennu in seven months. And we will be in contact with you, I hope, Dante. Again, thank you for doing this, and best of continued success as OSIRIS-REx

continues its progress toward that sample collection event. All right, thank you, Matt. That's Dante Loretta, Professor of Planetary Science and Cosmochemistry at the University of Arizona's Lunar and Planetary Laboratory, and, of course, the Principal Investigator for the OSIRIS-REx mission, which is orbiting Bennu as we speak. Time for What's Up on Planetary Radio. Bruce Betts is the chief scientist of the Planetary Society, also our chief astronomer.

My chief astronomer. I am your chief astronomy. I'm changing my business cards again. I'm Matt's chief astronomer. And how appropriate because you do give us this tour of the night sky every week, and I'm ready for another one of those. Let's start in the morning and then come to something nifty in the evening sky. So in the pre-dawn east, we've got Mars looking reddish, still with the Ant and Scorpius over to its right, also looking reddish. We've got Jupiter down to its lower left. And eventually over the coming weeks, you'll have Saturn coming up and Mars coming together with Jupiter and Saturn.

It's going to be wonderful. But right now, it's pretty much Mars with very bright Jupiter low to the horizon in the east. Now, in the west west in the early evening, you have probably noticed super bright Venus hanging out over there, and it will continue to do so for the coming weeks. And we've got fun conjunctions happening. So set aside the early evening Monday, January 27th. Venus and the moon will be hanging out relatively near each other

with a crescent moon, so that'll be lovely. But if you've got a telescope that you've got a field of view that's fairly wide of a degree, half a degree, you can check out Neptune hanging out near Venus that evening. And they're actually even closer if you're in Europe, but still will be close here. But you will definitely need a decent telescope to see Blueish Neptune next to Venus. But I thought that was kind of spiffy. So there you go. There's your chief astronomer's report.

Two days ago, we were out with friends and one of our friends looked up and said, oh, what's that? Do you know what that is, Matt? I said, yes, it's Venus. And he said, how do you know? And I said, because Bruce Betts told me so. That's really my goal is to have as many people say that in casual discussions with these other than Neptune, easy to see night sky type things. Fun. We move on to this week in space history, which was decidedly not fun. It's that time of the year again,

1967, the Apollo one fire killed three astronauts. 1986 this week, the Challenger accident killed seven astronauts. So it is the beginning of our, our week of memorial and remembrance of the American astronaut tragedies, because in next week we have the 2003 anniversary of Columbia. It is worth remembering, obviously. Let's hope that this week never again has these kinds of connotations added to it.

There, of course, was happy news in Spaceland. added to it. There, of course, was happy news in Spaceland. So in 1986, Voyager 2 flew past Uranus and gave us our only spacecraft view of the interesting Uranian system. Alright, we move on to Random Space Fact! Even though it's two million light years away, the Andromeda galaxy is about six times the width of the sun or moon in the sky as seen from earth six times wider than the moon in the night sky

now that's with long exposure imaging displaying the outer edges of the galaxy but that's just stunning how large that beast is. This is what threw me off for years with my telescope when I was trying to find Andromeda, because I was expecting this tiny little spirally thing, and I just wasn't thinking big enough. It's a fuzzy blob, and it's a big fuzzy blob. All right, we move on to the trivia contest. I pointed out there are two dwarf planets that have moons that rhyme and asked you to name the dwarf planets and the two rhyming moons at each. And I know we did well, Matt, because you shared. I did.

And this did become a bit of a poetry festival, a space poetry festival. And it's not that, you know, the best poem was going to win. We'll reveal the winner in moments. But we did get some nice poems that Bruce and I are going to share with you. Here's the first one, which is a nice way to tell you what the correct answer was. One of them's Namaka, and Hayaka is the other. Another dwarf with rhyming moons is Pluto, who is flaunting. Nicks and sticks. They're tiny, but they match what Bruce is wanting. They do indeed. They do indeed.

Very nice. Nick Bell, first-time winner, Crawfordsville, Indiana. He's our winner. He came up with exactly those same rhyming moons and did not need to provide and did not provide one himself. Although he did say, 18th and the 25th for my driving. He was on a big trip visiting family. Thanks. Well, you know, we're always happy to keep people company, Nick. And we're also happy to award you a Planetary Radio t-shirt and some cool Planetary Radio stickers, including the new Planetary Radio sticker from chopshopstore.com, where the Planetary Society store is. You got another one of these poems for us? I do indeed, from longtime regular listener Mel Powell.

Pluto has nicks and Pluto has sticks. Thanks, New Horizons, for those neighborhood picks. Three moons don't rhyme, but they're still in the mix. Haumea is harder. He, Aca, and Namaca. A third rhyme is tough. Les, your name is Chewbacca? Bravo.

And brava for Kay Gilbert in Manhattan Beach, California. Pluto's moons, called nicks and sticks, have Greek names. Very brief. Haumea has moons that use a different le motif. Hayaka and Namaka from Hawaiian lore honor goddesses who circle round their mother's shore. And you get to wrap it up with one that I think has a very clever finish. I think it has a very clever finish. From Joseph Poutre in New Jersey,

Haumea ellipsoid swiftly spins out in the void, broken from our thought hiiaka, closer, smaller kin namaka. Pluto, that most famous dwarf, even more than golfer dwarf, a naming many want to nix, but IU still says it sticks. Isn't that great? It sticks.

And the other one I love about this, of course, is I am such a big fan of Tim Conway. I'm so sorry that we lost him. One of the funniest people ever. And of course, he was golfer Dorf. Yes. It's diminutive golfer Dorf. I guess we can move on. New trivia contest. What mission and what astronauts were involved in the first haircut in space? That's right. First haircut in space mission and astronauts go to planetary.org slash radio contest. Wow. I never would have seen that one coming. Clip me close, I guess. That's a pretty weak attempt. You have until January 29, Wednesday at 8 a.m. Pacific time to get us this answer.

One more week, we will award a Planetary Radio t-shirt and those three cool stickers from the Planetary Society, including the Planetary Radio sticker. That's it. We're done. All right, everybody. Go out there. Look up in the night sky and think about. No, no, no, no, no. Thank you.

Good night. You did it in your head, though, didn't you? Who could not do it? You can't help it. Roger Rabbit did it best your head, though, didn't you? Who could not do it? You can't help it. Roger Rabbit did it best. Two bits. He's worth far more than that. That's the chief scientist of the Planetary Society, Bruce Betts,

who joins us every week here for What's Up. A big PlanRad thank you to all the cosmic poets out there who sent us their rhymes. Planetary Radio is produced by the Planetary Society in Pasadena, California and is made possible by its meteoric members. You can be a shooting star in our firmament. Join us at planetary.org slash membership. Mark Hilverda is our associate producer. Josh Doyle composed our theme, which is arranged and performed by Peter Schlosser.

I'm Matt Kaplan. Ad astra. our theme, which is arranged and performed by Peter Schlosser. I'm Matt Kaplan at ASCO.