Planetary Radio • Jan 22, 2020

The Coming Descent to Asteroid Bennu

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Dante Lauretta

OSIRIS-REx Principal Investigator for University of Arizona

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Bruce Betts

Chief Scientist / LightSail Program Manager for The Planetary Society

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Mat Kaplan

Senior Communications Adviser and former Host of Planetary Radio for The Planetary Society

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?

Bennu PolyCam mosaic
Bennu PolyCam mosaic This mosaic image of asteroid Bennu is composed of 12 PolyCam images collected on Dec. 2, 2018, by the OSIRIS-REx spacecraft from a range of 15 miles (24 km).Image: NASA / Goddard / University of Arizona
Bennu Sample Site with OSIRIS-REx Overlay
Bennu Sample Site with OSIRIS-REx Overlay This image shows sample site Nightingale, OSIRIS-REx’s primary sample collection site on asteroid Bennu. The image is overlaid with a graphic of the OSIRIS-REx spacecraft to illustrate the scale of the site.Image: NASA / Goddard / University of Arizona
Bennu Candidate Sample Site: Nightingale
Bennu Candidate Sample Site: Nightingale Site Nightingale is located on asteroid Bennu at 43° E and 56° N. It is a small crater encompassed by a larger crater with a 70 meter radius) near Bennu’s north pole. Nightingale has 4 areas that are being evaluated for sample collection. The first, with a 5 meter radius, is located in the northeast region of the crater. The second area, also 5 meter radius, is located slightly west of the crater’s center. The third area has an 8 meter radius, and reaches from the crater’s northern rim to its center. The fourth and largest area, with a 10 meter radius, encompasses nearly the entire crater. Nightingale contains mostly fine-grained, dark material and it has the lowest albedo and the lowest temperature of the four candidate sites. Nightingale’s regolith also has the highest color variation, which suggests the presence of diverse materials. Additionally, this region’s spectral signatures strongly indicate that carbon-rich minerals are present. This image was taken by OSIRIS REx's OCAMS (PolyCam) instrument on 29 March 2019.Image: NASA/Goddard/University of Arizona
Boulders on the Horizon
Boulders on the Horizon This image shows several large boulders positioned on asteroid Bennu’s equatorial ridge. The image was taken by the PolyCam camera on NASA’s OSIRIS-REx spacecraft on 12 April 2019 from an altitude of 2800 meters. The field of view is 40.3 meters wide. For scale, the largest boulder on the horizon is more than 5.2 meters tall, which is about the height of a two-story house. The image was obtained during Flyby 6B of the mission’s Detailed Survey: Baseball Diamond phase. When the image was taken, the spacecraft was over the northern hemisphere, pointing PolyCam south and to the west.Image: NASA / GSFC / UA

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Mat Kaplan: [00:00:00] The coming perilous descent to asteroid Bennu, this week on Planetary Radio. Welcome. I'm Mat Kaplan of The Planetary Society with more of the human adventure across our solar system and beyond. Dante Lauretta 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 it's 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 Bats. Remember me inviting you last week to check out my monthly Planetary Radio newsletter? The January edition is now available and you can [00:01:00] easily subscribe by visiting That's to add to your already sublime plan rad 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 Principle 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 NASA welcomed 11 brand new astronauts in a graduation ceremony. The six women among them include a geologist and a biologist. There are two Canadians. It's safe to assume some of them will be riding either the [00:02:00] 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 semi-finalists 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 Here is its creator, Jason Davis. Jason, how significant is successful [00:03:00] test by, uh, SpaceX of the Crew Dragon capsule?

Jason Davis: Pretty significant. This actually checks off their last milestone of the initial Commercial Crew Awards that date back, uh, [laughing] many years. I'd have to look up the exact date, but, uh, 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, uh, to the International Space Station."

Mat Kaplan: So I imagine they're still looking at that data, although everything certainly looked like it was 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?

Jason Davis: It does, yeah. In the press conference after the, uh, the test that had representatives from both SpaceX and NASA, terms that were getting thrown around were second quarter [00:04:00] of this year, uh, I believe someone said April. It is actually looking promising barring any other, um, setback that comes up along the way. But they did say the initial look at the data, uh, checked out and um, you know, all the parachutes seem to work perfectly. The, uh, ship was recovered quickly and, you know, is on its way back to shore. Now by all indications, and we've said this so many times, [laughing] it really does look like this might happen this year.

Mat Kaplan: I caught the last portion of that, uh, press briefing with Jim Bridenstine, the NASA Administrator, sitting right next to Elon Musk, and Bridenstine looked like a pretty happy guy.

Jason Davis: [laughs] He did. He is just the latest administrator who has had to deal with some setbacks, um, I guess the other being, uh, Charlie Bolden. It's promising his commercial crew and commercial cargo have turned out to be in, 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 [00:05:00] some that come to mind would be, uh, SpaceX did a s- 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. That every step forward they take, they, they take a couple back.

Jim Bridenstine expressed, you know, a lot of frustration with them before, but also he's clearly happy now that it seems like this, this final milestone is out of the way and they can get serious about, uh, setting a date for the, the real test flight.

Mat Kaplan: So, of course, you've also made me think of Boeing's, uh, ups and downs with their CST-100, the, 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, uh, carry humans up there?

Jason Davis: They have not said yet whether or not it will require another flight. This was when, uh, Boeing tried to do its [00:06:00] uncrewed demonstration flight and there was a problem where the thrusters didn't fire properly to raise them to the stations altitude to actually complete the docking. Spacecraft came back to earth okay, and, uh, it turned out to be a relatively minor glitch in the 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, um, could, could make this happen this year.

Mat Kaplan: I don't want to say that there's a new space race underway here, but, uh, [laughing] but it will be interesting to see which of these new spacecraft makes it up there with the astronauts first. Jason, I'm sure we'll be checking back with you to talk about this as it continues to develop. Thanks.

Jason Davis: Definitely. Thank you Mat.

Mat Kaplan: OSIRIS-Rex, you don't hear it spelled out very often. It's actually a pretty cool acronym. Origins Spectral Interpretation Resource [00:07:00] 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 Lauretta, can tell you many more. Actually, he is 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 Cosmo Chemistry at the University of Arizona's Lunar and Planetary Laboratory. He's also the driving force behind XTRONAUT, 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, uh, now it has just been a few weeks, uh, [00:08:00] well, December 12th that you made this momentous announcement of, uh, where OSIRIS-Rex will be descending down to this asteroid to grab that, that first precious sample. Congratulations first of all, on all of this.

Dante Lauretta: Thank you Mat. 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.

Mat Kaplan: [laughs] 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.

Dante Lauretta: Yeah. Bennu is certainly challenging us, uh, 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 [00:09:00] 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.

Mat Kaplan: [laughs] Uh, and the same thing happened with Hayabusa2. 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? Uh, isn't Bennu more challenging than you expected it to be as you were approaching?

Dante Lauretta: 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, it's 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 [00:10:00] 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.

Mat Kaplan: No. [laughs] It's amazing to look at. I mean, it- it's spectacular, but not what you'd probably want to, uh, uh, drop a spacecraft down onto to pick up a, 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, uh, has, uh, probably the most appropriate name for any mission I've ever seen, Couldn't be easier or more appropriate. Not only will they be able to see, uh, still images of pretty much the entire asteroid, but also these fantastic assimilated 3D flyovers [00:11:00] of these, uh, these candidates that you looked at for, for making this, uh, this first collection. Tell us about the one that you've chosen.

Dante Lauretta: Yeah, so first let's talk about that dataset, 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, uh, 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-

Mat Kaplan: Wow.

Dante Lauretta: ... 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 [00:12:00] five centimeter per pixel resolution. The overlay of those two data sets produced that amazing global shape bottle of the asteroid that you've probably seen rotating. And then as we were 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 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 [00:13:00] 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 Waterbury minerals and we're interested in organics. They stay cooler, those higher latitudes 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 to 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.

Mat Kaplan: Oh, great. That, that, I know it's always on every mission. It is a challenge balancing science versus, uh, the safety of the spacecraft. It's, uh, exciting [00:14:00] and, and courageous to hear that, uh, science may have slightly tipped the balance at least a little bit in this case. When you say that the northern latitudes or the, the polar lat- latitudes on the asteroid are somewhat better protected or stay cooler, is that because Bennu is, is spinning on its axis much like a planet and, and just doesn't get as much sunlight, uh, toward the poles?

Dante Lauretta: Yeah, that's exactly right, Mat. 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, reason I don't say zero degrees is because it actually is a retrograde rotator. So in the solar system, uh, coordinate system, it's 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 [00:15:00] direct, uh, 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.

Mat Kaplan: Okay. So Nightingale it is. And yet [laughs] Bennu was still throwing up big challenges. I mean I read that your target area is only about what? One 10th of what you had hoped to find to, to drop OSIRIS-REx down onto. Talk about challenges. How have you adapted to this, um, unexpected, uh, reduction in your target?

Dante Lauretta: Yeah. Not only what we hope to find, but what we designed the spacecraft to do. [laughing] So we really built a navigation system which was using a guidance, navigation and control LIDAR [00:16:00] 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 Sea 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 a hundred meters in diameter, and then lots and lots of them that are 10 meters, five meters and two meters and, 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 five meter radius. And as we know, area [00:17:00] 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.

Mat Kaplan: [laughs]

Dante Lauretta: We had put a backup guidance system on the spacecraft called Natural Feature Tracking. So what this system does, we're gonna 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 [00:18:00] 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 five meter guidance accuracy that Bennu is levying on us.

Mat Kaplan: Is there a parallel in this new approach, speaking literally, to what the Mars 2020 Rover is expected to do in about a year? Uh, we've talked on this show about how it will for the first time be using its knowledge of the terrain of, of its target, thanks to images taken by the Mars Reconnaissance Orbiter. Sounds like you're gonna [00:19:00] be doing the same thing except that OSIRIS-REx had to collect its own image database.

Dante Lauretta: That's right. Yeah. Mars 2020 we'll be doing a terrain relative navigation, so it has one chance to fire thrusters during its EDL sequence. So it's gonna come in, it's gonna do a very similar kind of calculation. It's gonna see where it is and what it sees in its field of view. It's gonna determine the six degree state, so its position and velocity and 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, uh, a hazard. The big difference with OSIRIS-REx is that we're not a one way trip, right?

Mat Kaplan: [laughs]

Dante Lauretta: 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 gonna come down on an area we've identified as a hazard, it can just say, "Okay, timeout, fire thrusters, back away from the [00:20:00] 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?

Mat Kaplan: [laughs]

Dante Lauretta: We're coming in at 10 centimeters per second. In fact, uh, just two weeks ago we did a real time wall clock simulation of the tag day. So we watched what it's gonna 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.

Mat Kaplan: [laughs]

Dante Lauretta: It's really slow and gentle, and so an abort maneuver is not a penalty in terms of fuel. Uh, it really is a matter of time, 'cause it takes us a while to reset and, and then reestablish the trajectory to go in for another sample attempt.

Mat Kaplan: So no seven minutes of terror [00:21:00] here. Also like-

Dante Lauretta: Yeah, it's more like four and a half hours [crosstalk 00:21:03]there yet.

Mat Kaplan: [laughs] All right. 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, uh, based on this programming that you'll have done. Uh, or do you have more ability to sort of manually say, "Oh no, we don't like that, uh, OSIRIS-Rex so back off"?

Dante Lauretta: 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 re-establish contact with the spacecraft. Uh, 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, gonna be, you know, frightening and nail biting-

Mat Kaplan: [laughs] Yeah.

Dante Lauretta: ... because that's when all kinds of things can [00:22:00] 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 back away thrusters, we should very quickly reestablish contact with the vehicle. But yeah, it's a smart little spacecraft. It's gonna 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.

Mat Kaplan: I can only imagine the anxiety of designing the algorithm that's going to decide, uh, what is too hazardous and what is just right. I mean is there a concern, uh, 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, to avoid a, a touchdown that, that actually might've been okay?

Dante Lauretta: That's, you've, you've really hit the nail on the head there Mat.

Mat Kaplan: [laughs]

Dante Lauretta: That is the debate that we are wrestling with internally, where we have tuneable parameters. How much risk do you want to accept? It comes down to kind of a [00:23:00] probabilistic calculation. What is the likelihood that you are actually gonna make contact with a hazardous location on the asteroid surface? The requirement that we levied was that the spacecraft has a h- 99% chance of s- remaining safe during sampling, but proving that it's 99% is not an easy task, and are we really willing to accept that 1%, uh, risk of the spacecraft suffering damage to the point where it would be unable to return the sample?

Mat Kaplan: More from Dante Lauretta is coming right up.

Casey Dreier: 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 Dreier, 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 DC and meet with members of Congress face to face and advocate for space. To learn more, go to [00:24:00]

Mat Kaplan: We're back with Dante Lauretta, Principal Investigator for the OSIRIS-REx asteroid sample return mission. You were a co-investigator on the Hayabusa2 mission, did that spacecraft's sample collection success, very recently, did it give you and your team more confidence?

Dante Lauretta: Yeah, it's a great honor to be part of the Hayabusa2 mission. Uh, I've been huge fans of their program since the first Hayabusa, and uh, 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, uh, 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 [00:25:00] 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 [inaudible 00:25:12] who's the project manager over there, uh, 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.

Mat Kaplan: That is absolutely wonderful to hear. Um, you mentioned the sample collection mechanisms are quite different, uh, between Hayabusa2 and yours. You've done this before but would you review for us once again how exactly once you get down to the surface, uh, you're going to be able to pick up, uh, those precious bits.

Dante Lauretta: Absolutely. So OSIRIS-REx is going after a large bulk sample and that's one of the distinctions between us and the Hayabusa2 system, [00:26:00] 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 ancient technology, right?

Mat Kaplan: [laughs] Never thought of that, but I know what you mean. I've seen it.

Dante Lauretta: Yeah. You're pushing air through a filter and you're trying to catch the, 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. Uh, so we placed 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 [00:27:00] there's no air at the asteroid, it's an airless body, so we brought three different bottles of high purity nitrogen gas.

And as soon as we'd sense contact with the asteroid surface, we'd open up one of those bottles and we'd 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. Uh, the science requirement is 60 grams. We're confident Nightingale gives us the best chance of meeting that requirement.

Mat Kaplan: Fantastic. Uh, 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, uh, the one that we call Planet Vac [00:28:00] that, uh, we've worked with that company, Honeybee Robotics on, which might be headed to the moon, uh, in the coming years. Uh, 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, this sample, 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.

Dante Lauretta: This is an area where we are actively developing the plans right now and es- establishing the new hypotheses that have, uh, 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 surface. You know, one of the big surprises was [00:29:00] 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 Ryugu both have, seems to maybe date from the formation of the asteroid, which, uh, according to our model, was from a disruption of a much larger asteroid, about a billion years ago in the main asteroid belt.

So the first thing I wanna 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 [00:30:00] want to get a sample as quickly as possible within days of being on earth into a gamma ray counting facility. And we've just started a conversation with a, 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.

Mat Kaplan: Wow.

Dante Lauretta: 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 that we pick up. And now we've got a plan for each one of those, 'cause each one of those needs its own detailed [00:31:00] geologic and geochemical investigation to understand the story that's recorded in there. So a lot of it is gonna 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 gonna want to know its bulk composition, we're going to want to do radio isotope 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 that 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 [00:32:00] 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.

Mat Kaplan: Do you expect that like those, uh, 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, are going to be delivering science for maybe decades to come?

Dante Lauretta: 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 [00:33:00] gonna be even smarter. They're gonna have better instruments, they're gonna know more about asteroids, and they're gonna 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-

Mat Kaplan: [laughs]

Dante Lauretta: 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 gonna be really interested in this asteroid over 100 years from now.

Mat Kaplan: And so in the 22nd century, which I, 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, as a [00:34:00] target for this mission.

Dante Lauretta: 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 150 year timeframe. And I know that sounds like a long time for you and me, but on a, 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, i- impact medication 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?"

Mat Kaplan: [00:35:00] Let's talk a little bit for at least a couple of minutes before we turn to other topics, uh, about what you have already learned about Bennu. You've touched on this. You've already found organics, and, and just finding this, this amazingly rich, uh, surface, unexpected surface, which by the way, it occurs to me that this is, uh, more evidence of why it is so important for us to get up close and personal with asteroids, right?

Dante Lauretta: 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-

Mat Kaplan: Exactly. That's where I was hoping we go.

Dante Lauretta: 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 to 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 [00:36:00] 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, uh, the immediate response was for spacecraft safety is 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 inner planetary dust population. Other ones are actually bound in orbit around the asteroid. So Bennu as we're seeing, has this constant population of many 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 reimpacting with the surface. So this is a completely unexpected phenomena. Bennu is now part of a rare class of asteroids we call [00:37:00] 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- you'd say, what is the degree in order of the field? And it's a spherical harmonic expansion, uh, technique that's used to characterize the field in this way. Our requirement was to get down to fourth degree, and we were gonna 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, uh, 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 [00:38:00] gravity field probes, uh, by watching these things zip around this asteroid, and we're solving the gravity field to eighth degree now.

Mat Kaplan: Wow.

Dante Lauretta: So well on 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 fa- 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.

Mat Kaplan: But is it possible that the asteroid Bennu is, uh, a little bit common?

Dante Lauretta: I would say yes and no. Uh, 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 in training dust particles and then lifting them off the surface of the comment. And we've looked, you know, we have two fantastic spectrometers [inaudible 00:38:51] 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 [00:39:00] 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 micro meteoroid 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, uh, 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 got a water rich surface, it is not gonna take much to heat that up and maybe drive off particles. And then the micro meteoroids might be adding that little kick of energy to, to kind of jumpstart the process.

Mat Kaplan: So [00:40:00] even with the unexpected challenges that it presents, is Bennu looking as exciting or even more exciting, uh, as a, as your choice for this spacecraft, uh, as you were hoping it would be years ago before the launch?

Dante Lauretta: Mat, I can honestly say the past year has been the most exciting time of my life. [laughs] Without a doubt. Uh, I mean, a- as you can imagine, it's a great honor to be leading an, 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, 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 [00:41:00] 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, uh, it's a, 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, uh, a bigger problem than we, uh, 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 gonna get a sample off this asteroid.

Mat Kaplan: Can't wait. Looking forward to it, Dante. Before I let you go, I saw on your Twitter feed that, uh, 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?

Dante Lauretta: 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 [00:42:00] next generation, and in 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, 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 game play 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 [00:43:00] Tucson and I said, "Hey, we would like to come and do an afterschool 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, 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. 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 theme board games. And not just my board games, they play all kinds of different science theme board games. [00:44:00] 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, and the kids are coming 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 is 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 [00:45:00] the end of the semester, we do a big field trip here to the University of Arizona. We either come to the OSIRIS-REx Operation 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, et cetera.

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, to demonstrate the effectiveness of this program.

Mat Kaplan: 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, uh, a local elementary school and uh, and uh, an area, an underprivileged area of, uh, town, and excite kids with a science. Just the way that, uh, you and your students are doing, uh, with these games and the other activities that are going on. And I, I can tell you, I saw it in the kids' faces, it is a thrilling and very rewarding thing to do. And so I, I [00:46:00] thank you for putting that together. About those games, listeners who've been with us for a while remember the original XTRONAUT, followed by, now by Constellations.

I'm much more familiar with XTRONAUT, but I guess you are about to unveil, uh, a second version, a 2.0 version of XTRONAUT?

Dante Lauretta: We also had a third game called Downlink: The Game of Planetary Discovery. And that's a more advanced game. Uh, as a gamer, I wanted something that was a 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 XTRONAUT 2.0, uh, and really this isn't, uh, showing my growth as a game designer. XTRONAUT 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, uh, 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 XTRONAUT 2.0, we're super excited about the [00:47:00] 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-

Mat Kaplan: That's great.

Dante Lauretta: ... 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. Uh, 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 it can really, uh, foil your attempt to get off the launchpad. 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 XTRONAUT that I've played where it can kind of drag on [00:48:00] 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, uh, in, 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.

Mat Kaplan: Oh, great. Stay tuned listeners, because you may be hearing more about, uh, XTRONAUT 2.0, uh, and this kickstarter campaign in the coming days. Before I let you go, Dante, what is XTRONAUT Beyond?

Dante Lauretta: 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 space flight is dropping. Uh, if there's one thing that I know how to do, it's how to design a, 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 [00:49:00] 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. Uh, these can range from 15 to $40 million, uh, if you want to do an orbiter or a fly by.

If you wanna land something, that's more expensive. So that's, it's gonna 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.

Mat Kaplan: Part of this growing democratization of, uh, planetary science and space exploration, uh, 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,, and it says in remembrance [00:50:00] of Michael J. Drake, could you remind us of, uh, why this website and to a degree this mission, uh, are dedicated to your former colleague?

Dante Lauretta: Yeah. Thank you Mat. Uh, Mike was an incredibly important person in my life and in the development of a OSIRIS-REx. I've been on this program, now, I'm actually two weeks away from my 16 year anniversary on this mission. 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 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 [crosstalk 00:50:49]

Mat Kaplan: [laughs]

Dante Lauretta: Did I screw something up or what? Am I in trouble? But Mike was like, "Hey, uh, working with Lockheed Martin, we're developing an asteroid sample return mission and I would like you to be [00:51:00] the deputy principal investigator on this program."

Mat Kaplan: Wow.

Dante Lauretta: 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. Uh, 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, uh, 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 in, 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 [00:52:00] was quite honestly scared. I was like, "I don't know that I can do this, Mike." And he, 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, uh, brings tears to my eyes to think that he's not here to see all, all of this data from Bennu.

Mat Kaplan: Thank you for that Dante. Thank you for this entire conversation. It's a great place for us to, uh, to end it. But, uh, I very much look forward to, uh, our next conversation as we, uh, steadily progress toward that time. Well, this summer, right? You're shooting for August for that first attempt?

Dante Lauretta: August 25th is the tag date right now. If everything goes according to plan, uh, we will be contacting the service of Bennu in seven months.

Mat Kaplan: And we will be in contact with [00:53:00] you, I hope Dante. Again, thank you for doing this and uh, best of continued successes. Uh, OSIRIS-REx continues Its, uh, progress toward that sample collection event.

Dante Lauretta: All right, thank you Mat.

Mat Kaplan: That's Dante Lauretta, Professor of Planetary Science and Cosmo Chemistry 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.[laughs]

Bruce Betts: I am your chief astronomy. [laughing] I'm changing my business cards again. I'm Mat's chief astronomer.

Mat Kaplan: [laughs] And, 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.

Bruce Betts: Let's start in the morning and then come to something nifty in the evening sky. So in the pre-dawn [00:54:00] east, we've got Mars looking reddish, uh, still with, uh, Antares and Scorpius over to it's 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 gonna be wonderful. But right now it's pretty much Mars with a very bright [inaudible 00:54:21] on the horizon in the east.

Now in the west in the early evening, you've probably noticed super bright Venus hanging out over there and it will continue to do so for the coming weeks. And we've got, uh, fun conjunctions happening. So set aside the evening, 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 uh, if you've, if you've got a telescope that you've got to feel the view that's fairly wide of a degree, half a degree, you can check out Neptune hanging out near Venus that evening and, uh, [00:55:00] tie. 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 astronomers report.

Mat Kaplan: [laughs] 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, Mat?" I said, "Yes, it's Venus."

Bruce Betts: [laughs]

Mat Kaplan: And uh, he, he said, "How do you know?" And I said, "Because Bruce Betts told me so."

Bruce Betts: [laughing] That's really my goal, is to have as many people say that in casual discussions with, uh, these... Other than Neptune, easy to see night sky type things. Fun. We move on to this weekend space history, which was decidedly not fun. Uh, it's that time of the year again, 1967, the Apollo 1 fire killed three astronauts. 1986 this week, the Challenger accident killed seven astronauts. So, [00:56:00] uh, 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.

Mat Kaplan: It is worth remembering, obviously. Um, let's hope that this week, uh, never again has these kinds of connotations added to it.

Bruce Betts: There, there of course was happy news in Spaceland. So all, in 1986, Voyager 2 flew past Uranus and gave us our only spacecraft view of the interesting Uranian system. All right. 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, uh, [00:57:00] imaging displaying the outer edges of the galaxy. But that's just stunning how large that beast is.

Mat Kaplan: 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 [laughing] I just wasn't, I wasn't thinking big enough.

Bruce Betts: 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 Mat, because you shared.

Mat Kaplan: 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 gonna win. Uh, we'll reveal the winner in moments, but we did get some nice poems that Bruce and I are gonna, gonna share with you. Here's the first one, which is a nice way to tell you what the correct answer was. It's from our poet laureate Dave Fairchild in Kansas. [00:58:00] Haumea has a pair of moons that orbit near each other. One of them is Namaka and Hiʻiaka is the other. Another dwarf with rhyming moons is Pluto who is flaunting Nix and Styx. They're tiny, but they match what Bruce is wanting.

Bruce Betts: They do indeed, indeed. Very nice.

Mat Kaplan: Nick Bell, first-time winter Crawfordsville Indiana. He's our winner. He came up with exactly those same rhyming moons and, uh, did not need to provide and did not provide one himself, although he did say, "Hope you and the rest of the Planetary Society had a wonderful holiday. Great new years." He said, "I had enough forethought to save your two episodes from December 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 c- company Nick, and we're also happy to award you a Planetary Radio T-shirt and some cool planetary radio stickers including the [00:59:00] new Planetary Radio sticker from, where the Planetary Society store is. You're gonna know one of these poems for us.

Bruce Betts: I do indeed from a longtime regular listener, Mel Powell. Pluto has Nix and Pluto has Styx. Thanks new horizons for those neighborhood picks. Three moons don't rhyme, but they're still in the mix. Haumea is [inaudible 00:59:24]Hi'iaka and Namaka. A third rhyme is tough, less your name is [Chewbacca 00:59:31]

Mat Kaplan: [laughs] Bravo and Brava for K. Gilbert in Manhattan Beach, California. Pluto's moons called Nix and Styx have Greek names. Very brief. Haumea has moons that use a different lay motif. Hi'iaka and Namaka from Hawaiian lore honor goddesses who circled round their mother's shore. And you get to wrap it up with, uh, with one that [01:00:00] I think is just very, has a very clever finish.

Bruce Betts: From Joseph [Putray 01:00:04] in New Jersey. Haumea ellipsoid swiftly spins out in the void broken from our thought Hi'iaka, closer, smaller kin, Namaka. Pluto that most famous dwarf even more than golfer Dorf. A naming many want to Nix, but IU still says it Styx.

Mat Kaplan: [laughs] Isn't that great? It Styx. 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. Uh, and of course he was golfer Dorf.

Bruce Betts: [laughs] Yes, it's diminutive golfer Dorf.

Mat Kaplan: I guess we can move on.

Bruce Betts: New trivia contest. What mission and what astronauts were involved in the first haircut in space? That's right. First [01:01:00] haircut in space mission and astronauts go to

Mat Kaplan: Wow. Uh, I never would have seen that one coming. Uh, there, there's a cl- clip me close, I guess. He's-

Bruce Betts: [laughs]

Mat Kaplan: That's a pretty weak attempt. You have until January 29, Wednesday at 8:00 AM Pacific time to get us to 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.

Bruce Betts: All right. Everybody go out there and Look out in the night sky and think about, nah, nah, nah, nah, nah. Thank you, and good night.

Mat Kaplan: [laughs]

Bruce Betts: You did it in your head though, didn't you?

Mat Kaplan: Uh, who could, who could not do it? You can't help it. Roger Rabbit did it best to bits. He's worth far more than that.

Bruce Betts: [laughs]

Mat Kaplan: That's the Chief Scientist of the Planetary Society, Bruce Betts, who joins us every week here for What's Up. A big Plan rad thank you to [01:02:00] 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 Mark Hilverda is our associate producer, Josh Doyle composed our theme, which is arranged and performed by Peter Schlosser. I'm Mat Kaplan. Ad astra.