Planetary Radio: Space Exploration, Astronomy and Science - It’s Asteroid Week with NASA’s Planetary Defense Officer

Episode Date: June 27, 2018

The dinosaurs regret their lack of a space program.  200 million years later, humans are gearing up to defend themselves from a species-ending rock.  The many challenges involved are addressed in a new strategic action plan created by sixteen agencies of the US government.  NASA’s Planetary Defense Officer, Lindley Johnson, and his associate, Kelly Fast, take us inside the plan.  Planetary Society CEO Bill Nye the Science Guy applauds the growing worldwide attention to Near Earth Objects. By the time you read this Hayabusa2 will have reached asteroid Ryugu.  Senior editor Emily Lakdawalla has a mission update. And Bruce Betts is all over Asteroid Week in a new What’s Up segment.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Watch for falling rocks. It's Asteroid 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. There's a brand new Strategic Action Plan for dealing with near-Earth objects, or NEOs, those million or so asteroids and comets that threaten our planet, NASA Planetary Defense Officer Lindley Johnson will take us through the plan with support from Kelly Fast, the agency's Near Earth Object Observations Program Manager. Later, Bruce Betts will carry the theme forward in a special NEO edition of What's Up. To introduce us to the topic, I present the

CEO of the Planetary Society, Bill Nye, the science guy. Bill, who'd have thought that Asteroid Week would become a worldwide celebration, but then I guess it's a worldwide threat. Yes, Matt, it's a worldwide threat. It's a very low probability event that the Earth will get hit with an asteroid, but it is very high consequence. So as I like to say, you know, when I was in Carl Sagan's class, dropping a name, when I was in Carl Sagan's class in 1977, he talked a lot about the Tunguska event. This is a thing in Siberia in 1908, as the calendar is now reckoned on June 30th. You know, at that time, they were on the Julian calendar in some parts of the world.

Nobody knew really what it was for two years. People went up there and took pictures two years later. That's how remote the Tunguska, what we now call airburst event was. They didn't really use the term airburst when I was in school. So this is an object that hits the Earth's atmosphere so fast, how fast is it, that it explodes and creates these enormous shock waves, shock waves akin to those you would see in rocket exhaust. And you probably remember Chelyabinsk five years ago, pronouncing it as best I can. Da. Da. We don't want this to happen. So the key, everybody,

is early detection. We got to go out there and look. So because of the June 30th Tunguska event in 1908, we now call this Asteroid Week. Woo! And so we at the Planetary Society work very hard on this. And all three of our pillars of effort, we have excellent journalism about it. The solar sail has certain applications for asteroid detection. And with our Shoemaker NEO, Near Earth Object Grants, we fund amateur astronomers around the world looking for asteroids. And by the way, an amateur astronomer is a whole

nother thing from an amateur tennis player. An amateur astronomer really contributes a great deal to the science of astronomy because the sky is vast and it's fascinating and the people who become fascinated with it are often excellent scientists and observers. And then the third thing we do is advocate. We go to U.S. Congress especially, the limited extent European Space Agency, and petition these men and women to make sure that we fund the search for asteroids. Early detection is the key. In real estate, it's location, location, location. In asteroids, it's early detection, early detection, early detection. And so the objective,

Matt, is what? To kick asteroid. That's brilliant. Let's go kick some asteroid. Thank you, Bill. Thank you, Matt. That's the CEO of the Planetary Society. He joins us now and then here on the show. The Planetary Report is the Planetary Society's great magazine. The June edition features an article about sample return, one of the most challenging and rewarding things humans and robots can do in space. Senior editor Emily Lakdawalla reports on a mission that has reached a major milestone in its progress toward returning material from an asteroid.

Emily, it just happens that on the day this episode of Planetary Radio becomes available to our audience, that is also the day that Hayabusa will arrive at long last at its target. But even now, as we speak a couple of days ahead of time, this little rock is becoming, looks like a pretty interesting place to visit. Matt, this is one of my absolute favorite parts of planetary exploration. No matter how big or how small a world is, seeing it for the first time,

turning it from a point of light into a place with shape and topography and geology and history, it's just the best. And so we're now seeing Ryugu for the first time from Hayabusa 2. It's turned from a point of light into a funky little shape, kind of looks like a top. It's kind of a jewel shape, sort of pointy at the poles and round in the middle, but kind of faceted. It seems a little strange, but according to radar data on many near-Earth asteroids, it's actually a pretty common shape for a near-Earth asteroid, probably a result of it

being a spinning rubble pile. They tend to get into this sort of shape. So it's expected, but also new. There's some big boulders and a funky bright spot at the North Pole that Hayabusa 2 is going to have to figure out. And yeah, it'll be pulling into not exactly an orbit, but sort of a co-orbit with this tiny little object on the day, hopefully, that people listen to this at a distance of only 20 kilometers away. I was going to ask you about the light and dark areas that are already visible. Just loose material on the surface? I mean, what is the thinking on that? Well, from what we can see from a distance, I can definitely see some large boulders. Those may not be bright or dark. It just may be that because they're large, they're catching the sunlight. They're more perpendicular or they're

casting shadows. So that's what might cause those bright and dark spots. But there is also this hint of some kind of groove on its southern hemisphere. There are a couple of things that definitely look like impact craters. I suspect that as we get closer and closer, we're going to see more kind of muted impact craters, more boulders, more gravel. I'm guessing that the surface is going to look quite a lot like the previous asteroid visited by another spacecraft, Hayabusa 2's predecessor, Hayabusa, which visited Itokawa some years ago and saw this strangely gravelly surface. I'm getting the feeling that it's going to look kind of similar, but the asteroid's a completely different shape. What is just ahead

after Hayabusa 2 arrives? Well, they have to do a sort of a first survey just to make their maps they're going to be doing all of the rest of their scientific work on and then there will be periods of dropping closer and closer at some point they're going to have to spend some time within a kilometer of the asteroid and what they'll be doing down there is very important although they'll be doing imaging that's one thing you might might want to be close for You also have to have the spacecraft sense the gravity field around this tiny, lumpy object. You need a very detailed understanding of what the gravity is in the space right around the asteroid if you want to touch down safely. And that's what's ahead for Hayabusa 2 eventually, is that they're going to be touching down this fall, possibly releasing these little boxy micro-rovers and collecting a sample.

All right, Emily, very appropriate topic for Asteroid Week 2018. Thank you very much. And I hope we can talk to you again soon. Thank you, Matt. That's Emily Lakwala, senior editor for the Planetary Society, who joins us from time to time here at the top of the show. Which would you rather be, the Planetary Protection Officer or the Planetary Defense Officer? NASA has great individuals in both jobs. Lindley Johnson is the agency's first ever Planetary Defense Officer.

He has joined us many times in the past. Lindley previously had the much less sexy title of Near-Earth Object Programs Executive. He also has served as program executive at NASA headquarters for the Epoxy mission. He was in a Colorado hotel room when I reached him for a conversation about a big step forward in how the United States will prepare for the next asteroid or comet that threatens our planet.

Joining us from NASA HQ in Washington was Kelly Fast. She is the Near-Earth Object Observations Program Manager in the Planetary Defense Coordination Office. This very accomplished astronomer is also Lead Discipline Scientist for the Solar System Observations Program, Program Scientist for NASA's Infrared Telescope Facility, and program scientist for the MAVEN mission that is orbiting Mars. Lindley and Kelly, welcome back to Planetary Radio in what is the most appropriate of all weeks, particularly because of the release of this very interesting document, a 20-page document that I read a couple of days ago, called the National Near-Earth Object Preparedness Strategy and Action Plan, which your office, the Planetary Defense Office at NASA, had an awful lot to do with,

although so did a lot of other agencies. In fact, Lindley, I noticed that if I counted correctly, there were 16 different agencies identified as contributing to or collaborating on this document. That's a pretty impressive list of agencies for the federal government. That's right, Matt. This was an all-of-government effort to develop an all-of-government plan for better being prepared in case an asteroid impact threat was discovered. My boss, Bill Nye, the science guy, he opened this week's episode by reminding us that disastrous neo-impacts have a very low probability,

but very high consequences if you're unlucky enough to be under one. That's what this is all about, isn't it? That's right. An impact of any significance is extremely rare, maybe once a century at most, but very high consequence, particularly if it were to impact near a metropolitan area. The level of devastation could exceed anything that we've seen from hurricanes, earthquakes, volcanoes. could exceed anything that we've seen from hurricanes, earthquakes, volcanoes. So that's why the U.S. government has invested some time and interest in assessing our current level of preparedness for such a disaster

and then developing this preparedness plan to guide our activities over the next 10 years to get ourselves in a better position if something like that were detected in space. To illustrate the destructive power of one of these impacts, there is a figure in well up front in this report, this plan, which I had not seen before. area of New York City and surrounding and overlays the destruction zone from the Tunguska impact over that. Tunguska, of course, that big explosion, that airburst that flattened so much of the forest land in Russia back at the beginning of the 20th century. That is a very chilling illustration. It is, but it is representative of the kind of forces we're

dealing with here. You know, that event happened on 30 June of 1908, exactly 110 years ago this week. As I said, something like this is very rare, but perhaps once a century we would have to deal with something like this. Which is pretty frequently, considering the destructive power of one of these, if it came down over a populated area. And I was also interested to see in the graphs that a relatively small number of the asteroids of the sort that caused the Tunguska of that size have been found, and fewer yet of the size that exploded over Chelyabinsk barely five years ago. And that's in spite of wonderful progress that has been made in recent years,

but it looks like we've got quite a ways to go. That's certainly true. Our approach and strategy in our Near Earth Object Observations Program is try to take on the big ones first, the ones that could be truly disastrous, a global disaster, find the one kilometer and larger ones. We're about 96 percent complete in that population, maybe 30 to 40 still out there that our predictions of the population tell us that we still need to be looking for. So really good progress there. Our current charge from Congress is to find population down to 140 meters in size. We've made pretty good progress there, but not at the rate that we would like. There are about 25,000 estimated in that population, and we're just over

8,000 now in our catalog, so we're about a third of the way there, but a little ways to go. Now, for the smaller ones, like Tunguska and such, that's a real challenge. They're very small, hard to detect out in space, and there are literally hundreds of thousands, maybe millions when you talk about shell events. That's a challenge for the future, but to cut down the risk of an unwarned impact by a 100-meter object is our current objective. We're making good progress on that. Kelly, one of the tasks, and I'll come back to these goals and tasks in a moment that are in the plan, but one that's identified is to better understand, it says, how the dynamical and physical properties of a NEO will help determine the threat

it presents. It sounds like this is basically saying that size matters, but it's not the only thing that matters with asteroids. Right, that's true. Size does matter, but it also matters in the case of an impactor, perhaps what its approach would be through the atmosphere, where it is, where it might impact on the Earth. So that's why in the strategy, it's really broad in terms of general guidance for where things should go. But already, the Near-Earth Object Observations Program, we do fund research that looks into such things. What is it besides just size that matters? It's composition, it's density, it its trajectory. And so all of that does come into

play. And it's something that folks in the program are looking at already. Yeah, I've got right over my head here on a shelf. I guess it shouldn't be over my head in Southern California, considering our earthquake probability here. But there's a little meteorite that was given to me years ago, solid metal. It's an iron nickel one. I guess you're in a lot more trouble if one of those comes down on you rather than one of these so-called carbonaceous asteroids. That's right. If something is very dense and metallic, that's going to be a different situation from something that's maybe rocky or fluffier that might burn up more easily in the atmosphere.

And so all of that does need to be taken into account, determining what the impact damage could potentially be. I want to point out, though, that the iron population, that's a relatively small percentage of the overall population of these objects. That's one of the things we're set up to do is find these things in space, learn as much about their characteristics as we can for an impact threat so that we have the ability to make an assessment of how bad the effects might be for a particular impact and be able to advise the national authorities and decision makers about what might be prudent to do.

Lindley, let's go back to the plan itself. There are five overarching strategic goals, and there are timelines for each of more than 30 tasks. Within those goals, we can't go through all of those 30-something tasks, although we will provide a link to the plan on the show page for this week at planetary.org slash radio, and I encourage listeners to take a look at it. It's pretty interesting. But can you take us quickly through those five overall goals?

Well, sure. Of course, the first one is detection, tracking, and characterization of the population. That's the most important thing, highest priority thing to do, is we have to find them first. We can't do anything about it unless we find them. The second goal deals with improving our modeling capabilities. And this gets back to our ability to assess whether an asteroid is, first of all, going to be an impact threat or orbit modeling and those kinds of things. And then our modeling of the characteristics of the asteroid population to try to understand as much as we can about the characteristics of a particular asteroid based upon what we've seen previously in the models. Also in modeling is the effects as an asteroid passes through the atmosphere, what happens to it,

what causes it to break up, and then what could be the effects for an asteroid of a certain size and characteristics. The third goal deals with our ability to come up with technologies and techniques to be able to deflect or disrupt an asteroid while it's still in space. That gets to activities like NASA is undertaking right now with our double asteroid redirection test, our first demonstration of the technology and technique that might be used to deflect an asteroid. Goal four is about working with the international community, the international collaboration, both in detecting, tracking, characterizing these objects and in working what we might do to mitigate it. That type of activity, as we've talked about before, we've been working through entities that have been set up through the Committee on Peaceful

Uses of Outer Space, like the International Asteroid Warning Network and the Asteroid Space Mission Planning and Advisory Group, the forum for space agencies to get together and talk about technologies and techniques and collaborative projects in that area. And then finally is clarifying and better defining our processes and procedures for notifying the authorities and the activities that happen downstream of that, getting the whole interagency activities involved. After, of course, notification has gone up to the White House and over to Congress and to the agencies, processes and procedures for getting spun up, getting the emergency response community involved for activities to protect both the citizens and the infrastructure of the nation should a impact be predicted to occur. It seems to me that what this group of agencies came up with, it does parallel what has been

discussed and concluded at those biannual planetary defense conferences that bring together the international community, although with very substantial involvement by the United States. I missed the last one of those, but I know you're a regular at those. Do you see some similarities there in these agendas? Well, that's certainly not by accident. The planetary defense conferences, the work with the international community in this area provided valuable guidance as to what needs to be done, what are the important things to pay attention to. Those conferences and the exercises that we have had with them are all activities that

helped inform our work on this action plan to assess our current capabilities for those kinds of things and point out where we needed to improve things. Kelly, the first couple of those goals seem to fall largely in your area as the program manager for observing near-Earth objects, not just asteroids, we should point out, but comets as well that come in generally from a lot farther out. What's your feeling about how we're doing and our ability to see these things and characterize them and figure out where they're headed? Well, it's true what Lindley said earlier.

We've got to find them, and so that's the goal of this program is find them, find them, find them. In the program, the available capabilities, the latest technologies, whatever is available out there is what is being used. We have an avenue for organizations to propose to join the program and to join the search, and they can be peer-reviewed and have that opportunity. And so we have partnerships with places like the University of Arizona and University of Hawaii and their ground-based telescopic facilities there. And they're producing many of the discoveries, most of the discoveries that are being made. And then

other organizations and individuals funded by NASA and all around the world are continuing to provide follow-up observations and characterization observations. So with what's out there, we're making the progress that we can, but continuing to look for new avenues, We're making the progress that we can, but continuing to look for new avenues, speeding things up so that we can put a bigger dent in that to-be-found category. How useful will additional space-based observation capabilities be? And I'm thinking of mission proposals like NEOCAM, the one that is still in development. Well, there have been groups convened over the years to look at that question, and most recently an NEO science definition team that was convened to look at that, to look at accelerating the search. And they have been consistently pointing to the need for a space-based

infrared capability, and so NASA's continuing to look at that, to look at the development of such capability, to add it to the search. Lindley, I'm glad you made a reference to the DART mission. Even though the plan says that demonstrating near-Earth object deflection and disruption is a long-term goal, I mean, as you said, this is kind of a first move in that direction, right? I mean, unless you count the Deep Impact mission of some years ago. Yeah, well, Deep Impact was about science and not deflecting an asteroid, but similar technologies. But yes, actually, nature has provided us a prime opportunity to do a test with the close approach of the DITIMO system. And when I say close, it's still going to be several million miles away in the fall of 2022. If we launch DART, it's scheduled for launch

in the summer of 2021. And it will encounter Didymos system in October of 2022. And it's close enough to the Earth that the system, the asteroid and its moon can be observed by ground-based telescopes, both optical telescopes and radar, so that we can get a look at the effects of the impact on the moon's orbit around the primary, determine how much we were able to change its orbital path, and then assess how effective the DART impactor was, given our modeling of the forces of the impact and what we know about the ejecta that it will blow off the surface of the moon. We're modeling all that ahead of time, and then we'll compare what the results were to our models.

And that will prove our models and have a better understanding of what it takes to be able to move an asteroid. That's a pretty exciting event to look forward to. I'm sure we'll be right on top of it at the Planetary Society, and hopefully with this radio show, radio show podcast, if it's still underway. Well, as I mentioned, there are exciting things going on right now in this area with the approach of the Japanese Hayabusa 2 mission to Ruhugu. This fall, our Cyrus Rex mission will approach the asteroid Bennu to start its examination of the asteroid and determine where it wants to take a sample and bring back to Earth. So it's an exciting year for asteroid science. I want to go back to how this all came together.

I talked about, if I counted right, 16 different agencies that came together to create this plan. Lindley, you've been in this game for a long time. Representatives of that many disparate agencies within the U.S. federal government coming together. I don't know how often that happens. Well, let's not call it disparate. But on this particular issue, this was the first time we've had this many agencies involved. Now, this wasn't something that happened overnight. The work on this strategy and action plan actually began back in 2015. We first wrote a strategy document in 2016 that was published at the very end of the last administration to be followed by an action plan.

This document then is the compilation of the strategy and action plan published just a year and a half after the new administration. So continuing the effort that's been going on for several years and almost a seamless continuation of the efforts. And the other thing is the president's budget request for our FY19 budget is considerably increased to $150 million. We're hoping Congress includes that in their appropriated budget for FY19 because it will allow us then to pursue DART mission to its launch, also in efforts on a space-based IR capability in the next couple of years. So that's the infrared capability to look for these things from space, like the NEOCAM mission and others have proposed. like the NEOCAM mission and others have proposed.

You mentioned that the plan talks about coordination and notification and coordination with other nations, with the U.S. states, and other nongovernmental organizations, I assume, maybe even including the Planetary Society. What kind of response do you see from the international community? Are people around the world taking this threat more seriously? Oh, yes. Nations around the world, the discussions that we've had in the Committee on Peaceful Uses of Outer Space over the last three years led to a setup of International Asteroid Warning Network and the same page. Of course, nations are involved to various levels depending upon their capabilities,

but we have very strong support from the member states of the UN. Kelly, is this a part of your job, the coordination with the international agencies regarding observation and characterization? Well, at least as part of representing the Near-Earth Object Observations Program, but we also have other people who work with our international partners through the International Asteroid Warning Network, our colleagues at the Planetary Data System Small Bodies Node, who now manage the Minor Planet Center as a sub-node, are also hosting the International Asteroid Warning Network website, bringing the U.S. capabilities to the international stage through the International Asteroid Warning Network,

and just helping to facilitate it by hosting the website and providing other tools. Lindley wants to talk about TC4. Sorry, what was that, Lindley? Lindley was noting the exercise involving the asteroid 2012 TC4, which was a small asteroid. It was known it was going to make a close approach to Earth last fall. It was known it wasn't going to impact, but it was going to be a close approach, but still wasn't known exactly what that approach was going to be. be. And so it provided an opportunity to work with people within the Near-Earth Object Observations Program at NASA and then extended to the International Asteroid Warning Network, where people around the world were involved recovering 2012 TC4 to find it again on its way

toward Earth, getting enough observations to get a better orbit determination through the Minor Planet Center and through the Center for Near-Earth Object Studies out at JPL. So that was all a very valuable exercise, but also communications, even for us here at NASA headquarters to treat it as a communications exercise for our notification process to send up through the agency and to other agencies and to the White House. So it was a very valuable exercise just to see how things might work in a real-world situation. Lindley, this reminds me of those dramatic tabletop exercises that take place during the Planetary Defense Conferences. I think I was at the first one that that was, one of these was done back in Flagstaff, Arizona. That's addressed in the plan

as well, because you really find that people discover there's far more to dealing with news that one of these objects is coming our way than might have been expected. Well, yes, it's a challenge all the way up and down the line from the time we find them to getting to better orbits, determining whether they're a threat or not, and then the communication and coordination of the information that we have so that we're making the best information available not only to our governments but to the public about any possible threat. But that process really gets started by stories like this, broadcasts like this, informing the public about what it is we're doing and capabilities we have and the capabilities that we're trying to improve so that it's not a big surprise to the public that someday we might have an impact that we have to deal with.

Well, we'll keep trying to do our part at the Planetary Society. It's a high priority around here. Let me wrap up with just asking you, what happens next in terms of implementing this plan that's now on paper and has been put together by so many parts of the U.S. government? Well, there is a newly formed subcommittee on space hazards and security that the activities conducted under this action plan will report to the group that has developed this plan. The various agencies, the people involved in that will take things that are assigned to them and have at least an annual review of our progress against the action plan to report to the Subcommittee on Space Enhancement and Security.

I want to thank you both for giving us a little insight into this plan and the current state of our defense efforts against these big rocks, one of which is out there and surely has our name on it. And we just need to find it, characterize it, figure out exactly when it's coming our way and what we're going to do about it. It will happen, probably not anytime soon. We hope not anytime soon. Time is usually on our side. Yeah, well, that's true. Fingers crossed. I'll just thank you again for being a part of this and look forward to talking to you in the future as the search continues. Thank you, Matt.

Thank you. Lindley Johnson is NASA's first ever planetary defense officer. Before that, he ran the Near Earth Objects Program as the program executive in the Planetary Sciences Division. Kelly Fast, working with him, is the Near Earth Object Observation Program Manager in the Planetary Defense Coordination Office. That's the formal name of the planetary defense side of NASA in the Planetary Science Division. Time for What's Up on Planetary Radio during Asteroid Week. And we are going to continue in exactly that theme when we talk to the chief scientist of the Planetary Society, Bruce Betts. Welcome back and happy asteroids.

Happy asteroids and Asteroid Week and Asteroid Day. Yeah, I figure, you know, we haven't been hit by one yet, at least not lately. So that's reason to be happy. Oh, that's a good point. Well, happy Asteroid Week, everyone. There is a lot going on, even within the confines, the very broad confines of the Planetary Society, having to do with celebrating this week. And you're at the center of that.

I just saw today your FAQ about asteroids and near-Earth objects. Indeed. We've just posted it on the website under blogs. You can find my frequently asteroid questions. Anyway, I start with, you know, what is an asteroid, and then talk about whether asteroids will hit Earth in statistics. And check it out if you're looking to get those questions answered. And we've also got a bunch of other stuff coming up on our website over the next few days and next few weeks, including coverage of Hayabusa 2 and OSIRIS-REx and things about the importance of sample return. Updates on our Shoemaker-Neo grant winners. Astronomers around the world that Planetary Society has awarded grants to to help them track and characterize asteroids. Are you excited, Matt? It's great.

Yes, I am thrilled that planetary defense is a big part, a major component of the mission of the Planetary Society. I mean, as the boss says, we're just trying to save the world. All right, I'm going to tell you what's up in the night sky. And I will continue to be excited about planets in the night sky. I was just checking them out this week with a small telescope. We got Venus over in the west in the early evening. We've got Jupiter in the south high up in the early evening looking bright, but not quite as bright as Venus. Then we've got Saturn coming up around sunset in the east and looking less bright, but super cool. You put a telescope on it. Turns out Saturn has rings. And then coming up a little

later in the evening, I know, go ahead, alert the presses. Alert the presses? I'll do it in Latin. And then Mars coming up later in the evening and Mars headed towards its opposition, its closest approach to Earth in 15 years happening at the end of july getting brighter and brighter already brighter than the brightest star in the sky and soon to be as bright as jupiter and if you check it out on june 30th it'll be hanging out near the moon always bright and as i mentioned last week you can still catch vesta the brightest asteroid if you're in a dark site you can actually check it out with just your eyes. It isn't Sagittarius. You're going to want to look up a finder chart for that one. All right,

we move on to this week in space history to somber and significant events. 1971, the Soyuz 11 crew died during re-entry. And in 1908, the reason they've decided asteroid day falls this week, 1908, the Tunguska impact where a roughly 40, 50 meter asteroid hit over the Tunguska river in Siberia, leveling 2000 square kilometers of forest, about 50% larger than the city of Los Angeles. percent larger than the city of Los Angeles. We move on to random space fact. About one million near-Earth asteroids, so asteroids that come within 1.3 AU of the sun, where AU is the distance between the Earth and the sun on average, about one million of those are predicted to be large enough to cause major damage or destruction if they impacted Earth. We've only just begun to find them. That complements what we heard from Lindley Johnson and Kelly Fass, but that was not a

fact that they included. I guessed right. Thank you. Let's go on to the contest. I asked you who was in Earth orbit at the same time as the first female in space, Valentina the same time as the first female in space, Valentina Tereshkova, she was in Vostok 6. Who else was in orbit? Tell us, Matt, how'd we do? Very big response. Just about everybody paid more attention to Valentina for the obvious reason that she was the first woman. I feel kind of bad for the gentleman, the cosmonaut, therefore, who was up there at the same time.

In fact, they were the first two to be in space at the same time and got fairly close to each other. I'm sure you have more about that. Random.org picked Sander Elwick, Sander Elwick in the Netherlands, who in his most recent entry before this said, pick me, pick me. Well, it just took a week or two. And he says that that compatriot and companion to Valentina Tereshkova was Valery Bykovsky, flying Vostok 5, launched two days before she headed for low Earth orbit. That is correct. All right, Sander, you win.

And that means you are going to get that last signed hardcover copy of Chasing New Horizons, the epic first mission to Pluto. And that, of course, is the book Tracing, Chronicling the Mission, the Ongoing Mission of New Horizons by Alan Stern and David Grinspoon. a 200-point itelescope.net astronomy account. And if you are quick with that, if they get that account set up quickly, you can use it to take a look at Mars during that close pass that Bruce was just telling us about. I got to Mars, no surprise. David Shanks and Andrew Kerr

were among those who said that Valeri, he does have one record. He circled the Earth for four days, 23 hours and seven minutes. It's still a record for solo space travel. Did you have anything to add about either him or Valentina? Well, I will note, as you kind of said, they came within a few kilometers of each other and established radio contact with each other. Do you know this story, which we heard also from a lot

of people, among them Douglas Gay King? Vostok 6, that's her ship, wandered out of its orbit, had to land near today's Kazakhstan-Mongolia-China border, where she was greeted by villagers who helped her out of her suit and served her dinner. She later was reprimanded for not undergoing medical tests first. Yes, I had heard that. The wild, wild west of spaceflight. Dave Fairchild, our poet laureate. Valentina Tereshkova holds a most important place. She took flight in Vostok 6 and of her gender first in space. Two days after V. Bakovsky launched in 1963, she would join him up in orbit and her place in history. Oh, that's nice.

Marko Vidic, a listener among those that we have in Croatia, he says there is an asteroid in the main belt given the name 1671 Chyka, which was her call sign, Valentina's call sign when she was on orbit. It means seagull in Russian. He says, I think that's a great way to show appreciation for what she did. Here's another way. It came from Eric Kunz. He says, on a personal note, my youngest daughter's middle name is Valentina, as an homage to

Ms. Tereshkova. Wow. We're ready for next time. All right. So here's your new question. Why is the near-Earth asteroid Hayabusa 2 is visiting named Ryugu? Don't trust my pronunciation. Why is it named Ryugu? What's it named after? Go to planetary.org slash radio contest. And you have until Wednesday, July 4th. The 4th of July has some significance here in the

United States at 8 a.m. Pacific time to get us this answer. And if you are chosen by random.org and have the right answer, a Planetary Radio t-shirt will be headed your way, along with a 200-point itelescope.net account from that network of, worldwide network of telescopes. Maybe someday they'll put them elsewhere too, but right now they're just worldwide. That network based in Australia, and that's worth a couple hundred bucks U.S. We can wrap it up for Asteroid Week. All right, everybody, go out there, look up in the night sky, and think about, if you made a three-dimensional model of an asteroid, what would you make it out of?

Thank you, and good night. I would make mine out of iron and nickel. Well, there you go. That's Bruce Betts. He's the chief scientist for the Planetary Society. This week, Asteroid Weekend, all weeks,

and joins us every week here on What's Up. How about mashed potatoes? This means something. Planetary Radio is produced by the Planetary Society in Pasadena, California, and is made possible

by its planet-defending members. Mary Liz Bender is our associate producer. Josh Doyle composed our theme, which was arranged and performed by Peter Schlosser. I'm Matt Kaplan. Ad Astra.