← Big Ideas Lab
Big Ideas Lab
Planetary Defense (Part 1)
00:23:35
In 2013, a house-sized asteroid exploded over Chelyabinsk, Russia, with the force of 30 atomic bombs. A century earlier, an asteroid impact flattened 830 square miles of Siberian forest. In this episode, we uncover how planetary defense has evolved from theory to reality—why asteroid threats are more real than most people think—and what it will take to stop a civilization-ending impact. Because the next asteroid isn’t a question of if—but when.
Loading summary
Transcript47 lines
- [00:07]
Narrator
On a frigid morning in Russia, February 2013, the sky suddenly burst open. Then a bright flash. A sonic boom. Windows shattered across the city of Chelyabinsk as a house sized asteroid exploded in the atmosphere 14 miles above the ground and released energy 30 times more powerful than the atomic bomb dropped on Hiroshima. Thousands were injured and shocked as the heavens revealed one of the Earth's oldest threats. An asteroid traveling at 40,000 miles per hour, delivering a cosmic warning without warning. The explosion was equivalent to 440,000 tons of dynamite. It generated a shockwave that blew out windows over 200 square miles, leaving the city blanketed in glass. More than a century earlier, in 1908, another asteroid blast flattened 830 square miles of forest deep in the Siberian wilderness, an area roughly the size of Houston. This explosion was known as the Tunguska Event. The shockwave was so powerful, it circled the globe twice. Despite its massive energy, no impact crater was found because the asteroid disintegrated entirely in the atmosphere before reaching the ground.
- [01:42]
Expert 1
Folks who are listening should not be worried in their day to day life about these kinds of events. But when something occurs once every 500 years, that doesn't necessarily mean that it'll be 500 years before the next one hits.
- [01:53]
Narrator
While scientists estimate that tens of millions of asteroids the size of Chelyabinsk or larger linger within our solar system, only a fraction of their trajectories have been cataloged or monitored by astronomers. Their elusive nature underscores their danger. These ancient wanderers of the cosmos hover overhead like a hidden menace. Unpredictable and uncharted, they can slip past our satellites unnoticed. A team of scientists at Lawrence Livermore National Laboratory are spearheading the fight against cosmic threats with cutting edge technology to deflect asteroids and defend Earth from potential devastation.
- [02:34]
Expert 2
It's one of the only natural disasters we actually have the power to prevent through science and technology. So why not try? I think it's worth it.
- [02:49]
Narrator
Welcome to the Big Ideas Lab. Your weekly exploration inside Livermore National Laboratory. Hear untold stories, meet boundary pushing pioneers, and get unparalleled access inside the gates. From national security challenges to computing revolutions, discover the innovations that are shaping tomorrow. Today, Lawrence Livermore National Laboratory is opening its doors to a new wave of talent. If you're driven by curiosity and a desire to solve complex challenges, the lab has a job opening for you. Currently, there are 139 open positions. These include opportunities in science, engineering, business, administration, and the skilled trades. From enhancing national security to pioneering new energy sources and advancing scientific frontiers. Lawrence Livermore National Laboratory is where you can make your mark on the world. Today's open roles include lead power grid engineer, laser modeling, physicist, postdoctoral researcher, OCEC program leader, and chief data architect. But the list doesn't end there. Explore all available positions@llnl.gov careers. Each opportunity comes with a comprehensive benefits package tailored to your lifestyle and future. Join a workplace that champions professional growth, fosters collaboration, inspires innovation, and drives the pursuit of excellence. If you are ready to contribute to work that matters, visit llnl.govcareers to explore all the current job listings. That's llnl.govcareers. your expertise could very well be the highlight of our next podcast interview. Don't wait Hollywood has historically portrayed asteroid threats with nail biting high stakes drama. It was called Orpheus the Meteor. Like in the movie Meteor from 1979.
- [05:13]
Expert 2
Its power is greater than all the.
- [05:15]
Narrator
Hydrogen bombs and Armageddon from 1998. That's what we call a global killer. The end of mankind. Or don't look up. In 2021, we discovered a very large comet.
- [05:27]
Expert 2
Oh, good for you. It's headed directly towards Earth.
- [05:30]
Narrator
This comet is what we call a planet killer. In these save the world from disaster movies, heroic figures race against time and the unknown. In reality, defending Earth from asteroids is a calculated, methodical process where the real heroes are the scientists. Before diving into what it takes to save the world from these threats from above, let's begin with the fundamentals. What exactly is an asteroid? Asteroids are rocky fragments left over from the formation of the solar system. They orbit the sun like planets, but are smaller, ranging from tiny pebbles to city sized boulders. While most are clustered in the asteroid belt between Mars and Jupiter, some venture closer to Earth, crossing our path as they fly through space.
- [06:19]
Expert 2
Asteroids are not these perfectly smooth surfaces. They're very collisionally processed. They have rubble pile structures. So lots of boulders of different sizes. There's lots of smaller sized ones, fewer big ones.
- [06:32]
Narrator
Megan Bruxeill is a physicist and former leader of the Planetary Defense Program at Lawrence Livermore National Laboratory.
- [06:40]
Expert 2
Asteroids are pretty dark. They don't reflect a lot of light. And so we have a really good idea of where all the bigger ones are. Things that are a kilometer or larger. Larger that would be a dinosaur level extinction.
- [06:52]
Narrator
There are roughly half a billion asteroids in our solar system, with over 30,000 classified as near Earth asteroids, meaning they travel within 4.6 million miles of the sun and occasionally pass through Earth's orbit. What began with early stargazers marveling at celestial bodies has evolved into a sophisticated science of tracking and Understanding objects that approach Earth. At Lawrence Livermore National Laboratory, a dedicated team is at the forefront of what is called planetary defense, working to detect, track and divert potentially dangerous asteroids.
- [07:32]
Expert 2
Planetary defense is the field of study concerned with how to protect Earth from hazardous comets and asteroids. And that can include observing them ahead of time so that we know where they are and when they might impact Earth, how to mitigate by preventing them from impacting Earth at all. It's typically staged as either a deflection, the gentle nudge so it misses the Earth, or disruption when you break it up into lots of little bits. And lastly, if we don't have time to completely prevent an impact, we can still mitigate the effects of the impact by being able to advise on emergency response. So if we know what kind of damage is going to be felt here on Earth, we can advise on evacuations and securing of critical infrastructure. There's a ton of work in planetary defense to have full preparedness for the threat that we know awaits us. As an example, NASA was given a mandate to find 90% of asteroids 140 meters or larger by 2020, and they're only at 45%. So there's a lot of threats out there that we don't know where they are or if and when they're going to be a threat to.
- [08:43]
Narrator
On Earth, more than 100 large asteroids pass dangerously close to Earth every year. Close meaning within 28 million miles of our planet's surface. On average, a car sized asteroid enters the atmosphere about once a year, creating a spectacular fireball that burns up before reaching the ground.
- [09:04]
Expert 2
You can visualize, ok, the sun is at the center of our solar system and Earth is orbiting around it. And then if you go out past Mars, you get to the asteroid belt between Mars and Jupiter and the Near Earth. Asteroids are perturbed inward from the asteroid belt and they have these orbits that can intersect Earth's orbit. And some of them are more circular looking, some of them are more elliptical looking, some of them are higher inclinations, they're at an angle relative to the plane of the solar system. There's millions of them, if you go down to the smaller sizes, but there's tens of thousands have been discovered already, and they discover them at the rate of about 2 to 3,000 a year.
- [09:46]
Narrator
With thousands of near Earth asteroids discovered every year, the need to understand their potential risks is important. They vary in shape, size, density and composition from solid rock to loose clusters of rubble. These factors can dramatically change the way we attempt to redirect or destroy them.
- [10:07]
Expert 2
If you hit something too aggressively. And you're trying to deflect it and keep it all in one piece. But you're a little too aggressive, and it starts to fall apart. Well, that's not great, because then you have something that it's harder to predict. What the two big fragments are going to do over longer time scales. If you want to break it into lots of pieces, it's better to do it with feeling, like, really aggressively. Break it into lots of pieces that are well dispersed. And don't pose any threat to the Earth.
- [10:32]
Narrator
So what happens when we know an asteroid is on a direct collision course with Earth? How do scientists act decisively. To alter its path or neutralize the threat entirely? One solution is something called kinetic impact. Kinetic impact involves hitting asteroids with a spacecraft at high velocity. The impact changes the asteroid's trajectory and momentum, which in turn changes its orbit. And in 2022, this idea became reality. Here's design physicist Katie Kumamoto, who currently leads the planetary defense program.
- [11:10]
Katie Kumamoto
For a kinetic impact, the most conservative case, we can think of as just a momentum transfer. So we have momentum in the spacecraft. We hit the asteroid, and we, at the very least, will transfer that momentum to the asteroid. Now, the asteroid's much bigger. So even though our spacecraft was going really fast, it was much smaller. And so we only apply a small velocity change to the asteroid. But depending on the properties, the mechanical properties of the asteroid. We actually get this extra push from any ejecta that we produce. When you hit this kind of pile of rocks. You spray a bunch of damaged rock material. Back in the direction that the spacecraft was coming.
- [11:45]
Expert 2
For the average near Earth asteroid orbit. If you give it a 1 cm2 per second change in velocity 10 years in advance. That's enough for it to then miss the Earth. And you don't want to give it so big of a shove. That it starts to come apart accidentally. And so whether it can sustain 1cm per second 10 years in advance is another question. Depends on the size. If you had 20 years warning, you could get away with a gentler nudge. So a half a centimeter per second. And gentler is better. Because then we don't have to transport as much mass if we're doing kinetic impact.
- [12:19]
Narrator
Asteroid deflection is a delicate balance. Too much force and you risk fracturing the asteroid into hazardous fragments. Too little, and you might not shift it off course in time. So preparation is critical. Simulations and exercises are vital. Allowing experts to practice calculated deflections. With the right amount of force. But for a long time. This was just theory, concepts and calculations that only existed in the realm of computer models. To truly test these techniques, scientists needed more than just simulations. They needed to try it on a real asteroid. Lawrence Livermore National Laboratory invites you to join a diverse team of professionals. The Lab is currently hiring a lead power grid engineer, a laser modeling physicist, postdoctoral researcher, an OCEC program leader, a chief data architect, and 139 other positions for scientists, engineers, IT experts, administrative and business professionals, welders, and more. At Lawrence Livermore National Laboratory, your contributions are not just jobs, they're a chance to make an impact. From strengthening US Security to leading the charge in revolutionary energy solutions and expanding the boundaries of scientific knowledge, the Lab values collaboration, innovation and excellence, offering a supportive workspace and comprehensive benefits to ensure your well being and secure your future. Seize the opportunity to help solve something monumental. Dive into the wide variety of job openings@llnl.gov this is your chance to join a team dedicated to a mission that matters. That's llnl.govcareers. your expertise might just be the spotlight in our next podcast interview. Don't delay. The DART or Double Asteroid Redirection Test mission was NASA's first full scale test of planetary defense, designed to see if a spacecraft could alter the course of an asteroid by directly impacting it. In 2021, the DART spacecraft targeted Dimorphos, a small moonlet orbiting a larger asteroid, Didymus.
- [14:55]
Expert 2
It's humanity's first attempt at altering the motion of any celestial body.
- [15:00]
Katie Kumamoto
The DART mission was the first full scale planetary defense application test where what we did is we had the DART spacecraft and we just sent it hurtling at an asteroid to strike it and change its velocity in space, protecting Earth from potentially deadly objects in space. And so this was just a test. The target of the DART mission was not a threat to Earth, but we were proving that in the event that an asteroid was on a collision course, we would be able to move it by just hitting it really, really hard.
- [15:30]
Narrator
DART was launched in November of 2021.
- [15:33]
Katie Kumamoto
NASA is about to intentionally crash a spacecraft into an asteroid and they're going to do it right here on live tomorrow.
- [15:38]
Narrator
And 10 months later, Dart collided with Dimorphos at high speed.
- [15:43]
Katie Kumamoto
Everybody's watching on the TV screens because we're getting live images streamed back about one per second, 14,000 miles an hour. And so we can see, oh, we've successfully targeted Dimorphos. Oh, we can actually see Dimorphos for the first time as more than a pinprick of light getting closer and Closer. We're here just in the final few seconds. And the signal that we actually hit Dimorphos was actually, we get this final partial image. Where the spacecraft got destroyed before it could send back the full image. And when that popped up on the screen. The like screaming and elation of we actually did. This first planetary defense test was a success. And I think we can clap to that. Everyone. We have successfully moved an asteroid. That's incredible. It was electrifying.
- [16:30]
Narrator
This mission demonstrated that a kinetic impact. Could be used to deflect an asteroid's path.
- [16:36]
Expert 2
NASA's DART spacecraft has successfully crashed into an asteroid.
- [16:40]
Narrator
Potentially keeping it from hitting Earth if detected early enough.
- [16:43]
Katie Kumamoto
The Dart spacecraft successfully struck Dimorphos, which was its target asteroid. And it changed its velocity by close to 3 millimeters per second. Which doesn't sound like very much. But for deflecting an asteroid for planetary defense purposes, that's actually a sweet spot.
- [16:59]
Narrator
Dart was proof that we can, in fact, redirect a celestial danger. NASA has been able to show that they can potentially save life as we know it. The success of the Dart mission Not only demonstrated our ability to redirect a potential cosmic threat. But also underscored the importance of understanding the complex variables at play. Beyond the celebration of impact and deflection. Lies the meticulous work of predicting how different types of asteroids. Each with unique shapes, compositions, and structures. Might respond to such an intervention. Modeling these variables isn't straightforward. For instance, the goal isn't to destroy the asteroid. But to deflect it. Achieving this reliably depends on understanding. How the asteroid's specific characteristics. Influence its response to impact. These same characteristics can also influence. How an asteroid reacts to atmospheric interaction. If it remains on a collision course with Earth.
- [17:59]
Expert 1
Some of this high fidelity modeling is very early in maturity. So what we were trying to do is develop very descriptive simulations. Of the solid object Coming into the atmosphere. And breaking up in the atmosphere.
- [18:12]
Narrator
Jason Pearl is a physicist with the Planetary Defense Group. At Lawrence Livermore National Laboratory. He focuses on modeling asteroid air bursts. Events where smaller asteroids break up in the atmosphere. Before reaching the ground. The energy released during an airburst. Is comparable to a nuclear explosion. With potentially devastating effects. Accurate modeling involves predicting how an asteroid might break apart in the atmosphere. And depends upon how different asteroid types behave. Rubble pile asteroids, for example, present unique challenges. These loosely bound clusters of rocks and dust. May fragment more easily than solid asteroids. But their debris can disperse unpredictably. Spreading over a much larger area.
- [19:01]
Expert 1
I think it's very early in this line of research. There's a lot of work to be done. Most of the work so far in the airburst side. Has been making sure that we're doing our due diligence, Figuring out if we're modeling things correctly.
- [19:13]
Narrator
One example of this work Came from analyzing the Chelyabinsk event, A near Earth asteroid that exploded in the atmosphere Over Chelyabinsk, Russia, back in 2013. Jason's team used high fidelity models to simulate the asteroid's behavior. And their results suggested the Chelyabinsk asteroid Possibly entered Earth's atmosphere As a single solid piece. Many asteroids in near Earth space Are thought to be rubble piles. So this was significant. Understanding whether an asteroid is solid Or a rubble pile Is critical, as it influences how an asteroid Would respond To impact or deflection.
- [19:53]
Expert 1
When these explode, it's on the order of kilotons to even megatons of energy. These objects, what are these made out of? What kind of shapes are they? How are these things arranged? You might have something that's like a solid chunk. You might have something that's composed of the buckshot, where it's just a pile of gravel. So there's a whole range of different materials, too.
- [20:12]
Narrator
Every fragment and detail matters. Each high fidelity simulation Allows scientists To account For A range of possible scenarios. Before a real asteroid is in sight. And while Jason's team Has made strides, Modeling asteroid behavior Remains a frontier in planetary defense research, Requiring ever more precise simulations and an understanding of complex physics.
- [20:36]
Expert 1
You could have something like a comet where it's composed of ice. You could have a variety of other materials that are called chondrites. But it's essentially this composite of different materials, Kind of like rocks. When they come in, it's roughly like, on the order of 20 kilometers per second. So it's Mach 60. It's very quick. And so the whole event Might be order of a few seconds. And when it comes in, A shockwave forms and you get some superheated gas on the surface of the object. And this will start to melt and vaporize the surface. And eventually the object Will fragment or break up.
- [21:11]
Narrator
The incredible energy and variety of these space objects. Pose unique challenges for scientists with each new discovery. They're faced with unknowns, from the materials Asteroids are made of. To the unpredictable ways they might break apart. But what if the biggest challenge Isn't the asteroids themselves, but the tools we trust to deflect them? Scientists have found that every component of the design of the spacecraft matter. Each detail can affect the force delivered to the asteroid and how it reacts for example, the shape of the spacecraft impacts how much force is transferred in a collision.
- [21:51]
Expert 2
Sometimes it's just a grind that you're making things better and better slowly. But then there are these surprises. An example of that would be how much the spacecraft geometry, the details of that matter. For the deflection result for dart. So DART is not a sphere. It's a box with two giant solar panels attached to it. And the box part is about the size of a refrigerator. But for convenience, people often will model it as a sphere or just one box to simplify the geometry. And when you include all of that realistic engineering detail. It actually does affect the results. And it's less effective by about 25%. And how much momentum it delivers to the asteroid.
- [22:33]
Narrator
A streamlined model might suggest one result. While a more realistic model accounting for every solar panel and structure might might reveal something entirely different. Ultimately affecting the asteroid's response. And then there are logistical timing, coordination and resources. Planetary defense requires years, preferably decades of advanced detection. To prevent a potential impact. These challenges mean that planetary defense missions involve not only technical accuracy. But also long term planning and international cooperation. To prepare for a coordinated response.
- [23:11]
Expert 2
The DART mission was a nice microcosm of how we could collaborate internationally. We had a lot of European collaborators on that for years. As part of the Planetary Defense Conference. Which is international and moves all over. The next one's going to be in South Africa, which is the first time it's been in the Southern Hemisphere, actually. And South Africa has some really good telescopes they use for the DART mission as well. We collaborate there, go through the tabletop exercises together through these planetary defense conferences.
- [23:39]
Narrator
Planetary defense is an international problem that could affect any country. This developing field will need continued research, refinement and international cooperation. Every mission and model adds to our understanding. But there's still a long way to go. Before we have a fully tested reliable defense system. Agencies around the world are working together to build a coordinated defense strategy. This includes data sharing initiatives, joint research projects, and conferences. Where experts from around the world come together to discuss new developments. And run simulations on hypothetical impact scenarios. These collaborations ensure that the world is ready to act together if and when it's necessary.
- [24:23]
Expert 2
It's an international problem. It could affect any country. There is a special responsibility on the space faring nations. To advance our methods and and technology to be able to protect not just ourselves, but any country that might be affected. There's a lot of discussion of the politics and law around planetary defense at these conferences too. Because if someone's gonna do something and they accidentally push it into another country. Well, that's the big problem, right? That can create fear of touching anything, doing anything, and then just taking the hit, which would be bad for everybody to really embrace that mentality, just to take the hit. So we collaborate. It's a worldwide effort, and it brings a lot of different shared interests across different disciplines together. So astronomy, physics, geology, engineering.
- [25:11]
Narrator
To face a threat as complex as an asteroid on a collision course, we'll need all the resources we can get. Future missions are essential not just for practice, but for real world understanding of how to approach these space rocks with greater precision. Scientists hope to learn more about asteroid composition, improve prediction models, and ultimately gain confidence in our ability to avert a disaster. In the end, planetary defense isn't just about the science. It's about preparation for the day we might need to act. The more we prepare, the better we can protect our planet from the cosmic threats that have been around for billions of years. These efforts are a reminder of both our vulnerability and our resilience, a testament to human ingenuity and the determination to protect our world from forces beyond our control. Lawrence Livermore National Laboratory is opening its doors to a new wave of talent. Whether you're a scientist, an IT professional, a welder, an administrative or business professional, or an engineer, Lawrence Livermore National Laboratory has an opportunity for you. From enhancing national security to pioneering new energy sources and advancing scientific frontiers, Lawrence Livermore National Laboratory is where you can make your mark on the world. Lawrence Livermore National Laboratory's culture is rooted in collaboration, innovation, and the pursuit of excellence. We offer a work environment that supports your professional growth and a benefits package that looks after your well being and future. Are you ready to contribute to work that matters? Visit llnl.govcareers to explore current job openings and learn more about the application process. Don't miss the chance to be a part of a mission driven, driven team working on projects that make the impossible possible. Visit llnl.govcareers now to view the current job listings. Remember, that's llnl.govcareers. your expertise could be the highlight of our next podcast interview. Don't wait, explore the possibilities today. Thank you for tuning in to Big Ideas Lab. If you loved what you heard, please let us know by leaving a rating and review. And if you haven't already, don't forget to hit the Follow or Subscribe button in your podcast app to keep up with our latest episode. Thanks for listening.