This Week, NASA Is Pretending An Asteroid Is On Its Way To Smack The Earth

Apr 29, 2019
Originally published on April 30, 2019 3:01 pm

The asteroid is in a horrible orbit and has a 1% chance of striking Earth in just eight years. And — thank goodness — it doesn't really exist.

It's a fictitious asteroid that's the focus of a realistic exercise devised for scientists and engineers from around the world who are attending the 2019 Planetary Defense Conference being held this week outside Washington, D.C.

A real asteroid of this size, should it ever hit the planet, could wipe out an entire city.

"This is a threat that could happen, even though it's extremely unlikely," says Paul Chodas, director of the Center for Near-Earth Object Studies at NASA's Jet Propulsion Laboratory, who created this realistic simulation. "Our goal here is to go through all of the steps that we would have to go through."

He says a lot has been learned from three previous drills held at past international conferences and from other asteroid exercises that have been separately conducted by officials at NASA and the Federal Emergency Management Agency.

This time around, the pretend asteroid is around 300 to 1,000 feet across and was spotted around 35 million miles away. What's known about its fake trajectory indicates that it has a 1% chance of hitting our planet in 2027.

On the webpage for imaginary asteroid "2019 PDC," NASA warns that it "does not describe a real potential asteroid impact."

Chodas deliberately designed this pretend threat to stress the international system for decision-making. Every day at this conference in College Park, Md., experts will gather to discuss new information that Chodas gives them from his prepared script.

"The asteroid is not in a convenient orbit at all," he says. "It's not like one of these asteroids that we go to with our science missions, where you get to pick a nice asteroid that's easy to get to. In planetary defense, the asteroid picks you."

And while eight years might seem like plenty of time to get ready, Chodas says that's actually a challenging schedule because experts would like to conduct multiple missions to the pretend asteroid to gather information.

"You don't even know really if it's going to hit the Earth, and yet because the schedule is tight, you have to begin preparations to study the asteroid," he explains. "You don't know the size, really, and the size is a key parameter. So you need reconnaissance missions first."

Asteroid experts will have to make decisions about how to try to deflect the asteroid, whether by pushing it with spacecraft or maybe even by detonating a nuclear weapon. If those efforts failed and the asteroid were still headed toward Earth, emergency managers would have to contemplate a mass evacuation of the strike zone.

In real life, asteroid hunters have discovered almost all the really large space rocks that could possibly create a devastating global catastrophe, Chodas says.

"That part of the hazard has been addressed," he says. "We have in fact discovered almost all of the really large asteroids."

But asteroids that are the size of the fake one in this exercise, he says, are more numerous. They also hit the Earth more frequently (although it's still tens of thousands of years between impacts).

"The majority of that population" of smaller asteroids, Chodas says, "has yet to be found."

Last year, the federal government released an action plan laying out steps to take over the next decade to better prepare for this kind of low-probability, high-consequence threat.

Copyright 2019 NPR. To see more, visit https://www.npr.org.

AILSA CHANG, HOST:

Today marks the beginning of the 2019 Planetary Defense Conference. Experts from around the world have gathered outside Washington, D.C., to discuss how to protect the Earth from the threat of a devastating impact from a giant asteroid just in case. And a big part of this week-long meeting is working through a detailed simulation of an asteroid strike - whoa.

NPR's science correspondent Nell Greenfieldboyce is here with us now to tell us about this asteroid exercise. Hey, Nell.

NELL GREENFIELDBOYCE, BYLINE: Hello.

CHANG: So what exactly happens at a conference on planetary defense?

GREENFIELDBOYCE: OK, so this is just a gathering of people from China, Russia, the United States, France, all over. They're scientists. They're engineers. They're people who know how to, you know, calculate trajectories to see what's coming our way...

CHANG: Yeah.

GREENFIELDBOYCE: ...People who know how to design missions or know how to use telescopes to find these things. And also people from the Federal Emergency Management Agency...

CHANG: Oh.

GREENFIELDBOYCE: ...So you know, decision-makers.

CHANG: FEMA.

GREENFIELDBOYCE: It's all the kind of people that we would depend on if there was an actual threat from an asteroid. They come together. They hold one of these events every couple years, and they have these drills. So so far, they've had, like, three drills at the conferences. And then NASA and FEMA have independently had their own exercises.

CHANG: I had no idea this was going on. What does an asteroid impact exercise look like? I mean, how does one simulate the collision of an asteroid and the Earth?

GREENFIELDBOYCE: So basically it's a tabletop exercise.

CHANG: (Laughter).

GREENFIELDBOYCE: You're not actually simulating the collision.

CHANG: Good to hear.

GREENFIELDBOYCE: Someone devises this scenario, and they spend part of their conference - part of the week - kind of working through it. It's like a choose-your-own-adventure kind of thing, or like a Dungeons & Dragons kind of game. But this is completely serious roleplaying. What they're working through this time is a pretend asteroid that they're saying was discovered recently. It's 300 to a thousand feet across - so pretty big. It's been detected about 35 million miles away and has a 1 percent chance of striking the Earth eight years from now.

CHANG: OK.

GREENFIELDBOYCE: So remember; this is all fake. It's all made-up. But a rock this size could totally take out a city. And so over the course of this week, as this pretend asteroid gets closer, every day they're going to be making decisions and getting new information and kind of playing out the whole thing.

So I talked to the guy who devised this. His name is Paul Chodas, and he's director of the Center for Near-Earth Object Studies at NASA's Jet Propulsion Laboratory. And he says he deliberately designed this to sort of stress the whole system.

PAUL CHODAS: The asteroid is not in a convenient orbit at all. It's not like one of these asteroids that we go to with our science missions where, you know, you get to pick a nice asteroid that's easy to get to. In planetary defense, the asteroid picks you.

GREENFIELDBOYCE: He says he planned this so that there's eight years' advance notice. And that sounds like a lot of time, but really it's not because they would want to plan multiple missions to go see this space rock and get more information and, you know, ultimately try to shift its trajectory.

CHANG: So how likely is it that something like this would actually happen?

GREENFIELDBOYCE: So for asteroids in the size that's being played out in this scenario - so, like, 300 to a thousand feet - it is tens of thousands of years between impacts. So you know, it's not very likely to happen anytime soon.

CHANG: That's mildly reassuring.

GREENFIELDBOYCE: But the thing is it could happen. I mean, the vast majority of asteroids in this size range have yet to be spotted by NASA.

CHANG: OK, so just remind everyone, this is still a hypothetical scenario. Seriously, though, if an asteroid were to be barreling towards the Earth, what are the options? I mean, how do you actually avoid a collision?

GREENFIELDBOYCE: Well, you would try to knock it off course. I mean, basically you would send spacecraft to either, like, push it - like, literally sort of knock it away. Or in some cases, they do talk about nuclear weapons. I mean, that's a real possibility.

CHANG: So this conference wraps Friday. You are absolutely going to have to come back and tell us what happens.

GREENFIELDBOYCE: I will. But remember; this is all just a fake drill. It's nothing real. They are not working off a real scenario.

CHANG: That's NPR science correspondent Nell Greenfieldboyce. Thanks, Nell.

GREENFIELDBOYCE: Thank you. Transcript provided by NPR, Copyright NPR.

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