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COLLEGE PARK, Md. – It's a nightmare scenario to imagine: a big asteroid Directly headed to a major American city, Denver, less than eight years after astronomers spotted the space rock.
Fortunately, this asteroid, called PDC 2019, is a fiction. This is the original idea of Paul Chodas, a specialist in modeling near-Earth object trajectories at NASA's Jet Propulsion Laboratory in California, and his colleagues in the US. ;a scenario Conference on Planetary Defense of the International Academy of Astronautics taking place here this week.
"The idea is to make a realistic simulation of an asteroid heading towards Earth, then to study everything we would know and what we would not know and how the story is going to be. would develop, "Chodas told Space.com. His task, which he had started more than six months before the start of the conference, was to create all the parameters of a non-existent but realistic asteroid that would allow scientists, mission designers, emergency managers to and other decision-makers to think about what they would do if such a scenario were to take place in real life.
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Chodas is well suited to the task, given his real work in NASA Near Earth Research Center, which hosts a database of just over 20,000 asteroids whose orbits are close to Earth and which carries them in detailed models to predict their future trajectory and determine if they exhibit a risk for humans. None of the known asteroids in the widest class – that is, those whose size exceeds 140 meters (460 feet) – pose such a danger in the foreseeable future.
But our luck can change. And this prospect worries the global defense experts, who focus on the risk that nearby asteroids pose on Earth. From where the conference and scenario exercise taking place here now.
For each scenario developed by Chodas, it starts with a given impact site – this time, Denver. Then, it develops an orbit that allows astronomers to have missed the object after observing the sky for decades. "It's a kind of orbit engineering on my part," said Chodas. "We are working all the history on the back of the place." But he does his best to keep the story interesting at every step of the process in order to build a solid story.
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This means ensuring that the hypothetical orbit allows scientists to locate the object early enough so that humans have time to react, but not so soon as it is a simple answer. "The eight years are deliberately defined as something that would put pressure on the schedule for mitigation, for diversion," said Chodas.
This priority also allows him to define the impact corridor – the corridor along the Earth that crosses the hypothetical orbit of the asteroid, where the two bodies could theoretically collide. When the hypothetical asteroid was at the origindetected"It was not just Denver that could have been a victim, but Hawaii, the San Francisco Bay Area, New York, and much of Africa were all under threat.
To build the scenario, Chodas also had to decide what kind of information he was distributing about the asteroid and when. It is extremely difficult to accurately measure the mass, so that when the scenario is unfolding, the candidates for the answer must use vague estimates. A first flying mission starting soon after the first detection discovers that the hypothetical object is what scientists call a binary contact – two pieces of fused space rock.
This is a key element of the plot for Chodas in the scenario of this conference because, as usual, he chose to make things more complicated for those who are tackling the problem asteroids. In the hypothetical scenario, when spacecraft arrives to collide with the asteroid and slow down, they accidentally break the space rock instead. As conference participants learned yesterday (May 2), the most important document turns out to be harmless, but the smallest segment goes to Earth – and this time, scientists can not predict where it will fall. along a strip that stretches from Lincoln, Nebraska, to New York, to the Atlantic Ocean.
"It's not just an orbit and it's done, we have to involve all the planetary defense communities," Chodas said. "We usually like to study how the deflection works and all the challenges that arise there."
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Conference participants will face a new set of challenges before having to explain what they would do and why – and how it would work for people on the ground. "Every day, it seems like we are making the task more and more difficult … so that we can stress the community and ask them to consider the worst case scenario," said Chodas. "When you have a population at risk, it makes it a stressful decision, perhaps, and sobering."
Chodas has been designing hypothetical asteroids since the 1990s, and as the exercise teams have multiplied, the scenarios have become much more detailed and complicated. In turn, the global defense community recognized new complications – and began to think about these potential obstacles before real people became at risk.
So, of course, Chodas launched an asteroid in Denver. But it is not personal. "I have no bad intentions here," Chodas said. But an easy scenario will not do the job, and he does not hesitate to give an extra twist where he can. "I like to add color because a story is not believable if there are no colored pieces around the edges."
Email Meghan Bartels to [email protected] or follow her @meghanbartels. follow us on Twitter @Spacedotcom and on Facebook.
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