Asteroid moon Dimorphos as seen by NASA’s DART spacecraft 11 seconds before the impact that shifted its path through space, during the first test of asteroid deflection.
Johns Hopkins University Applied Physics Laboratory/NASA
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Johns Hopkins University Applied Physics Laboratory/NASA
Imagine if scientists discovered a giant asteroid with a 72% chance of hitting Earth within about 14 years – a space rock so big it could not only destroy a city, but devastate an entire region.
This is the hypothetical scenario that asteroid experts, NASA employees, federal emergency officials and their international partners recently discussed as part of a tabletop simulation designed to improve the nation’s ability to respond to future asteroid threats, according to a just released report by the space agency.
“At this time, we know of no asteroids of substantial size that will impact Earth in the next hundred years,” said Terik Daly, supervisor of the planetary defense section at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland.
“But we also know,” says Daly, “that we don’t know where most of the asteroids large enough to cause regional devastation are located.”
NASA experts and federal emergency management officials dealing with a hypothetical incoming asteroid threat in April 2024.
Ed Whitman/NASA/Johns Hopkins University Applied Physics Laboratory
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Ed Whitman/NASA/Johns Hopkins University Applied Physics Laboratory
Astronomers estimate that there are roughly 25,000 of these “near-Earth objects” with a diameter of 450 feet (140 meters) or larger, but only about 43% have been found so far, according to material prepared for the tabletop exercise, held in Laurel in April was held. , Md.
The event was just the latest in a series of exercises that planetary defense experts have held every few years to practice how they would handle news of a potentially planet-threatening asteroid — and it’s the first since NASA’s DART mission , who showed that ramming a spacecraft into an asteroid could change its path through space.
This time, just after the discovery of the fictional asteroid, scientists estimated its size at between 60 and almost 800 meters in diameter.
Even an asteroid at the smaller end of that range could have a big impact depending on where it hits Earth, said Lindley Johnson, NASA’s Planetary Defense Officer Emeritus.
While “a 200-foot asteroid hitting somewhere in the middle of the ocean” wouldn’t be a real problem, he says, the same asteroid hitting near a metropolitan area would be “a serious situation.”
Because telescopes would only see such an asteroid as a bright spot in space, Daly says, “there will be very large uncertainties in the asteroid’s properties, and that leads to very large uncertainties about what the consequences would be if it were to hit the ground.” hit, as well as major uncertainties about what it would take to prevent that asteroid from hitting the ground.”
Furthermore, this particular scenario unnervingly determined that scientists wouldn’t be able to learn more about this threat for another six months, when telescopes would be able to see the asteroid again and reassess its trajectory.
Participants in the exercise discussed three options: simply wait and do nothing until the next telescope observations; launching a US-led space mission to fly a spacecraft past the asteroid to get more information; or creating an effort to build a more expensive spacecraft that would be able to spend time around the asteroid and possibly even change its path through space.
Unlike previous asteroid threat simulations, this one did not have a dramatic ending. “We actually got stuck in one moment throughout the entire exercise. We didn’t fast forward,” Daly said.
As a result, attendees had ample time to discuss how to communicate both the uncertainties and the urgent need to act. They also discussed how funding and other practical considerations could play a role in decision-making processes in federal agencies and Congress.
Daly says that in previous discussions, technical experts tended to assume that access to financing would not be an issue in such an unprecedented situation, but “the reality is absolutely that cost was a concern and a factor.”
The NASA report on the exercise notes that “many stakeholders indicated that they would like as much information about the asteroid as possible as quickly as possible, but expressed skepticism that funding would be forthcoming to obtain such information without more definitive knowledge of the risk.”
While representatives of space agencies had a clear preference for taking quick action, “what would political leaders actually do?” says Daly. “That was really an open question that lingered the whole time.”
Preparing some kind of spacecraft, finding the right launch window for it, and getting it to travel through space to an asteroid “eats up a decade of time pretty quickly,” Johnson says. “So that’s certainly a concern from a technology perspective.”
But giving something like 14 years’ notice will seem like a lot of time to emergency managers and disaster responders, said Leviticus “LA” Lewis, a Federal Emergency Management Agency official assigned to work with NASA.
Lewis notes that emergency managers should think about devoting resources to this seemingly distant threat, while also responding to more immediate hazards such as tornadoes and hurricanes. “It will be a special challenge,” he says.
In the meantime, NASA is on track to launch a new asteroid-detecting telescope in the fall of 2027, Johnson says.
“We need to discover what’s out there, determine their orbits, and then determine whether they pose an impact hazard to Earth over time,” he says.