Asteroid headed for Earth? NASA’s simulation explores how the nation might respond

Imagine if scientists discovered a giant asteroid with a 72% chance of hitting Earth in about 14 years—a space rock so big it could not only wipe out a city, but destroy an entire region.

That’s the hypothetical scenario that asteroid experts, NASA employees, federal emergency management officials and their international partners recently discussed as part of a tabletop simulation designed to improve the nation’s ability to respond to threats of asteroids in the future, according to a newly published report. from the space agency.

“Right now we don’t know of any significant-sized asteroids that will hit Earth for the next hundred years,” says 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 are that are large enough to cause regional destruction.”

Astronomers estimate there are approximately 25,000 of these “near-Earth objects” that are 140 meters or larger, but only about 43% have been found to date, according to materials prepared for the tabletop exercise held in April in Laurel. , Md.

The event was just the latest in a series of exercises planetary defense experts have held every two years to practice how they would handle news of a potentially planet-threatening asteroid — and the first since NASA’s DART mission, which showed that crashing a spacecraft into an asteroid can change its path through space.

This time, shortly after the discovery of the fictional asteroid, scientists estimated its size to be anywhere from 60 meters to almost 800 meters.

Even an asteroid on the smaller end of that radius could have a big impact, depending on where it hits Earth, says Lindley Johnson, NASA’s Planetary Protection Officer Emeritus.

While “a 60-meter asteroid hitting somewhere in the middle of the ocean” wouldn’t be a real problem, he says, the same asteroid hitting the ground near a metropolitan area would be “a serious situation.”

Because telescopes would only see such an asteroid as a point of light in space, Daly says, “we’re going to have very large uncertainties in the asteroid’s properties, and that leads to very large uncertainties about what the consequences would be if was to hit the earth, as well as huge uncertainties about what it would take to stop that asteroid from hitting the earth.”

Furthermore, this particular scenario worryingly determined that scientists would not be able to learn more about this threat for more than six months, when telescopes could again spot the asteroid and make another assessment of its trajectory. his.

Participants in the exercise discussed three options: simply waiting and doing nothing until the next observations of the telescope; launching a US-led space mission to have a spacecraft fly by 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 perhaps even change its path through space.

Unlike previous simulations of the asteroid threat, this one did not have a dramatic ending. “We were actually stuck at a point in time for the duration of the exercise. We didn’t move forward,” says Daly.

As a result, attendees had plenty of time to discuss how to communicate both uncertainty and the urgent need to act. They also discussed how funding and other practical considerations can play into decision-making processes in federal agencies and Congress.

Daly says in previous discussions, technical experts tended to assume that access to finance would not be an issue in such an unprecedented situation, but “the reality is, absolutely, cost was a concern and a factor”.

NASA’s report on the exercise notes that “many stakeholders expressed that they would like as much information about the asteroid as soon as possible, but expressed skepticism that funding would be forthcoming to obtain a such information without more definitive knowledge of the risk”.

While representatives of space institutions had a clear preference to take quick action, “what would political leaders actually do?” Daly says. “That was really an open question that remained throughout.”

Getting a spacecraft ready, finding the right launch window for it, and getting it traveling through space to an asteroid “eats up a decade very quickly,” says Johnson. “So that’s certainly a concern, looking at it from a technology standpoint.”

But something like 14 years of advance notice will seem like a lot of time to emergency managers and disaster responders, says Leviticus “LA” Lewis, a Federal Emergency Management Agency employee assigned to work with NASA.

Lewis notes that emergency managers will have to think about dedicating resources to this seemingly distant threat while also responding to more immediate dangers like tornadoes and hurricanes. “It will be a special challenge,” he says.

Meanwhile, NASA is on track to launch a new asteroid-finding telescope in the fall of 2027, Johnson says.

“We need to find out what’s out there, determine their orbits, and then determine whether they represent a risk of impacting Earth over time,” he says.