When a 65-foot-wide meteor exploded in the sky on Feb. 15, 2013 with the power of 20 atomic bombs, Vladimir Petrov was 20 miles directly below it, standing on a snowy street in Korkino, Russia, by the coal mine where he worked. It was 9:20am on a Friday and most of the town was just waking up or heading to work. It was around 0°F (-18°C), frigid but not unusual for February in the small town between the Ural Mountains and Siberia.

Petrov felt a sudden burst of heat, and as he’d describe to scientists investigating the damage weeks later, it was as though he’d suddenly gotten severely sunburned—within days, his skin would start flaking.



A 65-foot meteor exploded near Chelyabinsk, Russia in 2013. Source: GIPHY

In and around Chelyabinsk, the regional capital about 20 miles away, people were blown off their feet, windows shattered, and doors blew off buildings. The air smelled like gunpowder and sulfur. Schools were closed and emergency responders rushed to the area. Within hours, footage shot by locals made international headlines: a freak asteroid had entered the atmosphere and exploded, sending more than 1,600 people to hospitals (most, luckily, with minor injuries) and causing millions of dollars of damage. And no one had seen it coming.

As fate would have it, right when the asteroid exploded, Lindley Johnson, then-executive director of NASA’s Near-Earth Object Observation Program, was in Vienna developing an asteroid defense plan to share the next day with the United Nations’ Committee on the Peaceful Uses of Outer Space. “We had worked up our recommendations and were going to be briefing them to the subcommittee the day after,” Johnson recalls. “Chelyabinsk was sort of Mother Nature’s putting an exclamation point on [it].”

NASA has been tracking near-Earth asteroids—those within 30 million miles of Earth’s orbit— since 1998, but its funding has only recently begun to catch up to the scale of its efforts. In 2014, the Near-Earth Object Program saw its annual budget nearly double, from $20.4 million to $40 million. In 2016, it went up again to $50 million, and NASA established a new office dedicated specifically to planetary defense. Johnson was named NASA’s first planetary defense officer.

NASA’s Planetary Defense Coordination Office does not expect a major asteroid impact in the near future, which is good because we are far from prepared. Current technology would not be able to detect another asteroid like the one that exploded over Chelyabinsk. That’s because it approached from the direction of the sun, and our telescopes primarily observe the sky at night, when we’re facing the opposite direction.

But even when it comes to asteroids that aren’t obscured from view, NASA is years behind schedule in mapping out even the largest asteroids in our neighborhood. On April 19, an asteroid 2,000 feet wide will pass by a million miles from Earth, the biggest space rock to get that close to the planet in more than a decade. The incredibly bright 2014 JO25, twice as a reflective as the moon, was first spotted three years ago. And there’s no real plan about what we would do if we detected one coming our way.

Which is why, when they rehearse asteroid impact scenarios each year with the Federal Emergency Management Agency, the asteroids still hit us every time.

Here’s the scenario:

It’s 2016, and about 250 million miles from Earth, a chunk of silicon rock 400 ft in diameter is ripped out of the asteroid belt by the gravity of Jupiter and Mars. As it whizzes through outer space at tens of thousands of miles per hour, it gets closer and closer to Earth.

When ground-based telescopes finally spot the asteroid, tens of millions of miles away, it’s just an unconfirmed data point swept into a constantly growing database at the Minor Planet Center operated by the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts. Amateur astronomers and international observatories attempt to corroborate the observation, and as more data pours in, the center’s computers calculate the asteroid’s orbit.

When the asteroid finally gets flagged as a potential hazard, Johnson and a group of other scientists get a warning text message from the center’s computers. Meanwhile civilian enthusiasts—who tend to get especially excited by space objects that could potentially pose threats to Earth—take their own images and calculate their own trajectories (there’s free software that helps them do the math).

More observatories around the world corroborate the data, and NASA discovers the asteroid has a small but real chance of hitting Earth—2%—in 2020. When it comes to planetary defense, anything over 1% is enough to kick a lot of procedures into gear.

The Planetary Defense Coordination Office brings in the U.S. Air Force and Department of Defense, as well as the Federal Emergency Management Agency, to initiate discussions about what can be done and prepare the public messaging. Even though much of the public will already know—with all observational data available online and a world of amateurs connected to social media, there’s no hiding an asteroid with a diameter six times that of the one that exploded over Chelyabinsk.

There’s no hope of deflecting or destroying the asteroid—that would not only take more notice, but would also require technology that doesn’t exist yet. And there’s still only a 2% chance it will hit Earth anyway.

But in doomsday exercises, asteroids don’t glide safely past.

With more observations, the small chance of the asteroid hitting Earth is recalculated as an all-but-certainty.

When it’s clear the asteroid’s headed for the west coast of the US, NASA loops in the California Governor’s Office of Emergency Services (Cal OES), which is surprised to discover there’s nothing America’s space administration can do to protect them, even with years of notice.

“I was thinking very simplistically, ‘can’t you just nuke the thing to change its path by a degree?’” says Dan Bout, assistant director for response at Cal OES, about his response to the bad news in the doomsday exercise. The physicists told him “No, that’s not something we can do right now.”

It’s a harsh reminder that America’s anti-asteroid arsenal is not up to the standards we expect from science fiction. It was by sheer luck that they even noticed this 400-foot-wide asteroid—NASA’s congressional mandate is to locate all existing near-Earth objects 140 meters (460 ft) or larger by 2020. But even after years of monitoring, it’s not even a third of the way there, and there’s no sign that it will catch up by then.

“I would have thought we have these really robust capabilities of looking out into space and seeing what the threats are,” Bout says. “And we have a lot of people and a lot of capabilities, but maybe not as robust as I thought we had.”

In the last few months before the impact, localities start alerting residents of evacuations by reverse 911 and social media, moving them out in waves; ideally, the relocation happens in incremental steps to avoid chaos and ensure sufficient infrastructure is still usable. No one can force people to leave their homes, but authorities go door-to-door to those that don’t leave and inform them they’re in imminent danger, which is generally enough to clear out most reluctant homeowners..

The California Governor’s Office would help reroute all traffic from the Los Angeles port (which transfers more than $1 billion of trade per day) to another city on the California coast. They would have to work with airlines to plan for abandoning LAX, and dismantle power plants in a way that somehow avoided fuel shortages for those on later evacuation waves.

As for the impact itself, that’s pure physics.A 120-meter silicon rock hitting Los Angeles between 18 and 19 km per second would explode with more than 600 times the energy of the nuclear bomb America dropped on Hiroshima, assuming a typical impact angle and consistent surface composition where it lands. It would also leave a crater a mile wide, according to an online simulation program by Imperial College London and Purdue University.

The entire urban center of Los Angeles would be obliterated, along with the port. The area would be unlivable for months, if not years. ”You’re not going to return to the way things were,” said Bout.

For the most part, this scenario is realistic. The only piece that’s especially unlikely is that an asteroid so large would hit so soon, based on models of how many asteroids are out there, and global observations of small “fireballs” that explode in the atmosphere. Experts estimate that Chelyabinsk-sized asteroids might hit Earth once or twice a century, and larger ones far less often. NASA hopes it will have hundreds of years to prepare for the next inevitable major asteroid impact—in which case, the response would look completely different from the recent rehearsals.

Either way, we need to get prepared. To start, we need better detection technology—instruments that don’t just look up when it’s clear and after dark. Then we’ve got to develop methods to stop projected impacts from actually happening.

Most of NASA’s tentative strategies for this fall under two categories: deflection (changing its orbit so it doesn’t hit up) and disruption (breaking it to bits). NASA’s National Near-Earth Object Preparedness Strategy published last December makes clear that it still doesn’t have much of a plan for either. But it has a lot of ideas.

Deflection takes a lot of time, but it’s likely the safest solution: there’s no risk of blasting one dangerous asteroid into many smaller, still-dangerous asteroids. If the asteroid is far away and reasonably small, stopping it could be as simple as launching a “kinetic impactor” (or a few of them) into the asteroid to slow it down or reroute it—basically, sending a high speed spacecraft into the rock to force it out of its current trajectory. But NASA’s also considering other options, like launching an extremely massive object into the asteroid’s vicinity, where it could slowly tug at the space rock with its own gravity. Of course, neither of these ideas have ever been tested.

An even more novel idea is to leverage something called the “YORP effect,” a small force created when asteroids take in sunlight and release heat. If NASA launched a satellite that (somehow) coated one side of the asteroid with paint, it could theoretically make small changes to the asteroid’s trajectory without the tremendous cost of launching an object big enough to knock the space rock out of orbit.

Disruption—smashing the asteroid—could be extremely dangerous, and would probably only be used as a last resort, or in a situation where the asteroid was extremely large, and breaking it down could potentially reduce (but not stop) the damage. Scientists sometimes toss around the idea of blasting asteroids with nuclear weapons, but this would violate the 1967 Outer Space Treaty , risk weaponizing outer space, and still potentially fail to neutralize the original threat.

There’s an incredibly long way to go; NASA still has to deal with things as basic as agreeing on “common terminology” to describe asteroid data and measurements with its international partners.

But the government is currently clamoring to make planetary defense a priority. Lamar Smith, chair of the House Committee on Science, Space, and Technology, hopes to pass a bill to “revitalize” asteroid defense efforts between international governments and private companies “so that we may bring our best efforts to protect the public,” he wrote in a statement to Quartz .

Speaking with Quartz in the early days of the Donald Trump presidency, Lindley Johnson was not concerned that the new administration’s changes to NASA will impede his office’s momentum. Robert S. Walker and Peter Navarro, two of the president’s policy advisors during the 2016 campaign, derided the agency’s work in “politically correct environmental monitoring,” as they referred to climate change research in an Op-Ed , but the administration has not publicly spoken about NASA’s work preparing for existential threats.

“The Planetary Defense Coordination Office is part of the planetary science division of the science mission directorate here at NASA. It’s separate from Earth Science, so we don’t see any impacts to what we’re doing here,” Johnson says. “We’ve had pretty universal support of our efforts, so we have not had a specific discussion with the transition team on this yet, but we’re expecting to continue on the way they are.”

Two months later, Trump signed a bill scrapping funds for NASA’s asteroid redirect mission. It would have provided a chance for them to test a gravity tractor, one of the leading ideas for deflecting asteroids. According to the Office of Management and Budget’s “Blueprint to Make America Great Again,” this would allow NASA to focus on deep-space activities and to “accommodate increasing development costs.”

Johnson says this isn’t an indicator of tepidness toward his office. Asteroid deflection can be demonstrated in other missions, he noted, and their current work cataloguing the largest near-Earth asteroids is proceeding as usual.

“Nothing in the Administration’s Budget Outline changes our Planetary Defense priorities – in fact the budget appears to be quite supportive of efforts within Planetary Science where the PDCO resides,” he told Quartz by email.

At least some NASA officials appear open to embracing “America First” as a policy for space research.

Jim Green, head of NASA’s planetary science division, says preparing for asteroid impacts is exactly the type of mission for which NASA exists. “We are the world’s experts at what we do,” Green says. “And what we do is actually extremely important for the survival of this species. So I don’t think that’s going to change.”

“When we do the things that we do, we make America great.”