Science | March 8, 2022 3:40 pm

Does NASA Have the Ability to Shoot Down a Life-Threatening Asteroid?

If "Don't Look Up" happens in real life, we do have some options

A comet flying past Earth.
NASA has only identified 40% of large-scale "near-Earth" asteroids.
Anton Petrus/Getty

Considering that in the last two years we’ve seen six million people die from a global virus, a mob of Americans attack the Capitol Building and the first major land war in Europe since the end of World War II, you’d be excused for forgetting a scary headline from the summer of 2019.

In retrospect, though? Holy shit. In July of that year, an asteroid that some scientists referred to as a “a city-killer” narrowly missed hitting Earth, as The Washington Post reported at the time. To be fair, it missed us by about 45,000 miles, but that’s less than twice the equatorial circumference of the planet, or only about a fifth of the way to the Moon — which, for those who study such things, is “uncomfortably close.”

While this asteroid wouldn’t have caused an extinction-level event, scientists concluded its impact would’ve been similar to the detonation of a “very large nuclear weapon.” It’s statistically unlikely that an asteroid would crash into a city, but if it landed close enough to one, the damage would be incomprehensible.

At the time, researchers were extremely rattled by the asteroid (officially named Asteroid 2019 OK) — not solely for the risk it posed, but because they didn’t see it coming. Due to its size, the speed at which it was traveling and a cosmic phenomenon known as “slow apparent motion,” which makes certain asteroids appear stationary, Asteroid 2019 OK evaded discovery on “Near-Earth Object surveys.”

In other words, we didn’t know anything about it until it was too late. At which point we just got really lucky. In 2019, a lead scientist at the Royal Institute of Australia told The Washington Post: “[We need] a global dedicated approach [to detecting asteroids]. Sooner or later there will be one with our name on it. It’s just a matter of when, not if … It’s not a Hollywood movie. It is a clear and present danger.”

Now, years later, many of us trace our recent knowledge about asteroids and comets to a Hollywood movie: Don’t Look Up, the star-studded, Adam McKay-directed film that was released by Netflix at the end of last year. In the film, the approaching comet is a real no-doubter. It’s guaranteed to hit Earth, and functions more as an allegory for climate change.

In the real world, though, conflating various threats in order to impart commentary on the perils of capitalism isn’t particularly helpful. Remember, we’re on a rock floating in space. We’ve exploited that rock and have already started paying the consequences. But we’re simultaneously at the mercy of other floating rocks. It’s all dangerous.

And while we’re working hard (some of us, at least) to fight climate change with boots on the ground, we also have to continue looking up, and anticipate more abrupt forms of destruction. This work is called planetary defense, and NASA finds about 30 so-called “near-Earth asteroids” a week. Even still, they’ve only able to track an estimated 40% of the bigger ones, described as larger than 140 meters in size.

One helpful inlet into this process is NASA’s planned response to Bennu, an asteroid that could potentially hit Earth in September 2135, which would wipe out an entire continent, at the least. Instead of nuking the asteroid, or otherwise shooting it out of the sky (a popular suggestion from armchair experts on Reddit or commenting on YouTube videos), NASA drafted a plan called Hypervelocity Asteroid Mitigation Mission for Emergency Response (HAMMER).

Basically, the science suggests that sending some sort of spacecraft into the path of an asteroid can change its orbit, and send it off course. While exploding a nuclear warhead near an asteroid could backfire (if it doesn’t work, you could suddenly have a radioactive asteroid careening towards your planet), there’s also a plan to test kamikaze-style probes later this year, in a program called the Double Asteroid Redirection Test (DART).

As Freethink points out, this will be the world’s “first full-scale planetary defense mission.” Unlike the movies, we’re not unrolling this program at the eleventh hour, just before an asteroid eats our planet. The test will involve an asteroid called Didymos, which is 6.8 million miles away from Earth and poses zero risk to our planet.

Something to keep in mind? Planetary defense accounts for just 0.7% of NASA’s budget, and 0.02% of the entire American defense budget. If the last two years have taught us anything, we definitely need money for protecting ourselves on terra firma. But there’s danger lurking in the skies, too. We’d be wise to pay attention.