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SALT LAKE CITY — Hollywood loves the "death from above" meme and particularly so if pending annihilation comes in the form of a fiery rock hurtling toward Earth.
Occasionally the puny movie humans avoid catastrophe altogether, thanks to scientific genius, a la Sean Connery in 1979's "Meteor" or cartoonish machismo in the case of Bruce Willis-as-savior in the circa 1998 "Armageddon." Other times, planetary extinction is side-stepped but not without mayhem, as in 1998's "Deep Impact." Last year's satirical "Don't Look Up" took a more ripped-from-headlines approach when humanity's last chance to avoid an incoming comet is co-opted by an ego-driven tech billionaire.
Lindley Johnson, NASA's Planetary Defense Office, discounted the common cinematic renderings of Earth-bound asteroids but noted the compelling storyline has a long history in movies and literature.
"This situation, asteroid impact, has been a popular genre for science fiction books and movies for a long time," Johnson said at a NASA-hosted press conference earlier this week. "It captures the public imagination. But, that's all Hollywood and movies. They have to make it exciting and, you know, we find the asteroid only 18 days before it's going to impact and everyone runs around with their hair on fire."
But, big-screen dramas aside, planetary defense is a real thing and NASA is on the cusp of the first real-world test of how best to deflect an Earth-bound rock. And it's one with plenty of intrigue and excitement including a livestream of the experiment with a script that's hoping for an ending with a bang.
Sponsored by NASA's Planetary Defense Coordination Office and led by the Johns Hopkins University Applied Physics Laboratory, the Double Asteroid Redirection Test, or DART, is a $325 million project that aims to crash a 1,260 pound spacecraft traveling at 14,000 mph into Dimorphos, an asteroid that's 525 feet in diameter and 7 million miles from Earth.
The point of the exercise is to see how significantly the current path of Dimorphos can be altered by the impact in a technique NASA calls "asteroid deflector by kinetic impactor."
Dimorphos is a moonlet asteroid, orbiting a larger asteroid named Didymos, which is about a half-mile in diameter. Mission officials have stressed that the binary system "is not on a path to collide with Earth and therefore poses no actual threat to the planet" but is the "perfect testing ground" to see if an asteroid's natural path can be altered via a high-velocity impact.
And, thanks to an onboard camera system that will be streaming one-image-per-second back to Earth, mission engineers along with the viewing public will have a real-time view, albeit one delayed by the 45 seconds or so that it takes for the video to process and stream back to Earth-based receivers, capturing DART's approach and collision with Dimorphos.
We're moving an asteroid. ... We are changing the motion of a natural celestial body in space. Humanity has never done that before and this is stuff of science fiction books and really corny episodes of 'Star Trek' from when I was a kid. And now it's real.
–Tom Statler, NASA program scientist
While DART will be recording video right up to the moment of its own demise, plenty of other "eyes" will be on the collision, including a slew of Earth-bound telescopes as well as a number of spaced-based observers.
NASA says the Hubble and James Webb Space Telescopes will be turned toward the Didymos system for the event, as will the Lucy space probe. DART was also carrying a small cube satellite designed and built by the Italian Space Agency that it launched about two weeks ago on its way to the target. The LICIACube will have the closest third-party view of the crash from its position at 55km, around 34 miles, from Dimorphos at the time of impact, according to NASA.
Launched atop a SpaceX Falcon 9 rocket from California's Vandenberg Space Force Base in California last November, the DART spacecraft will shift from human controls to a fully autonomous, onboard "smartnav" navigation system about four hours before its meeting with Dimorphos.
Being able to launch a spacecraft that is able to independently find and target a rogue asteroid is a critical element of the DART experiment, according to NASA Program Scientist Tom Statler.
"The first test ... (is) our ability to build an autonomously guided spacecraft that will actually achieve the kinetic impact on the asteroid," Statler said at the NASA press conference. "The second test is the test of how the actual asteroid responds to the kinetic impact.
"Because at the end of the day, the real question is how effectively did we move the asteroid. And, can this technique of kinetic impact be used in the future if we ever needed to."
Statler said the expectation is that DART's impact on Dimorphos will change the asteroid's speed by 1% or so, but it could take weeks or even months to determine the exact level of disruption.
While this may seem like a minor change, the ability to create even a minute change in an asteroid or comet's trajectory toward Earth, with sufficient lead time, could create the difference between some future near-miss or direct hit.
In an attempt to lay the groundwork for identifying an Earth-bound rock with enough time to take evasive action, NASA says it is currently pursuing a congressional budget appropriation to move forward with the Near-Earth Object Surveyor space telescope (NEO Surveyor).
Hoping for a 2026 launch date, NASA said the NEO Surveyor is designed to help advance NASA's planetary defense efforts to discover and characterize most of the potentially hazardous asteroids and comets that come within 30 million miles of Earth's orbit. These are collectively known as near-earth objects, or NEOs.
Because at the end of the day, the real question is how effectively did we move the asteroid. And, can this technique of kinetic impact be used in the future if we ever needed to?
–Tom Statler, NASA program scientist
Right now, no known asteroid larger than 140 meters in size has a significant chance to hit Earth for the next 100 years, but only about 40% of those asteroids have been found as of October 2021, according to NASA.
As the collective knowledge-base and expertise grows to include comprehensive identification and tracking of future potential hazards from space, Statler said the DART mission will help prepare the residents of Terra Prime to take effective action in the event of some distant, pending catastrophe. And it's an experiment without precedent.
"We're moving an asteroid," Statler said. "We are changing the motion of a natural celestial body in space. Humanity has never done that before and this is stuff of science fiction books and really corny episodes of 'Star Trek' from when I was a kid. And now it's real.
"And that's kind of astonishing, that we are actually doing that and what that bodes for the future of what we can do as well as our discussions of what, as humanity, we should do. It opens up an amazing frontier and that is very exciting."
NASA says DART's impact with Dimorphos should happen around 5:14 p.m. MT on Monday, Sept. 26. The agency's full broadcast of the event begins at 4 p.m. MT that day and can be viewed on YouTube. A non-commentary feed from DART's onboard camera begins at 3:30 p.m. on Monday.
