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NASA successfully slammed a satellite into an asteroid yesterday, in a first-of-its-kind test of our planetary defense capabilities. Like something out of a blockbuster movie, the objective of the interstellar collision was to see if we can alter the trajectory of an approaching comet with a human-made object.

We won’t know if the experiment accomplished its goal for another two months or more. But the collision portion of the test was a resounding success. And best of all, NASA’s Double Asteroid Redirection Test (DART) spacecraft sent back some really cool asteroid collision images, along with a video of its final moments.

What is the Double Asteroid Redirection Test (DART)?

Final images in B&W from NASA's DART spacecraft, which slammed into an asteroid.
“Asteroid Didymos (top left) and its moonlet, Dimorphos, about 2.5 minutes before the impact of NASA’s DART spacecraft. The image was taken by the onboard DRACO imager from a distance of 570 miles (920 kilometers). This image was the last to contain a complete view of both asteroids. Didymos is roughly 2,500 feet (780 meters) in diameter; Dimorphos is about 525 feet (160 meters) in length. Ecliptic north is toward the bottom of the image. This image is shown as it appears on the DRACO detector and is mirror flipped across the x-axis from reality.” NASA/Johns Hopkins APL

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NASA’s DART project is seven years and $325 million in the making. If that price sounds high, consider the fact that information gleaned from the experiment could one day save our planet from total or partial destruction.

The DART spacecraft, which was about the size of a four-door sedan, launched into space 10 months ago. Its ultimate target, an egg-shaped Asteroid named Dimorphos, is about 525-foot-wide. The goal was not to destroy Dimorphos—you’d need a much bigger spacecraft for that—but rather to nudge it enough to adjust its orbit around another, larger asteroid, Didymos (the two are considered “twin” asteroids).

Final images in B&W from NASA's DART spacecraft, which slammed into an asteroid.
“The last complete image of asteroid moonlet Dimorphos, taken by the DRACO imager on NASA’s DART mission from ~7 miles (12 kilometers) from the asteroid and 2 seconds before impact. The image shows a patch of the asteroid that is 100 feet (31 meters) across. Ecliptic north is toward the bottom of the image. This image is shown as it appears on the DRACO detector and is mirror flipped across the x-axis from reality.” NASA/Johns Hopkins APL

“This really is about asteroid deflection, not disruption. This isn’t going to blow up the asteroid,” says Nancy Chabot, DART coordination lead at the Johns Hopkins University’s Applied Physics Laboratory. It’ll be a little while before we know whether or not the kinetic impact altered the asteroid’s trajectory. But if it did, it’ll be a huge accomplishment for science and humanity. And even if it didn’t, just making contact is a huge achievement in itself.

“DART’s success provides a significant addition to the essential toolbox we must have to protect Earth from a devastating impact by an asteroid. This demonstrates we are no longer powerless to prevent this type of natural disaster,” said Lindley Johnson, NASA’s planetary defense officer.

Asteroid collision images

Final images in B&W from NASA's DART spacecraft, which slammed into an asteroid.
“The last complete image of asteroid moonlet Dimorphos, taken by the DRACO imager on NASA’s DART mission from ~7 miles (12 kilometers) from the asteroid and 2 seconds before impact. The image shows a patch of the asteroid that is 100 feet (31 meters) across. Ecliptic north is toward the bottom of the image. This image is shown as it appears on the DRACO detector and is mirror flipped across the x-axis from reality.” NASA/Johns Hopkins APL

The DART spacecraft made contact with Dimorphos at around 7:16 p.m. Eastern Time on Monday, September 26. And thanks to the craft’s onboard “DRACO imager” camera—operated by Johns Hopkins Applied Physics Laboratory (APL) in Maryland—we got a front-row seat to that exact moment, which was also live-streamed to the public. See the video below.

Initially, the DART spacecraft targeted the larger, more visible Didymos asteroid, before switching to its smaller twin during the mission’s final hour. NASA lost command of the spacecraft in the final minutes before impact, which occurred at a leisurely speed of 14,000 miles per hour.

The final four images show the spacecraft passing by Didymos with Dimorphos growing larger and larger in the frame until we see only its surface. And then, KABOOM, the last frame is almost completely red due to the transmission cutting. According to NASA, that image was taken just four miles from the surface of the asteroid and one second before impact.

Final images in B&W from NASA's DART spacecraft, which slammed into an asteroid.
“DART’s final look at the asteroid moonlet Dimorphos before impact. The spacecraft’s on board DRACO imager took this final image ~4 miles (~6 kilometers) from the asteroid and only 1 second before impact. DART’s impact occurred during transmission of the image to Earth, resulting in a partial picture. The image shows a patch of the asteroid that is 51 feet 16 meters) across. Ecliptic north is toward the bottom of the image. This image is shown as it appears on the DRACO detector and is mirror flipped across the x-axis from reality.” NASA/Johns Hopkins APL

What’s next for DART?

It’s worth mentioning that Dimorphos and Didymos are more than 7 million miles from Earth and pose no threat. However, there are plenty of unknown objects yet to be identified by scientists, and at least some of these could potentially make contact with our planet. This is why the DART experiment doesn’t end with this initial impact.

Another smaller spacecraft was hanging around nearby to observe the collision. And countless land-based telescopes also witnessed it. While it may take a few weeks before we get additional views from space, videos from the ground are already circulating, like this one captured by the ATLAS asteroid tracking telescope.

Additionally, the European Space Agency plans to send up its hera spacecraft in the next few years to further investigate the aftermath of the test. For now, we’ll keep our fingers crossed that everything went according to plan as we eagerly anticipate more asteroid collision images.

Dan Bracaglia
Dan Bracaglia

Dan Bracaglia, the News & Features editor at Popular Photography, has been covering imaging and camera technology for 13 years, with work appearing—both written and photographic—in publications including American Photo magazine, Digital Photography Review, Popular Science magazine, the Star-Ledger, Sound & Vision magazine, and of course, Popular Photography. Contact the author here.

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