Congratulations to the DART mission teams! On Monday, September 26, at 23:14 UTC, in front of a global audience, the Double Asteroid Redirection Test successfully hit the tiny, 160-meter asteroid Dimorphos. Images streamed in from the onboard camera, DRACO, as the spacecraft approached the rocky surface, ending with a barely started image before going dark. But what a set of images they were up until then.

When the feed first went live, DART was still focused on Didymos, the larger of the binary asteroids, also referred to as the primary, as the spacecraft could not yet resolve the two bodies separately. Then, around T minus one hour, the autonomous system, or SMART Nav, needed to detect Didymoon, begin tracking the satellite, and lock onto it. During the SETI Institute’s live stream, DART Lead Investigator Andy Cheng announced that the spacecraft had achieved all of those goals and was on approach to the target. Moments later, Dimorphos was finally resolvable in the DRACO live feed.

Over the next 45 minutes, features on both Didymos and Dimorphos began to come into view, revealing that the pair are mostly like rubble pile asteroids similar to Ryugu and community favorite, Bennu. Boulders and craters and even a few flatter areas were clearly visible, and we expect that the images will be heavily analyzed over the coming weeks.

Due to the slight delay between sending the images and receiving them, about the scheduled time of the impact, Dimorphos began to fill the camera, eventually ending with that previously mentioned barely begun image. The spacecraft successfully hit the target, and everyone watching cheered to see it.

This mission was the first-ever planetary defense test, and NASA Administrator Bill Nelson said: At its core, DART represents an unprecedented success for planetary defense, but it is also a mission of unity with a real benefit for all humanity. As NASA studies the cosmos and our home planet, we’re also working to protect that home, and this international collaboration turned science fiction into science fact, demonstrating one way to protect Earth.

Of course, the day’s activities did not stop there. Numerous telescopes around the world and in space, including ATLAS, ALMA Observatory, Hubble Space Telescope, and a network of amateur astronomers, all had their instruments turned toward the collision. Within a few hours, ATLAS posted on social media a gif of the Didymos system brightening and visibly ejecting a cloud of debris, confirming the impact.

One of the events we were waiting for is visual confirmation and images from DART’s companion CubeSat, LICIACube, provided by the Italian Space Agency. LICIACube was released from DART fifteen days ago and only carries a tiny antenna, so the images will have to be downlinked one by one over the next few weeks, and the first two of those images were shared late Monday night. Between the CubeSat and the other telescopes tuning in, scientists will have a wealth of information to analyze, including answering the question: Did we actually change the orbit of Dimorphos?

We will bring you the answer here on Daily Space as soon as NASA announces the result.

One last note, as we mentioned last week, in 2024, the European Space Agency plans to launch Hera, a spacecraft that will arrive in 2026 at the Didymos system, and take observations of both asteroids. Hera will be in the company of two CubeSats to take a complete survey, focusing especially on the impact crater left behind… because after this week, we suspect that there is an impact crater to observe.

We’ll have links to all the images released so far in our show notes at DailySpace.org.

More Information

DART’s Small Satellite Companion Tests Camera Prior to Dimorphos Impact (NASA)

ESA to capture light from deflected asteroid’s new plume (ESA)

DLR press release

NASA press release

PSI press release