NASA’s DART spacecraft is no more, but its final view is magnificent.
The double asteroid redirect test (DART) was designed to test kinetic impact, a technique humans could use to adjust the orbit of a menacing asteroid and keep Earth out of danger. Kinetic impact is just a more scientific way of describing slamming something heavy and moving quickly through a asteroid. So that’s precisely what the DART spacecraft did tonight (September 26) at 7:14 p.m. EDT (2314 GMT), crashing into a small asteroid called Dimorphos. And the result is a series of truly spectacular images.
“They exceeded my expectations,” said Nancy Chabot, DART mission coordinator and planetary scientist at the Johns Hopkins University Applied Physics Laboratory, during NASA’s broadcast of the event tonight.
Related: NASA’s DART asteroid impact mission explained in pictures
Until DART’s short-lived visit, scientists knew very little about Dimorphos, which orbits a larger asteroid called Didymos; the system appears as a mere bright spot to telescopes on Earth. But the spacecraft captured images all the way, sending home an image every second, with our final view of the asteroid taken about two and a half seconds before the crash, according to a schedule provided by NASA before the crash. ‘impact.
The images are valuable because scientists have seen very few asteroids up close. As the final DART images arrived on Earth, members of the mission team – and anyone listening to the live stream – saw an incredible field of angular gray rocks interspersed with pebbles, gravel and dust.
“I know other scientists like me on the team are already pointing to these images and saying, ‘Did you see that rock? Did you see that smooth area?'” Chabot said.
The images closely resemble photographs taken by the Japanese Hayabusa2 mission in asteroid Ryugu and NASA’s OSIRIS-REx mission to the asteroid Bennu. Both of these space rocks were so-called “rubble-pile” asteroids, named for the spreading rocks seen on their surfaces. However, while both of these asteroids were diamond-shaped, Dimorphos appears more like a “space potato” in images captured by DART as it approaches.
DART was equipped with a single instrument, the Didymos Reconnaissance and Asteroid Camera for Optical Navigation, or DRACO. Prior to capturing the incredible final stream, DRACO was also tasked with helping steer the spacecraft towards Dimorphos – an impressive feat considering DRACO could only spot the moon about an hour and a half before impact.
Over the next few days, scientists will receive more images of Dimorphos, those taken by the Light Italian Cubesat for Imaging Asteroids (LICIACube), a tiny spacecraft that accompanied DART until earlier this month. LICIACube flew over the impact site just three minutes after the collision, photographing the cloud of debris that the DART’s sudden arrival hurled into space. However, the cubesat also turned its two cameras to the unscarred side of Dimorphos, giving scientists additional data on the space rock.
And scientists have another opportunity to see Dimorphos in detail, this time much longer. The European Space Agency will launch Hera, a follow-up mission, in 2024. Hera will arrive in 2026 and, unlike DART, will remain in the neighborhood, exploring both Dimorphos and Didymos. The mission will give scientists better insight into the impact crater itself after the dust has settled, as well as the natural state of the asteroids.
Email Meghan Bartels at mbartels@space.com or follow her on Twitter @meghanbartels (opens in a new tab). Follow us on Twitter @Espacedotcom (opens in a new tab) and on Facebook (opens in a new tab).