At a press conference shortly before NASA’s Double Asteroid Redirection Test (DART) spacecraft hit an asteroid, a reporter tried to get a sense of what would happen when a pile of metal and electronics crashed into a pile of rubble left over from the birth of the solar system. “Give us an idea of this fight between our spacecraft and this rock,” the journalist asked a scientist from the applied physics laboratory.
“The spaceship is going to lose,” joked Nancy Chabot of APL.
The amazing thing about this loss is that we were able to experience it in real time, as the last image from DART’s onboard camera was cut off after only a small fraction of it was transmitted to Earth.
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One of the last images taken that captures the two objects of the Didymos system: Didymos and its smaller companion Dimorphos, the latter being the target of DART
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As DART approached, Dimorphos gradually filled his camera’s field of view.
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The final image taken and transmitted by DART before its planned catastrophic teardown.
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The one that didn’t quite succeed, as the image data transmission was interrupted by the destruction of all the transmission equipment.
Details of the crash landing/impact of the spacecraft on the asteroid Dimorphos had to be captured on cameras that were a little further from the point of impact. Many of them are available now, so we’ve put together a collection and describe a bit of what you can see.
The closest cameras we had were aboard LICIACube, a cubesat that was flown into space aboard DART and then separated a few weeks before impact. LICIACube had two on-board cameras (named Luke and Leia), one that does wide-field imaging and one that can focus on details better. The Italian Space Agency, which led the LICIACube mission, did not say which camera produced which image, but released a number of them, including a distant view of the collision, close-ups taken shortly after and an animation showing the sudden brightening after the collision dispersed the material into space.
For those uncertain, the collision did not produce enough light to be seen in these images. Instead, debris ejected from the asteroid by DART reflected far more sunlight than the asteroid could on its own.
The brightening was significant enough that ground-based telescopes also picked up the brightening; in a few cases, their operators uploaded the images as they became available. The two I found show the Didymos/Dimorphos system moving peacefully past the background stars from Earth’s perspective (with most of the light reflected off the much larger Didymos). Suddenly, the object brightens considerably, the debris gradually moving to one side of the asteroids.
There are two major differences between the images. An image taken by Project ATLAS, which is based in Hawaii but has telescopes there, in South America and South Africa – the collision was only visible from the last of them. In its image, the asteroid is moving from right to left against the background stars.
ATLAS observations of DART spacecraft impact at Didymos! pic.twitter.com/26IKwB9VSo
— ATLAS Project (@fallingstarIfA) September 27, 2022
In contrast, data from the Las Cumbres Observatory from a telescope in South Africa show that the Didymos system is moving through the star field in the opposite orientation. But it also contains some pretty important information: timestamps for every exposure in the animation, which clearly shows that most of the action took place over about half an hour.
Animation (accelerated 500x) of one of the @LCO_Globaltelescope from 1 meter to @SAAO South Africa showing the effects of #DARTMission impact on Dimorphos (Still no threat to Earth… Long straight footage is camera artifact) pic.twitter.com/StYWtLArgG
—Tim Lister (@astrosnapper) September 27, 2022
ESA has also produced a video of the collision which covers the same period, and posted it online.