NASA's DART spacecraft finally found its target and hit the surface of a distant asteroid Dimorphos at 2:14 AM. Greek time in the early hours of Tuesday.
An hour before impact, the asteroid Dimorphos was not even visible in images from the spacecraft. In some of the first images sent back to Earth, even its larger companion Gemini looked like a single speck against a black sea.
The DART spacecraft it was moving at 22.500 kilometers per hour (14.000 miles per hour) and the details appeared quickly. Viewers on Earth saw the rough surface of Gemini pass by the DART spacecraft as it headed toward Dimorphos.
In the final seconds of DART's life the Dimorph blocks filled the screen and then turned bright red, indicating a loss of signal. The DART had reached its final destination.
Watch its final seconds from Nasa's tweet:
IMPACT SUCCESS! Watch from #DARTMISsion's DRACO Camera, as the vending machine-sized spacecraft successfully collides with asteroid Dimorphos, which is the size of a football stadium and poses no threat to Earth. pic.twitter.com/7bXipPkjWD
- NASA (@NASA) September 26, 2022
Telescopes around the world (and in space) now turn their attention to the scene of the conflict. They'll be watching to see how much the impact changed Dimorph's motion.
The crash is part of the first practical planetary defense experiment, a test to see if humanity might one day be able to redirect the course of an asteroid headed for our planet.
The option tested by DART is one of the most direct. If we hit something on an asteroid, will it change the way that asteroid moves? Because the orbit of Dimorphos is influenced by the other asteroid, Gemini, as well as by Earth, researchers will soon have an answer to this question.
Asteroid Dimorphos is relatively small, so scientists couldn't see it until shortly before the collision. But telescopes can see both Gemini and Dimorphos.
And now they expect to see Dimorphos' orbit speed up after the collision, but it remains to be seen how well the asteroid's behavior will match the models computers that they have done.
It will probably take a few months to get a full answer on how much the DART mission changed the trajectory of Dimorphos. But in the meantime, the latest images from the spacecraft offer plenty of tantalizing details for researchers.