Dart Hits a Bullseye

...."The mass of the DART spacecraft at the time of its kinetic impact with Dimorphos is expected to be roughly 570 kilograms (1260 pounds), depending on the amount of fuel used by the spacecraft prior to the kinetic impact event. The mass of Dimorphos has not been directly measured, but using assumptions for the asteroid’s density and size, the mass of Dimorphos is estimated as roughly 5 billion kilograms. Additional detailed information about the Didymos binary asteroid system and DART’s planned kinetic impact geometry can be found in this publication. Furthermore, the change in Dimorphos's orbit by DART’s kinetic impact is designed to bring its orbit slightly closer to Didymos.

...Currently, the orbital period of Dimorphos around Didymos is 11 hours and 55 minutes, and the separation between the centers of the two asteroids is 1.18 kilometers (0.73 miles). ...

This pic was snapped less than 1 second before impact...

..."The DART team said it expects to shorten the orbital path of Dimorphos by 10 minutes but would consider at least 73 seconds a success, proving the exercise as a viable technique to deflect an asteroid on a collision course with Earth - if one were ever discovered."...

https://dart.jhuapl.edu/Mission/index.php