The DART mission will target two asteroids closely orbiting each other – Didymos (780 m across) and Dimorphos (160m wide), which revolves around Didymos. Both of them orbit the Sun and are no threat to Earth.
The goal of the mission is to hit Dimorphos with the spacecraft in order to alter its path and speed. Although its trajectory will not change much, this mission will help scientists learn how to change the course of asteroids that could potentially be dangerous. The collision is expected to reduce the asteroid's speed by 1% and slow its orbital period around Didymos by a few minutes.
About 55 minutes after the launch, the spacecraft separated from the second stage of the Falcon 9 rocket. NASA has already received the signals from the probe that is preparing for the beginning of its 10-month journey.
Between September 26 and October 1, 2022, the spacecraft will crash into Dimorphos at a speed of 24,000 km/h. At that time, Didymos and Dimorphos will approach our planet at about 11 million kilometers.
Ten days before the planned collision, a miniature LICIACube cubesat will separate from the DART spacecraft to monitor the process and broadcast the impact on Earth.
A few years later, the European Space Agency's Hera mission will reach Dimorphos to assess the impact of the collision and refine the new orbit of the asteroid.