Imagine trying to change the path of an object in space without blowing it apart. In September twenty twenty-two, NASA tested that idea by sending a spacecraft into a small asteroid moon called Dimorphos. The mission was named DART, short for Double Asteroid Redirection Test. Dimorphos was orbiting a larger asteroid called Didymos. DART did not try to destroy either object. Instead, it used a kinetic impact: the spacecraft hit Dimorphos at high speed and transferred some of its motion to the asteroid. The goal was simple to describe but difficult to achieve. Could a planned collision make a measurable change in an asteroid's orbit? The answer came from careful observations of the two objects moving around each other.