DART

A NASA spacecraft whose launch window opens tomorrow is being sent on a suicide mission. It will destroy itself by slamming into a small asteroid. By doing so, it may help save lives by keeping future asteroids from slamming into Earth.
DART — the Double Asteroid Redirection Test — will arrive at a binary asteroid in about 10 months. The larger member of the system, Didymos, is a half-mile in diameter. Its companion, Dimorphos, is only about a tenth of a mile across.
DART will hit Dimorphos head on, at a speed of about 15,000 miles per hour. The impact should change the smaller space rock’s orbit. Astronomers will use several telescopes to track the impact and its aftermath to see how much the orbit changes.
The goal is to help determine if we could deflect an asteroid on a collision course with Earth. An asteroid the size of Dimorphos could cause a lot of damage. And a larger asteroid could cause a global catastrophe. If we know about the impact far enough in advance, though, we might