The asteroid belt is mostly empty space.
Between Mars and Jupiter lies the asteroid belt (aka. the “main asteroid belt”, as there are other areas with asteroids in our Solar System). Within this belt there are millions to billions of asteroids made up of rock and metals. Some are tiny particles but the largest is Ceres which is 580 miles in diameter. Large or small they’re hurdling through space at speeds up to 40,000 mph, so if one flew into a space craft it could be disastrous. Fortunately this isn’t really a problem.
Unlike asteroid belts in sci-fi movies, our main asteroid belt is not an obstacle course. Most of the asteroid belt is empty space. The four largest asteroids alone make up more than half the total mass of the entire belt and if you combined all of the asteroids together it would still be smaller than our moon. The average distance between asteroids is around 600,000 miles. According to Alan Stern of the Southwest Research Institute, “… if you want to come close enough to an asteroid to make detailed studies of it, you have to aim for one.” The odds of a spacecraft hitting one is less than 1 in a billion. It’s easier to fly through the asteroid belt than it is to actually hit an asteroid.