Spread out over a massive region between the orbits of Mars and Jupiter, the Main Belt contains a few hundred asteroids greater than 100 kilometers in diameter, over a thousand objects greater than 30 kilometers in size, and countless smaller ones. Despite this, the total mass of asteroids in the belt is only a fraction of one of the inner planets, meaning that asteroids are spread out over great distances. A spacecraft flying through the belt is highly unlikely to encounter an asteroid unless it deliberately navigates toward it.
The rich, easily accessible mineral deposits in the Belt were a major link in transhumanity’s first steps toward the outer system. Automated mining and high-impulse ion boosters enabled outer system colonists to move metal-rich Main Belt asteroids into the orbits of Jupiter, Saturn, and beyond, where metallic asteroids are much scarcer. This activity continues to this day as transhumanity pushes further out into the system.
Hundreds of small habitats, mostly involved in prospecting activities, dot the belt. Distant from Earth, settlements in the belt were largely spared the devastation of the Fall. Both hypercorp and autonomous outposts flourish here. Derelict habitats abandoned when nearby asteroids were boosted into the outer system or depleted are common here as well, though some of these are now occupied by residents who are best left to their solitude.