Asteroid Mining

Asteroids (in our belt) are the most common source of raw material. They can be mined and transported more easily than a similar volume of mass extracted from a planet. Asteroids are very valuable and small ones can contain billions of tons of raw material. For this reason, individual prospectors, small and large development corporations are keen to profit from resources like nickel, iron, platinum and iridium. Water ice and ammonia are also useful.

Asteroids may be collected and moved as a whole towards central processing locations. Gravity tugs can be used to pull them. Small ships may land on the surface and construct thrusters and processors on the surface from material mined there, turning the asteroid itself into a ship which flies to its destination.

They may also be broken up into smaller sizes to make mining and collection more manageable.

Working-class humans in the The Expanse that mine asteroids are called the "belters".