Moons

Moons are almost always orbiting around a planet. They have no atmosphere and a light gravitational pull. Most ships can not visit moons unless they have strong enough engines. Moons have some minerals, but nothing strikingly unique. Because moons are formed differently than asteroids, they sometimes have different assortments of minerals. Other than that, some moons may have small outposts located on the surface. Moons are relatively small and usually have at least 2 security ships patrolling the area. Therefore, you can only mine a certain amount, like an asteroid belt.