<p>Mining is the main source of commodities used in manufacturing industry on Earth. Besides the Earth, there are many celestial bodies that contain precious metals and minerals. The crust of Earth is poor in containing precious metals and minerals. Space mining will be the main source of metals in near future. It will affect the world economy in many aspects and will have tremendous effects on global economy due to falling metal prices. The values of gold reserves of central banks and of private gold investors will be dropped dramatically. Metal abundance will cause the industry to develop by leveling up. Space mining has many features that are different from terrestrial mining. Asteroid mining will be the first step of space mining. Working in microgravity and vacuum environment are main difficulties in asteroid mining. Beside the technical difficulties that it contains, transportation cost is by far the biggest cost item in space mining in case the mined material is to be transported to Earth. This paper studies main aspects of space mining and analysis possible economic, legal and environmental effects of it on global economy.</p>