Why mine asteroids? Planetary Resources said: There are over 1,500 asteroids that are as easy to get to as the surface of the Moon. Asteroid resources have some unique characteristics that make them especially attractive. Unlike Earth, where heavier metals are close to the core, metals in asteroids are distributed throughout their body, making them easier to extract. Asteroids contain valuable and useful materials like iron, nickel, water, and rare platinum group metals, often in significantly higher concentration than found in mines on Earth.