Plot: Part 2 explores which are the best asteroids to mine - and how? In Space, using Zero Gravity - or on Earth? How can their metals and the liquids be used for deep space exploration, as propellant or pit stops - and are any of the metals useful on Earth? With a visit to the Colorado Center of Space Resources, we explore the engineering and technology needed to extract materials from the asteroids. We reveal the three top companies in the race - TransAstra and their autonomous spacecrafts, OffWorld and their autonomous mining robots, and Atem Engineering, who find solutions for discovery and assessment of Near-Earth Asteroids