Executives said Tuesday they're also developing a foundry designed to produce metal parts from nickel, an element abundant in asteroids, and operate in space, and a class of "Harvestor" craft to extract valuable material from the asteroids.

CNN: 'Fireflies' to scope out space rocks for mining

In most auto factories, the leftover steel cutouts are stacked up, then sold to a foundry, where they are melted with other bits of steel and converted into scrap metal.

FORBES: How GM Makes $1 Billion A Year By Recycling Waste