Could asteroid mining ever pay off, or is it still science fiction?

Asteroid mining is hypothetical and technically possible, but it has not paid off, and whether it ever will is disputed. It means extracting materials from asteroids and other minor planets, including near-Earth objects. The ideas are old, and the practice is tiny: as of 2024 only about 127 grams of asteroid material had been brought to Earth, by science missions, not mining ones.

Why consider it at all? Earth's stronger gravity pulled heavy, iron-loving elements into its core early on, leaving the crust short of them until a rain of asteroid impacts brought metals such as gold, nickel and platinum back. In 1997 it was speculated that a small metallic asteroid 1.6 km across contains more than US$20 trillion worth of industrial and precious metals. Hypothetically, water from ice could also refuel orbiting propellant depots.

Reality is harder. Notable challenges include the high cost of spaceflight, unreliable identification of suitable asteroids, and the difficulty of extracting usable material in space. Some economic analyses indicate that returning asteroid material to Earth costs far more than it is worth, while other studies suggest large profits using solar power. The quality of the ore and the cost of the equipment are, today, unknown and can only be speculated on.

There is a built-in puzzle. An economist remarked that any outside source of precious metals could lower prices enough to doom the venture, by rapidly increasing supply.