Asteroid Mining, Belt Mining

Pacman Miner
Image from Todd Drashner

The process of extracting useful minerals and other substances from asteroids.

Because of their small and easily manageable size, individual asteroids are very valuable. They have no gravity wells, making it relatively easy to move materials to habitat constructions in orbit. Even a small asteroid of a few hundred meters diameter can contain billions of tons of raw material. For this reason, individual prospectors (the so called belters) are willing to gamble life-savings against the cost of relativistic transport, mining rights, and so on, and quite a few do make it rich. Both small and large development corporations are also very keen to get their hands on asteroids. Many asteroids, most particularly nickel-iron rocks, contain varying amounts minerals: platinum, iridium, and sometimes radioactives, while carbonaceous chondrites are prized for being a rich source of volatiles and very occasionally fullerenes and amino acids). Water ice and ammonia are also very useful.

The main difficulties facing an asteroid miner include
  1. A lack of atmosphere for aerobraking; landing on Earth is made easier because of this useful deceleration aid.
  2. Minimal Oberth Effect making it expensive in delta-vee to decelerate into orbit round an asteroid,
  3. Irregular shape, making any orbit around an asteroid chaotic and potentially dangerous ( try plotting a close orbit around Kleopatra without hitting one or other of the protuding ends).
  4. Rapid rotation- for asteroids smaller than 100m the rotation may be fast enough that you could be thrown off the surface.
  5. Tumbling- many asteroids probably rotate around more than one axis, which also makes it difficult to land.
The small gravity field of an asteroid also causes problems, as mined material may drift away and volatiles can be lost to evaporation. For this reason most mining occurs inside flexible, sealed domes or in sealed tunnels inside the object. Very small asteroids can be entirely enclosed by an envolope miner vessel, kmown for historical reasons as a Pacman Miner or Pacminer. The rapid rotation of small asteroids also causes problems when they need to be moved or deflected- various kinds of gravity tug can be used for this purpose without contact with the rotating object.

Many individual asteroids and whole asteroid belts have been exploited by self-replicating Neumann devices, which sometimes develop various degrees of autonomy or sentience and establish civilisations of their own.

Occasionally an asteroid or asteroid belt will be discovered with an unusual configuration that makes it valuable for scientific or even aesthetic purposes. Even more rare, the hulk of an ancient ship or a neumann may be recovered, often centuries or millenia old, drifting in a belt. The salvage rights of such a find can make a belter rich for a life. Rarest and most prized of all are alien artifacts, although the possibility of such a find is more a part of myth and legend than pragmatic reality.
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Development Notes
Text by M. Alan Kazlev, additional comments by Steve Bowers
Initially published on 08 October 2001.