Efficient mining of small asteroids and comets is made difficult by the very weak gravity and rapid rotation of most such objects. Any material extracted from such small objects is likely to drift away, or even be flung away by centrifugal force. For this reason the envelope mining ship, or Pacman Miner was developed. The Pacman Miner ship approaches a small asteroid and matches its rotation, then surrounds it entirely using an extendable loop with a flexible bag attached. The ship then closes the loop like a hinge so that the object is entirely surrounded by the bag. The mining ship can now process the object without losing any dust, volatiles or other material. The bag generally becomes inflated due to evaporating volatiles, making the Pacman Miner appear spherical; using this atmosphere as a source of friction, the asteroid can be gently despun.
The spherical appearance of the enclosure and the capacious closing gape of the ship resembles a character from a very early Information Age electronic game — the Pacman. Hence the name of this mining system.
Text by James Ramsay and Steve Bowers
Initially published on 07 May 2009.