The MUD Core 2651 takes place on a planet, Core, orbiting the dwarf star Hermes 571-G. The atmosphere of the planet is unbreathable, being primarily a mixture of carbon dioxide and methane.
Players of the MUD take the role of miners working for The Company, an interstellar corporation of tremendous scale. The Company claimed Core under an obscure clause in the Counter Empire Act of 2149, and defends it against invasion using an ad hoc militia under the Corporation Militia Law of 2375. The reason for this exercise in corporate sovereignty is that deep inside the crust of Core can be found an element previously undiscovered in nature, corezite, that allows the faster than light Carpenter drives to perform at greater efficiency and speed.
More information on Core 2651 can be found at www.coremud.org