TrekMUSH is an adult-themed recreation of Gene Roddenbury's Star Trek universe, but projected 20 years into the future of the broadcast timeline. It purports to have been launched and operating since 1993. The website and perhaps the MUSH itself is claimed as a subsidiary of Amethyst-Ree Unlimited (presumably a sole proprietorship).
"There are 10 player-character empires available to choose from, with 40 races and 500 active players." (TrekMUSH.org)
Players must first connect to the ATS service to apply for access.
On September 22nd, 2013, connect was refused at the ATS port (ats.trekmush.org 1701) and also at the "simulator" port (gz.trekmush.org 1702). It is not certain if or when the MUSH shut down, or for how long.
The simulator port of 1702 no longer works as there are simulators designed within the game in the OOC area and the game is still open. Unsure why connection was refused on September 22nd 2013 but it was open then and is still open.