Starships & Spacemen
Starships & Spacemen is a roleplaying game originally developed by Fantasy Games Unlimited in 1978 and is now supported in a second edition by Goblinoid Games since 2013.
The game is designed to emulate Star Trek the Original Series/Animated Series adventures with a few minor tweaks. Due to licensing issues, however, it can't use any trademarked work. As such, it largely filed off the serial numbers and renamed races, locations, tech and more.
The second edition of the game is a retroclone of Basic D&D.