Gurps: Prime Directive - Core Rulebook

GURPS Prime Directive allows characters to be anything, from the bridge crew to the Marines, from diplomats to archaeologists, from a bunch of reserve officers looking to recapture the adventures of their long-lost youth, to a squadron of fighter pilots whose parties are as wild as their dogfights. Or you could be a Prime Team, Star Fleet's elite problem solving teams that combine the skills of scientists, diplomats, and commandos.