Prime Directive is a role-playing game set in the Star Trek-derived Star Fleet Universe. The game has gone through two different incarnations.

Prime Directive RPG

The original Prime Directive game was an in-house design by the Amarillo Design Bureau. It used a D6-based system similar to the Shadowrun and Star Wars RPGs. The greatest complaint was that it limited choice of characters to members of a Prime Team or a similar group, not allowing players to be captains and such. Also, since the rules were unique to this game, and only vaguely similar to other systems, many players were not willing to the time and effort into learning them.

The published books for the game included the core rulebook, a Federation sourcebook, and a few adventures.

GURPS Prime Directive

After the failure of the original concept, the publishers of Star Fleet Battles fished around for a new version of the RPG utilizing an established rules set. Eventually, they approached Steve Jackson Games to utilize the Powered by GURPS format.

The new version dispensed with the restrictions on characters, opening the doors for players to play virtually any type character they wished. The move to GURPS also allowed some cross-genre moves to be made, and to include some limited elements of the Traveller Universe.

At this writing, the core rulebook, GURPS Klingon and GURPS Module Prime Alpha (a generic supplement) have been released for this new system. Supplements for the Federation and Romulans are in the writing stages.

Prime Teams

Prime Teams were a concept pioneered in the original Prime Directive game. The concept was a specialized 'Landing Party' that could do a wide variety of functions, including science, negotiations, and combat. The concept was developed by the designers who wished to avoid the television and movie cliché of having the Captain and primary bridge personnel always putting themselves in danger. Prime Teams were criticised by some as being essentially a Star Fleet version of the "adventuring party" found in numerous Dungeons & Dragons-style fantasy games.

While "Prime Teams" themselves are a Federation designation, nearly every race had their own equivalent.