General Order One

General Order One, also known as the Prime Directive, was a regulation employed by the United Federation of Planets and its main exploratory agency, Starfleet. The regulation dictated that Federation and Starfleet entities were forbidden from interfering in the natural development of cultures that had not reached a certain level of advancement on their own. This was most often interpreted as refraining from making contact with an alien species before it had developed warp drive or subspace technology on its own, though there were a number of ways in which this basic framework might be complicated by varying circumstances.

The Prime Directive was considered Starfleet's most important ethical directive, superseding even other generally accepted ethical guidelines such as preserving life and preventing death.

Thelon III and the Nevis Stone
Several years prior to 2339, Andorian archeologist Silla Sh'thaasreth inadvertently violated the Prime Directive while studying the pre-warp culture on Thelon III while working as part of the Vulcan Science Academy. After discovering the Nevis Stone, she removed it for further study, at the time believing the artifact was no longer an important element of Thelonian culture.

Subsequently, it was discovered that the artifact had extreme ongoing significance to the Thelonians and that its removal had caused equally extreme disruption to the planet's culture. By the time this significance had been realized by Sh'thaasreth and her colleagues, Thelonian society had already regressed by approximately a thousand years. Sh'thaasreth subsequently argued in favor of returning the Nevis Stone, despite the fact that doing so would most likely not undo the damage already done and its mysterious return could be considered a further violation of the Prime Directive. Ultimately, she was overruled and Vulcan Science Academy decided to keep the Nevis Stone in its position for further study. Thelonian civilization has yet to recover from the disruption caused by the stone's disappearance.

Ivexian Life Forms
In 2339, the starship USS Tempest (NCC-10535) encountered a non-humanoid life form on Ivex II, at the time also being mined for dilithium by a Klingon mining operation. The lifeforms and the Klingons had already come into conflict with each other, as the Klingons' mining operations destroyed the lifeforms' habitat. The Tempest crew first learned about the lifeforms from the Klingons, who spent little consideration on the ethical ramifications of destroying another creature's habitat. With little information, the Tempest crew were at first unsure whether the Prime Directive would apply to the situation, though shortly thereafter they were able to make first contact with the lifeforms in a way that allowed the lifeforms to explicitly ask for help. With first contact made and help explicitly requested, Prime Directive considerations no longer applied and the Tempest crew were able to intervene without its restrictions.

Zandaran Ark Ship
In 2339, the starship Tempest investigated a multi-kilometer long spacecraft that contained an alien society inhabiting its main volume. The craft was evidently a generational ark ship whose inhabitants had forgotten the nature of their home and believed the ship to be the extent of the known universe. While the society that had constructed the ark ship clearly had an understanding of the broader universe, the inhabitants at the time of the Tempest 's investigation had forgotten that knowledge. Ultimately, Captain Rye-jae Maddox determined that the Prime Directive did apply in this case and chose not to reveal the nature of their existence to the ships' inhabitants. Subsequent to the Tempest 's initial investigation, Starfleet dispatched a science vessel to continue observation without further contact.