Grade One Planet

Grade One Planets, or Class One Planets, were developing planets under a protected status until they reached Grade Two status, at which point first contact teams could visit. Their societies were pre-industrial, nomadic, tribal, and feudal. One these worlds the most advanced machine was the wheel. While it was forbidden to interfere in the planet's development and let the inhabitants know of off-worlders, any visitors could not damage indigenous cultural artifacts.

Bellotron was a Grade One Planet with a matriarchal society. (AUDIO: The Bellotron Incident)

As Grade One and Grade Three Planets share similar descriptions, they are likely meant to be the same.