STAR CHART: PLANETS -
PLANETARY CLASSIFICATION - N, O, P

Class-N example mentioned in the above STSC illustration: Venus is the second planet in the Sol system. In 2371 several terraforming stations are in operation on Venus, [DS9: Past Tense]. During Chakotay's first year at Starfleet Academy, he trained as a pilot over Earth's North American continent and spent a couple of months on Venus to learn how to handle atmospheric storms. He later learned to "dodge asteroids" in that system's asteroid belt. [#50 and #51 Future's End]

Class-N example mentioned in the above STSC illustration: Argo is not specifically mentioned in Encyclopaedia. The Argos system is an uninhabited star system in Federation space in the Alpha Quadrant, near the flight path of the Crystalline Entity after it destroys the Melona IV colony in 2368, [TNG: Silicon Avatar]. Star charts of the Argosian Sector are stored in the navigational computer on Deep Space 9, [DS9: Babel]; the star charts seen on the computer monitor screen in that story are, however, not those of the Argosian Sector as incorrect ones are displayed by mistake. Many years ago, an Argosian threw a drink in Benjamin Sisko's face, [DS9: Dax].

Class-P example mentioned in the above STSC illustration: Exo III is a barely habitable planet whose sun had, by the mid-23rd century, been fading for half a million years. It was once the home of a technically advanced humanoid civilization, known later as "the Old Ones". Exo III's inhabitants moved underground as their sun dimmed. In doing so, they fostered a mechanistic, impersonal society. Eventually, they began to fear the sophisticated androids they had built, but by that time the androids had become advanced enough to develop the instinct for self-preservation and the androids eventually destroyed their makers. Noted archaeologist Roger Korby disappeared there, and two expeditions failed to find him prior to the Enterprise NCC-1701 rescue mission of 2266. [TOS: What Are Little Girls Made Of?] screenshot (left-hand picture only) of Nurse Chapel of the Enterprise NCC-1701 with Korby and, in the background, two androids