|DATABASE > DATABANKS > PLANETS > Class M - Terrestrial|
for a planet with a nitrogen-hydrogen atmosphere. Class-M planets provide
comfortable living conditions for a longer time, and the are suited for permanent
accomodation of humanoids.
A precise definition of planet classes can only be found in non-canon sources, e.g. in the UFP Info Terminal (external link). At least, K and L planet classes that also provide breathable air, but seem to designate desert planets, are mentioned in a couple of episodes. Star Trek inherently focuses on Earth-like planets for dramaturgical reasons, since no spacesuits are necessary and suitable sets are easy to find. Still, inhabitable planets seem to ubiquitous, and every time a shuttle is about to crash, there is "occasionally" a Class-M or at least Class-K or L planet in the vicinity. ENT: "Strange New World" establishes that the term "Class M" is obviously derived from Vulcan "Minshara-Class".