Planetary Classification

Modifying Canon for the Modern World

Projects such as TRAPPIST and the Kepler Telescope have expanded our knowledge of the wide variety of potential planets. We have discovered worlds seldom considered by science before now: "Super-Earths," "Hot Jupiters," and Hycean "Ocean Worlds," we have come to understand are quite commonplace. We have also come to know that most stars likely have some planets, and that Type M and Type K stars are the most logical candidates for "Super-Habitability"- long periods of life-friendly conditions that will stretch into tens, even hundreds of billions of years. Reality has trumped some science theory as well- we are finding planets with orbits in binary star systems for example. Where science and science fiction seem farther apart (at least for now) is finding habitable planets around hot stars: A, B and O type stars. Here, Sim central continues to take some creative license in the vein of Star Trek's model.

To try to keep up with this, the mods of the Ulysses sim decided to revamp Star Trek's traditional planetary classification system and try to expand it. There have been a few changes, and a little shuffling around. But we hope you will recognize the bones and features set forth by the franchise.

Planetary Classifications

Sim Central has sought to expand upon the definitions of planets using the traditional classification system but also includes optional sub-type descriptors and size variants.

Habitable Planets

Habitable Classes of Planetary Bodies

Habitable Planetary Classes

Science has discovered that life is the norm in the universe, not the exception. However, humanoid life, based on DNA-like analogs similar to Humans, is somewhat rare. The Habitable classes of planets are those which are friendly (or at least survivable long-term) to oxygen-breathing, carbon-based life forms. These planets have, in some form, all elements necessary for survival: sunlight, water, nutrition, and a fairly temperate, reliable climate.

Class H (Harsh)

Class H worlds are generally habitable, at least in part, but have reduced resources or favorable elements compared to a Class M world. Harsh planets often lack water, have thin but breathable atmospheres, extremely turbulent and destructive weather, or else have wild temperature swings. Life can and does spring from such worlds, but tends to be hardy, homogeneous (alike) and located in the most habitable pockets of the planet. Because so many Class H worlds possess life forms and ecosystems already, they are seldom considered for terraformation. Class L and Class H worlds have some similarities, the criteria being that Class H worlds have pockets or zones of habitability whereas most Class L worlds are universally less conducive to humanoid life.

Class M (Minshara/Habitable)

Class M worlds, or Minshara in the Vulcan planetary classification system, are near-Earth like and generally habitable. However, they come in a wide variety of subtypes and compositions. The criteria for a Minshara class is that it must have a breathable atmosphere for baseline humanoid life, must have tolerable temperate zones conducive to plant and animal life, and must have liquid water to sustain biological life forms. Most Minshara class worlds exist in the "Goldilocks Zone" of a parent star, a swath of potential orbits that allow for liquid water.

Class O (Oceanic)

Class O planets have all the elements conducive to life as most humanoids understand it. The main criteria for Class O status is that 85% or more of the planet is covered in water. Such worlds vary widely but otherwise meet Minshara requirements. Such worlds are different than Class W worlds- they are terrestrial worlds with rocky-metallic cores whereas Class W worlds are large bodies of differentiated liquids.

Borderline Planets

Borderline Planetary Classes

The Borderline classes of planets are survivable with technological gear or for short-term durations. Federation science recognizes some of these worlds as potentially habitable with technology or with planet-scale geo-engineering and atmospheric changes. But as they are now, they are too hostile for a typical humanoid to survive on for very long.

Uninhabitable Planets

Uninhabitable Planetary Classes

Uninhabitable planets are those that have very little to offer a typical oxygen-breathing, carbon-based life form. They lack almost all the ingredients necessary for such life to survive. The Federation does occasionally colonize such worlds, but these are enclosed facilities with biospheres sealed and independent of the surrounding planet.

Class C (Carbonaceous)

The versatile qualities of carbon make carbon-dominated planets unlike those found with silica, iron-silicate, or water in their composition. Carbon is present in most worlds but when it dominates due to a lack of iron or silicate building materials, the result is uninhabitable- and extremely alien.

Carbon sublimates- it moves from solid straight to a gas- therefore only under extreme pressure and temperature would carbon gas behave like a liquid. Tectonic activity cannot happen within a carbon-based world- carbon does not form its own version of magma. Carbon is an active element that bonds with many other elements with ease, quickly fixing to the building block materials we recognize as necessary for life. At this level of atomic dominance, carbon forms compounds completely alien or inconducive to Human life. An irony, as most lifeforms in the known galaxy are carbon-based.

Carbon-dominated worlds almost never have expansive oceans or polar caps. Free carbon will bond with oxygen and hydrogen long before the latter can form water. By the same token, very few carbon worlds have any appreciable level of free oxygen.

Class D (Dead, Dormant)

A Class D world is a "dead" or "dormant" planet that has never had all of the necessary ingredients to support life as Humanoid beings know it. They may possess some of the necessary elements- water ice, traces of oxygen, organic compounds- but not in abundance enough to support life in the long term. However, life may have existed or exists in transience as space-borne life that inhabits these bodies as a habitat. A "classic" Class D world is an asteroid, dead moon, or a "round rock in space."

Hostile Planets

Hostile Planetary Classes

Hostile worlds are not merely uninhabitable- they are a challenge (or even impossible) for advanced technology to keep a humanoid alive and safe. Such worlds are so alien to the humanoid condition that their environments may not be accessible with current technology. However, a number of Hostile planet types are known to exhibit life- but not life with any relation or similarity to most humanoids.

Class E (Elastic/Exothermic)

Class E worlds can theoretically be found throughout a solar system, though the vast majority will be located in the terrestrial, rocky zones of the inner system. A broad category, Class E covers very young worlds which will reclassify into any number of planetary types, but Class E also includes some perpetually resurfacing, heavily bombarded worlds- and worlds simply so close to their stars that their surfaces remain partially or completely molten. Some Class E worlds are beginning differentiation through pressure, while others may have active, roiling molten cores that have not yet calmed enough to allow a continuous rocky surface. The defining characteristic of Class E planet is persistent, widespread lava and magma activity on the surface.

Class T (Toxic)

Toxic worlds are rocky, terrestrial bodies which are not conducive to life as Humans and most humanoids understand it. They have geological or atmospheric chemistries that are damaging, harmful, or lethal to most known life forms and their technology. Life has been found on such worlds (such as atmospheric archaeobacteria on Venus) but it is seldom recognized as compatible with a life matrix Humans are a part of. Toxic worlds vary widely, classified by their compositional elements more than the features of their terrain. Class T worlds can be found in every orbital zone around a star, but begin life as terrestrial (rocky) bodies. They may have thick or thin atmospheres and may or may not have metallic cores enough to generate a magnetic field.