USS Eclipse — Planetary Classification Guide

1. Major planetary classes

These are the primary classes used to describe a world's general environment and suitability for life.

Class	Classification	General description	Typical habitability
D	Planetoid / airless moon	Small, rocky body with little or no atmosphere; often an asteroid-sized world or moon.	Uninhabitable without life support
H	Desert / arid world	Hot, dry terrain with scarce surface water and potentially thin or hazardous air.	Usually hostile; limited settlement possible
J	Gas giant	Large planet dominated by thick hydrogen-rich atmospheres, powerful storms, and extreme pressure.	No conventional surface settlement
K	Adaptable world	Rocky, relatively barren planet with a thin or unsuitable atmosphere; may be habitable with pressure domes or environmental systems.	Habitable with support
L	Marginal world	A marginally habitable rocky planet, sometimes with vegetation but limited animal life and an atmosphere that may require assistance.	Potentially habitable
M	Terrestrial / Minshara-class	Temperate, Earth-like environment with a generally breathable atmosphere and abundant liquid water.	Habitable to many humanoid species
N	Reducing / greenhouse world	Extremely hot planet with a dense atmosphere, commonly rich in carbon dioxide and other hazardous gases.	Generally uninhabitable
O	Pelagic / ocean world	Planet whose surface is overwhelmingly covered by liquid water.	Potentially habitable; depends on atmosphere and aquatic conditions
P	Glaciated world	Planet dominated by ice sheets, frozen oceans, and extremely cold conditions.	Limited; specialized habitats may be needed
R	Rogue planet	A planet not orbiting a star; any warmth may come from internal geothermal activity.	Usually hostile; subsurface habitats are conceivable
T	Gas giant / ringed giant	A giant planet with a deep atmosphere; some expanded references distinguish it from Class J by size or ring systems.	No conventional surface settlement
Y	Demon world	Extremely hostile world with toxic or corrosive atmospheric conditions, dangerous heat, and potentially lethal radiation.	Extremely hazardous

2. Additional planetary types for Starfleet survey reports

Cryogenic / Ice World
A planet or moon covered in ice, with frozen oceans, glaciers, or subsurface liquid water. May conceal microbial life or ecosystems beneath the ice.

Oceanic World
A world dominated by open water, potentially supporting complex aquatic life, floating settlements, or underwater civilizations.

Volcanic World
Characterized by active volcanism, tectonic instability, lava fields, and significant geothermal energy. Atmospheres may contain toxic volcanic gases.

Desert World
Arid terrain, scarce liquid water, and extreme temperature variations. Some worlds may support specialized native organisms or established settlements.

Jungle / Tropical World
Extensive forests, high humidity, dense vegetation, and potentially complex ecosystems. Pathogens, toxins, and unfamiliar organisms may complicate away missions.

Crystalline / Mineral World
Unusual mineral formations or extensive crystalline structures dominate the surface. Useful for geology and materials research; exotic formations should not automatically be assumed to be artificial or alive.

Toxic / Corrosive World
An atmosphere or surface chemistry hazardous to humanoid life, potentially requiring environmental suits, atmospheric shielding, or remote probes.

Terrestrial World
A rocky planet with landmasses, oceans, and a solid surface. It may be habitable, marginal, barren, or hostile depending on its atmosphere and climate.

3. Special classifications

These categories describe a world's status or unusual properties, rather than its ordinary environmental class.

Classification	Description
Uninhabited	No known permanent population; native life may still exist.
Uninhabitable	Conditions prevent unprotected humanoid habitation.
Life-bearing	Evidence of native organisms, from microbial life to complex ecosystems.
Pre-warp civilization	A native society that has not developed faster-than-light travel. Relevant to Prime Directive considerations.
Warp-capable civilization	A native society with faster-than-light travel capability.
Federation member world	A planet formally represented within the United Federation of Planets.
Colony world	A planet settled by a recognized government or population group.
Formerly inhabited	Evidence of a previous civilization, abandoned settlement, or extinct population.
Classified / restricted world	A world subject to special access, research, quarantine, or security restrictions.
Anomalous world	A planet displaying unusual temporal, spatial, subspace, gravitational, or other phenomena.