Planets are classified by generic properties which help quickly identify and understand the potential risks and opportunities present when one is discovered. Following are the various classifications, starting with the most popular and then in alphabetical order after. Identifying parameter ranges for gravity, atmospheric pressure, and temperature are given, though care must be taken to understand these are generic identifiers and it’s possible to have a class of planet where one parameter may fall outside this range.
Gravity is given in G which is multiples of Earth’s gravity, which is equivalent to 9.81 m/s2, Atmosphere is given in units of atm, where 1 atm is equal to Earth’s average atmospheric pressure and equal to 1.01 x 105 N/m2, and finally temperature is given in Celsius, an Earth standard which is 273 degrees above absolute zero. Additional risks and rewards for each planetary classification are also suggested, though not limited to what is presented.
Class-D
Class-D planets are the first with any potential for activity or interesting features that may be of interest to a Starfleet crew. These are typically asteroids or moons and tend to be the most common in a star system due to the lack of atmosphere and their smaller, indiscriminate size. If only in orbit around a star (likely in a belt of like objects) it is considered an asteroid, and if it is in the gravitational field of a planet, it is considered a moon.
RELEVANT STATISTICS:
Gravity: 0.01 – 1 G
Atmosphere: < 0.001 atm
Temperature: -100 to -75⁰ C
RISKS: Space environmental suits must be worn on the surface at all times due to the low temperature and lack of atmosphere. The low gravity may also cause mechanical and physical difficulties.
REWARDS: The abundance of these types of planetoid results in a significant amount of resources such as water ice and metals.
Class-H
There are a handful of unique planets that fall under the Class-H category. Class-H planets are primarily desert-like and slightly smaller than most Class-M planets. They are hot and dry with very little surface water. They are only slightly habitable for the majority of humanoids, and some adjustments may need to be made to make it comfortable to live.
RELEVANT STATISTICS:
Gravity: 0.6-1.4 G
Atmosphere: 0.7 - 1.5 atm
Temperature: 0–50⁰ C
RISKS: The hazards of Class-H planets will likely be due to higher temperatures. Additionally, it is possible that some form of radiation is what initiated the desert-like conditions. This may result in residual radiation that over long periods of time may affect any humanoids. Atmospheric composition may be hazardous. There is likely little water to be found on these planets.
REWARDS: Under emergency situations, it is possible to survive on a Class-H planet for a short period of time. Studying the past conditions and planetary evolution of Class-H planets may also help understand different environmental conditions that could predict the future of Class-M planets.
Class-J
The most common gas giant planets fall under the Class-J category. These tend to be large planets and can orbit at any distance from the parent star. The atmospheres are dense and mostly hydrogen with no known surface to land on or inhabit. It is possible to set up orbital stations around the planet or within the outer atmosphere. This is particularly beneficial for mining hydrogen and other elements. With no discernible surface, the atmospheric pressure and temperature statistics are highly variable and irrelevant for visiting.
RELEVANT STATISTICS:
Gravity: 0.8–4 G (at the top of the atmosphere)
RISKS: The massive and dense atmospheres can be incredibly hazardous when entering. Additionally, there are high temperatures and radiation within the clouds.
REWARDS: Class-J planets frequently have Class-M worlds orbiting as moons.
Class-K
Unlike Class-J planets with no discernible surface, Class-K worlds have a solid surface but are nearly impossible to survive on without extensive terraforming. A key identifier of a Class-K world is its frigid temperatures. These temperatures may be due to an almost total lack of atmosphere such as Mars, or a significant distance from the home star which does not allow for heat absorption despite the potential presence of a dense atmosphere.
A further classifier if the atmosphere is present, is if it is breathable by the majority of Starfleet personnel, so planets high in methane or argon would be considered uninhabitable Class-K planets. Only in extreme emergencies should crew consider setting foot on a Class-K world, and only if there are enough supplies and facilities to isolate the shelter from the surrounding environment.
RELEVANT STATISTICS:
Gravity: 0.5-2.0 G
Atmosphere: 0.001 to 10 atm
Temperature: -100–0⁰ C
RISKS: Hazards on Class-K worlds are primarily due to the lack of or incompatible atmosphere. The temperature may be mitigated for short periods of time.
REWARDS: Atmospheres of Class-K worlds (if the atmosphere is present) could be a source of unique chemical structures such as methane or hydrocarbon chains.
Class-L
Planets which possess some life but are largely uninhabitable are considered Class-L planets. These have limited vegetation and hardly any animal creatures. The planets are likely early in their evolution and so larger creatures and a more diverse food chain have yet to develop. The atmospheres are likely high in oxygen and argon and have compositions unfriendly to most humanoid crew members.
RELEVANT STATISTICS:
Gravity: 0.6-1.4 G
Atmosphere: 0.7 - 2.5 atm
Temperature: -10–60⁰ C
RISKS: Class-L planets are sometimes confused as a Class-M planet, so care must be taken to carefully analyze the atmospheric composition as well as the biological life present to make a clear determination before landing on the surface. Without proper precautions, and especially in emergency situations, a crew could find themselves in a dire scenario if on the surface of a Class-L world.
REWARDS: These worlds offer an opportunity for exogeologists and exobiologists to examine planets early in their evolutionary processes. The majority of Class-L worlds have primitive atmospheres, life, and geological formations.
Class-M
Class-M is the most important and primary planet for the purposes of Starfleet tracking and databases. This is because these planets are considered habitable, and more specifically, Earth-like. While it is acknowledged there are many types of life-forms that could consider other classes liveable, Class-M planets are more likely to have advanced species that may be considered by the Federation, but, more importantly, can offer safe harbor to Starfleet personnel in a crisis. The “M” designation is short for “Minshara,” which is the Vulcan designation for a planet suitable for humanoid life.
The major geological characteristic which enables a Class-M planet is a molten rock mantle surrounding a metallic core. This creates a magnetic field which protects the atmosphere from erosion due to solar winds and subsequently retains liquid water on the surface due to atmospheric pressure.
RELEVANT STATISTICS:
Gravity: 0.6-1.4 G
Atmosphere: 0.8-1.2 atm
Temperature: -25–45⁰ C
RISKS: Dependent on the planet, there are no standard risks that are common across all Class-M planets.
REWARDS: There is a high likelihood of exobiological discoveries, and potential first contact with advanced civilizations if appropriate cautions are taken.
Class-T
Compared to the Class-J planets, Class-T are considered “ultra-giants” and are widely thought to be the largest objects that could even be classified as planets. If not orbiting in a star system, a Class-T planet would be considered a “brown dwarf” or a early star that never reached a high enough density to increase the temperature or begin fusion. Most Class-T planets are found in early star systems while the surrounding planetary system is still continuing to form.
If not flung from the star due to its high mass, the surrounding atmosphere will likely be sapped by other objects near its orbit and redistributed to the still-forming star system. Like Class-J planets, the atmospheric pressure and temperature statistics are widely variable throughout the planet and therefore are irrelevant.
RELEVANT STATISTICS:
Gravity: 2–15 G (at the surface of the atmosphere)
RISKS: As with any young star system, the material within is incredibly turbulent and has not settled into predictable orbits. Observations of a Class T planet run the risk of collisions with other objects and disrupted gravity fields.
REWARDS: Studying the early formation of star systems is of particular interest to astrophysicists and such data may help understand future evolution of nearby star-forming nebulae.
Class-Y
Also known as “Demon Planets” these worlds are noted for their incredibly dense and toxic atmosphere, high temperatures, and significant radiation fields. Any one of these parameters makes a planet difficult to study from the surface, but, combined, significantly increases the risk of unpredictable and catastrophic events. The atmospheric composition and radiation fields of these Class-Y worlds also makes sensor analysis from orbit nearly impossible. This class of planets is considered by Starfleet to be the least hospitable to humanoid life and are almost instantaneously fatal if special protections are not taken.
RELEVANT STATISTICS:
Gravity: 0.5–1.5 G
Atmosphere: 2–200 atm
Temperature: 40–800 ⁰ C
RISKS: Radiation, atmospheric pressure, and temperature are all deadly on the surface of a Class Y planet.
REWARDS: There is no advantage or possible reward worth the risks on a Class-Y planet.
PLANETARY ANOMALIES
While every attempt has been made to categorize potential planetary worlds, there will always be unique circumstances and anomalies. Any planet that does not fit the standard classification is requested by Starfleet to have further analysis performed and logged. Some examples of anomalous worlds deemed worthy of further evaluation include binary planet systems, planets with temperatures or atmospheres thought to be impossible based on the distance from the parent star, or apparently hostile environments which have an abundance of lifeforms present.
Another interest for Starfleet scientists and engineers is planets which exhibit indicators of past life and technology but for some reason are now abandoned. Studying these worlds helps understand the impact of advanced technology on a planet’s evolution as well as the possible future of Federation worlds.