SDO habitability index

The SDO habitability index or HI score is a system for classifying planets based on their habitability, with an elmian bias. It was created by the SDO during their early ventures into the universe after the discovery of the Dess, and has been consistently expanded upon ever since.

Classes

HI0

HI0 planets are not only completely uninhabitable to elmians, they are also dangerous to colonise. These planets may present extreme temperatures, may be too close to their star and receive excessive UV radiation from it, experience frequent collisions, or any other factor that may render the planet deadly. A classic example of a HI0 planet is ShE022-I, which sits at an orbit so low it will end up tearing the planet apart within the next million years.

HI1

HI1 planets are uninhabitable, but colonisable. Colonies in HI1 planets may be domed or underground, made to be comfortable for life on the planet. An example of this is Torch, whose toxic atmosphere renders it unbearable to live on the surface, but has been inhabited by elmians and juleans in subterranean and domed colonies for hundreds of years.

HI2

HI2 planets are on their way to being inhabitable, but require terraforming for life on their surface to be survivable. This is most commonly due to their atmosphere, either being composed of toxic gases, not containing enough oxygen, and/or being low-pressure.

HI3

HI3 planets are fully inhabitable and require little to no terraforming. These planets are exceedingly rare, and may already present complete biospheres, at which point colonisation may be discouraged.