2

Cold worldsCold, dominated by glaciers and tundra

Some varieties of slime mold have managed to evolve forming a mucous-like outer shell against the atmosphere and then feeding and growing off the chemical byproducts of its erosion

Outpost

TL1, medieval technology

Inert gas, useless for respiration

3

Variable cold with temperate places

For one reason or another, life simply never evolved on these worlds, leaving them a blank slate for the agricultural

Fewer than a million inhabitants

TL4, modern postech

Airless or thin to the point of suffocation

4

Variable cold with temperate places

For one reason or another, life simply never evolved on these worlds, leaving them a blank slate for the agricultural

Fewer than a million inhabitants

TL2, early Industrial Age tech

Airless or thin to the point of suffocation

5

Temperate, Earthlike in its ranges

Substantial portion of the native life is biologically compatible with human nutritional needs.

Several million inhabitants

TL4+, postech with specialties

Breathable mix

6

Temperate, Earthlike in its ranges

Substantial portion of the native life is biologically compatible with human nutritional needs.

Several million inhabitants

TL4, modern postech

Breathable mix

7

Temperate, Earthlike in its ranges

Substantial portion of the native life is biologically compatible with human nutritional needs.

Several million inhabitants

TL4, modern postech

Breathable mix

8

Variable warm, with temperate places

Immiscible biospheres are not friendly to humans. None of the local plants or animals are edible

Hundreds of millions of inhabitants

TL4, modern postech

Thick, but breathable with a pressure mask

9

Variable warm, with temperate places

Immiscible biospheres are not friendly to humans. None of the local plants or animals are edible

Hundreds of millions of inhabitants

TL3, tech like that of present-day Earth

Thick, but breathable with a pressure mask

10

Warm, tropical and hotter in places

Substantial portion of the native life is biologically compatible with human nutritional needs.

Billions of inhabitants

TL3, tech like that of present-day Earth

Invasive, penetrating suit seals

11

Warm, tropical and hotter in places

Engineered biospheres

Alien inhabitants

TL4+, postech with specialties

Both corrosive and invasive in its effects

12

Burning, intolerably hot on its surface

Substantial portion of the native life is biologically compatible with human nutritional needs.

Outpost

TL5, pretech with surviving infrastructure

Thick, but breathable with a pressure mask