Taking a guess at what the “air” inside most spaceports and starships must be like in the Traveller Universe.
HUMAN DEFAULT (EARTH STANDARD)
* Gravity: 1.0 G
* Air Composition: 78% nitrogen, 21% oxygen, 0.9% argon, 0.1% other (carbon dioxide, nitrous oxides, methane, ozone, water vapor).
* Air Humidity: 60% RH (relative humidity)
* Air Pressure: 1 bar / 101.3 kPa (14.7 psi)
* Air Temperature: Around 72 degrees F (22 degrees C)
The above standards are used on the International Space Station (ISS) circa 2020.
The major sophont “alien” species in Traveller closely share these environmental standards.
UNIVERSAL WORLD PROFILE (UWP)
Starport / Size / Atmosphere / Hydrographics / Population / Government / Law / Tech
* Guaran/Hive (Hivers): A565800-F (much lighter gravity, slightly drier; also note light levels will be much darker)
* Kilrai (Aslan): A876986-E (tainted by human standards)
* Kirur/Thirty (K’kree): B863A03-F (much drier; also note the simulated smell of the herd)
* Lair/Grnouf (Vargr): A8859B9-F (slightly drier)
* Terra (Solomani Humans): A867A69-F
* Zhdant/Gaval (Zhodani Humans): A6547C8-F (thin air, lighter gravity)
* Unknown (Droyne)
For comparison, “hostile” terrestrial worlds…
* Gravity: 0.9 G
* Air Composition: 96% carbon dioxide, 3.5% nitrogen, 0.5% other gases (carbon monoxide, argon, sulfur dioxide, water vapor)
* Air Humidity: 0.1% RH (relative humidity) (liquid water boiled away)
* Air Pressure: 95 bars
* Air Temperature: Around 820 degrees F (437 degrees C)
Note: 224 mph (360 kph) winds, sulfuric acid clouds, runaway greenhouse effect, air pressure similar to diving 3,000 feet beneath the ocean
* Gravity: 0.38 G
* Air Composition: 95% carbon dioxide, 2.6% nitrogen, 1.9% argon, 0.16% oxygen, 0.06% carbon monoxide
* Air Humidity: Varies by day (dry) to night (100%)
* Air Pressure: 6.518 millibars / 0.095 psi
* Air Temperature: Around -80 degrees F (-60 degrees C)
Note: Atmosphere over 100 times thinner than Earth, water exists but almost never in liquid state.