Ad Astra Per Arcana
Air in Wildspace
In a number of cases the amount of time that the air envelope around a man-sized human-equivalent creature will last is given as 2d10 times ten minutes. For convenience this may be considered to be roughly equivalent to two man-hours of air.
A ship’s air is calculated in man-days. A ship has four months of air for its standard crew, which is one human-sized crew member per ton. Hence a ship has tonnage x 28 × 4 man-days of air at the start of its voyage, i.e. 112 man-days per ton. Note that a continually burning torch or equivalent (such as a cooking stove) will use as much air as a human-equivalent, but GMs may choose to ignore this for simplicity. Based on how many crew are on board, and if this changes, the number of man-days remaining can be easily calculated. When two bodies meet in space, and it is assumed their atmospheres have thoroughly mixed, add together the number of man-days each had remaining, then divide this between the two in proportion to their size.
- Fresh air is completely breathable. The air around an individual body remains fresh for 2d10 times ten minutes. Air around a larger body (one ton or more) remains fresh for four months if the vessel carries a normal crew.
- Fouled air is stale and partially depleted. It is humid and smells bad. Air becomes fouled after the first 2d10 times ten minutes around a single body and remains fouled until the 300th minute (end of the 5th hour). For example, if the air was fresh for 120 minutes, it would be fouled for 180 minutes, for a total of 300 minutes. …
- Deadly air … becomes deadly at the beginning of the 301st minute (6th hour) … Anyone trapped inside a deadly atmosphere is treated under the Suffocation rules as if they are undergoing Slow Suffocation.
Image by Syreene