Spelljammer-Adventures In Realm Space
Breathing and Air in Space
Breathing in Space
As a character ascends a mountain, the air becomes thinner and thinner, until finally it becomes the unbreathable vacuum of wildspace.
Fortunately, all bodies take an envelope of air with them, and this provides some breathable atmosphere. Unfortunately, this envelope is rarely large enough to support life for very long.
A single, human-sized body drags along with it enough air to last 2-20 rounds. If that human-sized body is standing on a rock 100 cubic yards in size (roughly 40 feet in diameter). It may have enough air to survive for several months.
Larger-than-man-sze creatures (ogres and giants, for example) drag along enough air to last twice as long, 4-40 rounds.
Larger objects, such as ships, are rated for their tonnage. Each ton represents 100 cubic yards of space, which brings along enough air to support one human-size crew member for four to eight months. A 30 ton frigate, therefore could support 30 crew members for four to eight months under normal circumstances, and double that under reduced circumstances. The minimum size for a usable ship in space is 1 ton (100 cubic yards). The limitations on moving a ship through space determines the upper limit of ship size.
The air envelope around a body or ship can be one of three classes or qualities-fresh, fouled, or deadly. Air can change from one quality to another over time.
Fresh Air is completely breathable. The air around an individual body remains fresh for 2-20 rounds. 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 2-20 rounds around a single body and remains fouled until the 30th turn. The air around a ship is fouled from the beginning of the fifth month until the end of the eighth month. All attack rolls and ability checks made by characters or creatures that must breathe air have a -2 penalty if the air is fouled.
Deadly Air is completely depleted and filled with carbon dioxide. It cannot support life. The air around an individual becomes deadly at the beginning of the 31rst turn, that around a ship becomes deadly at the beginning of the ninth month in space. Anyone trapped inside a deadly atmosphere must make a endurance check each round. Failure means the character passes out. A second failure brings death. Only fresh (or fouled) air can revive the character after he passes out.
Most trips aboard ship take less than four months to complete, or at least present the opportunity to replenish and refresh the air supply within four months. Air usually is not a problem except in extreme cases and emergencies.
Changes aboard ship can affect how long the remaining air will last, adding and losing people onto the ship will decrease the amount of time it takes to degrade or increase it, respectively.
When two bodies meet in space, their atmosphere is exchanged. The class of the air in the smaller body becomes that of the larger body. If the smaller body is at least two thirds the size of the larger, both get one half as much air as the larger had remaining. If the smaller is less than two thirds the size of the larger, both get the larger’s full supply of air, minus one week.
The same thing applies to two individuals exchanging atmosphere. An individual has no effect on a ship’s atmosphere, however, unless the individual is at least huge.
A number of creatures can survive in space without air (undead or magical creatures such as golems, for example). They are unaffected by the status of the air envelopes around them. Certain spells and magical items provide additional protection to the star traveler who may find himself in deep space without a ship.
Classes of atmosphere operate in the same manner in the phlogiston as they do in wildspace. However, when the atmosphere goes deadly, a special property to the phlogiston takes over. Instead of dying the individual lapses into suspended animation until the atmosphere around him is recharged. Living flesh turns gray and stonelike and remains that way until the individual is rescued. By following along the flow, a ship or individual will eventually drift near a sphere, where recovery is at least possible. Note that rescue is not necessarily by someone with good intentions.
Crystal shells usually have no atmosphere of their own, either inside or outside. There are many asteroids and planets that lack atmosphere as well, in contradiction of normal physical laws.