There are many special materials to be found in the vastness of space.
Aetherite is a supernatural mineral forged from the destruction of ancient ley lines. Naturally occurring or “raw,” aetherite appears as growths of brightly phosphorescent blue crystals that shed light as a torch. Aetherite in its natural form has the following qualities.
Morphic qualities: When exposed to at least 1 point of electricity damage or 30 points of fire damage from a single attack, aetherite sublimates into a cloud of highly-charged plasma. Each point of electricity damage (or every 30 points of fire damage) is enough to transform 1 cubic foot of aetherite into 5 cubic feet of aetheric plasma.
This plasma cloud sheds light like a torch and persists for 1 round per cubic foot of space. Any creature caught in the cloud or that enters the cloud must succeed at a DC 15 Reflex save or take 6d6 points of damage per round that is half fire and half electricity damage. Creatures adjacent to the plasma cloud are exposed to moderate aetherite radiation, while those inside the cloud are exposed to high aetherite radiation (see below). This cloud affects incorporeal creatures as if it were a force effect. At the end of the plasma cloud’s duration, it rains down into a cobalt-colored liquid slurry traced with veins of vibrant azure that fills a volume equal to half the total size of the solid aetherite that sublimated.
Liquid aetherite slurry sheds light like a candle and is no longer radioactive but is highly toxic.
After exposure to 1 point of cold damage (or 1 hour at normal temperature), the slurry hardens back into loose aetherite crystals that weigh half as much as they did before sublimation. These crystals are no longer radioactive and are worth twice the market value of raw aetherite. Aetherite slurry remains in liquid form if kept at a temperature of 70 degrees or higher.
Radioactive: Unrefined aetherite emits a dangerous form of radiation that can potentially strip the soul from a living creature. Small amounts of unrefined aetherite emit low radiation that only affects creatures holding or carrying it. However, in larger quantities aetherite radiation has a wider area. For every 5-foot space occupied by raw aetherite, there is a cumulative 10-foot radius of low radiation. Aetheric radiation is blocked by a thin sheet of lead, and raw aetherite is commonly transported in special sealed, lead-lined containers for safety purposes.
Like standard radiation, aetherite radiation is an emanation poison, affecting creatures exposed within its area, with the intensity of radiation increasing the closer a creature gets to its source. Aetherite radiation lists the maximum level in an area nearest the source, with its strength reduced by one level for each increment of distance away from the source. For example, a high-radiation source with a radius of 10 feet affects creatures as medium radiation from 10 to 20 feet away, and low radiation at 20 to 30 feet, and is not harmful beyond that radius.
Creatures killed by aetherite radiation or aetherite sickness have a 50% chance to rise as a corporeal undead with the aetherwarped template. Creatures that become dissociated or comatose from aetherite sickness cannot save against possession effects, such as a ghost’s malevolence ability.
Raw aetherite in its solid form has a hardness of 5 and 10 hp per inch of thickness, takes double damage from bludgeoning attacks, and takes no damage from force effects.
Aetherite, depleted: Depleted aetherite is specially refined aetherite that has been alchemically tailored to be as hard as steel, and lacks the ability to act as a capacitor for aetheric energy. Weapons forged from depleted aetherite count as magic weapons for the purpose of bypassing damage reduction. Also, adding any magical enhancements to a depleted aetherite weapon costs 10% less than normal. This decrease is applied the first time the item is enhanced, not once per ability added. Weapons, armor and tools forged from refined aetherite are considered masterwork and weapons count as magic for overcoming damage reduction.
Depleted aetherite has a hardness of 10 and 20 hp per inch of thickness.
Aetherite, refined: Refined aetherite comes from raw aetherite that has been exposed to aetherite’s morphic states thousands of times in an industrial aetherite refinery. The process requires the aetherite to be compressed and compounded with new aetheric crystals created from the same procedure and exposed to a continuous electrical current. Refined aetherite is of an extremely high quality and is used in all aethertech devices, including aetheric capacitors. Refined aetherite no longer sublimates and is locked in its crystalline state. Instead, when exposed to heat or electricity the crystal releases stored aetheric energy and can even be recharged to contain new energy when combined with the proper equipment. Refined aetherite is neither radioactive nor toxic and sheds light like a candle when charged with units of aetheric energy.
Refined aetherite has 30 hit points per inch of thickness and has hardness 10.
Vacuum Creatures exposed to a vacuum cannot breathe and immediately begin to suffocate. The Starfinder Roleplaying Game Core Rulebook contains basic rules for vacuum and decompression, but the rules below offer optional expansions to those rules, which might be especially useful if running a campaign in a lower technology area or involving creatures unused to navigating the vacuum of space or an airless planetoid.
Slow Suffocation: A Medium character can breathe easily for 6 hours in a sealed chamber measuring 10 feet on a side. After that time, the character takes 1d6 points of nonlethal damage every 15 minutes. Each additional Medium character or significant fire source (a torch, for example) proportionally reduces the time the air will last. Once rendered unconscious through the accumulation of nonlethal damage, the character begins to take lethal damage at the same rate.
Small characters consume half as much air as Medium characters. If the sealed chamber, such as a spacecraft or habitat module of a damaged moon base, you must determine the speed at which air is escaping, decreasing how long characters can survive by a proportional amount.
Spellcasting in a Vacuum: Vacuum presents particular difficulties to spellcasters that need to breathe, requiring a successful concentration check (DC 15 + spell level) to avoid losing the spell. In addition, a spellcaster using verbal components cannot hold their breath to avoid suffocation and must use the breath they were holding to cast the spell. Casting a spell as a standard action reduces the caster’s remaining breath to 0 rounds, while casting a spell as a swift action leaves her with 1d6 rounds of breath remaining. Spells with casting time of 1 round or longer cannot be cast in a vacuum by a caster that needs to breathe.
Creatures that do not need to breathe need not make this check and do not expend additional breath by casting spells, though taking any standard or full-round action consumes 1 additional round of breath as normal.
Fire Effects: Spells that create fire are especially difficult to use in a vacuum, requiring a separate concentration check (DC 20 + spell level) to successfully cast, creating a momentary surge of heat that lasts long enough to deal damage and otherwise create effects with an instantaneous duration but then dissipates. Even then, such effects are weakened and grant a +2 circumstance bonus on saving throws. Supernatural fire effects are ineffective in a vacuum unless the character creating them succeeds on a DC 20 level check.
Specific abilities may obviate this requirement, and creatures native to space (such as outer dragons) may use supernatural fire effects without difficulty at the GM’s discretion.
Gases: Gases, vapors, mist, and the like dissipate quickly in a vacuum, with their duration reduced by one step in the following order: 1 hour/level, 10 minutes/level, 1 minute/level, 1 round/level.
Effects that normally persist for only 1 round/level have their duration reduced by 50%.
Preparing Spells in Space: Lacking common reference points for timekeeping such as an ordinary passage of day and night, spellcasters in space (especially if not native to an extraterrestrial environment) may have trouble timing their preparation of spells. You may allow PCs to prepare spells without difficulty, but if you wish to enforce a period of learning how to study the rhythms of space you may require some form of magical or mechanical timekeeping device.
Sonic Effects: Sonic effects are equally as difficult to use in a vacuum as fire effects, as described above, creating at best an instantaneous burst of energy that deals damage and then dissipates.
In addition, because a vacuum does not conduct sound, any effect that must be heard is ineffective, such as a siren’s song or many bardic performances.
Effect At each state of impaired and beyond, the victim must succeed at a DC 18 Fortitude saving throw or contract the aetherite sickness disease (see below).
Type disease; Save Fortitude (same DC as the level of radiation that caused the radiation sickness); Track mental; Frequency 1/day
Effect Aetherite sickness isn’t contagious.
Cure 3 consecutive saves; Cure 2 saves.