Upper Atmosphere
The stratosphere and the mesosphere: air thin enough that a wing gets no useful lift from it and thick enough to burn up a body entering at speed. It is stable, dry and stratified, so it is the best place on a world to hold a platform in position, and the ozone layer or its equivalent sits in it and absorbs radiation that would otherwise reach the ground.
Crossing it
- Navigate
- DC 10
- Forage
- Nothing to find
- Notice
- DC 8
A pressure suit is required, and lift must come from buoyancy, thrust or a Rift effect.
Exposure
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Temperatures below about zero degrees Fahrenheit, or any water near freezing, made worse by wind.
CON save, DC 10, rising by 1 for each hour after the first. End of each hour. One level of exhaustion.
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Cold-weather gear
Proper layers, a sealed suit or a heated shelter removes the save. Wet layers give disadvantage on it instead.
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Immersion
A creature in near-freezing water makes the save each minute instead of each hour, and is Incapacitated at three levels of exhaustion.
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Gear
Unheated power cells lose half their charge, and any check made with bare hands after an hour of exposure has disadvantage.
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Adapted
A creature native to a cold world, or with resistance to cold damage, ignores the save.
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In play
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No lift
A wing produces no useful lift above the tropopause. Flight here is buoyancy, thrust or a Rift effect.
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No air
Unprotected breathing is impossible. Treat an exposed creature as Suffocating. A pressure suit or a sealed hull is required throughout.
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Stable
No weather and almost no turbulence. A platform left here holds position for months.
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Entry heating
Anything entering from above at orbital speed takes 8d10 fire damage per round until it slows, unless it is shielded.
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Ionizing dose
Unshielded, a creature gains a level of exhaustion each hour. A long rest does not clear it. A Medicine check at DC 12, a restorative spell or antiradiation drugs remove it. Rated shielding removes the effect, and most powered plate raises the interval to four hours.
Variations
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Stratosphere
Warming with height, dry and layered. The shielding layer sits in it.
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Mesosphere
The coldest air on the world, where falling objects burn up.
Worlds it occurs on
- Ionic A rocky world inside a field strong enough to hold a permanent ion storm across its surface and atmosphere.
- Rime A frozen world with a crystalline ice surface, cold enough that most of its atmosphere has condensed onto the ground.
- Terran (Arctic) A rocky world covered in ice for most of the year but habitable, with open water at the margin in summer.
- Terran (Arid) A hot, dry rocky world habitable at its edges, with dune seas across the interior.
- Terran (Barren) Rock and wasteland with a thin atmosphere or none, habitable but sparsely settled.
- Terran (Oceanic) A world of ocean from pole to pole, with land only where a volcano has kept up.
- Terran (Verdant) A rocky world with liquid water, breathable air and a magnetic field to protect them, rare and the cause of most wars.
- Zephyr A gas world with no surface, crossed by fast bands of wind that run at different speeds.
