Near Space

Crossing it

Navigate

DC 12

Forage

Nothing to find

Notice

DC 8

Vacuum in every practical sense, with enough drag to end an orbit.

Exposure

• Vacuum

  No pressure and no air to breathe, with survival measured in rounds.

  • Countdown

    Without a seal, a creature holds out for a number of rounds equal to its Constitution modifier, minimum 1. At the end of that time its hit points drop to -1, unless they are already lower, and it is dying. It cannot be stabilized or regain hit points until it can breathe.

  • Decompressed

    Exposure inflicts the Decompressed condition, which a return to pressure does not by itself remove.

  • Holding your breath

    Holding a breath in vacuum ruptures the lungs. A creature that does so takes 2d6 damage on the first round and gains no benefit from the attempt.

  • Sound

    Sound does not travel. Verbal spell components, shouted orders and Perception by hearing all fail across open vacuum. Suit comms and touch are the only channels.

  • Unfiltered light

    Without air to filter it, the star's output arrives unreduced. An hour of unshielded exposure in direct sunlight counts as a failed Contaminated Atmosphere save against radiological dose.

• Zero Gravity

  Free fall, where there is no down, no moving body stops on its own, and a missed handhold leaves a creature adrift.

  • Movement

    Moving requires a surface to push from. A creature with nothing in reach continues in the direction it last moved until it reaches something.

  • Changing course

    Changing direction mid-drift requires a DC 12 Dexterity (Acrobatics) check. On a failure the creature continues as it was.

  • Melee

    An unanchored melee attack has disadvantage and pushes the attacker 10 feet away from the target after it resolves.

  • No falling

    There is no up, no down and no falling damage. A creature cannot be knocked Prone, and the Prone condition does not apply.

  • Mag boots

    Magnetic boots or a tether remove every entry above while a ferrous surface is underfoot, at the cost of half movement.

In play

• Vacuum

  Treat as vacuum for breathing, pressure and heat. The temperature figure for this layer describes individual molecules and has no effect on a suit.

• Decay

  An uncorrected orbit here loses altitude and re-enters in 1d6 months. Anything abandoned in this layer comes down.

• Ionized

  Radio through this layer is unreliable and worse in a solar storm. Treat comms as a Magnetic Disturbance during one.

• 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

• Thermosphere

  Where low orbit sits and where an aurora forms.

• Exosphere

  The outermost layer, where the last molecules leak away. It has no sharp boundary with space.

Worlds it occurs on

• City A planet whose surface is entirely built over, with no open ground and all air, water and food imported.
• Foundry World A world converted end to end into industrial plant, with an exhaust atmosphere and a day set by shifts.
• Ore A world made of one material throughout, with no biosphere and no weather, mined under contract.
• Rime A frozen world with a crystalline ice surface, cold enough that most of its atmosphere has condensed onto the ground.
• Ruin A destroyed planet, now a cracked body or a drifting field of fragments.
• 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.