Ring System

Debris inside a world's Roche limit, where tides tear a body apart faster than it can reassemble. A ring is a dense, thin sheet that damages vessels crossing it, and it is the standard place to lose a pursuer.

Extraplanetary

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.
Low Gravity

Gravity below about 0.4g, where a push-off sends a creature farther than expected and stopping takes planning.
- Movement
  
  Ground movement is normal, but any push-off sends the creature farther. A creature that Dashes continues an extra 10 feet in the same direction at the end of its turn unless it spends 5 feet stopping.
- Melee
  
  A melee attack made without an anchor point pushes the attacker 5 feet away from the target after the attack resolves.
- Jumps and falls
  
  Jump distances are tripled and falling damage is halved. A fall of under 40 feet does none.
- Carrying capacity
  
  Carrying capacity is tripled. Mass is unchanged, so anything being carried is as hard to start and stop as it is at normal gravity.
- 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

Debris

Inside the ring plane, a vessel takes 1d10 hull damage per round unless a DC 15 Piloting check is made. Crossing the plane perpendicularly takes one round.
Cover

The ring plane blocks sensors completely. A vessel inside it cannot be found and cannot see out.
Shepherds

Small moons hold the gaps open. The gaps are the only safe lanes, and they are charted.
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.