Gas giant orbit

Gas giant orbit
Jupiter and its Great Red Spot, by the Hubble telescope · NASA, ESA, and A. Simon (Goddard Space Flight Center), Public domain, Wikimedia Commons

A banded world of storms as wide as continents fills half the sky. Skimmers dive into its upper air for fuel, its moons hide stations and secrets, and its radiation belts cook the careless.

Light
Lit
Going
Slow

Hear it

Hazards

  • Vacuum. No air at all: an unprotected person stays conscious for about ten to fifteen seconds, the moisture on the tongue boils, and death follows within minutes. A suit, a helmet that seals and an air supply are the price of every step. D&D 5e: With no breath to hold, a creature without air gains 1 Exhaustion level at the end of each of its turns until it can breathe; it then loses all the Exhaustion it gained this way. Starfinder 2e: Vacuum (GM Core): no breathable air, so the creature suffocates, and it takes minor bludgeoning damage (1d6 to 2d6) every minute; with no propulsion it is untethered. Armour environmental protections cover vacuum for a number of days equal to the armour's item level (minimum 1). Archives of Nethys
  • Radiation belt. Close to a giant planet, its magnetic field traps particles in belts fierce enough to kill an unshielded person in days and fry electronics. Every hour outside counts, and shielding is measured in metres of ice or rock. D&D 5e (House rule): House rule: a creature outside without shielding makes a DC 12 Constitution saving throw at the end of each hour, the DC rising by 1 each hour; on a failure it takes 2d10 Necrotic damage and gains 1 Exhaustion level. This Exhaustion goes only with a Long Rest under shielding. Starfinder 2e: Radiation sickness, extreme (GM Core): disease 10, Fortitude DC 27, onset 2 hours; 3d8, then 4d8, then 5d8 poison damage with sickened 1 to 3, each stage an hour, and death at stage 4. Strong radiation also leaves electronics glitching or dead. Archives of Nethys
  • Weightlessness. Nothing falls. A person drifts in the direction they last pushed, tools float away if not tied down, and a fight is a matter of handholds. D&D 5e (House rule): House rule: a creature without a Fly Speed moves only by pushing off a surface, at its Speed in a straight line, until it meets another. Each attack it makes without a handhold has Disadvantage unless it has trained for weightlessness. Starfinder 2e: Zero gravity (GM Core): creatures are clumsy 1, off-guard and untethered; they move by Push Off from something their size or larger, or with propulsion. They lift and carry ten times as much, and thrown ranges are multiplied by 10. Archives of Nethys

What may happen

  1. A storm older than any human nation turns slowly on the giant's face.
  2. A fuel skimmer climbs back out of the cloud tops, trailing glowing gas.
  3. One of the giant's moons rises over its rim, and with it a station's lights.
  4. Auroras ring the giant's pole, larger than a whole planet.
  5. The radio fills with the giant's own roar, bursts and whistles from its magnetic field.
  6. The rings cast a thin dark band across the giant’s clouds, sharp as a ruled line.
  7. The ship’s course brushes a radiation belt, and the alarms send everyone into the shielded core for an hour.
  8. A small base on an inner moon blinks its landing lights. Its crew has not had visitors in four months.
  9. On the giant’s night side, lightning flashes across cloud tops wider than continents, silent through the viewport.
  10. The cloud bands have shifted since the last pass. The meteorologist redraws her charts with a sigh.
  11. A fuel tanker docks with the refinery station, swollen with gas skimmed from the giant’s upper air.
  12. The ship dips into the giant’s upper air to slow down. The hull glows, and everyone holds on.
  13. Up close the rings are ice, chunks from pebbles to boulders, sparkling in the sun.
  14. Two refineries are cutting fuel prices against each other. Their agents race to meet every ship that docks.
  15. A comet falls toward the giant, its tail stretched behind it. The astronomers on the station stop work to watch.
  16. A moon crosses the face of the giant, its shadow a black dot crawling over the clouds.
  17. A skimmer pilot named Joss, still shaking from a hard dive, tells the party the clouds tried to keep him this time.
  18. The station crew bet on whose dosimeter reads highest by the end of the month. The winner buys the drinks.
  19. A yellow moon glows faintly at its edges, where volcanoes throw sulphur into space.
  20. A white storm has broken out in the giant’s southern clouds, growing visibly from one orbit to the next.
  21. The ship passes into the giant’s shadow. The sun vanishes, the cabin cools, and the rings light up from behind.
  22. The moon colony’s customs officer, a stern young man, insists on scanning every crate for radiation before it lands.
  23. An old atmospheric probe drifts in a decaying orbit, its parachute canister unopened.
  24. The station’s habitat sits behind thick water tanks. The crew swims in the shield on rest days.
  25. The giant rises over the moon’s horizon, filling a third of the sky, and no one on the dock says a word.

Adventure hooks

  1. A fuel skimmer went too deep and its crew is calling from below the cloud tops, out of fuel.
  2. Something huge rises from the storms each time the moon passes overhead.
  3. Two moons' stations are on the edge of war over skimming rights.
  4. The giant's radio roar carries a pattern, and the pattern answers when you reply.

Who and what is met

Each is an SRD stat block under another name, as game masters reskin them.

Other places among the stars

Orbital station, Derelict ship, Colony outpost, Precursor ruin, Asteroid field, Deep space relay, Terraforming works, Prison hulk, Research lab, Crashed freighter, Nebula, Neon city, Junktown, Spaceport, War front, Alien hive, Living ship, Undersea base, Lava foundry

This work includes material from the System Reference Document 5.2.1 ("SRD 5.2.1") by Wizards of the Coast LLC, available at https://www.dndbeyond.com/srd. The SRD 5.2.1 is licensed under the Creative Commons Attribution 4.0 International License, available at https://creativecommons.org/licenses/by/4.0/legalcode.

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