Different models for fantasy space travel

After some thought, I decided to put together some ideas for space fantasy campaigns. To that end, I would present several different models for space travel physics as distinct campaign setting cosmologies.

Aristotelia, the setting of celestial spheres

This setting is based on Blood & Treasure, Dark Dungeons, and Voidspanners.

In Aristotelia, the physics of space travel are very different from reality. The night sky is actually the surface of a massive "celestial sphere" that encompasses the solar system. Outside of the sphere is the "luminiferous aether" and access to other celestial spheres in the universe.

Celestial spheres are not all made the same, but may have different local physics. One sphere might be heliocentric while another is geocentric. One sphere might be filled with an airless "void" (astronauts carry their own air supply without needing suits), while another is full of a breathable "ether." One sphere might have its inner and outer planes as inner and outer planets inside the sphere, while another has its inner planes inside the sphere and its outer planes outside the sphere.

Propulsion systems include:

• Sails of Skysailing are a magical effect that allow ships to fly through the air, void, and luminiferous aether. These are made from the silk of phase spiders and may be attached to conventional sailing ships.
• Void engines are magical items that propel vessels through the void. These need to be activated by a power source, such as a wand, a wizard, or a sacrificial victim.
• Ether sails are magical sails that ride the ether winds. These do not need a power source, but they are only effective in ether currents.
• Tree ships are rare vessels created by elfin druids.

Alhazenia, the setting of outer space

This setting is based on all those settings in which astronomy and outer space operates as it does in real life.

In Alhazenia, star systems and outer space functions as it does in reality. This makes it easy for a player familiar with modern astronomy to enter the setting. There are multiple competing methods for space travel, not one universal method used across the universe. These include fantasy magic, science fiction technology, and more based on a variety of different power sources.

Power sources harnessed for applications as propulsion systems include:

• Magic. Wizards can cast spells or create magic items that allow space travel.
• FTL drive. Seen in Dragonstar, Starfinder, and many other settings. These are taken straight out of scifi, so read scifi for details. I dislike this approach as I find it lazy and bland.
• Flux culler. Seen in Aether & Flux: Sailing the Traverse. These non-magical devices generate the electrical force known as "flux," which provides propulsion by interacting repulsively with the "aether" suffusing the universe.
• Aetherdrive. Seen in Aethera Campaign Setting. These are "magic-technology hybrids" powered by "highly toxic crystals" with "naturally telekinetic properties."

Fitting the planes of existence into Alhazenia requires more work. I should save that for a future post.

Planes and planets

Although space travel seems fairly unpopular in OGL fantasy gaming, it has appeared in surprisingly diverse forms.

Portal travel only. By default, most fantasy campaign settings limit themselves to a single planet. If multiple planets are introduced, then they will generally be reachable only through portal or by traveling through one of the transitive planes. (WarCraft is a popular example.) Spacecraft either don't exist or are so rare that the PCs won't be expected to ride inside one. This model seems to be the most common for settings that involve multiple worlds, such as Golarion's Distant Worlds supplement, presumably because space travel occupies a lot more conceptual space.

Science fantasy. When space travel gets involved as a standard fixture of the setting, the most common manifestation is what some label the "science fantasy" subgenre. (Star Wars is a popular example.) What I don't like about this model is that tabletop settings, like Dragonstar, Starfinder, or Starjammer, typically sloppily throw scifi and fantasy conventions into a blender with only the clumsiest attempts to integrate them. Magic and technology exist side-by-side, operating on completely different rules.

Magitech space fantasy. However, some settings don't lazily throw scifi tech into a standard fantasy setting and pretend it works. Instead, they might devise magitech spacecraft to match the fantasy setting. Campaign settings like Shadow of the Spider Moon, Aether & Flux, Aethera, and Necropunk are examples. They rely on technology powered by magic or alternate physical laws, sometimes having multiple competing methods.

Retro space fantasy. The science fantasy and space fantasy subgenres still assume that space operates like it does in reality: explosive decompression, empty vacuum, etc. However, some settings go even further with the fantastical elements, jettisoning real physics entirely. Spelljammer introduces breathing in space, crystal spheres, phlogiston, geocentric systems, and so forth. This model is recycled by some OSR settings like Voidspanners and Dark Dungeons.

Planes as planets. The models I mentioned so far still assume that space travel is limited to the "material plane" (as D&D calls it) and that planar travel operates by an entirely separate subsystem. However, that doesn't have to be the case either. 3pp like Classic Play: The Book of the Planes and Blood & Treasure suggest that the planes could be arranged in the same way as planets and visited through fantastical means of space travel. At this point, there is no distinction between space travel and planar travel.


ADDENDUM 11/19/2019: Honorable mentions to Aetherial Adventures and Cabbages & Kings: The Steampunk Renaissance.

Revising the transitive planes

As the D&D rules and campaign settings have developed over their history, so too has the planar cosmology changed over time. This has left numerous irregularities, such the existence of several transitive planes with almost identical utility. More below the break...

Fantasy space travel primer

At I explained previously, one of the key changes in my cosmology is merging the Ethereal, Astral and Faerie planes. Furthermore, this plane serves a dual role as outer space: space travel may allow travelers to visit other planes as though they were planets or islands on the sea!