D&D: Spelljammer Differences Between Wildspace & The Astral Sea

D&D's Spelljammer campaign setting lets players travel Wildspace and the Astral Sea, but how do they differ from each other?

The Spelljammer campaign setting has been updated for the current edition of Dungeons & Dragons, with new rules for Wildspace and the introduction of the Astral Sea. Spelljammer debuted over thirty years ago as part of AD&D, where it was considered one of the D&D multiverse's oddest settings. The setting would be referred to in many references in brief cameos, but a full version of Spelljammer wouldn't return until 2022.

Spelljammer was always seen as the odd one out among the D&D settings, as it used magic and fantasy to introduce science fiction concepts into the game. The players are able to travel through space and explore planets, but they do so using a sailing ship that has been enchanted to function as a spaceship. There are aliens out there, but they're no stranger than the monsters that most parties face during a regular campaign. The idea of elves and dwarves piloting galleons through space might have been a hard sell back in the '80s, but fans asked for Spelljammer to return for decades, and it's finally back.

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The D&D spelljammer ships provide gravity and oxygen, allowing the crew to survive when they leave their planet. Spelljammer has two different environments that exist outside a planetary body: Wildspace and the Astral Sea. Once the players depart on their first Spelljammer adventure, they will have to survive in these new environments, as they are the ocean they will need to travel in order to explore the cosmos.

In AD&D, the version of the universe presented in Spelljamer was different than how it is now. The various D&D campaign settings existed within crystal spheres, which could contain an entire planetary system, complete with planets, suns and moons. The D&D campaign settings had specific crystals spheres, with the Forgotten Realms existing within Realmsapce, Dragonlance existing within Krynnspace, Greyhawk existing within Greyspace, and Dark Sun was part of the D&D multiverse within Athasspace. The crystal spheres were made of an impenetrable material, but some spells could allow characters to travel through them, while some openings already existed for ships to travel through. The Athasspace crystal sphere is interesting, as it was totally impassable, which meant that characters from other settings could not visit it. This was likely created to explain why all of Dark Sun's geographical problems haven't been solved by helpful parties of adventurers.

Within the crystal spheres, the space surrounding the worlds and other planetary bodies was called Wildspace. This acts in a similar manner to the vacuum of space in the real world, with the exception of characters receiving a brief air bubble when they travel through Wildspace on their own. The main goal of the spelljammer ships is to provide a breathable atmosphere and gravity field for the crew, as they're not going to get very far without this protection.

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In D&D's original Spelljammer campaign setting, the space between crystal spheres was called The Phlogiston. This was formed of a substance called phlogiston, which was described as a rainbow-colored ocean of ether, which the crystal spheres floated within. The players could "sail" across rivers of phlogiston in order to reach their destination. Phlogiston was similar to Wildspace in terms of breathable atmosphere and oxygen, but it was also unusually flammable, to the point where characters need to be extra careful about using fire when beyond a crystal sphere. The D&D campaign worlds had a rough equivalent to shipping channels, but The Phlogiston was never truly stable or reliable.

In D&D 5e's Spelljammer: Adventures in Space, the rules of the universe are now different. The crystal spheres and The Phlogiston are gone in D&D 5e. Instead, the D&D campaign worlds exist in bubbles of Wildspace that float in the Astral Plane. The names of the crystal sphere systems are still used in D&D 5e, such as Realmspace for the Forgotten Realms, so those should be familiar to longtime fans. The absence of the crystal spheres means that players can simply fly out of their Wildspace system without impediment, so long as they have the means to do so. Each world and planetory body has its own gravity and atmosphere, which is also true of the spelljammer ships, so having access to one is pretty much a necessity for exploring Wildspace.

The Phlogisten has been replaced with D&D's Astral Plane and the Astral Sea. The different Wildspace sectors exist within the Astral Sea, which has the properties of the Astral Plane, meaning that players don't need to breathe, and gravity is no longer a concern, as they can move using the power of their mind. A creature with an Intelligence score can float through the Astral Sea and they even have a general idea of the direction of locations, so someone who wishes to travel to Realmspace will eventually get there. The other notable aspect of the Astral Sea is that characters don't age there, allowing them to be immortal, though their aging will resume when they enter Wildspace. Characters in the Astral Sea also don't need to eat or breathe, so making a break for the barrier of Wildspace might be an option for players running out of supplies.

The D&D 5e Spelljammer campaign setting is more forgiving than it was in AD&D, especially when it comes to the Astral Sea. The fact that players have access to the new air bubble spell also makes Wildspace a lot less threatening, or at least it does when the party hits level three. If the players have access to a spelljammer ship, then they're able to travel anywhere in the D&D multiverse, and the biggest threat is the ship being totally destroyed.

This doesn't mean that spelljammer ships are the only way to travel, as magical spells are a much faster way to travel between worlds, but they mostly exist in the hands of high-level spellcasters. The last option is magical portals, but these can also be hard to find. The use of a spelljammer ship in a Dungeons & Dragons campaign is all about the journey, not the destination, and the current iteration of the Spelljammer campaign setting is easier to explore than ever before.

Scott has been writing for Screen Rant since 2016 and regularly contributes to The Gamer. He has previously written articles and video scripts for websites like Cracked, Dorkly, Topless Robot, and TopTenz. A graduate of Edge Hill University in the UK, Scott started out as a film student before moving into journalism. It turned out that wasting a childhood playing video games, reading comic books, and watching movies could be used for finding employment, regardless of what any career advisor might tell you. Scott specializes in gaming and has loved the medium since the early ‘90s when his first console was a ZX Spectrum that used to take 40 minutes to load a game from a tape cassette player to a black and white TV set. Scott now writes game reviews for Screen Rant and The Gamer, as well as news reports, opinion pieces, and game guides. He can be contacted on LinkedIn.