Spelljammer 5e - Tumblr Posts
Okay well, since tumblr mangles image quality, here's the same stuff on DeviantArt.
Okay kids, strap in. Uncle Spy has some worldbuilding to lay on ya.
So the new Spelljammer 5e was announced a few months back, releasing in August (it's just turned June as I write this). Since then my friend and I have been gushing about it and planning some stuff around it, but one of the things that always struck me as disappointing about original Spelljammer was how... boring the Forgotten Realms solar system (Realmspace, where Abeir-Toril lies) was. It's much smaller than our solar system: eight planets, and only one of those is explicitly a giant planet (Coliar, said to be a "gas giant" but really more like a small ice giant). Two of them (Garden and H'Catha) aren't actually planets either, just constructs the size of dwarf planets. Two other planets are just ocean worlds, one with a sargasso sea around its equator and the other full of rocky atolls. Only two planets have any moons at all, to boot. Simply put: there's not a lot to look at, really. I'm hoping the new Spelljammer canon will retcon this and give Toril a larger, more varied solar system with more giant worlds and moon systems.
HOWEVER, there's another factor at play here. I made a character who's a space bard, directly inspired by all the filk I've been listening to lately. The problem is... a good chunk of that filk either A) uses names (planets, programs, people, etc) specific to real life space exploration and/or B) is rocketpunk instead of sailpunk like Spelljammer is intended to be. That got me thinking... I'd had a vague idea for a rocketpunk alt-Toril in the back of my mind for a while –a universe where the magical beings of the Forgotten Realms had reached the stars not through magicked-up sailing ships with atmosphere bubbles, but through magicked-up classic rockets– and this seemed like the perfect excuse to deploy that idea and start hammering it into a more coherent shape.

All of this added up to... well, something! Behold, my attempt to have my cake and eat it too: Terraspace.
This map was made using the template/assets developed by DeviantArt user slimysomething.
Terraspace is a fantasy version of our solar system within the wider Spelljammer setting where elves and dwarves and beastfolk all sing the rocketpunk blues. The Apollo Program exists as part of their history, but Apollo 13 was fine because of hasty Purify Air enchantments and some innovative abjuration. Dragons funded the Space Race. That sorta bullshit. Also, spiced up the solar system with a little idealism, as you can see; part of that was also me leaning into old Golden Age pulpy SF concepts like Jungle Venus and Pyramids of Mars. I don't thhhhhhink this counts as a new worldbuilding project,,, yet? Stay tuned I guess.
The Midnight Sea

Look, more Spelljammer stuff! SJ5E is only a few weeks away now, and the collaborative setting my friends and I have been building up in anticipation of it is really taking shape. So I'd like to share some things about the Midnight Sea!
The planar cosmography of the Midnight Sea universe is a little different than prior 5e canon. As stated in the previews for Spelljammer 5e, all wildspace systems are pockets of material plane which exist within the greater astral plane, though our homebrewing efforts have resolved to address the Feywild and Shadowfell as parallels to these material planes. The celestial and infernal planes, meanwhile, border the astral plane directly and mark the outer bounds of the known universe (the galaxy shown here), arranged in a loop to form the collective outer planes. The outer planes are represented by prominent constellations that form a sixteen-part zodiac used to navigate the astral sea. By contrast, the elemental planes exist at a lower energy state than the rest of the planar system, while the ethereal plane exists in a higher energy state than the rest of the planar system. Both function, therefore, as a sort of hyperspace and subspace pairing with normal space. Being the source of magic, the ethereal plane lends its energy to the lower planes via the Weave, which is then harnessed to fulfill the extreme energy cost of interstellar travel: the technomagical process of spelljamming.
The Midnight Sea is a galaxy, specifically our galaxy: what we would call the Milky Way. Indeed, the inhabitants of Terraspace (the fantastical version of our solar system) do call it the Milky Way! However, unlike our galaxy, it is the only galaxy in this universe, and its constituent star systems -as pockets of the material plane gestalt- possess mildly varying physical principles based on their location relative to the outer planes. At the center of this galaxy lies a supermassive black hole, the Cataract, about which swirls a vast region of distorted spacetime called the Maelstrom where the planar boundaries are weaker, strengthening the influence of interplanar magic on the local systems. Four major systems bear notable influence from one of the four primordial elements, while a fifth has a strong manifestation of the Weave and an unusual connection to the outer plane of Arvandor, and a sixth is so deep within the Maelstrom that the Material, Feywild, and Shadowfell planes blur together. The outer edge of the Maelstrom is a hub of interstellar civilization, but venturing deeper is quite dangerous.
The systems seen on the map here are all major systems; there are thousands more unseen in this representation. Many of these major systems are original creations (like Terraspace) or pulled in some way from the depths of the Spelljammer 3e fan website (like Banesun), but in the spirit of WotC's recent trend of linking their MtG settings to the DnD settings, we have included a few prominent MtG "planes" as part of bespoke systems: Theros lies in Nyxspace, Amonkhet lies in Godspace, Ravnica lies in Guildspace, and of course Dominaria lies in Gatespace. Though the map may look rather bare now, we expect to fill out the map more in time, as we sail the stars of the Midnight Sea.