Worlds of Design: How Would You Design For Spelljammer?

I enjoyed playing Spelljammer in conjunction with the 1e D&D rules back in the day - I'm a naval guy at heart. For those who don't remember, it's FRPG in outer space, with different physics and magical spaceships that often resemble creatures such as sharks or wasps, for 7th-13th level. (There was a brief version in Dungeon Magazine for 3e as well.) I read that we may see a new version for 5e, so I dug out some old notes in order to discuss the design of the original game.

Picture courtesy of Pixabay.​

Spelljammer included core rules, supplements, adventures. The rules and published adventures are chaotic, inconsistent, as though there was no editorial oversight. Sometimes they don't even enforce the major rule that the helmsman has lost all his spells for the day, or the major rule that the strategic (not tactical) speed of all ships is the same.

The former highlights the biggest problem for an adventuring party that controls a 'jammer, one of the characters (two, if the ship is under power 24 hours) must give up his spells to helm the ship, which means either:

• the players with spell-casters should have an extra character because one will be mostly-useless when out in wildspace, or
• NPCs take care of the helming, often a lowish-level type since the low level doesn't affect strategic speed even though it affects tactical speed. But in battle either the players sacrifice one of their high level spell-casters, or they are at a disadvantage in maneuver (another reason to board, if you can get close enough).

The weapons are ridiculously accurate. This is not unusual for fantasy games: most people don't realize how hard it is during combat to hit a target with anything, even with a pistol at a range of less than 10 feet. (That's why automatic weapons are so popular.) Yet rarely, in a battle, was a ship destroyed (I remember my 40 ton galleon disintegrating!); instead, boarding action was the order of the day. So Spelljammer battles often become the equivalent of encounters in buildings (castle, cathedral, etc.), two or three ships locked together with otherwise-fairly-typical D&D combat going on (with 3D action). I have deck plans found online that can be printed out at a size for actual play (square grids). One of my player's made a physical Hammership (for combat, not for looks) that I still have, about four feet long.

The tonnage of ships (which is supposed to be gross tonnage, that is, volume) is sometimes way out of proportion with the deck plans. Somewhere I have a list of the squares of the deck plans compared with the tonnage, and it varies wildly. Once again, no effective editorial oversight.

The biggest flaw was one of behavior. If you had a substantial sized flying vessel would you go out into (wild)space looking for trouble, or would you stay on the planet and use your nigh-invulnerable super bomber as a means for terrestrial combat? Even if you have nothing that would explode and can only drop rocks, you've got a stupendous advantage; but gunpowder and bombards are available in this game. The assumption of the Spelljammer rules was that no one would ever do this! I can't recall rules for conducting a battle in this context.

The game included many new monsters. The spiderlike Neogi are built up as major bad guys, but aren't dangerous compared with (insane) beholder-filled ships - Just Say No! Ships full of Illithids and their slaves are scary enough, thank you.

I drafted a set of standalone rules to solve these problems, but never finished them. More recently, I tested a game of fleet battles using some of Spelljammer's ideas. Maybe someday I'll finish one or the other, but first we'll see what Wizards of the Coast are going to do.

 

[Tranquilis]

I was never a fan of the crystal spheres as such, I thought of them as simply how folks in the magic using part of the multiverse made sense of the existence of parallel universes.
On that basis, I can happily live with all sorts of crossovers or leakages of ideas between alternate universes, and given how often that has come up in fiction since SJ originally appeared, I can see lots of groups wanting to use a new SJ as an entry point for crossovers to the non-magic using part of the multiverse.

I agree. I never liked the idea that when an adventurer on Oerth looked up at the night sky, he was really seeing gems set into a crystal sphere instead of actual other stars - or whatever that particular crystal sphere had instead of stars (e.g. elementals, etc.).

The phlogiston could still exist, pushed away like the RL solar system termination shock or whatever.

I also had a problem rectifying Spelljamming denizens of any race - especially elves, humans, etc. - not totally going anti-Prime Directive and letting their unfortunate world-locked cousins know how superior they were. I always got the impression there is an almost “hush hush” atmosphere about SJ tech and the realities of other worlds for the vast majority of a world’s population, but I can’t see the same SJ brigands and vagabonds keeping it to themselves very well.

I own and have read the SJ comics, but they absolutely did not make any sense to me as a coherent story.

 

[David Howery]

heh. I remember running a brief sojourn from my FR campaign into Spelljammer... at the same time it came out, I happened to buy some Aliens gaming figures from some now-lost RPG and some of the first Aliens vs. Predators comics... so guess what was in my SJ campaign?

 

[Dungeonosophy]

If one take into consideration the worlds of D&D, each edition and game system is its own separate Reality Tangent. Check out Alternity's Tangent book discussing this.

Thanks for your comments conclave.

Yeah, the "Up, Away, and Beyond" DRAGON mag article by then-D&D brand manager Bruce Heard is the most explicit explanation in regard to the actual "game systems" being different in-story Realities. Cool to draw the Alternity "Tangent" concept in too. Yes.

In regard to Realities (i.e. "game system-based Tangents", as opposed to alternate storyline-based Tangents), there are nine main Tangents:

* Original Reality (OD&D)
* Classic Reality (CD&D / B/X D&D / BECMI D&D)
* First Reality (AD&D 1E)
* Second Reality (AD&D 2E)
* Saga Reality (Saga system, as seen in Krynn, and also a DRAGON mag article about using Saga cards for other worlds)
* Third Reality (3E/3.5E/d20 Modern)
* Fourth Reality (4E)
* Fifth Reality (5E)

Presumably all of the D&D Worlds exist in all nine Realities. For example, in the DRAGON mag article, Bruce Heard mentions the possibility that Oerth also exists in the Classic (BECMI) Reality. And all nine Realities have always existed in the past, present, future.

As for where "Earth" is it is not in the same reality as the D&D Worlds. As stated many, many times with Greyhawk.... Earth is one of the many alternate Oerth(s). The includes Aerth from "Dangerous Journey's", Nerath from 4th Edition, and a few others.
The world of Mystara has never really been...well settled upon... as some say that "it" is an alternate Earth and others saying "no". Plus people forget there are many multiple "Earth" tangents, thanks to the D20 system and previous TSR games including Marvel/Conan Earth, Gamma World Earth, Top Secret Earth, Adventures of Indian Jones Earth, Starcraft Earth, Buck Rogers 25 Century Earth, and many others.

To say that Earth is not in the same reality as the D&D Worlds requires more explanations and definitions. And there are various "canonical" "placements" of Earth, most of which are contradictory. So these different Earths must be different Tangents. For example:

* 1) The Oerth-Yarth-Aerth-Earth continuum of Gary Gygax which you mention. Murlynd visited Earth and got his six-shooters. Since these adventures occurred in Gary's home campaign, they might be dated to the OD&D era. Though later touched on in AD&D1e (and Mythus system!).

* 2) In the BECMI boxed sets, the Known World (then known as "Urt", not "Mystara"), was said to be our Earth! But in a fantastic Jurassic past. And the Immortals were later perceived in Earth history as the "gods". Yet there were cross-overs with the Earth-based "Boot Hill", "Dawn Patrol", and "Gangbusters" via the Alternate World Gates in the Book of Marvelous Magic. An AD&D bard crosses over through one of the gates too. And there's an Immortal-level module where the PCs visit Chicago! Presumably this is time-travel, since Urt is the same planet as Earth. And the Averoignians come to Urt from France.

* 3) But in the Rules Cyclopedia/Wrath of the Immortals-reboot of Mystara, Earth (called there "Laterre") was said to be in a different Dimension, known as the Dimension of Myth.

* 4) IIRC, the AD&D 1E Manual of the Planes implied that each D&D World (Krynn, Oerth, Abeir-Toril), and also Earth, is an Alternate Prime Material Plane, each with their own "outer space". They couldn't reach each other by starcraft, because they are entirely different Material Planes. The Babylonian and Egyptian cultures come to Forgotten Realms from Earth.

* 5) IIRC, in AD&D 2E, there were two main Earth settings: the "magic Earth" of the Historical Reference series and the "Gothic Earth" of Masque of the Red Death. (Discounting licensed settings such as Buck Rodgers and Indiana Jones.) In Roger Moore's chronomancy article, Historical Reference Earth is called "magic Earth". The Wizards Three visited Earth. In contrast to 1E, all D&D Worlds were moved into a single Material Plane, the Spelljammer cosmology within the Great Wheel. I don't remember if or how 2E located "magic Earth" and "Gothic Earth" vis-a-vis the Spelljammer/Great Wheel.

* 6) In 3E, Earth was reachable via the Plane of Shadow. It would have its own Cosmology/Planar framework, since each world had its own Cosmology in 3E, which were only linked via a shared Plane of Shadow. Like you say, the various d20 Modern/Future/Past campaign models must be different Tangents of Earth within the 3E/d20 Modern Reality. There was at least one 3e-era Ravenloft novel set on Earth.

* 7) I don't know if or how 4E addressed Earth as a D&D setting. Except that Gamma World was explicitly branded as a 4E D&D setting.

* 8) I don't know how/where Earth will be located in the 5E cosmology. That's what this thread is about!

I would consider all of these to be Tangents of "D&D Earth", each which could theoretically be depicted through any of the "game system" Realities.

 

[Staffan]

Some issues with old-style Spelljammer:

* Helms were really expensive (compared to ships - a helm cost 100,000 gp or 250,000 gp, and a small ship could be something like 10,000), and nigh-indestructible. That meant that a valid method of piracy would be to destroy the opposing ship and just take their helm. That's silly, so it needs to be rebalanced.

* Spelljammer should be its own setting first and foremost, with travel between other settings de-emphasized. Something like the Astromundi Cluster should be the default Spelljammer setting. Astromundi also had the advantage of not having many planet-sized things around, thus answering the question: "Why don't the Shou use their spelljammers to trade with Zakhara, Maztica, and Faerûn at an enormous advantage over nautical ships, instead of sending them into space?" Best of both worlds would be an approach similar to the one Paizo takes with Starfinder: focus on a particular solar system, but specify that there are lots beyond it that can be covered as needed. And add to that a little about how to integrate it with existing settings for those who wish to do so.

* Turn down the silliness a bit. I mean, Spelljammer without Giant Space Hamsters wouldn't be the same, but maybe they don't have to be front-and-center?

 

[Ath-kethin]

* Turn down the silliness a bit. I mean, Spelljammer without Giant Space Hamsters wouldn't be the same, but maybe they don't have to be front-and-center?

You have to love the sliding scale for "silliness" in a game that includes flumphs, sentient trees, and 60,000 slight variations on the concept of "elf."

 

[Jay Verkuilen]

I'm running a not-Spelljammer/not-Planescape/Rod of Seven Parts game using a heavily hacked 2E rules. It's set in the Astral Sea and has a decidedly post-apocalyptic feel.

I'm not really using any of this content per se, but there has been a lot of sailing around in the Astral Sea, fighting with gith pirates, and various other things, including a lot of Law vs Chaos and clockwork madness, literally and figuratively. Recently there's been a lot of planar travel.

One of my "rules" was that I would be sure to use monsters that I hadn't before, so there have been some really crazy stuff. The Astral environment has been pretty cool to explore, too. The PCs have learned to exploit it in various ways, although it's very dangerous, as it turns out one of the deep hazards of the Astral Sea is that too much exposure leads to madness and, eventually, undeath.

 

[barasawa]

We had a lot of fun in Spelljammer, but never saw many of those issues you were talking about.

As to ship destruction, it did sometimes occur, but was more often a boarding action once somebody realized they weren't going to win by ship abilities alone. Nobody wants to die with their ship disintegrating under them after all.

The neogi weren't encountered often, they were more of the boogieman of the fringes and dark areas type. It's not that they were super powerful individually, it's that they could field a lot of ships and overwhelm an invasion target when they wanted to.

Illithid and Beholder ships. If it wasn't one they were on at least neutral terms with, the players avoided them like a genital exploding plague of demonic doom! They weren't seen too often, and unlike the neogi, other than their specific feuds, they tended to not bother the other ships lest they become banned and hunted down. They may have had power, but they didn't have sufficient numbers to be belligerent to anyone they encountered.

Dropping rocks and bombs and just plain using the cannons. Yeah, it could happen, but it wasn't done. If it was a space location, dropping anything had to be within the gravity plain of the target to work, and range penalties do apply, even when dropping straight down. (Go to a big bridge, and try to drop a coin onto the foundation pillar from right above it. You might be surprised what happens. Don't do it if anybody is nearby, you don't want an accident.)
Of course, if you use your guns, there's no reason why your would be target won't use theirs. For that matter, even space based 'ground' installations can have more and bigger guns than any ship. If it's a planet that deals with spelljammers, they know what to expect. If it's a planet that doesn't know about them, they still aren't unarmed. It is a magical universe, and lightning bolts work there too. For that matter, cities and things may have magical defenses against that kind of stuff, so you'd have to get within their fighting range to do anything anyway. After all, you don't need spelljammers to have to develop defenses against flyers. Like magic carpets, wizards, dragons, rocs, harpies, the occasional rain of stones, etc.

In our campaigns, it seemed the players usually tried to avoid planets unless they had to. Not sure why, but we never really made planetfall unless we had to.

As to the elves, they kind of alternated between belligerent and bossy neutrals, to snooty and overbearing allies, depending on whether they needed our help or not. Even the PC elves that came from planetside didn't like them much.

Now the Giff were loved by our players, even if for the simple reason that they were a sure fire way to find guns and smokepowder when they needed them. Giff rarely had more smokepower than they could use, but they definitely knew everywhere it was possible to get more! It seems strange that happy go luck adventuring weirdos would always want to make friends and party with the victorian military style explosion freaks, but it kept happening. There were several companies of Giff that invited them over for drinks at the pub when they were both in port. They even liked my rather quiet wizard that tried to stay out of the way, apparently because they found out about his large collection of exploding boxes. Basically he tended to put everything in boxes trapped with explosive runes. It tended to cut down on the repeat thefts.

 

[Shasarak]

I'd blow it up and start over from scratch, with a specific and SELF-CONTAINED setting in mind (unpolluted by crossover with existing game settings of ANY kind - leave that to people that want to house-rule such stuff in at their own risk). Spelljammer had an overwhelming amount of large and small-scale problems with settings, game mechanics, even general concepts. It was fun when I first ran it - and did so VERY fast and loose, glossing over massive chunks of mechanics and the values that were assigned to things. But that's no way to run a railroad, as it were.

It sounds like you are describing the old Astromundi Cluster boxed set there which had the unfortunate honour of being IMO the worst Spelljammer campaign setting. There is no reason to tread down that path again.

 

[DammitVictor]

... indeed mixing any and ALL settings for maximum kitchen sink dishwater...

That is the best possible phrase to describe why I hate "kitchen sink" D&D settings. So perfect. Joink!

 

[Man in the Funny Hat]

Well, that's a valid perspective, and the approach of the 3E-era SJ minigame. But, then why bother with making it part of the D&D Multiverse?...(which does still exist in 5E).

It's very simple: Because it dictates that any setting it is attached to shifts its tone and focus to that of Spelljammer, and thus everything about those settings that made them unique and worthwhile AS stand-alone settings is gutted in favor of a willfully undefined Frankenstein kit-bash of settings.

Spelljammer's justification for how that always works was that groundling worlds don't care what happens in wildspace, and nobody in wildspace really cares about groundling worlds. Not only does that beg the immediately obvious question of, "Then why bother?", but it's so patently ridiculous that the world-shattering advantages of spelljamming ships being introduced to a world that DOESN'T already have them is deliberately ignored. As soon as you question that attitude of, "neither side will care about the other and never the twain shall mingle," it all goes pear-shaped. If they aren't going to mix then why have both settings (not that Spelljammer really IS a setting in itself, it's more a leech that attaches to other settings )? If they are going to mix then how can it be in any way sensible that the established ground setting doesn't actually change, or that the spelljamming interlopers won't see all the worlds to conquer, the markets to monopolize, the entire economic structures to collapse and insanely profit thereby?

Castles can be bombed into rubble by dropping rocks from a stable, hovering spelljammer overhead that is out of range of spells and missiles - so every castle, EVERYWHERE, has a vested interest in obtaining spelljammers to either do such bombing themselves, or to park one overhead to prevent that.

The first spelljamming ship that moves goods with absolute safety and impunity in LESS THAN A DAY what it takes an overland caravan to move at great risk and expense in months of overland travel will break world economics almost overnight. You can move a ship load of food from Greyhawk to the Pomarj in about 2 hours. You can effectively move 100 caravans worth of goods from several sources all over Kara-Tur to Waterdeep in 24 hours, limited only by the time it takes to actually load/unload rather than actually TRAVEL - and without need of scores of caravan guards to defend from bandits, monsters, adverse terrain, and the weather. Hand a spelljamming captain an invoice in the morning for goods from a merchant on the other side of the world in Evermeet, and you can have it delivered to you in Shadowdale by noon. Congratulations, you've just "invented" Faerun FedEx. That isn't the Forgotten Realms anymore, and it's barely still Spelljammer (or at least what Spelljammer seems to WANT to be). Who needs to have an army lay siege to a castle when you can drop wave after wave after wave troops at the tops of the walls or even right in the center of the courtyard? That's if you don't just want to rubble it from on high of course. Need to consult a book from the library in Candlekeep? Hop in your Elven Flitter and fly down there and be back for supper.

And yet, when it comes to connecting game worlds together I have only just realized how BAD it is at doing so. As things are written, a round trip from, say, Oerth to Faerun would average nearly a year. If you did indeed want to have those two settings mixed up a lot, it's hard to do so as Spelljammer is originally structured. Just getting to the limit of the crystal sphere when leaving from Oerth, moving at a million miles a day, it will take 80 days. Entering the phlogiston, the trip between the two spheres will take a hugely random 10-100 days. Getting from the limit of its sphere to actually landing on Aebir-Toril will be around 30 days. So 120 to 210 days, or 4-7 months ONE WAY. Round trip: 8-14 months. Though touted as a great way to connect wildly different game worlds, as written it can't be done casually and any such journey would be more like The Odyssey, the Voyage of the Dawn Treader, or maybe something done by Columbus or Magellan. Teleportation or planar travel, which had been around in D&D rules already for at least 10 years before Spelljammer, are far faster and even safer and more reliable means of crossing to other game worlds - assuming that IS what you wanted to actually DO with Spelljammer.

 

[Dannyalcatraz]

victorian military style explosion freaks

Great name for a band/album/song!

 

[Dannyalcatraz]

On Spelljammer silliness: GSHs are required, IMHO, but need not be front & center. They could be a rare commodity, like Bugatti Veryons- rarely seen, but often discussed.

OTOH...

The Arcane animal husbandry employed by the gnomes who created GSHs could be quite...risky, resulting in all kinds of things. In the other 5Ed Spelljammer speculation thread, I joked about them creating miniature Kaiju. That’s a plot hook waiting to happen, and we’ve seen how fun it can be.

Inhabitants on a nice, jungle covered world buy loads of mini-Kaiju. Some escape..breed...

[video=youtube;dMjQ3hA9mEA]https://www.youtube.com/watch?v=dMjQ3hA9mEA&sns=em[/video]

[video=youtube;sd8Rk8_dUh4]https://www.youtube.com/watch?v=sd8Rk8_dUh4&sns=em[/video]

 

[Dungeonosophy]

It's very simple: Because it dictates that any setting it is attached to shifts its tone and focus to that of Spelljammer, and thus everything about those settings that made them unique and worthwhile AS stand-alone settings is gutted in favor of a willfully undefined Frankenstein kit-bash of settings.

The Forgotten Realms books (and other world-specific books) wouldn't bring Spelljammers in as a core element - because, as you say, space-travel is not essential to the tone of each setting...and for many campaigns it would be a distraction. But, vice versa, visiting strange new worlds is essential to the Spelljammer setting! I mean, sure, WotC could just do something like the 3E SJ minigame, and just focus on one corner of space, and not touch on the existing D&D worlds. And if they use the Curse of Strahd approach, they will just do one big adventure set in an iconic locale. But it just doesn't make sense to me to offer a D&D-in-Space book...but to ignore the location of the various D&D worlds! Even if the 5E SJ book is a single adventure, why not have a beautiful, detailed map of the D&D Galaxy as an appendix and show all the published worlds and spheres? Though I understand what you're saying in regard to the distinct tone of each published setting, in another sense, they are not "stand-alone" settings. The 5E PHB explicitly says all those worlds (Athas, Blackmoor, Oerth, Eberron, Toril, Krynn, Mystara, Aebrynis) are all in the same D&D Multiverse...in the same Material Plane.

Castles can be bombed into rubble by dropping rocks from a stable, hovering spelljammer overhead that is out of range of spells and missiles - so every castle, EVERYWHERE, has a vested interest in obtaining spelljammers to either do such bombing themselves, or to park one overhead to prevent that.

Yeah but at least two of the main D&D worlds already have airships built into the setting...Mystara (in a big way) and Eberron. Mystara was barely tied to the Spelljammer series (IIRC there was just one product and a DRAGON magazine article which mentioned Spelljammers in Mystara), but there are three nations (Alphatia, Thyatis, and Heldann) which have big Skyship fleets which are an integral part of the setting...and the world doesn't fall apart. Despite the presence of Skyships, castles and armies and caravan travel are mostly the same as in any other fantasy world. Most every D&D world already has flying carpets, attacking dragons, and all sorts of aerial assaults. Yeah, if a DM chose to introduce an invasion of Spelljammers into their sleepy fantasy world, it'd be a huge campaign event...just as would the invasion of the world by Tiamat, or Demigorgon, or the F.S.S. Beagle, or a Tarrasque, or the Night of the Comet, or whatever. Those cataclysmic events aren't essential to the tone of the setting, but they're well within the range of events which a Spelljammer product would address.

And yet, when it comes to connecting game worlds together I have only just realized how BAD it is at doing so. As things are written, a round trip from, say, Oerth to Faerun would average nearly a year. {...} Teleportation or planar travel, which had been around in D&D rules already for at least 10 years before Spelljammer, are far faster and even safer and more reliable means of crossing to other game worlds - assuming that IS what you wanted to actually DO with Spelljammer.

That's a good point. I'm all for changing the way Spelljamming works...whatever maximizes the fun. Also, I'm for offering full support for world-hopping campaigns (for those DMs who are interested)...and not only via Spelljammer, but also a 5E Chronomancer, and a 5E Planescape.

 

[Dragonhelm]

Here's an article I wrote about Spelljammer during the 3rd edition days, but I think a lot of the themes work here too.

Creating Spelljammer for 3rd Edition

Short version is that Spelljammer should be both its own setting and a way to travel between settings.

 

[maceochaid]

I think 4th edition had it right, move away from Spelljammers as dealing with traveling between crystal spheres and instead make it a pathway through the Astral Sea to the outer planes. What I like about the spell jamming helms is that they do provide good resource attrition for the exploration pillar, wizards on long journey have to spend spell slots to move, but the emphasis should be on balancing how that resources works out. Don't try and link worlds with Spelljammer, it will just make the canon murky. Dragonlance canon itself gets contradictory, trying to reconcile it with Athas and Toril is impossible. Treat it as a setting in it's own right and toss in a throw away line "Spelljammers are possibly way to access other worlds." But spill as little ink as possible on trying to reconcile it.

 

[Jhaelen]

I think 4th edition had it right, move away from Spelljammers as dealing with traveling between crystal spheres and instead make it a pathway through the Astral Sea to the outer planes. What I like about the spell jamming helms is that they do provide good resource attrition for the exploration pillar, wizards on long journey have to spend spell slots to move, but the emphasis should be on balancing how that resources works out. Don't try and link worlds with Spelljammer, it will just make the canon murky. Dragonlance canon itself gets contradictory, trying to reconcile it with Athas and Toril is impossible. Treat it as a setting in it's own right and toss in a throw away line "Spelljammers are possibly way to access other worlds." But spill as little ink as possible on trying to reconcile it.

I agree that's the most reasonable implementation of Spelljammer.

To be honest, in 4e I didn't even think of the 'Astral Sea' as a fresh take on Spelljammer. But you're totally right! "The Plane Above" and "The Plane Below" were also among my favorite supplements for 4e. By putting Spelljammer in the Astral Plane you neatly avoid all of the complications that the weird cosmology around crystal spheres and the phlogiston created. I didn't like Spelljammer in 2e, but I'd totally dig the 'Astral Sea' version.

 

[delericho]

Mystara was barely tied to the Spelljammer series (IIRC there was just one product and a DRAGON magazine article which mentioned Spelljammers in Mystara)...

For a very long time, Mystara was a D&D setting rather than an AD&D setting - for legal reasons, TSR had to maintain a very strict line between these two strands. Consequently, Mystara products couldn't link to Spelljammer.

Eventually, the various legal issues were reconciled, and Mystara had at least some books published for AD&D (I own a Monstrous Compendium appendix for the setting). I would guess those few links you mention are probably from about that time.

 

[delericho]

How would I design for Spelljammer?

Firstly, I'd make it mostly it's own setting - the 'big three' of Realmspace, Greyspace and Krynnspace would exist (along with Athas-space, Eberron-space, etc), but I'd move them waaay over to the side of the map. Links between Spelljammer and those other settings would need to be vanishingly rare - as noted, this is needed to avoid polluting those settings. (I would fix the Shou by casting the Spelljamming empire as an offshoot who departed the Realms centuries, and two editions ago, and who had been utterly cut off by one of the Realms-Shaking Events - an in-setting retcon )

I would remove the "Phlogiston is explosive" point of lore. That's a small thing, but necessary because I also want:

At least some ships should be mounted with cannon, and other black-powder weapons. (And, of course, the Giff just love these.) Also, I would have at least some Steampunk ships and helms in the mix.

I would also remove the "spellcasters lose their slots" bit of lore, since it's just pain (and was largely ignored anyway). And, in fact, I'd be inclined to get rid of the requirement that the helmsman be a caster anyway - base it on character level rather than caster level.

They need to introduce some things into the setting to make for an economy - if Krynn offers all the standard fantasy gear, and the Realms also offers all the same standard fantasy gear, how can there be trade between the two, especially if it's inherently slow and costly? So maybe there's a fleet of ships hunting for Space-whales for the oil, or miners extracting Residuum from various worldlets, or similar. (And the more they can make these into adventure-fodder, the better for everyone of course.)

I'd be disinclined to make the Elven Armada the "bad guys" - arrogant, officious and generally annoying, yes, but even more annoying because most of the time they're right. However, I'd be inclined to view them as a paper tiger - the Unhuman War was hugely destructive, to the extent that although they won the Elven Armada has had it's back broken and will never recover. Of course, the elves are desperate to hide this fact... and it also means that when the Scro get around to kicking off the Second Unhuman War there isn't actually anyone in a position to stop them.

The setting needs more settlements, especially small-ish settlements with distinct characters (and not just "this is the dwarf city", "this is the elf city" - they need to allow for a comfortable mix of races, yet not all feel the same).

And it also needs more mysterious locations. The Spelljammer is all well and good, but it's only one example - the PCs really need something to quest for in their second campaign as well.

 

[Dannyalcatraz]

I don’t agree with all of that, but much of that is pretty solid.

 

[Thomas Bowman]

Spelljammer is fantasy space travel, so I would keep it as an add on to the D&D game, it is Dungeons and Dragons onboard magical flying ships in space, so I would keep the boarding action, and keep all the rules. I would not go in the direction of Starfinder, I would resist the temptation to introduce new tech to the game, by keeping it all magical but as D&D in space. I would use the monsters in the Monster Manuals as aliens. The one thing Starfinder does is it makes its setting "Science Fictional" without it actually being science fiction. As far as Science Fiction role playing games modeled after Dungeons and Dragons I liked the Buck Rogers XXV RPG.

The game was actually a hard science fiction role playing game despite its pulpish artwork. They published a more pulpish version later that I didn't like, but the original role playing game was great!, and it was compatible with Dungeons and Dragons at that time. I think we could make a 5e version of Buck Rogers XXV, what do you think?