# SPELLJAMMER 5E
## Introduction to Spelljammer
## The Geography of Space
### Crystal Spheres
Crystal Spheres are exactly what their name entails; they are gigantic spheres made out of magic crystal. These spheres are also sometimes referred to as Crystal Shells. A Crystal Sphere contains all of the planets, moons and suns of each fantasy campaign world.
##### Celestial Body Size Classification
| SIZE CLASS | DIAMETER IN MILES | DIAMETER IN KILOMETERS |
|:-|:-:|:-:|
| Size A | Less than 10 | Less than 16 |
| Size B | 10-100 | 16-161 |
| Size C | 101-1000 | 162-1609 |
| Size D | 1001-4000 | 1610-6437 |
| Size E | 4001-10000 | 6438-16093 |
| Size F | 10001-40000 | 16094-64374 |
| Size G | 40001-100000 | 64375-160934 |
| Size H | 100001-1000000 | 160935-1609344 |
| Size I | 1000001-10000000 | 1609345-16093440 |
| Size J | 10000001 and greater | 16093441 and greater |
##### Celestial Body Type Classification
| Class | Description |
|:-|:-|
| Airbody | A world composed of air and cloud, with the posibility of small floating islands of solid ground |
| Earthbody | A "standard" world with solid ground, often with water, trees, mountains, etc. |
| Firebody | A world composed of fire. Often home to fire elementals. Also sometimes servince as a "sun" to other worlds in a sphere. |
| Waterbody | A world composed almost entirely of water. A Waterbody is composed of always less that 2% landmasses on its surface. |
### Wildspace
Between all of the celestial bodies in each Crystal Sphere is a void known as Wildspace. Wildspace is the equivalent of space in the real world. There is no air or gravity within Wildspace.
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### The Phlogiston
The Phlogiston is an endless ocean filled with a multicolored flammable element that is neither air, earth, fire or water. The Crystal Spheres actually float along within the Phlogiston. Currents also flow through the Phlogiston that act as express lanes for Spelljammer ships traveling between the spheres. Like Wildspace there is no air or gravity within the Phlogiston.
## Peculiarities of Space
### Air
Since there is no breathable air in Wildspace or the Phlogiston suffocation may seem like a certainty for groundlings journeying into space. Space-faring races do not worry about such things though. Any celestial body larger that is more than 1 mile (1.6 km) in diameter generates its own breathable atmosphere. This atmosphere extends from the surface to the edge of Wildspace.
A functioning Spelljammer Helm generates a magical field which will hold breathable air in an atmosphere surrounding the ship with a pocket of breathable air. This pocket extends thirty feet (9.1 meters) out from all points of the ship’s structure and is enough for the maximum crew of each ship to breathe normally on deck. Should the Spelljammer Helm be disabled or destroyed the air pocket will slowly begin to dissipate, but enough breathable air will remain for the crew to survive for seven days.
When a spelljamming craft exits an atmosphere, whether a planet, asteroid, or other, the mystic energy of the ships spelljamming helm drags with it a pocket of breathable air that will supply the ships rated passenger complement of medium creatures for 3 months.
<div class='descriptive'>
##### Air Supply
The standard Squid Ship as a crew of 12/45. This means that it requires 12 crew, but can hold up to 45 crew & passengers. This means that the Squid Ship could supply 45 medium beings for 3 months.
</div>
A ship will always carry its full bubble of air when departing an atmosphere, even with a reduced crew. Because of this, an understaffed crew is able to remain afield for much longer periods. For example, if the above Squid Ship had only its 12 crew on board along with 10 others (a total of 22) this is half of its 45 maximum. With half the passengers, the bubble would last twice as long, or 6 months.
##### Creature Sizes
| Size | Air use |
|:-------|:-------------|
| Tiny | 1/4th Normal |
| Small | Half Normal |
| Medium | Normal |
| Large | Twice Normal |
| Huge | 4x Normal |
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#### Breathing when overboard
Normally, all is well when you are on board your ship, but what happens when you fall (or get thrown) overboard?
Luckily, spelljammers are not the only things in existance that possess mystic fields to which air clings.
All magic items also possess minute amounts of mystic gravity. Although the amount of gravity does sometimes vary from item to item (consult your DM), in general, you can consult the chart below for the amount of mystic gravity, and as such air, that a magic item will hold to after leaving a ships bubble.
##### Magic Item Gravities
| Size | Air Held |
|:-----------|:-------------|
| Common | +15 seconds |
| Uncommon | +30 seconds |
| Rare | +45 seconds |
| Very Rare | +60 seconds |
| Legendary | +90 seconds |
| Unique Artifact | +180 seconds |
### Gravity
There is no gravity in Wildspace or the Phlogiston. However all Spelljammer ships and celestial bodies larger than 25 feet (7.6 meters) in diameter generate a gravitational pull equal to that of Earth’s gravity. For a celestial body the force of gravity acts much like it does in our world. Any creature or smaller object on the surface of the body is pulled towards the center. The gravity field of a celestial body extends from its center to the edge of Wildspace.
On a Spelljammer ship this force manifests as a gravity plane along the ship’s long axis. Creatures or smaller objects above this plane are pulled down by this force; creatures or smaller objects that are below are pulled up. The gravity plane of a ship or object extends the same distance as the air envelope.
Creatures or objects that fall off of the deck of a Spelljammer ship will fall through the gravity plane and then be pulled back up towards the bottom of the ship. This makes it possible for a creature or object to bob up and down next to a ship.
The lack of gravity in Wildspace and the Phlogiston affects the travel of normal ranged weapons. Missiles fired beyond a gravity field have an extended range. The long range of the weapon listed in the Player’s Handbook is the normal range in space and the new long range is four times that number. Melee combat is also possible outside of the gravity field, but all attacks are made with Disadvantage.
### Fire
Within the air envelope of a Spelljammer ship or a celestial body normal and magical fire functions exactly as it would on the ground. However, the lack of air in Wildspace has an affect on fires. Magical fire like Fireball can be cast normally outside of an air pocket, but this fire has no chance of catching anything ablaze. Normal fire will not function at all outside of an air envelope in Wildspace.
Fire in the Phlogiston is extremely deadly. The Phlogiston permeates the air envelope of a Spelljammer ship making an explosive mixture. Spelljammer crews know to extinguish all flames before exiting a Crystal Sphere, however, accidents do happen. The following table shows some examples of fire damage in the Phlogiston.
| TYPE OF FLAME | FIREBALL DAMAGE | AREA OF EFFECT
|:-|:-|:-|
| Lit Candle | 1d6 | 4 inches/ 10.2 cm diameter
| Lit Lantern | 3d6 | 1 foot/ 0.3 m diameter
| Cooking Fire | 3d6 | 3 feet/ 0.9 m diameter
| Fireball | Spell damage X 3 | Spell area of effect X 3
Casting any spell that creates magical fire in the Phlogiston causes the spell to immediately trigger with the caster as the center of the area of effect.
Fire on the deck of a Spelljammer ship is also very dangerous. Shipboard fires will expand at a rate of 1 foot (0.3 m) per round. Initially a fire can be put out by one crew member in one round. Every round the fire is allowed to expand increases the number of crew members and rounds needed to extinguish the flames by one.
### Magic
Magic functions exactly the same from Crystal Sphere to Crystal Sphere. Spells that can cast in the Forgotten Realms can also be cast on Krynn or any other world *providing that the diety or power granting your spells has a presence in the new sphere*.
#### Divine Magic in the Phlogiston
However, magic in the Phlogiston is a different story altogether. The Phlogiston is cut off from any of the major powers that inhabit the Crystal Spheres. It is difficult for a cleric, paladin or druid to communicate with their deity or force of nature outside of a crystal sphere. 3rd-level or higher spells of these classes *regained* be cast while in the phlogiston. Spells of 3rd level or higher which were already prepared can be cast, but will not be regained until you are able to rest within a sphere and communte again.
***Clerics in distant Spheres.*** Additionally, if a cleric's deity does not have an established group of worshippers somewhere within a crystal sphere, that cleric's spellcasting is limited as above.
#### Planar Magic in the Phlogiston
The Phlogiston is also isolated from the other planes of existence. The peculiar nature of the Phlogiston makes it impossible to cast any spell that conjures celestials, elementals, fey, fiends, or any other extraplanar beings. Devices or spells that allow for planar travel will not function in the Phlogiston nor will any device or spell that creates or makes use of extradimensional space.
There is only one known type of magic, [Lunamancy](http://homebrewery.naturalcrit.com/share/SksWQubEe) which seems unexplainably unaffected by the phlogiston, and is able to be used normally.
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#### Spells in the Phlogiston
**The following spells will not function in the Phlogiston:**
- Astral Projection
- Augury
- Banishment
- Blink
- Commune
- Conjure Animals
- Conjure Celestial
- Conjure Elemental
- Conjure Fey
- Conjure Minor Elementals
- Conjure Woodland Being
- Contact Other Plane
- Demiplane
- Dimension Door
- Divination
- Etherealness
- Find Familiar
- Find Steed
- Gate
- Leomund’s Secret Chest
- Maze
- Mordenkainen’s Faithful Hound
- Mordenkainen’s Magnificent Mansion
- Planar Ally
- Planar Binding
- Plane Shift
- Spirit Guardians
- Teleport
**The following spells have limited effects when cast in the Phlogiston:**
- Banishing Smite – Reducing the target to 50 hit points or fewer does not banish it.
- Imprisonment – You may not choose Hedged Prison.
- See Invisibility – You are unable to see into the Ethereal Plane
- Sending – Messages have no chance of reaching a target on a different plane than you.
**The following magic items will not function in the Phlogiston:**
- Amulet of the Planes
- Bag of Devouring*
- Bag of Holding*
- Bowl of Commanding Water Elementals
- Brazier of Commanding Fire Elementals
- Censer of Controlling Air Elementals
- Cubic Gate
- Heward’s Handy Haversack*
- Horn of Valhalla
- Iron Flask
- Mirror of Life Trapping†
- Oil of Etherealness
- Plate Armor of Etherealness
- Portable Hole
- Quiver of Ehlonna*
- Stone of Controlling Earth Elementals
- Well of Many Worlds
*The extradimensional spaces housed within these items cannot be accessed from the Phlogiston, but anything previously stored within them remains within them.
†Any creature already trapped within the mirror’s extradimensional cells remains trapped while in the Phlogiston.
#### Additionally
The spells and items listed above do not form an all encompassing list. Any spell from other sources, homebrew, etc. which follow the same criteria or make use of the same planar linking as any of the spells or items above are simularly limited or non-functional.
#### Magic Items in the Phlogiston
**The following magic items have limited use in the Phlogiston:**
- Deck of Many Things- Drawing the Donjon or Skull cards seems to have no effect while in the Phlogiston, but they will take immediate effect upon entering a Crystal Sphere.
- Robe of Stars- The wearer is unable to enter the Astral Plane.
- Sending Stones- Messages have no chance of reaching a target on a different plane than you.
- Staff of Power- There is no chance of traveling to a random plane of existence to avoid the damage from a Retributive Strike.
- Staff of the Magi- There is no chance of traveling to a random plane of existence to avoid the damage from a Retributive Strike.
## Travel In Space
### Travel Between Spheres by Magic
The distances between the spheres is vast, almost impossibly so. Because of this, it seems particularly unreasonable to imagine it being particularly easy to magically move from one place to another. Teleportation magic is not sufficent to move from one sphere to another, but is capable of moving a being from one planet within a sphere to another within the same sphere.
In order to move between planets in different spheres, magic such as Planeshift must be used. In effect, consider each sphere to be a separate plane for the purpose of any spells or items used.
### Spelljammer Helms
Spelljamming is the means by which a ship moves through the Phlogiston or the void of Wildspace. Although there are many varied ways to accomplish this it is most often done through the use of a spelljammer helm. The majority of ships are equipped with either a major or a minor helm, although larger ships may have both with the minor helm acting as a backup. The spelljammer helm is a large chair or throne which can be operated by any character class with access to spell slots. The helm draws magic from the character and converts it into energy to move and maneuver a ship. A spelljamming character must remain seated and in full contact with the spelljammer helm during operation.
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Once a caster has piloted a spelljammer for 12 hours, they cannot pilot the ship again, even if they still possess more spell slots.
In order to pilot a spelljamming ship, a caster requires the following spell:
##### Operate Spelljammer Helm
***1st-level evocation***
- **Casting Time:** 1 action
- **Range:** Self
- **Components:** V, M (spelljammer helm)
- **Duration:** Concentration, up to 12 hours
A magical connection is formed between you and a Spelljammer helm giving you complete control of a ship. You are able to move the ship at a base Spelljammer Rating of 1. For the duration of the spell the ship feels like an extension of your body. Maneuvering the ship requires no more effort than moving your arm or leg normally would. If you lose physical contact with the spelljamming helm, your concentration is broken.
***At Higher Levels.*** When you cast this spell using a spell slot of 2nd level or higher, you can increase the base SR by one for each slot level above 1st.
***Bonuses.*** When you cast this spell using a Major helm as the material component, the total SR for the spell cast is increased by 2.
#### Types of Movement in Space
The travel speed of a spelljammer ship changes based on where the ship is being operated. The SR granted by the spelljammer helm and operator applies when a ship is being operated in the atmosphere of a celestial body or when the ship is engaged in combat. The boundary between planetary atmosphere and Wildspace varies between different planets, but generally rests at a distance of 1/10th of the diameter of the world..
##### Distance To Reach Wildspace
| SIZE CLASS | MILES ABOVE SURFACE | KILOMETERS ABOVE SURFACE |
|:--------------|:--------------|:--------------|
| A | 1 | 1.6
| B | 10 | 16.1
| C | 100 | 161
| D | 400 | 644
| E | 1000 | 1609
| F | 4000 | 6437
| G | 10000 | 16093
| H | 100000 | 160934
| I | 1000000 | 1609344
| J | 10000000 | 16093440
A spelljammer ship in Wildspace or the Phlogiston is not restricted by its SR. A ship traveling through Wildspace and avoiding any gravity fields will reach a speed of 4 million miles per hour (6437376 km/h) regardless of SR rating. The Phlogiston contains dense rivers of flammable ether that flow between Crystal Shells. Ships traveling in these currents can achieve speeds that are beyond measure. Ships travelling the philogiston do not measure speed, but rather in comparison to established route timeframes. For example, the trip from Greyspace to Realmspace normally takes 15 days. An especially fast ship might make the same journey in 12 days. That captain may describe his ship as making the Grey-Realm trip in +3 days.
However, travel is always limited by the endurance of the helm operator. A spellcaster may operate a spelljammer helm continuously for 12 hours but will begin to tire after 6. At the end of each hour thereafter the character must make a Constitution saving throw. The DC is 10 + 1 for each hour past 6 hours. On a failed saving throw, a character suffers one level of exhaustion (see appendix A in the PHB). Each exhaustion level gained from spelljamming reduces maximum SR by 1. This penalty persists until removed by an appropriate amount of rest. Regardless of exhaustion level after 12 hours of continuous operation of a spelljammer helm the operator will pass out and be unable to use any helm again until after a long rest.
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Many thanks to [The Worst DM](http://theworstdm.com/spelljammer-5e/) from whom I borrowed a great deal of the formatting for ideas in my own conversion.