[Raven Bloodmoon]

Don't forget mitigating factors like using a ritual in which the caster sacrifices all of his daily spells to power it. You'd be shocked at how much you can drop a DC that way. Especially with an epic mage....

[Black Faolan]

I couldn't find any rules for a single caster sacrificing more than one spell slot...

[Dthclaw]

No, single casters don't drop spell slots to power a spell.

BUT

You can have many, many casters - even low level ones - contribute spell slots to mitigate the primary caster's efforts.

[Black Faolan]

The astral Jump spell isn't supposed to be a ritual spell. It was designed to be a spell-like ability for the ship spirit, no one else needs to be able to actually cast it at the start. (it and the Instil Ship Spirit spell are going to on stone tablets dug out of old dragon hoards... with the attendant suggestion about where life on the planet came from)

That said, I did a little bit of re-wiring on both spells (still not so sure on the stats for the ship spirit...):

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Astral Jump
Transmutation[Teleportation]
Spellcraft DC: 209
Components: V, S
Casting Time: 1 minute
Range: Self
Target: One vessel
Duration: Instantaneous
Saving Throw: Will negates(harmless)
Spell Resistance: No

Allows a vessel of any size (if either cast by a caster aboard the vessel or by the vessel itself) to jump instantly through the Astral Plane. Maximum range of the jump is roughly 1,000 light years. Knowledge of the destination is non-essential, but the caster does need to specify a distance and direction.
The vessel must be in vacuum, at least five hundred thousand kilometres away from the nearest planet.

To Develop: 1,881,000gp; 38 days; 75,240xp Seeds: foresee (to preview destination) (DC 17) transport (DC 27). Factors: change from personal to area (+15 DC) change area to variable (contains hull of touched vessel) (ad-hoc, +200 DC). Mitigating Factors: Can only be used in space (ad-hoc, -50 DC)


Instil Star Ship Spirit
Conjuration, Transmutation
Spellcraft DC: 41
Components: V, S
Casting Time: 1 minute
Range: touch
Target: Vessel touched
Duration: Permanent
Saving Throw: None
Spell Resistance: Yes (harmless)

Infuses a selected vessel with an intelligent spirit. The vessel effectively becomes alive and intelligent (Colossal construct, Stats: Str-; Dex -; Con -; Int 3d6; Wis 3d6, Cha 2d6). The spirit is capable of speaking common, plus one language the caster knew per point of intelligence bonus.
The ship spirit is capable of using the following spells as spell-like abilities: At will: purify air, sphere of force(as wall of force but completely encases the ship) , 3/day greater teleport, 1/week Astral Jump.

To Develop: 369,000 gp; 8 days; 14,760xp. Seeds: Life (DC 27), Fortify (DC 17). Factors: Add at will purify air (ad hoc, +40 DC), add at will sphere of force (ad hoc, +50 DC), add 3/day greater teleport (Ad hoc, +21 DC), add 1/week Astral Jump (ad hoc, +30 DC), permanent (x5DC). Mitigating Factors: Casting Time: 1 day, 11 minutes (-12 DC), sixty additional casters contributing 8th level spell slots (-900)
(all spells, including Astral Jump, must be known by at least one participatory caster)

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So, basically, the arks are whatever the players decide to instill with ship spirits (one suggestion was made of islands), which by the nature of being ship spirits can maintain atmosphere, gravity and shields on their own, and can do both medium and long range travel. They don't particularly need to be able to move under their own power other than teleport.

Which brings us to the warships. Some are going to be instilled airships or naval ships, but some will probably be custom-built. These are also going to need greater maneuverability and at least some methods of engaging the enemy.

[Raven Bloodmoon]

Maneuverability: Magic. Just make another epic spell for it.

Weapon: Small pieces of matter moving at extremely high velocities. If a paint chip can crack the windshield of a space shuttle, imagine what a golfball could do.

[Black Faolan]

Bounce off of the wall of force surrounding the ship?

[Raven Bloodmoon]

Wall of force is not mobile. Makes it a really crappy shield.

[Black Faolan]

In this case, the only thing maintaining the atmosphere on some of the ships is the sphere of force effect. Also counter-acts most of the dangerous radiation, among other things.

I think I'm going to have to say that the sphere moves with the ship

For armaments, I'm thinking either allowing the ship spirit to assume control of any spell turrets attached to the hull, or creating a series of "Enhance Ship Spirit" epic spells that provide the spirit with some offensive spell-like abilities.

[Raven Bloodmoon]

If you want offensive spell-like abilities, not much beats Disintegrate with some sort of extended range.