aquilo-orbit-start

This is a mod for Factorio: Space Age.

Start on a space platform above Aquilo, processing asteroid chunks in the early game.
Drop resources down to Aquilo for the mid-game.
Unlock thrusters for the late game.

Every Aquilo start mod must make some significant changes to the vanilla experience.
The design goals for this mod are:

Retain the spirit of Aquilo having an incomplete supply of basic resources, heavily relying on dropped materials from space platforms, and even then having no access to stone.
Shift the cost and accessibility of space and Aquilo technology to be cheaper and earlier. Make space platforms and Aquilo feel like home.
This is not a "challenge mod". Numerous balance changes are introduced to keep the pace moving and keep the vibe chill. (Check out the mod settings if you want to turn this into a challenge mod.)
Don't change too many things beyond what the above requires.

This mod challenges you with cramped space, heating requirements, early game multi-surface logistics,
and the "sky block" style high-friction bootstrapping process both in orbit and on the surface.
As a reward, you get a "dessert first" progression where Aquilo-native endgame technologies are accessible before unlocking thrusters;
e.g. fusion reactor, railgun turret, rocket part productivity, and the inexhaustible supply of materials from asteroids.

While this modded experience is primarily designed to stand on its own, a secondary goal is to integrate into the Archipelago randomizer for Factorio: Space Age.
I wanted all 5 planets to show up in the starting_planet YAML option somehow while feeling like a randomizer rather than an overhaul.

Thanks to daid in the any-planet-start discussion forum for the inspirational idea for this mod.

Changes to make this possible

Starting in space

Large asteroids do not spawn above Aquilo, but still spawn normally just beyond Aquilo orbit in any direction.
Asteroid chunk spawn rate is increased in Aquilo orbit.
Asteroid productivity research is available in the early game.

This mod lets you press Enter to enter/exit the hub and walk around on a space platform.
You can hand-mine asteroid chunks as they float by, and you can hand-crush them just like an asteroid crusher can.
Almost all crusher recipes are unlocked from the start giving access to iron-ore, copper-ore, carbon, ice, and calcite immediately.
Only advanced-carbonic-asteroid-crushing remains locked, as there is no early game use for sulfur.

This mod provides a space-furnace, only buildable in space, that operates without any fuel or electricity with a 0.5 crafting speed and a 3x3 footprint.
That's half the speed of a stone furnace and more than double the space requirement.

This mod also provides a no-power basic-asteroid-collector and basic-crusher for the early game, operating at quarter speed.
Here are the recipes:

20 iron-ore + 10 carbon + 2 calcite = space-furnace
10 iron-plate + 5 iron-gear-wheel + 3 electronic-circuit = basic-asteroid-collector
10 iron-plate + 5 iron-gear-wheel + 3 electronic-circuit = basic-crusher

Inserters, assembling machines, and labs require power as usual.
Generating power requires solar panels, which are unlocked from the start.
Solar power is 60% effective in Aquilo orbit, as usual.
See also Balance.

Dropping to Aquilo's surface is locked behind two science packs.

No stone

Fitting the "dessert first" theme, this mod adds an alternate recipe to jump right to refined concrete, without being able to obtain stone-brick or regular concrete:

20 calcite + 8 iron-stick + 1 steel-plate + 100 water = 10 refined-concrete

The following recipes, which normally require concrete or stone-brick, have alternate versions that accept refined concrete instead:

heating-tower
cargo-landing-pad
electric-furnace
oil-refinery
rocket-silo

military-science-pack and production-science-pack are unobtainable until visiting another planet.

Aquilo mid-game

Landing on Aquilo gives access to crude-oil and chemical-science-pack.
You need refined-concrete for flooring and heating-tower for heating.

After dropping to the surface and before unlocking rocket silos,
it is recommended to use the respawn-to-any-planet mod to get back onto your starting space platform if necessary.

The cryogenic-science-pack recipe is unlocked shortly after chemical-science-pack.
The Aquilo block of research technologies are changed to be accessible in the mid-game, most requiring only automation, logistic, chemical, and cryogenic science packs.
Epic and legendary quality and fusion-reactor-equipment still require utility science packs.

Aquilo crafting recipes normally require several interplanetary items, such as superconductor.
This mod changes the recipes, replacing those ingredients with mundane items.
This gives access to powerful tools relatively cheaply and early.

These crafting ingredients are downgraded:

holmium-plate => copper-plate
superconductor => battery
supercapacitor => battery
tungsten-plate => steel-plate
tungsten-carbide => iron-plate
carbon-fiber => carbon

These recipes are modified by the above replacements:

lithium (holmium-plate)
cryogenic-plant (superconductor)
quantum-processor (carbon-fiber, superconductor, tungsten-carbide) (now craftable in cryogenic-plant)
fusion-power-cell (holmium-plate)
railgun (tungsten-steel, superconductor)
railgun-turret (tungsten-steel, superconductor, carbon-fiber)
fusion-reactor (tungsten-steel, superconductor)
fusion-generator (tungsten-steel, superconductor)
fusion-reactor-equipment (carbon-fiber, supercapacitor, tungsten-steel) (fission-reactor-equipment ingredient removed)
foundation (carbon-fiber, tungsten-steel) (still uncraftable until traveling to a planet with stone)

Notably unchanged is most of the cryogenic-science-pack chain:

(after lithium, which is changed)
lithium-plate
ammoniacal-solution-separation
solid-fuel-from-ammonia
fluoroketone-hot
fluoroketone-cold
cryogenic-science-pack

Space travel late game

Once rocket-silo is researched with chemical-science-pack, you can build thrusters, discover other planets, and travel as in the normal game.
Once you get stone from another planet, you can finally craft military-science-pack and production-science-pack.

Discovering the solar system edge requires science packs from Vulcanus, Gleba, and Fulgora, as usual.
Visiting Nauvis can be skipped until promethium science.

Balance

Several balance changes are enabled by default to speed up the early game, but you can turn them off if you want a more "authentic" experience.

Add an alternate recipe for space platform foundation that requires carbon instead of steel, making it much easier to craft.
Crafting space platform foundation gives 10 instead of 1.
Add an alternate recipe for space platform starter pack (and cargo bay) from electronic circuits. Space platforms can create space platforms without a rocket silo.
Aquilo ocean tiles destroy items, similar to lava.
There is an alternate recipe for electric furnace from refined concrete, allowing access to a decent furnace before visiting another planet.

And a few balance options are available that aren't enabled by default:

Boost the yield of the ice platform recipe.
Boost the yield of the new concrete from calcite recipe.
Boost the yield of the heat pipe recipe.