Hard Drive

Hard Drives are special parts obtained from Crash Sites used to unlock Alternate Recipes (see below). Crash Sites can be located using Object Scanner after Radio Signal Scanning has been researched in the M.A.M..

Each Hard Drive can be researched in the M.A.M. and results in a choice of one of 3 alternate blueprints, chosen from the pool below.

There are 89 Crash Sites., which means a total of 89 Hard Drives can be theoretically obtained. Four of them, however, require unreleased components to unlock ( and ), reducing the number to 85.

Two Hard Drives can be used for engineer inventory expansions, leaving 83 for alternate recipes. Currently, there are 70 Alternate Recipes, leaving 13 unused.

Alternate Recipes
Alternate recipes generally require different input materials than the original, trading between raw material consumption, space, power, simplicity and availability of material.

The set of blueprints to choose from is determined randomly at the beginning of the scan. Because of this, the player can keep re-rolling to get the desired blueprint by saving the game before researching a hard drive, then loading the save and waiting for another 10 minutes if the choices are undesirable. The recipes are determined on the beginning of the scan and are only shown to the player after the research concludes.

The selected alternate recipes is unlocked immediately after it is chosen. All alternate recipes can be only used in factory buildings, none in the Craft Bench; therefore, parts like Compacted Coal cannot be hand-crafted.

To allow an Alternate Recipe to be shown up after a Hard Drive research, the prerequisites as shown below must be fulfilled, whether it is Milestone, Research or other Alternate Recipe. This means if a player builds a factory that requires certain alternate recipes that they have not yet unlocked, they may need to find more Hard Drives than they anticipated in order to unlock the prerequisites blocking their intended alternate recipes.

Note: It appears that there are several alternate recipes that can be unlocked at Tier 3, despite involving a fluid (Water) making them Refinery recipes, which is not unlocked before Tier 5.

Important notes

 * The Hard Drive research is repeatable, as long as there are remaining alternate recipes to unlock.
 * Each alternate recipe can only be unlocked once, it will never appear in the selection screen again once it has been selected.
 * If you research a Hard Drive, and there is nothing more available to unlock, the Hard Drive will be returned to your inventory with the following message: "The analysis of Hard Drive is completed! No new research is available. Try again later after further progress. Your Hard Drive has been returned to you.".

Alternate recipe analysis
The analysis below is based on the target production of the following items, which is normally achievable in the late game, see this link for detailed production list->. This amount is chosen to max the coupon farming rate, while maintaining reasonable amount of parts on hands for building additional buildings. All resources on the map are fully utilized.

Useful recipes

 * Bolted Frame: Significantly improved production speed with negligible amount of Iron Ore loss.
 * Casted Screw, Steel Screw: "Casted Screw" has the same ratio of Iron Ingots to Screws, but removes the need to make Iron Rods first, and produces 25% faster as well. Prioritize "Casted Screw" first for increased production speed. "Steel Screw" is ultimately more resource-efficient, producing nearly 5 times as many Screws per Iron Ingot when combined with "Solid Steel Ingot", at the cost of more steps in the production chain.
 * Caterium Computer mixed with original recipe: The alternate recipe is preferred, however Caterium can get used up quickly and this is where the original recipe comes in handy to make up for it.
 * Cheap Silica: Limestone is abundant, using it to reduce the load in Raw Quartz is almost a necessity.
 * Compacted Coal: Not an alternative really. Used for Compacted Steel Ingot and Gun Powder to improve resource usage and production speed, and mandatory for the production of Turbofuel using either recipe.
 * Copper Rotor: Increased production speed by mixing Copper into it.
 * Diluted Packaged Fuel: Adds Water to *triple* the Heavy Oil Residue -> Fuel conversion ratio. Combine with "Heavy Oil Residue" for extremely efficient Crude Oil -> Fuel conversion ratios. This recipe is part of a loop that maximizes the utilization of Crude Oil for power using "Turbofuel", and "Compacted Coal", or for Rubber and Plastic using "Recycled Rubber" and "Recycled Plastic".
 * Electrode Aluminum Scrap: Relieves the Crude Oil consumption. It also has a better conversion rate.
 * Encased Industrial Pipe: Uses ~33% less steel per unit but is 50% slower to produce.
 * Gun Powder: All-round winner.
 * Fused Quickwire: Caterium is much more precious than Copper, so yes.
 * Heat Exchanger: Saves Crude Oil and Bauxite.
 * Heavy Encased Frame: All-round winner; only eats a little more Limestone.
 * Heavy Oil Residue: *Substantially* improves the Crude Oil -> Heavy Oil Residue conversion ratio. Combine with "Diluted Packaged Fuel" for extremely high Crude Oil -> Fuel ratios, which can be used for very efficient Turbofuel or Plastic/Rubber (via "Recycled Plastic"/"Recycled Rubber") production.
 * Infused Uranium Cell mixed with original recipe: The alternate recipe is preferred, use the original recipe to boost the production if Quartz and Caterium are insufficient.
 * Insulated Crystal Oscillator: A little bit of Crude Oil is worth it to save on Quartz.
 * Iron Wire mixed with original recipe. The original recipe is slightly more resource-efficient and is preferred, unless Copper is fully utilized. Can be used with Stitched Iron Plate for the most efficient Iron-only Reinforced Iron Plate production.
 * Nuclear Fuel Unit mixed with original recipe: The alternate recipe is preferred, unless Crystal Oscillators are insufficient.
 * Polyester Fabric: Necessary to automate the production of Filters.
 * Pure Caterium Ingot, Pure Copper Ingot, Pure Iron Ingot, Pure Quartz Crystal: Substantial increase in conversion ratio by just adding Water. Requires using Refineries for ore processing, though.  Recommend using "Copper Alloy Ingot" over "Pure Copper Ingot" until Copper Ore is fully utilized, due to production footprint and _substantially_ reduced production speed per building.
 * Radio Control System: Although Supercomputers seem to be difficult to produce, this recipe is actually an all-round winner.
 * Recycled Plastic, Recycled Rubber: More complex, but way better than original recipe. Use both along with Heavy Oil Residue and Diluted Packaged Fuel for extremely efficient Crude Oil to Plastic/Rubber production (~3 Rubber/Plastic per Crude Oil, compared to original 0.67 Rubber/Plastic per Crude Oil)
 * Silicone Circuit Board: Actually better than "Caterium Circuit Board" since no Oil is involved.
 * Solid Steel Ingot, Compacted Steel Ingot: "Solid Steel Ingot" is preferred, as it produces approximately 67% more Steel per Iron Ore (if also using Pure Iron Ingot). "Compacted Steel Ingot" can be used to reduce Coal demand, as it requires only 45% as much Coal per Steel Ingot, at the cost of requiring an equal amount of Sulfur, and an Assembler making Compacted Coal for every 2.22 Foundries.
 * Steamed Copper Sheet: Half the Copper Ingots per Sheet just by adding Water. Requires processing in a Refinery rather than a Constructor, however.
 * Stitched Iron Plate: The most resource-efficient recipe. Combining with "Iron Wire" removes the need for Copper Ingots, at the cost of a very small reduction in raw resource efficiency.
 * Turbo Rigour Motor: Necessary for large scale Turbo Motor Production. The key point is to reduce the need for Radio Control Units which are also not easy to be mass-produced.
 * Wet Concrete: Double the conversion ratio just by adding water. Requires using Refineries for processing, though.

Mid-game and niche recipes

 * Biocoal, Charcoal: Useful if Coal is in shortage and Biomass and Woods are in excess. However it is recommended to craft wood into biomass for other uses instead.
 * Bolted Iron Plate: A substantial boost in speed compared to original recipe, at the cost of ~10% more Iron Ingots per Plate. "Stitched Iron Plate" is a more resource efficient alternative.
 * Caterium Circuit Board: Very useful in mid game, however Silicone Circuit Board is more efficient in the late game.
 * Caterium Wire, Quickwire Stator, Fused Wire: Useful in mid-game where Caterium is plenty.
 * Coke Steel Ingot: A method to get rid of excess Heavy Oil Residue. Safety precaution such as an overflow system is recommended to prevent jamming the Oil production upstream.
 * Crystal Computer: Useful in mid game where Quartz is still in excess.
 * Iron Alloy Ingot, Copper Alloy Ingot: When paired together they produce more ingots compared to separated production chains. In later game, pure ingot recipes are more efficient. On their own, "Copper Alloy" is *much* more useful than "Iron  Alloy", as Iron is more than twice as common as Copper, so effectively turning Iron into Copper is extremely useful mid-game.
 * Polymer Resin: Greatly increases Crude to Polymer ratio and Polymer production speed, at the cost of Heavy Oil Residue or Fuel output. Can be useful for supplying a Polyester Fabric factory, but is substantially less efficient compared to the a Recycled Plastic/Recycled Rubber combo for producing Plastic and Rubber (see above).
 * Pure Aluminum Ingot: Simplified recipe, better power consumption, diminished conversion rate.
 * Rigour Motor: Useful in mid-game. In late game, Crystal Oscillators are used in more important recipes.
 * Silicone High-Speed Connector: Use Raw Quartz instead Caterium Ore. Useful for mid-game where Quartz is still in excess.
 * Steel Rod, Steeled Frame: Useful if Coal is plenty.
 * Steel Rotor: Shares the same types of ingredients as default Stator, which can simplify production setup. The resource consumption, however, is not efficient.
 * Turbofuel, Turbo Heavy Fuel: Useful for pre-nuclear setup. "Turbofuel" is preferred over "Turbo Heavy Fuel", as it has a better conversion rate from Heavy Oil Residue.  Combine with "Heavy Oil Residue" and "Diluted Packaged Fuel" for extremely efficient Fuel Generator supply, with the ability to run ~148 Fuel Generators (22,222 MW) from just 300 Crude Oil per minute.

Inefficient recipes

 * High Speed Wiring: The complexity involved does not justify the speed boost.
 * Coated Cable, Insulated Cable, Quickwire Cable: All involve Oil which is a limited resource.
 * Coated Iron Plate, Steel Coated Plate, Adhered Iron Plate: All involve Oil which is a limited resource.
 * Electrode Circuit Board: This recipe will use up your Crude Oil quickly.
 * Electromagnetic Connection Rod: Increased production speed comes at the cost of adding Crude Oil and increasing usage of Caterium (or adding Quartz, if using alternate Silicone High-Speed Connector recipe).
 * Fine Concrete, Rubber Concrete: Limestone is abundant and there is no reason to use alternate recipes involving rarer resources.
 * Heavy Flexible Frame: Oil is more precious than Coal so there is no reason to use this.
 * Plastic Smart Plating, Flexible Framework: All involve Oil which is a limited resource.
 * Seismic Nobelisk: Crystal Oscillators are used in more important recipes.
 * Signal Beacon: The requirement for Quartz and Coal does not justify its speed boost.

Diluted Packaged Fuel
This combination uses Heavy Oil Residue -> Diluted Packaged Fuel to increase the Crude Oil -> Fuel conversion ratio by 4.5x. This improved fuel ratio is then combined with Recycled Plastic and Recycled Rubber to produce 3 Plastic or Rubber per 1 Crude Oil input.

The fuel conversion can alternatively be used with Turbofuel and Compacted Coal to greatly improve energy generation, allowing a single oil node to supply over 11x as many Fuel Generators at maximum usage, compared to the normal Crude Oil to Fuel recipe. Even relative to directly using the Fuel produced by the Diluted Fuel combination, Turbofuel increases the number of generators that can be supplied by 2.78x, at the cost of requiring Coal and Sulfur input for the Compacted Coal.

Nuclear Fuel
The base conversion rate of Uranium to Nuclear Fuel Rods is 100:1. Uranium Ore converts to Uranium Pellets at 1:1, Uranium Pellets convert to Encased Uranium Cells at 4:1, and Encased Uranium Cells convert to Nuclear Fuel Rods at 25:1. In total, this allows a single normal Uranium node (600/m using a Mk.3 Miner at 250%) to supply 30 Nuclear Power Plants, for a total of 75,000 MW of power. The alternate recipes Infused Uranium Cell and Nuclear Fuel Unit drastically improve this ratio. Infused Uranium Cells convert Uranium Pellets to Encased Uranium Cells at an 8:7 ratio (compared to 4:1, a 250% improvement), and Nuclear Fuel Unit converts Encased Uranium Cells to Nuclear Fuel Rods at a 50:3 ratio (compared to 25:1, a 50% improvement). This increases the number of fuel rods generated by 5.25x, allowing a single normal Uranium node to supply 157.5 Nuclear Power Plants, for a total of 393,750 MW of power. This increases the maximum sustainable nuclear power output from 225 GW to 1181 GW.

Alloyed Ingots
Using Iron Alloy Ingot and Copper Alloy Ingot together can yield significant increases in both for the same input. Normal smelting yields 1 Ingot per Ore input. Iron Alloy Ingot increases yield to 2.5 Ingots per 1 Iron Ore, at the cost of requiring an equal amount of Copper Ore. Copper Alloy Ingot increases yield to 2 Ingots per 1 Copper Ore, at the cost of requiring half as much Iron Ore. If used together, the net number of Ingots is increased by 2-2.5x, depending on ratios of usage between the two recipes.

Steel Ingots
Using the normal recipe, 1 Steel Ingot is produced per Iron Ore and Coal input. Using Solid Steel Ingot combined with Pure Iron Ingot can increase this yield to 39 Steel Ingots for 14 Iron Ore and 26 Coal input. This is 2.79x as efficient with regards to Iron Ore, and 1.5x as efficient with regards to Coal.

Compacted Steel Ingot combined with Compacted Coal can be used instead to ease the demand on Coal at the cost of overall yield (relative to the Solid Steel Ingot recipe) and Sulfur. It provides 10 Steel Ingots for 6 Iron Ore, 3 Coal, and 3 Sulfur. Relative to the normal Steel Ingot recipe, this is 1.67x as efficient on Iron Ore, and 3.33x as efficient on Coal. Relative to the Solid Steel Ingot recipe, this produces only ~60% as many Steel Ingots per Iron Ore input, but requires only 45% as much Coal *per Ingot* (at the cost of requiring an equal amount of Sulfur).