Endgame Guide: Rockets, Low Density Structures & Steam

The endgame phase of Factorio is the stage where you move from a functioning factory to one optimized for very large-scale, sustained production, rocket launches, and open-ended progression (infinite research, high-tier modules, Space Age). This guide summarizes the core goals, resource requirements, production concerns, and late-game systems you will manage to reliably launch rockets and continue developing your factory after the nominal “win.”

Goals of endgame

Produce and launch repeated rockets (space science) at a chosen cadence.
Scale and sustain supply of the highest-tier intermediate products (low density structures, rocket parts, rocket control units, etc.).
Maximize throughput and efficiency with modules, beacons, and productivity where appropriate.
Continue progression via infinite technologies and optional Space Age mechanics.

Rocket and satellite production requirements

A completed rocket launch requires 100 rocket parts.
Each rocket part is made from several intermediates; producing 100 rocket parts (one full rocket) has very large raw-material costs: examples from crafting breakdowns show requirements on the order of tens to hundreds of thousands of units of petroleum products, copper/iron ore, coal, and water. Expect raw-material inputs measured in tens of thousands for ores and hundreds of thousands or hundreds of thousands of liquid units for oil/water when planning long-term launches.
Space science (satellites) require extra materials; launching a satellite adds further costs (coal, water, oil, copper, iron) on the order of thousands to tens of thousands of each resource.
Low Density Structures: in the base game, 10 low density structures are required per rocket part (thus 1000 low density structures per rocket). In the Space Age mode, that requirement is changed to 1 low density structure per rocket part (so 50 per rocket); Space Age also provides a research that grants productivity specifically for low density structures.

Plan your production lines explicitly for Low Density Structures (LDS) because they are one of the biggest mass consumers late-game.

Energy and high-temperature steam

Steam stores thermal energy proportional to its temperature above the environmental baseline. The energy content per steam unit increases linearly with temperature (energy added to raise temperature is stored). Steam produced by boilers is at 165 °C, while steam from heat exchangers (nuclear / thermal) is at 500 °C.
Steam has an energy-per-unit-per-degree relationship: each unit of fluid requires a fixed amount of energy per degree Celsius to heat. The practical implication: steam at higher temperatures contains substantially more usable energy per inventory/tank than lower-temperature steam — useful when planning energy storage and transport (e.g., steam tank buffering).
Steam pipes and tanks do not lose thermal energy simply from sitting or flowing; energy invested to make steam can be fully recovered by engines/turbines because those machines are mechanically modelled as 100% efficient for converting steam thermal content into their rated electrical output.

Example: a storage tank with 25,000 steam units at 165 °C holds very large amounts of energy; a tank at 500 °C of the same unit count holds multiple times more energy.

Scaling production: modules, beacons, and productivity

Late-game factories rely heavily on modules and beacons to increase throughput and/or productivity:
- Productivity modules increase the output per input; they are especially valuable on rocket-related recipes because they reduce raw-material demand per rocket part by increasing finished product yield.
- Performance modules and beacons allow you to concentrate effects and tune between raw throughput and energy consumption.
Space Age introduces item-specific productivity research for Low Density Structures, enabling higher effective yields for one of the most expensive rocket inputs.

When optimizing, prioritize productivity where it reduces bottleneck raw materials (e.g., heavy oil, petroleum gas, plastic, sulfur, batteries), and use speed/beacon setups where absolute factory throughput is the limiting factor.

Infinite technologies and continued progression

Infinite technologies are late-game repeatable researches that increase certain bonuses indefinitely as long as you supply science packs. They only increase numeric bonuses (no new items) and are intended as persistent targets after launching your first rocket.
Infinite techs require high-tier science (including space science packs in base game) and exhibit diminishing marginal returns per level; each additional level adds the same absolute bonus but contributes less relatively as the total grows.
Most infinite technologies are placed in the technology tree so they become available at the tail end of the tech progression; they are the primary driver for late-game research once you begin launching rockets.

Plan long-term science production if you intend to pursue many levels of infinite tech.

Factory layout and logistics for sustained launches

Throughput: design production branches for the most expensive intermediates (Low Density Structures, rocket control units, batteries, rocket fuel, advanced circuits) with overcapacity and buffer storage so single-line failures don’t stall launches.
Buffering: use large storage tanks for liquids (water, petroleum gas, heavy/light oil, lubricant) and large logistic chests for solids. Steam tanks at higher temperatures are particularly dense energy buffers for power systems.
Balancing and ratios: compute desired launch cadence (e.g., one rocket per X minutes) and scale each subassembly to meet per-minute consumption; apply productivity module yield when calculating raw input needs.
Supply security: secure raw ores and oilfields with backup trains or additional pumpjack fields to replace depletion; automation for refueling or supplying solid fuel/coal/rocket-fuel is critical.
Defense: late-game pollution and biter evolution may be high; keep automated defenses, repair, and turret ammo production online with priority.

Performance considerations

High-throughput oil and chemical processing chains can become CPU/UPS heavy. Use combinators sparsely and prefer simple belt/trains for bulk transport.
Use beacons judiciously; a few well-placed beacons with high-tier modules often outperform indiscriminate coverage and save circuit and performance costs.
Trains remain the most practical long-distance logistics solution for the massive resource flows needed for continuous rocket production.

Practical checklist for first sustained rocket launches

Automate full production of all rocket part subcomponents and ensure buffers sized for several launches.
Build a dedicated Low Density Structure line with productivity support and sufficient inputs (sulfur, plastic, advanced circuits, etc.).
Establish stable oil refining and cracking infrastructure to supply petroleum gas, light/heavy oils, and feedstocks (plastic, sulfur, lubricant).
Provide stable power: consider nuclear with high-temperature heat exchangers to produce 500 °C steam if you require dense energy storage and reduced space footprint.
Produce space science and plan for satellite assembly if you will launch satellites for space science packs.
Set up a space-silo-fed assembly and inserter configuration to automatically feed rocket parts and launch when a full complement is present.

By focusing on bottlenecks (Low Density Structures and petroleum derivatives), using productivity where it reduces scarce inputs, and buffering with high-capacity tanks and chests, you can scale from single-rocket launches to a continuous rocket production program and continue advancing through infinite technologies and Space Age content.