Deuterium

Deuterium is a stable heavier isotope of Hydrogen and a mid- to late-game material used in several advanced production chains. Its main uses are in Deuteron Fuel Rod, Strange Matter, and Plasma Capsule production. It can also be burned in Thermal Power Plant and in Icarus’s fuel chamber, but it provides the same performance as Hydrogen there, so it is generally not worth using as fuel.

In practice, Deuterium is mostly produced by reprocessing Hydrogen or collected directly from Gas Giant orbit via Orbital Collectors. It is also a key downstream bottleneck because Strange Matter requires 10 Deuterium, which makes Deuterium supply important for Gravity Matrix production. Small Carrier Rocket production also depends on Deuteron Fuel Rod, further increasing demand in the late game.

Fractionators are the standard way to produce Deuterium efficiently. Compared with Particle Colliders, a Fractionator setup is much more energy efficient, though it requires more space and usually works best in a simple loop with a buffer of Liquid Storage slowly refilled with Hydrogen. A common middle ground is to process Hydrogen in a 4-stack using the Automatic Piler: this increases throughput and remains more efficient than Particle Colliders while keeping the 1:1 Hydrogen-to-Deuterium conversion.

• Fractionator production is roughly 2.5 times more energy efficient than Particle Colliders when using Mk.III Conveyor Belts.
• A 4-stack Fractionator setup uses about 1.375 times as much energy per Deuterium as a normal Fractionator, but it reaches throughput closer to a Particle Collider line.
• Deuterium demand is especially high when Strange Matter production scales up.
• Direct collection from Gas Giants helps, but usually does not meet late-game demand by itself.
• Hydrogen balance matters, since late-game production also needs Hydrogen for Casimir Crystal chains.