Chemical Rocket Engine

Chemical Rocket Engines work by letting the propellant masses react chemically, expanding its volume dramatically, and ejecting the reaction product out of the rocket, creating thrust. Many of the current real-life rockets rely on this kind of propulsion.

Because Terra Invicta starts in the current age, several chemical drives are already unlocked without the need for research.

Common Characteristics

• High thrust. Chemical rockets feature extremely high thrust. The thrust of the Neutron and Diana drives are some of the highest in the game, outperforming alien drives effortlessly.
• Low exhaust velocity. Spaceships with the earlier chemical drives won't go far beyond Luna. Drives such as the Venture and Nova rocket fare better, and the Super Kronos Rocket is a big improvement. But even the most basic electrostatic drive will outperform any chemical drive with regard to efficiency.
• No power plant requirement. Chemical engines do not require power and have no restrictions on the power plant.

Details

Apex Solid Rocket

"Powerful but inefficient rocket that mixes polybutadiene acrylonitrile with an ammonium percholate[sic] oxidizer to produce thrust."

This engine is unlocked at the start of the campaign. There is no reason to use it over other the more powerful and efficient Neutron rocket, which is unlocked at the start too.

Meteor Liquid Rocket

"Mixing refined kerosene and liquid oxygen is ideal for reaching Earth orbit."

This engine is unlocked at the start of the campaign too. Like the Apex rocket, there is no reason to use it over other the Neutron rocket.

Neutron Liquid Rocket

"Hydrazine reacts with nitrogen textroxide[sic] to provide thrust."

Already unlocked at the start of the campaign. It has the highest thrust of any chemical rocket engine and the second highest in the game, making it extremely powerful for defensive ships. However, as with any chemical rocket, its efficiency is really low, making it the second lowest (just barely more efficient than the Resistojet, excluding the Apex and Meteor drives).

Venture Liquid Rocket

"Cryogenic liquid hydrogen mixes with oxygen for improved efficiency."

The Venture rocket is available from the beginning too. While having just less than half the thrust of the Neutron rocket (which still puts it well ahead of the aliens' thrust), it has a slightly improved efficiency. In addition, it uses water as propellant, which might be favorable depending on the amount of space resources available.

Diana Superheavy Rocket

"Heavy-duty liquid methane-oxygen rockets offer high thrust output."

The global research that unlocks the project for the Diana rocket is Advanced Chemical Rocketry (1000 Material Science). At roughly the same thrust as the Neutron drive, it features a very slightly improved efficiency. It also uses a combination of water and volatiles as fuel, instead of just volatiles.

Nova Liquid Rocket

"Stabilized hydrogen fuel offers heretofore impossible efficiency in chemical rockets."

The Nova rocket project depends on the project for the Diana rocket. It further trades the thrust in favor of efficiency. This makes it more efficient than all other chemical rockets before it, but still really inefficient compared to any other type of drive.

Super Kronos Liquid Rocket

"Metastable helium provides efficiencies only thought possible in electrical or nuclear drives."

This rocket engine is locked behind some higher research. Advanced Hydrogen Containment (20 000 Material Science) may unlock the Advanced Chemical Rockets project. It makes a significant jump in efficiency, placing it in a similar level as the worst of the electrostatic engines, while still delivering on relatively high thrust.

Comparison

Name	Thrust [N]	EV [km/s]	Propellant (per tank)	Mass [t]	Build costs	Required project
Apex Solid Rocket	14820000	2.6	10V	66	6.6M	Sold-Fuel Space Rockets
Meteor Liquid Rocket	15481000	2.98	6W 4V	17	1.7M	Liquid-Fuel Space Rockets
Neutron Liquid Rocket	20376000	3.1	10V	13	1.3M	Liquid-Fuel Space Rockets
Venture Liquid Rocket	9279600	4.44	10W	14	1.4M	Cryogenic-Fuel Space Rockets
Diana Superheavy Rocket	20160000	3.73	6W 4V	14	1.4M	Superheavy Chemical Rockets
Nova Liquid Rocket	7850000	5.6	10W	15	1.5M	Interplanetary Chemical Rockets
Super Kronos Liquid Rocket	2500000	21.6	9.98V 0.02F	10	1.0M	Advanced Chemical Rockets