Rocket Engines

Rocket Engines give you their max output in kN with this you can calculate what they can reasonably carry into orbit depending on the planet or moon you are on. Force = Mass * Acceleration. Acceleration is equal to the planet's gravity, Mass is given in kg per part of the rocket, and Force is kN. If your thrust force listed below is less than the weight of the rocket in kN then you will not even take off. It is better to have a thrust much higher than the weight of the rocket or else you risk running out of fuel on launch and on landing.

Liquid propellants bring greater efficiencies. Using Nitrous Oxide as oxidizer provides excessive thrust values. Keep in mind that N2O fuel mix is 1.9375 times heavier at same moles, or 2.15 times heavier at same volume, while thrust boost is around 1.5-1.7. Engine efficiency determines "bonus" thrust multiplier, meaning engine with higher efficiency will give more thrust consuming same amount of fuel. Thus using liquid engines is more favorable if one can cool fuel down, moreover Pressure Fed Engines consume fuel inversely proportional to its temperature. On the other hand if Volatiles and Oxygen are in excess (e.g. farm on Vulcan) is may be much easier to opt for Pressure Fed Gas Engine. It will provide ~40kN at 20°C.

Name	Power Usage, W	Rocket Mass Contribution, kg	Formal Max Thrust, kN	Tested Max Thrust, kN				Propellant consumption, mol/tick			Efficiency, %	Exhaust Velocity, km/s	Specifc Index Isp, s
				Using O2	Using N2O	Using O3	Using N2H4	Using O2	Using N2O	Using N2H4
Pumped Gas Engine	200	500	16.20	16.54	24.47	19.40	18.10	18.00	18.00		100	4.02	411
Pumped Liquid Engine	200	500	17.90	18.74	31.25	5.52	25.00	15.00	16.66		140	5.56	568
Pressure Fed Gas Engine	10	500	40.30	60.32	41.57			69.77	31.68		96	3.86	394
Pressure Fed Liquid Engine	20	500	29.30	38.84	59.70			27.23	28.16		160	6.31	644
Heavy Pressure Fed Gas Engine	10	750	62.60	93.87	64.75			118.45	53.83		88	3.54	361
Heavy Pressure Fed Liquid Engine	20	750	44.30	60.39	95.52			47.03	49.86		144	5.68	579
Update 0.2.6136.26812 - 01/28/2026 Rocket_Engines

Note: Hydrazine (N₂H₄) testing was performed at 282K (9C) for Liquid Pumped, and 500K (227C) for Gas Pumped engines. Methane and Ozone (O₃) tests performed at 128K (-145C) for Liquid Pumped, and 273K (0C) for Gas Pumped engines. Methane and Ozone performed very poorly in a liquid configuration.