Mass400 kg
Size100 x 100 x 100 cm
Push/Pull FluidAccept Push


The big thruster generates thrust through the combustion of liquid fuel with liquid oxygen. It can handle both CH4 (methane) and H2 (hydrogen) as its fuel. It uses a radial aerospike nozzle and it's very efficient at converting combustion energy directly to thrust. It can produce up to 1.8 MN of thrust from a flow rate of 100 Kg/s LOX and 12.5 Kg/s H2.


Connect high flow oxydizer and fuel to the fluid ports, high voltage for ignition, and send 1 in the data port to ignite.

Initial ignition will only occur when the flow rate is between 1 g/s and 50 kg/s, for either the fuel or the oxydizer.

When the fuel is H2, the optimal flow ratio is 8:1 (LOX:H2) and and ratio of < 1:1 may result in a flame out (no combustion). When the fuel is CH4, the optimal flow ratio is 4:1 (LOX:CH4) and and ratio of < 1:1 may result in a flame out (no combustion).

The igniter does not need to be kept on once combustion has begun, although it's a good idea to leave it on in case of a flame out. Ignition consumes 1000 watts continuously when on.

The big thruster's nozzle can gimbal with a variation of -10 to +10 degrees in two axes.

List of inputs

0Ignition0 or 1
1Gimbal X-1.0 to +1.0
2Gimbal Z-1.0 to +1.0

List of outputs

1Burned flowkg/s
2Unburned flowkg/s

If your fuel tank is pre-mixte, you don't need to use both fluid ports.