Monopropellant

	Monopropellant
Density	4 kg/l
Transferable	Yes
Tweakable	Yes
Drainable	Yes
Flow mode	Everywhere
Cost	1.2 /l
	0.3 /kg
Since version	0.18

Monopropellant is a resource that is used by most RCS thrusters along with the O-10 "Puff" MonoPropellant Fuel Engine. It is stored in separate tanks from liquid fuel or oxidizer (such as the Stratus-V Roundified Monopropellant Tank), and may be transferred around a vessel. Crew containing command modules also store a small quantity of monopropellant. Stored monopropellant is available to every thruster on a vessel. As of version 0.23.5, containers on earlier stages are drained before containers on later stages.

Monopropellant is also generally assumed to be used by the jetpacks worn by Kerbals on EVA. The jetpack is resupplied when the Kerbonaut enters a command module. As of version 1.6, this action does not remove any monopropellant from the craft's supply.

Real world equivalent

In reality, most manned vehicles burn a hypergolic (self-igniting) mix of some hydrazine-bearing chemical and dinitrogen tetroxide in their RCS thrusters. Monopropellant systems are more common on satellites and space probes, such as the Mariner-Voyager series.