Spaceflight Simulator Wiki

For the stack separator variant, see Separator

Side Separator or Booster Separator is a part mainly used to detach boosters from inner stages during flight. They are attached when building the rocket in the Build Editor.

They are recommended over rotated separators as side separators are lighter and more aerodynamic. Unlike regular separators, which look circular, side separators appear as two dark rectangular objects and separate in the middle. Each half will stay on the surface it's connected to, but will not have any mass to affect the craft's functionality.

If a stage is only used in space, and enclosed in a fairing during all atmospheric use before decoupling, a one-way Docking Port (to decouple from the craft with the expended stage) is preferable, because it uses half the area of a side separator, 5% less mass before decoupling and no mass after decoupling.


  • Side separators can also function as projectile weapons as their halves separate with great speed and force.
Basics ParachuteCapsuleHawk EngineValiant EngineKolibri EngineFuel TanksSeparatorSide SeparatorAerodynamic Nose ConeLanding Leg
6 Wide 6 Wide Aerodynamic Nose ConeFuel TanksTitan EngineSeparator
8 Wide 8 Wide Aerodynamic Nose ConeFuel TanksSeparator
10 Wide Fuel TanksSeparator
12 Wide Fuel TanksSeparator
Engines Hawk EngineValiant EngineKolibri EngineTitan EngineFrontier EngineRCS ThrustersIon Engine
Aerodynamic Parts ParachuteSide ParachuteAerodynamic Nose ConeAerodynamic Fuselage
Fairings Fairing
Structural Structural Part
Other Docking PortLanding LegsIon EngineProbeRCS ThrustersRover WheelsSolar Panel
Currently discontinued in Version 1.5
BatteryRadioisotope Thermoelectric Generator