Spaceflight Simulator Wiki

For the stack separator variant, see Separator

Side Separator or Booster Separator is a part mainly used to detach boosters from rocket 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 rocket'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 rocket 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.
  • These parts can even make force out of them just to launch a rocket. Many side separators with twice their separation force can launch a rocket possibly to orbit without engines. This is the only way to do rocket launches without any engines; the other one being the force of docking ports.
Basics ParachuteCapsuleHeat ShieldSeparatorFuel TanksHawk EngineValiant EngineKolibri EnginePeregrine EngineRCS ThrustersSide SeparatorSolid Rocket BoostersAerodynamic Nose ConeLanding Leg
6 Wide 6 Wide Aerodynamic Nose ConeFuel TanksSeparatorHeat ShieldEngine Base
8 Wide 8 Wide Aerodynamic Nose ConeFuel TanksSeparatorHeat ShieldEngine Base
10 Wide Fuel TanksSeparatorHeat ShieldEngine Base
12 Wide Fuel TanksSeparatorHeat ShieldEngine Base
Engines Titan EngineFrontier EngineHawk EnginePeregrine EngineValiant EngineKolibri EngineRCS ThrustersIon Engine
Aerodynamic Parts ParachuteSide ParachuteAerodynamic Nose ConeAerodynamic Fuselage
Fairings Fairing
Structural Structural Part
Other Docking PortLanding LegsIon EngineProbeRCS ThrustersWheelsSolar PanelFuel Pipe
Currently removed in Version 1.5
Removed in older versions
Probe (Large)Fairing AdapterAdapter