TT-38K Radial Decoupler

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TT-38K Radial Decoupler
Part image
Decoupler by
O.M.B. Demolition Enterprises
Cost (total) 600.00 Funds
Mass (total) 0.02500 t
Drag 0.2
Max. Temp. 2000 K
Volume  ?
Impact Tolerance 8 m/s
Research Stability.png Stability
Unlock cost 1 200 Funds
Since version 0.7.3
Part configuration decouplerRadialTT-38K.cfg
Ejection momentum 2500 Ns
Testing Environments
On the surface Yes
In the ocean Yes
On the launchpad Yes
In the atmosphere Yes
Sub orbital No
In an orbit No
On an escape No
Docked No
Test by staging Yes
Manually testable No

The TT-38K Radial Decoupler is a decoupler that allows for staging rockets horizontally and in parallel.

Product description

The TT-38K Radial Decoupler, like most other decouplers, is equipped with a (hopefully) small explosive charge, that will sever the structural linkage between itself and whatever it's connected to.

O.M.B. Demolition Enterprises


The TT-38K adds a stage to the rocket and when activated will jettison the decoupler as well as anything attached to it, much like the TD-12 Decoupler. Visually, the decoupler's legs are left behind, but they add no mass or drag to the parent part.

Since the TT-38K is radially attached, it can be used to attach additional parts to the side of a rocket stack, instead of below it. This makes it possible to stage parts in parallel, and is a critical component of asparagus staging. Additionally, by building a rocket horizontally, players can reduce wobble caused by extremely tall rockets.

If attaching a single part to the TT-38K, it is safest to attach it to the lower half of the decoupler. If a part is attached in this way, then when the decoupler is jettisoned, it will apply its outward force to the top of the jettisoned part, causing it to rotate away from (instead of rotating towards and colliding with) the rocket.

You will often find that if you have a long section of liquid fuel tanks or solid boosters that they can twist the joint and potentially break off or explode on your craft. For this reason it is wise to use the decoupler towards one end of the side pod and use EAS-4 Strut Connectors or autostruts to keep the other end steady (preferably a pair to help reduce the twisting the side pod might have).


  • In the past liquid fuel system modules could not be attached to a TT-38K; however, you could attach TT-38Ks to solid fuel system modules. An easy workaround used by many was simply attaching an RT-10 Solid Fuel Booster to the TT-38K and then stacking liquid fuel system modules below.
  • Since version 0.13 however the stock liquid fuel systems have been radially attachable and either fuel engines below them, or through use of the FTX-2 External Fuel Duct fuel line, also introduced in this version.


  • New model and texture
  • (undocumented) Ejection Force increased from 5 to 120
  • Decouplers now obey the second law of physics (Acceleration = Force/Mass)
  • (unimplemented) Increased the ejection force of Decouplers and Radial Decouplers (too underpowered after the physics fix)
  • Removed parent-wise fuel cross-feed from Radial Decouplers. Fuel Lines made that obsolete
  • (undocumented) Ejection Force decreased from 15 to 5
  • (undocumented) Radial decouplers can now cross-feed fuel
  • Radial decouplers now have their own module (they used to share modules with the stack decoupler)
  • Tweaked the Radial Decoupler separation. It can now eject lit SRBs safely away from the ship and not kill the crew every time
  • Initial Release