Tutorial:Changing Part Configuration Files

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This tutorial will explain how to change your part.CFG files to edit certain parts. This tutorial does NOT explain how to edit the actual part appearances. This tutorial assumes you are using KSP 0.25 or higher. Future versions are probably supported. The main topics covered here will be:

  • Finding the file(s)
  • Changing the name or description of the part.
  • Changing the amount of fuel, etc. and the issues associated with that.


  • Difficulty = Hard-Medium (Depends on experience.)
  • Estimated Time of Completion = As little as 5-15 minutes Longer if you edit more than one file or amount of edit.


As with any computer program, editing the files comes with the inherent risk that you could damage the program. This tutorial SHOULD NOT damage your game, but the KSP Wiki cannot guarantee that your game will be undamaged by editing part.cfg files. By proceeding you signify that you accept the risks involved in this undertaking and that the KSP Wiki is not responsible for any damage to your game or computer caused by your editing of the game files. Should your game malfunction, a full re-download may be required to fix the game. (Backing up the modified file is extremely recommend)

Step 1: Locating the CFG files

In general all configuration files required for this are in a subdirectory of GameData. Itself is a subdirectory of the root directory.

  • When you find the folder GameData, open it
  • From here you will find two other folders. The "NASAmission" folder, and the "Squad" folder. You may see more folders if you install mods for KSP. The "NASAmission" folder contains all the parts created with the help of NASA in the most recent update, like the four block engine, or the Launch Escape System. The "Squad" folder contains most of the stock parts, like the Command Pod Mk1, or the Mobile Processing Lab. We will open the "Squad" folder.
  • From here, you will find the folders containing just about every object in the game. Since we are editing parts, open the "Parts" folder (obviously). There is also a "SPP" directory which contain the parts from the Spaceplane+ mod integrated in 0.25.
  • From there, you will find more folders, each one representing a tab in the Vehicle Assembly Building (only true for Squad/NASA parts, and even then, not 100% accurate - see MK1, for example). For this tutorial, we are going to edit an engine! So, open the "Engine" folder.
  • Now you will see a folder for engine in the game. Lets edit the Rockomax "Skipper" Liquid Engine engine.
  • Open the "liquidEngineSkipper" folder. You will find all the files associated with that engine.
  • The only file we are interested in is the skipperLiquidEngine.cfg. All the other files are for the actual 3D model-what we see when we grab it in the VAB.
  • Now open the "skipperLiquidEngine.cfg" in a text editor of your choice. There are no special programs required.

Step 2: Editing the files

The following instructions work for both Windows and Mac.

  • Upon opening Part.CFG, you will see many confusing things written. Don't mess with the first things. Scroll down to the sub-tab "editor parameters".
  • Now lets see what each thing does.

Name (Above Partparemeters, at the top.)

This part is critical for correct gameplay. The reason is that if the name is the same as any other part overwrites to the modded one. Make sure that this does not match any other part.

Tech Required

In the CFG file, it is specifically called TechRequired. From here you can edit the name of the tech that you have to research in the R&D facility. Make sure you spell the name of the tech you want it to be correctly or the part will not appear or be usable in career mode.

Entry Cost

This is currently unused (as of KSP version 1.0.4) and will have no effect on the game. Keep in mind that if you change it and entry costs are implemented, the cost may carry over into the update.


This is the cost of the part when building with it in Career Mode.


This is the category the part appears under in the VAB or SPH. This can be any of the following (without quotations, case sensitive): "Pods", "FuelTank", "Engine", "specializedControl", "Structural", "Aero", "Utility", and "Science". You must spell this exactly right, and they are case sensitive. If you don't the part WILL NOT show up in either building.


Subcategories are currently not used (as of KSP version 1.0.4)


This is the name of the part that will show up when you mouse over the part in the VAB/SPH.


This is the description of the part that shows up in-game.

Basic information

You would see this if you go down a bit further:

   mass = 2.25
   dragModelType = default
   maximum_drag = 0.2
   minimum_drag = 0.2
   angularDrag = 2
   crashTolerance = 12
   maxTemp = 4000

"Mass" is pretty straight forward, and also "crashTolerance". Min and Max drag are the drag the part generate in different situations. For example, an air-intake's max drag can be up to something like 3. "maxTemp" is the max temperature your part tolerate, if the temperature goes beyond this point, you would most likely lose the part of your ship.

Specific impulse

For engines, you should find something like this: (This is the .cfg of the nuclear engine)

   key = 0 800
   key = 1 220

The "0 800" is the vacuum isp of the engine. The "0" seem like to be the atmosphere pressure when the isp is presented. The "0" is vacuum, and "1" is at sea level. But anyway, I wouldn't mess with the number over there. The "800" and "220" is the isp of the engine, and should be what you are looking for.


It's best not to mess with these unless you know what you're doing. These give the part special properties, like thrust and gimbal (in an engine). The parachute have a "module {name = parachute}", and the engines have "module {name = engine}", and under each, there's stuffs that defines it. For example, gimbal range, max and min thrust, heat production, etc. But anyway, say you have KAS, and want the Kerbals to grab something that's not in KAS's list, you can copy the module

   name = KASModuleGrab
   ... ...

Part to the part you desired and run the game. Be careful about this part, something weird would happen if something goes wrong in the Module area.

Moving on

Now, proceed further down in the file and locate the "Standard part parameters tab". From here you can edit the basic physics of the part, from its size to its crash tolerance. Each one is a numerical value that is unlimited.

Moving on more

Below that you will find the actual fuel and thrust for the part. These are spread out throughout the file and you will need to read through to find them. You can edit the minimum thrust or the maximum thrust. You can also edit just about anything related to how the part behaves in the game.

Finishing up

When you are done, save your work and open up KSP. See if your changes worked. If the game messes up, you did something wrong so restart. Here's just a couple things to make note of:

  • If you change the engines thrust, it will burn more fuel. So, if you change the thrust to an insane amount like 100000000000000, you will run out of fuel in about a millisecond. Just a word of advice.
  • Messing with stuff that was not covered in this tutorial is not recommended, as the author(s) have not experimented with them. If you do encounter any problems, re-downloading the game will fix them.
  • It is recommended that you always have a backup of the file you are editing so that you can quickly fix problems without having to re-download.

Thanks for reading, and happy editing!