kOS: Kerbal Operating System

Full Documentation


Getting started

PRINT "Hello World.".
PRINT "These are the documents for Kerbal Operating System.".

The do-it-yourself autopilot

kOS, or Kerbal Operating System, is a community-supported mod for the popular game Kerbal Space Program

kOS is an autopilot you script yourself. kOS is to programming, what Kerbal Space Program itself is to rocket science. You don’t have to know what you’re doing to get started, but you may find yourself learning a lot by accident as you play with it. And if you already know a lot about the topic, it will still be able to hold your interest. kOS is meant to scale with the skill level of the user. You can start off doing very small simple things with it, and get more and more into using its features as you go.

What it does

kOS introduces a few new parts that each contain a simulated computer capable of running programs written in its own scripting language called kerboscript. The computer has powerful smarts built in to the hardware that allow it to do complex spacecraft operations in one command, thus making it possible to make complex programs with only a few lines of script text.

The intent of kOS is to be a fully in-game item that lives inside the Kerbal’s universe. The program isn’t running on your own gaming computer, but rather it’s being run in a virtual machine that is simulated in the underlying Unity engine.

Get me Started!

There is a quickstart tutorial for people new to kOS that gets you off the ground with a very simple launching script, sufficient to be an introduction for people new to the mod. Go ahead and give it a try.


Like other Kerbal Space Program mods, simply copy the contents of the zip file into your Kerbal Space Program folder, where it will install into your GameData folder.

The mod is downloadable from a number of locations.


The page you are looking at right now is the entry point into the full documentation of kOS. See the full table of contents here: Full Documentation.

Online Community

kOS has an active community of users willing to help each other with ideas and algorithms.


kOS was originally begun as a mod by a single author, Kevin Laity aka Nivekk. Although the project has undergone massive changes since then and now has a very different underlying architecture and is under active development by a different set of people, none of that would have been possible without his original vision and work.