Welcome to openrocketengine’s documentation!


OpenRocketEngine performs the calculations for simple analysis and design of rocket engines. For a general overview of the philosophy behind designing rocket engines, refer to the rocket propulsion section of General Body of Knowledge (GBOK).


OpenRocketEngine only supports python 3.5 and above. Functionality with other python releases is untested and not guaranteed. Basic usage:

$ rocket config_file.cfg

Basic Usage

For basic usage, refer to `getting_started`_.

Note: checkout “Nomenclature” below if you are unsure about any of the variable used above

These input parameters are typical of what is used in industry design of rocket engines. If you are unfamiliar with this process, I recommend reading “Rocket Propulsion Elements” for basics, and “Mechanics and Thermodynamics of Propulsion” for a more rigorous mathematical overview.

To get these input parameters, you have essentially three options:

  1. free, but difficult to use
  2. generally trust worthy data
  1. Braeuing (http://www.braeunig.us/space/comb.htm)
  1. super simple and fast
  2. data is based on STANJAN (older version of CEA)
  3. no access to actual data files, so plot interpretation can result in signifant errors
  1. Testing
  1. challenging, but fun
  2. expensive and not really necessary given the resources above


Tc : chamber temperature thrust : Thrust pc : chamber pressure pa : ambient pressure MR : propellant mixture ratio MW : propellant gas molecular weight gamma : ratio of coefficient of heats