Getting Started

Designing a Rocket Engine

What does OpenRocketEngine Do?

OpenRocketEngine will perform some basic calculations for rocket thrust chamber designs. Additionally, it will be able to perform comparisions of different configurations.

This code was originally created with the intention of automating vehicle sizing trade studies.

Design Inputs


The physics behind the parameters mentioned here are not discussed. For a discussion on the physics behind the code refer to literature or gbok-propulsion.

The inputs are classified as either required or optional.

  • name: [str] The name of the engine; used for naming output files.
  • units: [str] (SI or Imperial)
  • thrust: [float] Engine thrust (duh)
  • Tc: [float] Chamber Temperature
  • pc: [float] Chamber Pressure
  • pe: [float] Exit Pressure
  • MR: [float] Mixture Ratio \(\frac{\dot{m}_{oxidizer}}{\dot{m}_{fuel}}\)

Configuration Files

openrocketengine takes a configuration file as the only input, specifying the engine propellant properties, pressures desired, and geometric design choices. Right now, there is only one possible combination of parameters that all have to be included in the config file. In the future, there may be additional options to automatically retrieve propellant properties from CEA.

Config files are usually named with the engine name and the revision number with a ‘.cfg’ suffix. I.e. RBF-rev01.cfg.

A typical configuration file looks like the following:

# This is a test configuration file for openrocketengine
# The parameters listed here are all the known parameters that openrocketengine can take as inputs.
# Refer to the official documentation for more implementation and usage details.
name RBF1
units SI
thrust 5000
Tc 3200
pc 2068000
pe 101325
MR 2.1
MW 18.9
gamma 2.31
# Geometric parameters
lstar 1.016
area_ratio 5.5

Running the program

openrocketengine can be fun from the command line with the command rocket:

$ rocket RBF-rev01.cfg


openrocketengine generates an output excel workbook with two sheets; one geometric parameters, and one for performance parameters.