Horizon 1: Python Simulations and Analysis

This repository is a collection of all of the code I wrote for Brazoswood's 2021-2022 Goddard program. Each year, we build a hybrid rocket from the ground up, launching it at the WSMR missile range after the school year. The program has improved steadily, with 5/5 successful flights, reaching 35,000" in 2021 and 43,000" in 2022.

However, there are many different problems that the design process entails. There are scripts in the repository for design optimization, simulation, and post-flight analysis. Though it is possible, the code was not written with the intention of being used as a library, rather as a reference for future years - if a future year faces a problem with using Python in the design process, they can find Goddard 2022's solution here.

User Guide

If you would like to use the code to simulate your rocket, there are several things that must be input input. After the repository is closed, you should open up the SimulateRocket file. This file is the main entrypoint for running a basic flight simulation, although you could easily use similar code in a different file to have the same effect.

To run either a rocket or a motor simulation, you need to have an Environment object. It will tells any simulation the time_increment and the atmospheric conditionss, including wind. The rocket also needs a motor, so you can either pass in an instance of CustomMotor (simulating all the combustion by hand) or you can specify a pre-defined thrust curve in the Motor class. Parachutes are also passed in as a separate list of Parachute objects.

Once your rocket is ready to go, there are several helper classes that loop through the frames of the flight: Simulation to iteratively sum forces and update the physics, and Logger to store the data and print events. Once all of the classes have been initialized and all references set, call .run() on the Simulation object. Here is a sample:

from environment import Environment
from src.rocketparts.motor import Motor
from rocket import Rocket
from src.rocketparts.parachute import ApogeeParachute, Parachute
from logger import RocketLogger 
from simulation import RocketSimulation

env = Environment({"time_increment": 0.1})
motor = Motor()
drogue_parachute = ApogeeParachute({"radius": 0.2})
main_parachute = Parachute()
rocket = Rocket(environment=env, motor=motor, parachutes=[drogue_parachute, main_parachute])
logger = RocketLogger(
    rocket,
    ['position', 'velocity', 'acceleration', 'rotation', 'angular_velocity',
     'angular_acceleration'])

logger.splitting_arrays = True

sim = RocketSimulation(environment=env, rocket=rocket, logger=logger)

sim.run_simulation()

Programming Conventions and Style

Visualization

The graphing is done using MatPlotLib since it provided easy integration with Pandas and Numpy.

I also have a ToBlender.py file which can export your .csv file to Blender 3D. Unfortunately, that file must be run inside of Blender's code editor, so it is mostly here for completeness, running it by itself will throw lots of errors.

Sources / Further Reading

• Notes on Multiple Degrees of Freedom for Goddard 2021-2022
• I really think this Topics in Advanced Model Rocketry book would have been super helpful, but I could never get my hands on it.
• The designNotes.md file has most of the information about programming-oriented decisions that I made.
• OpenRocket Technical Manual