Calculating stability thresholds for finless spin-stabilized projectiles

We're not too fancy here. Get started by cloning the repo git clone https://github.com/stanford-ssi/Spaceshot-Dynamics-Aero.git

You'll need some basic packages for scientific computing with Python

• Python 3.6 or higher
• numpy==1.16.2
• scipy==1.2.1
• matplotlib==3.0.3 And some more exotic ones
• numpy-quaternion==2020.11.2.17.0.49
• numba==0.43.1 Stabsim also relies on Digital DATCOM to calculate aerodynamic coefficients. A compile version of the fortran is provided but its unlikely to work for everyone's set up. If you experience issues with DATCOM

1. Download the Digital Datcom via Public Domain Aeronautical Software
2. Install the Fortran compiler gfortran. On Ubuntu this is as simple as

sudo apt update && sudo apt upgrade
sudo apt install gfortran

3. Compile stabsim/DigitalDATCOM/datcom.f using the legacy version of gfortran

gfortran -std=legacy datcom.f -o datcom

The process for running stabsim is currently being overhauled but the command-line interface should remain fairly stagnant. Examplesare provided in examples/. A sample is provided below for convenience

motor_dim = "data/H550_dim.csv"
motor_thrust = "data/H550_thrust.txt"
rocket = "data/Marvin.csv"
marvin_body = Rocket(os.path.join(script_dir, rocket))

H550 = load_motor(os.path.join(script_dir, motor_dim), os.path.join(script_dir, motor_thrust))
marvin = Profile(marvin_body, H550, 262, launch_altit=26000, length=25, timesteps=100)
vis.kinematics(marvin)
vis.spin(marvin)

As you can see, sample motors and airframe data is provided in the data\ folder. To run stabsim on a new configuration you'll need to provide

1. Dimensons of the motor as a csv
2. Thrust curve of the motor as a txt
3. Dimensions of the airframe as a csv
4. Dimensions of the airframe as a dcm Clearly this is a lot of data. The new GUI should make all of this a bit simpler but until then you'll have to bare with this.

End with an example of getting some data out of the system or using it for a little demo

• TKInter - Python Interface to TK GUI toolkit
• Digital DATCOM - by USAF via PDAD
• NRMLSISE-00 - atmospheric model

This project is licensed under the MIT License - see the LICENSE.md file for details

• The many many many folks who sweat and tears have gone into Spaceshot