Stabsim

Your one stop shop for finless spin-stabilized projectiles

Getting Started

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

Prerequisites

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 relies on Digital DATCOM to calculate aerodynamic coefficients. A compiled 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

Running Stabsim

Stabsim can be used as either as a python library or as an graphical application.

Command line interface

Even as stabsim's gui changes the command-line interface should remain fairly stagnant. Examples are 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 = Rocket.fromfile(os.path.join(script_dir, rocket))
h550 = Motor.fromfiles(os.path.join(script_dir, motor_dim), os.path.join(script_dir, motor_thrust))
baby_spacehot = Profile(marvin, h550, 262, launch_altit=26000, length=5,        timesteps=100)

vis.kinematics(baby_spacehot)
vis.spin(baby_spacehot)

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 information about the motor and the airframe. Motor information can be loaded using

1. the industry standard RASP file format
2. a csv with motor file specification
3. raw numerical values
4. any combination thereof

Airframe information can be loaded using

1. a csv file with airframe specifications
2. a DATCOM file with airframe specifications
3. some combination thereof For examples of how to format .csv files again refer to the data\ folder.

Graphical user interface

Clearly this is a lot of data. The graphical application makes it all a bit easier to manage. You can either load information using these file formats or manually input your vehicles specifications. Be warned that the GUI does abstract away a few features that are more readily accessible via the CLI.

Built With

• TKInter - Python Interface to TK GUI toolkit
• Sun Valley - A stunning theme for ttk based on Microsoft's Sun Valley visual style
• Digital DATCOM - by USAF via PDAD
• NRMLSISE-00 - atmospheric model

License

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

Acknowledgments

The many many many folks whose sweat and tears have gone into Spaceshot