STRATOS

Software-based Tool for Rapid Airship Transformation & Optimized Shaping

STRATOS is a comprehensive, open-source Python framework featuring a graphical user interface designed for the rapid parametric modeling, aerodynamic evaluation, and structural analysis of Lighter-Than-Air (LTA) platforms.

🚀 Key Features

1. Parametric Envelope Geometry

• Profile Series Support: Generate high-fidelity hull shapes using standard series including Gertler, NACA (symmetric), and the Dragon Dream profile.
• Multi-Lobe Configurations: Native support for monolobe, bilobe, and trilobe configurations, with customizable lateral and vertical offsets for complex hull combinations.
• Volumetric Dimensioning: Automatically scale and dimension envelope lengths to meet specific target volumes and payload requirements.
• Geometric Properties: Instantly calculates surface area, volume, projected areas (top/side), and Center of Volume (CV) for any hull configuration.

2. Superpressure Balloon Modeling

• Base Shapes: Generate Spherical, Prolate, and Oblate balloon geometries based on target volume and aspect ratio.
• Advanced Gore Models: Apply distinct gore modeling techniques including Pumpkin, Flat Facet, and Smooth Bumpy parameterizations.
• Bulge Amplitude & Power: Fine-tune balloon aesthetics and structural boundaries through customizable bulge amplitudes and fade powers.

3. Appendage Design (Wings & Fins)

• Airfoil Asset Manager: Import custom .dat files or generate NACA 4-digit profiles. Uses advanced fitting methods (CST and PARSEC) to parameterize imported coordinates.
• Parametric Fins: Automatically loft stabilizing fins with customizable root chord, height, taper ratio, sweep angle, and angular placement around the hull.
• Complex Wing Lofting: Generate full wing geometries directly on the hull using multi-station inputs (span, chord, sweep, dihedral, and twist).

4. Aerostat Performance Analysis

• Atmospheric Modeling: Integrated ISA atmospheric calculations for accurate lift estimations based on operational height, relative humidity, and lifting gas properties (purity, delta P, delta T).
• Ballonet Sizing: Configure the number of ballonets and calculate required ballonet volume and fabric mass for target operational altitudes.
• Thermal & Stress Analysis: Estimates envelope temperature and thermal stress based on solar flux, wind speed, material emissivity, absorptivity, and base strength.
• Lifespan Tracking: Projects material degradation using fatigue and UV degradation factors to estimate burst altitude and safety factors.

5. Hydrodynamic Added Mass Computation

• BEM Integration: Features a built-in potential flow solver using the Boundary Element Method (BEM).
• 6x6 Matrix Output: Computes the full 6x6 added mass matrix directly from the generated 3D surface mesh, essential for dynamic stability and control simulations.

6. Manufacturing & CAD Export

• Salome Integration: Operates Salome in the background for robust Boolean operations, surface lofting, and precise CAD solid generation.
• 2D Petal Generation: Flattens 3D hull geometries into 2D developed petal coordinates (distinct from the volumetric lobes) exported as .dat and .png files for physical envelope manufacturing.
• Multi-Format Export: Directly outputs industry-standard .STL, .STEP, and .BREP files for immediate use in CFD, FEA, or manufacturing pipelines.
• Real-time 3D Preview: Integrated PyVista plotting for interactive 3D visualization of the hull, edges, and appendages within the GUI.

💻 OS Compatibility

STRATOS relies heavily on the Salome CAD engine for its solid modeling backend.

• Windows: Fully supported natively.
• Linux: Highly feasible. Requires minor adjustments to the file dialog configurations and subprocess commands to point to Linux shell binaries.
• MacOS: Challenging. Salome does not offer native MacOS binaries. Mac users will currently need to run the CAD backend through a Linux Virtual Machine or Docker container.

🛠️ System Requirements

• Python 3.x
• Salome: Required for Boolean operations and STEP/BREP generation.

Python Libraries Required

• PySide6: Framework for the graphical user interface (GUI).
• PyVista & pyvistaqt: For 3D visualization and interactive plotting within the interface.
• PyMeshLab: For mesh decimation, filtering, and handling 3D surface geometries.
• NumPy & SciPy: For core mathematical computations, matrix operations, and potential flow solving.
• Matplotlib: For generating 2D performance graphs and petal plots.
• Shapely: For complex geometric calculations, specifically trilobe volume estimations.

To install all the required libraries, run the following command in your terminal or command prompt:

pip install PySide6 pyvista pyvistaqt pymeshlab numpy scipy matplotlib 

📥 Installation & Setup

1. Clone the repository to your local machine.
2. Install the required Python dependencies using the pip command provided above.
3. Download the CAD Engine: STRATOS requires Salome to process solid 3D geometry. Download the Windows version from the Official Salome Website.
4. Extract the downloaded Salome archive to a memorable location on your drive.
5. Run airship_gui.py to launch the STRATOS application.
6. Upon first launch, the GUI will prompt you to locate your run_SALOME.bat executable (found inside your extracted Salome folder) to link the CAD backend.

💡 Usage Workflow

STRATOS is driven by an intuitive tabbed interface. A standard workflow looks like this:

1. Select Dimensioning Mode: At the top of the interface, choose between Standard Mode (Length-based), Volumetric Mode, Super Pressure Balloon, or Aerostat.
2. Configure Hull Geometry: In the Envelope Geometry tab, pick a profile series (Gertler, NACA, Dragon Dream) and adjust parameters like L/D, prismatic coefficient, and nose/tail radii.
3. Design Appendages: Navigate to the Airfoil Design, Wing Design, or Fin Design tabs to import custom airfoils, loft wings, or place stabilizing fins onto your hull.
4. Aerostat Analysis (Optional): If in Aerostat mode, input environmental conditions and lifting gas properties to generate performance graphs and calculate burst altitude.
5. Generate & Export: Go to the Output tab, set your project name, choose your export format (STL, STEP, BREP), and click RUN GENERATION. View the 3D solid result directly in the built-in PyVista viewer, alongside the computed 6x6 added mass matrix!

📑 Cite As

Pedapudi Anantha Hari Arun, Sudarsan D. Naidu, Pranav Mittal, and Manikandan Murugaiah "STRATOS: Software-based Tool for Rapid Airship Translation & Optimized Shaping", https://github.com/O-P-E-N-MIT/STRATOS

📄 License

This project is distributed under the MIT License. See the LICENSE file for more information.