[AdaBatu]

Pull request type

• Code changes (bugfix, features)
• Code maintenance (tests)
• ReadMe, Docs and GitHub updates
  Checklist
• Tests for the changes have been added
• Documentation has been reviewed and updated
• Ruff checks passed for changed Python files
• All repository tests have passed locally
• CHANGELOG.md has been updated
  Current behavior
  RocketPy accepts externally supplied drag curves and provides analytical aerodynamic surface models, but cannot directly generate whole-vehicle aerodynamics using Missile DATCOM.
  New behavior
  Adds an opt-in integration using a user-supplied native DATCOM executable:
• Adds DATCOM fin helpers supporting HEX, ARC, NACA and custom sections, including multi-station planforms.
• Generates geometry from the assembled rocket and replaces component aerodynamic loads with DATCOM forces, moments and damping derivatives.
• Runs powered and coast cases in temporary directories, with configurable base drag and appropriate CG references.
• Supports adaptive Mach/alpha coverage and Reynolds-number schedules derived from the launch atmosphere and preliminary flights.
• Adds calibration against wind-tunnel coefficients, including datasets containing only Mach, alpha and CD.
• Adds comparison notebooks for recorded flights and the Asteria configuration.
  The executable is not distributed with RocketPy. Existing analytical equations remain unchanged.
  Breaking change
• No
  Additional information
  This implementation remains work in progress. DATCOM currently produces poor flight predictions for several comparison rockets, and the discrepancies are still being investigated.
  Fin cross-section assumptions, particularly trailing-edge thickness, substantially affect the results. Sensitivity runs improve agreement for GENESIS and Astra, but the actual section dimensions are unavailable; these alternatives are explicitly labelled as hypotheses.
  Validation includes:
• 327 passing targeted tests, including native DATCOM checks and existing RocketPy regressions.
• Reproduction of the manual’s published aerodynamic example.
• A successful strict Sphinx documentation build.
  Comparisons distinguish measurements, supplied drag curves and apogee-fitted CD. AST-HER has not flown; its comparison contains simulation results only. Protuberance and plume-interaction modelling are excluded.