Skip to content

VALIDATION.md

Latest commit

 

History

History
46 lines (35 loc) · 2.27 KB

VALIDATION.md

File metadata and controls

46 lines (35 loc) · 2.27 KB
Raw

Validation

TRAJECTUM treats validation as a traceable engineering activity rather than a visual or UI-level check. Reference cases should record the active geometry, mass model, propulsion inputs, aerodynamic assumptions, numerical method and comparison source.

Independent trajectory cross-check

The current CDR reference trajectory was independently cross-checked with RocketPy 1.13.0 using matched first-order assumptions:

  • 3-DOF point-mass flight model;
  • standard atmosphere and zero wind;
  • launch angle: 85°;
  • body diameter: 63 mm;
  • effective drag coefficient: Cd = 0.345;
  • initial mass: 1.590 kg;
  • post-burnout mass: 1.450 kg;
  • propellant mass: 0.140 kg;
  • motor dry mass: 0.350 kg;
  • burn time: 0.50 s;
  • the same time-varying A-100 RN/KNDX thrust curve;
  • numerical time-step control matched closely to the TRAJECTUM reference run.

Comparison

Quantity TRAJECTUM RocketPy Difference
Apogee 662.10 m 669.60 m +7.50 m (+1.13%)
Time to apogee 11.28 s 11.34 s +0.06 s
Maximum speed 128.95 m/s 129.83 m/s +0.88 m/s (+0.69%)
Maximum Mach 0.379 0.382 +0.003
Maximum dynamic pressure 10.15 kPa 10.29 kPa +0.14 kPa
Burnout altitude 36.56 m 36.74 m +0.18 m
Burnout speed 128.73 m/s 129.62 m/s +0.89 m/s
Burnout dynamic pressure 10.11 kPa 10.25 kPa +0.14 kPa

The comparison is an independent cross-check under matched assumptions, not a claim of full experimental validation. Agreement between two simulation tools does not replace motor testing, aerodynamic characterization, mass-property verification or flight-test data.

Validation policy

For future reference cases, TRAJECTUM should distinguish among:

  1. Analytical verification — comparison against closed-form or known limiting cases.
  2. Cross-tool verification — comparison against an independent implementation or external simulator.
  3. Input verification — confirmation of geometry, mass properties and propulsion data against drawings, CAD, measurement or test evidence.
  4. Experimental validation — comparison against physical test or flight data.

Numerical results should remain tied to a configuration revision so that a comparison can be reproduced after the vehicle model changes.