FA-69499 / Orbital propagation / Member archive

State vector from classical elements: Rotation matrix mixes the sign of one in-plane term · case 04

Inclined orbits are rotated into a skewed plane.

Member previewVariant 4 · 3 implementations · 7 checks per implementation

Case contract

Input [p, e, i, raan, argp, nu, mu] (km, degrees). Perifocal position r=p/(1+e cos nu)[cos nu, sin nu, 0] and velocity sqrt(mu/p)[-sin nu, e+cos nu, 0] are rotated to the inertial frame by R3(-raan)R1(-i)R3(-argp). Return [r rounded 4, v rounded 7].

Why this case matters

Orbit determination and mission planning chain many small conversions; one wrong branch or unit silently moves a spacecraft by kilometres.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
state vector from classical elements [26000, 0.7, 63.4, 270, 280, 10, 398600.4418]	`[[-6891.1889, -5263.8249, -12931.4731], [-0.2131056, -6.3785031, 1.6229816]]`	`[[-6475.5994, -5263.8249, -12931.4731], [0.8127286, -6.3785031, 1.6229816]]`	Failed

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