FA-69497 / Orbital propagation / Member archive

State vector from classical elements: Rotation matrix mixes the sign of one in-plane term · case 02

Inclined orbits are rotated into a skewed plane.

Member previewVariant 2 · 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 [12000, 0.4, 98.0, 300, 45, 250, 398600.4418]	`[[2229.4745, -4211.3181, -12476.7753], [1.3635491, -3.3947954, 4.0262806]]`	`[[4456.1689, -4211.3181, -12476.7753], [1.3065909, -3.3947954, 4.0262806]]`	Failed

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