FA-69512 / Orbital propagation / Member archive

State vector from classical elements: Conic radius uses 1 - e cos nu · case 02

Periapsis and apoapsis distances are swapped.

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 [8000, 0.2, 63.4, 200, 270, 120, 398600.4418]	`[[-5361.6463, -3684.1897, 3251.47], [2.9260598, -1.8478178, 5.4659665]]`	`[[-6553.1233, -4502.8986, 3974.0188], [2.9260598, -1.8478178, 5.4659665]]`	Failed

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