FA-69504 / Orbital propagation / Member archive

State vector from classical elements: Perifocal radial velocity has the wrong sign · case 04

The spacecraft flies its orbit backwards in the radial direction.

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 [9000, 0.1, 51.6, 100, 190, 330, 398600.4418]	`[[-381.3488, -7970.4999, 2220.0855], [2.7565346, 4.9471354, -4.5089095]]`	`[[-381.3488, -7970.4999, 2220.0855], [4.6015157, -1.3825381, -5.4145672]]`	Failed

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