FA-69769 / Orbital propagation / Member archive

Clohessy-Wiltshire relative motion: Radial offset drives along-track velocity with the wrong sign · case 04

A lower chaser appears to fall behind.

Member previewVariant 4 · 3 implementations · 7 checks per implementation

Case contract

Input [x0,y0,z0,vx0,vy0,vz0,n,t] with x radial, y along-track, z cross-track about a circular reference orbit of mean motion n. Return [x,y,z,vx,vy,vz] from the closed-form HCW solution, rounded to 6.

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
clohessy-wiltshire relative motion [-0.3, 2.0, -0.2, 0.0001, 0.0002, -0.0001, 0.0012, 4500.0]	`[-0.571404, 9.834915, -0.062542, 0.000589, -0.000727, -0.000249]`	`[-0.571404, 9.834915, -0.062542, 0.000589, 0.000851, -0.000249]`	Failed

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