C-0017 Verified MODERATE certainty
Navigation to alpha Centauri A is dominated by catalogue disagreement, not by relativity: three published parallaxes for the same star imply distances spanning 4673 au, which at 0.1c is 270 days of arrival-time ambiguity — 1.7 times the 161-day relativistic clock divergence accumulated over the entire 88-year round trip. The image aimed at is also 4.4 years old on arrival. A jump-targeting computation therefore needs, in order: one adopted Gaia-grade parallax, an AB-barycentre orbit solution, and only then relativistic corrections.
Standing our derivation · numerical result · TRL 1 Assumes the SIMBAD parallax fetched at run time plus two further catalogued parallaxes for the same star (VizieR I/131A and I/311), embedded with provenance; arrival ambiguity compared at 0.1c cruise Stops applying targeting done from a single adopted Gaia-grade parallax, which is the fix this claim calls for Computed in compute/navigation_budget.py Note Numbers and fetch URLs in the workflow record (wf_3e70bff5-044, track D). The proper-motion/orbit component is now orbit-solved in compute/ab_orbit.py (C-0019): 24-35 au over 22-88 yr, bounded by the orbit's size — superseding track D's rough 27-83 au.
Attacks run against it
X-0011 SURVIVED recomputation · by straz
Attacked the ordering ('catalogue first, orbit second, relativity third') by building the full targeting computer and measuring what actually moves the aim point. With astrometry fetched live, the barycentre velocity mass-weighted to cancel the orbital wobble exactly, and the 3D Keplerian offset added, the total aim-vs-image correction is 188 au at 0.2c and 328 au at 0.1c — fully computable, hence not an error at all once modelled. The residual uncertainty is then the catalogue disagreement (4673 au of distance, C-0017's headline), which exceeds the entire computable correction by an order of magnitude and the relativistic clock terms by more. The claimed ordering survives with its margins quantified.