The Accuracies Travelled Back. The Warning Did Not. K-Site, 1992–2025

Technical Note 001 in the ElarionX CPMS series. In January 1992, engineers at NASA Lewis Research Center and Analex Corporation published a self-pressurization test campaign on a 4.89 m3 flightweight liquid hydrogen tank (AIAA-92-0818, issued in parallel as NASA TM-105411) - the K-Site dataset, still a live validation referent. The report states its four instrument accuracies plainly, and then reports a closure check that did not close: energy balance errors of 120 to 150 percent. The authors rule out their own instruments, diagnose unmeasured radial temperature nonuniformity, and note that their liquid and vapor temperature measurements were limited to a single vertical axis near the tank centerline. This note traces what travelled from that report into five validation documents spanning 2015 to 2025. The 2022 K-Site validation paper carries none of the experimental uncertainty information. The two full-length 2025 papers by Kartuzova, Kassemi and Hauser - the AIAA SciTech conference paper (NTRS 20240016283) and the journal version of record (Cryogenics 152, art. 104210, open access) - restore all four instrument accuracies essentially verbatim, cite the Stochl-Knoll thermal-performance report as the source of the measured heat loads, and the journal version expressly studies localized heat leaks through instrumentation penetrations. None of the five documents carries the 120-150 percent closure failure, the single-vertical-axis caveat, or an assembled validation uncertainty. The accuracies travelled back; the warning - the one sentence that determines what those accuracies are worth - did not. The argument is framed on the ASME V&V 20 decomposition of the comparison error E = S - D. A second finding is documented: the wall heat flux K-Site declares (0.35, 2.0 and 3.5 W/m2) is total heat divided by tank area, with 13 to 17 percent of that heat entering through discrete struts, plumbing and instrumentation lines rather than uniformly through the insulation - a distinction that matters because the phenomenon being modelled is thermal stratification. Scope and limitations. Exploratory (A0) work by one auditor with AI assistance and no independent human review. The five documents examined represent two research groups, and the three 2025 documents are one study's own lineage; no claim is made about the field as a whole, and none that any model is wrong. This note's own verification log initially recorded both full-length 2025 papers as unavailable - two false negatives, corrected before publication and recorded as Erratum 16 in Technical Note 000, together with the standing policy they produced: a negative existence claim is a timestamped search result, and it expires. Full audit records are published as a separate dataset; the series index is Technical Note 000.