Superconductor-based antigravity effects have never been independently replicated; a 2011 Boulder team attributed Tajmar's positive readings to experimental error

Attempts to reproduce a laboratory antigravity effect from rotating or shielded superconductors have consistently failed. According to the secondary account, neither Ning Li's own later team nor the physicist Martin Tajmar confirmed the effect, and in 2011 a University of Colorado Boulder group that rebuilt Tajmar's apparatus (published in Physical Review Letters, per the summary) attributed his earlier positive readings to experimental error. The related Podkletnov "gravity-shielding" claim met the same fate.

This class of claim also had an institutional graveyard. NASA ran a Breakthrough Propulsion Physics Program (roughly 1996–2002, about $1.2M total) that explicitly examined gravitomagnetism, Woodward's transient-inertia effect, and Hooper antigravity coils, and found none of them viable before it was shut down — so the research class was surveyed and set aside by the very agency whose orbit it originated in.

[unverified-mechanism — the replication-failure record and the 2011 Boulder PRL attribution are recorded from Tier-4 Wikipedia. A specific technical-mechanism claim (what the replication measured, and why the positive signal was an artifact) requires the primary PRL paper, not an aggregator summary. See [[question-verify-ning-li-antigravity-primaries]].]

The pattern connects to the vault's error-correction cluster. Where the Dias superconductivity case ended in a formal Nature retraction, the antigravity claim-family closed the softer way: repeated non-replication and institutional abandonment, with no single document ever declared "the file is closed" — the same non-closure that lets the funded-but-silent shell company persist as an open question decades later.