Historical research guide · 0739 · 2003

Gravity modification experiment using a rotating superconducting disk and radio frequency fields

G. Hathaway · B. Cleveland · Y. Bao

In one minute

In 1992 Evgeny Podkletnov reported that a test mass hung above a large spinning, levitated superconducting disk lost a fraction of its weight. It is one of the boldest claims in laboratory physics, and the only way to know is to build the thing. George Hathaway, Blair Cleveland and Y. Bao did exactly that in Toronto, making their own large sintered yttrium-barium-copper-oxide disks — bi-layer, triple grain size — and sending one to Podkletnov himself, who judged it fit for the experiment. They levitated it over solenoidal coils with toroidal coils threaded through its central hole, drove them in two-phase mode with radio-frequency fields, and watched a suspended test mass on a balance good to one part in a hundred thousand. Across that campaign they saw no weight change and no gravity-like force at the 0.001 percent level. The disk, however, never turned faster than 550 revolutions per minute, and the effect Podkletnov described needed several thousand.

Connection

Chapter 11 is the superconductor-and-gravity thread, and this is its most carefully built replication: the closest published rebuild of the original experiment, by an experimentalist who worked with the original claimant on the disk itself. Chapter 1 keeps the replication ledger, and this is what a real entry looks like — a stated apparatus, a stated sensitivity, a stated bound, and a clearly named condition the rig did not reach.

From the source

The experiment was built to test the result reported by Podkletnov and colleagues, that a gravity-like force appears above a spinning superconducting disk. On the lead author’s own later account it represented, and still represents, the closest published replication of the original experiment.Abstract, opening sentence; and Hathaway’s own account in Defense Intelligence Reference Document DIA-08-1003-013, 2010, section on the Toronto replication
The apparatus used sintered yttrium-barium-copper-oxide bi-layer disks with triple grain size, levitated above either three or six individual solenoidal coils, with two toroidal coils threaded through the central hole of the disk and operated in two-phase mode to drive it.Abstract, apparatus description
The measured result is a bound: no weight modification and no gravity-like force was detected, to the 0.001 percent level of the apparatus sensitivity.Abstract, results sentence
The rotational speed reached in these runs was no greater than 550 revolutions per minute. Podkletnov’s own stated optimum condition for the maximum stable weight loss of about 0.3 percent was a disk turning at several thousand revolutions per minute with the rotation coils driven near 10⁵ hertz — so the bound was set roughly three hundred times finer than the claimed effect, but an order of magnitude below the rotation rate named for producing it.Abstract, apparatus description, read against Podkletnov’s stated conditions as recorded in DIA-08-1003-013, 2010, section on the 1992 experiment
The replication was not run blind. Podkletnov was actively involved in the experimental setup on the ceramic side, and one of the Toronto bi-layer disks was sent to him in Finland, where he pronounced it acceptable for experimentation. The paper also sets out the experimental difficulties intrinsic to the measurement and the critical data the original experiment did not supply.Hathaway’s own account in DIA-08-1003-013, 2010, section on the Toronto replication; and the paper’s discussion section as described there
What to watch, and what a stronger test would need: the same rig, with the same 0.001 percent balance sensitivity already demonstrated, taken into the regime the original claim actually names — a large bi-layer disk turning at several thousand revolutions per minute under a two-phase radio-frequency drive near 10⁵ hertz, at the low temperatures Podkletnov identified as necessary. Until a run reaches those parameters, the bound published here constrains the effect at low rotation and leaves the stated operating point untested.Abstract, apparatus description; conditions as stated by Podkletnov and recorded in DIA-08-1003-013, 2010

The way in

https://doi.org/10.1016/S0921-4534(02)02284-0

Historical source-access record. This guide links to the original; it does not reproduce the paper text.

SOURCE NOT REACHED IN FULL. Published as Physica C: Superconductivity, volume 385, issue 4, pages 488 to 500, April 2003, under the Elsevier journal licence; the only licence Crossref carries is Elsevier’s text-and-data-mining user licence, which is not a Creative Commons licence, so no text of the paper is reproduced here. OpenAlex, Unpaywall and Semantic Scholar all report the article closed with no repository copy, and the ScienceDirect page refused automated requests on 2026-09-08. The apparatus details and the result in the claims below come from the authors’ own published abstract as carried on the publisher’s record and read through a search index on 2026-09-08, retrieved twice by independent queries with identical wording, and their locators say so. The remaining claims come from the lead author’s own later account of this experiment: Defense Intelligence Reference Document DIA-08-1003-013, ’The Role of Superconductors in Gravity Research’, 23 March 2010, a United States Government work in the public domain, which is on this site at /library/stm-2aafe96904 and which calls the Physica C paper ’our own version’ of the Podkletnov replication. George D. Hathaway worked from Hathaway Consulting Services in Toronto.

How to cite it

G. Hathaway, B. Cleveland, Y. Bao (2003) Gravity modification experiment using a rotating superconducting disk and radio frequency fields doi:10.1016/S0921-4534(02)02284-0

Where it sits in the curriculum

Gravity control and superconductors