 The researcher and author Paul LaViolette has produced many self-published books on electrogravitics, making many claims over the years including his view that the technology could have helped to avoid another Space Shuttle Columbia disaster.Many claims as to the validity of electrogravitics as an anti-gravity force revolve around research and videos on the internet purported to show lifter-style capacitor devices working in a vacuum, therefore not receiving propulsion from ion drift or ion wind being generated in air.Followups on the claims (R. L. Talley in a 1990 U.S. Air Force study, NASA scientist Jonathan Campbell in a 2003 experiment, and Martin Tajmar in a 2004 paper) have found that no thrust could be observed in a vacuum, consistent with the phenomenon of ion wind.