|MadSci Network: Physics|
you are raising an interesting question. These gravity shielding experiments have been performed by Podkletnov and coworkers at Tampere University in Finnland, 1996 or so. They claimed that they would have reduced the gravitational field above a spinning high temperature superconductor. At that time nobody believed them. And Podkletnov even had to leave the university. In the meantime there has been some theoretical efforts to describe gravity shielding, above all by the Italian physicist G. Modanese. There is a collaboration in the states trying to reproduce the experimental results of Podkletnov. The experimental setup is very involved and it is hard to fabricate all the needed device, for example the superconducting disk. As long as Podklednov's results have not been reproduced by independent scientists and all possibilities that other effects may be responsible for what looks like a gravity shielding have been studied one cannot be sure. Search also our archives for "gravity shielding".
Try the links in the MadSci Library for more information on Physics.