Astrophysicists like Robert Nemiroff have shown, using Hubble photographs, that quantum foam does not exists. Further, the famous string theorists, Michio Kaku, in his April 2008 Space Show interview stated that string theories will require hundreds of years before gravity modification is feasible.
Therefore the need to fund research into alternative propulsion technologies to get us into space cheaper and quicker. We can be assured that such space technologies will filter down into terrestrial technologies.
I was surprised to find that the Cannae Drive received private placement funding in 2011 & that they are doing joint testing with NASA.
This video explain how this can be achieved and the benefits of doing so. The two organizations that are actively engaged in this endeavor are Propulsion Physics, Inc. and the Xodus One Foundation.
Please make donations through this link, http://xodusonefoundation.org/donation-page/
Thank you for you funding efforts.