In one minute

Puthoff, Little, and Ibison examine vacuum-related ideas for spaceflight and begin by setting propulsion constraints. They write that the center of mass-energy of an initially stationary isolated system cannot change position without outside forces. In their static crossed electric-and-magnetic-field example, a hidden mechanical momentum cancels the field momentum, leaving the whole system stationary. The paper describes ground-state experiments in Casimir cavities and a synchrotron test of the vacuum/ground-state relationship; at the time, the experiments had not succeeded. In its metric-engineering section, the paper treats the vacuum as a polarizable medium and presents that treatment as an engineering approach. The authors say the practical answer can emerge only through the exploratory work itself.

Engineering the Zero-Point Field and Polarizable Vacuum for Interstellar Flight