  Prior to 1988, traversable wormholes were just science fiction. Prior to
1994, warp drives were just fiction. Since then, these notions matured into
published scientific discourse, where key issues and unknowns continue to be
raised and investigated. In 2009, the American Institute of Aeronautics and
Astronautics published a peer-reviewed, expansive technical volume on these and
other investigations toward breakthrough propulsion. This paper summarizes the
key assertions from that 739-page volume, describing the collective
state-of-the-art and candidate research steps that will lead to discovering if,
or how, such breakthroughs might finally be achieved. Coverage includes:
prerequisites for space drive physics, manipulating gravity or inertia for
propulsion, lessons from superconductor experiments, null results with
"lifters", implications of photon momentum in media, quantum vacuum physics,
and the faster-than-light implications of general relativity and quantum
non-locality.
