There are topics in the space field that inflame passionate debate like few others. Bring up SpaceX, for example, and expect to see a phalanx of fans of the space transportation company square off against a cadre of its critics. Discussion of NASA’s Space Launch System heavy-lift booster, for example, frequently ends up in arguments on whether the vehicle is an essential element of any deep space exploration plans, or a pork barrel project. Middle ground is hard to come by; it is, after all, in the crossfire.
Another topic that, perhaps more surprisingly, also generates polarized debate is work on alternative propulsion systems. These efforts, done on the fringes of the research community, seek to exploit aspects of physics that may seem counterintuitive or simply incomprehensive to the average person to permit radical advances in space transportation. When a new development in this area is announced, as was the case a few weeks ago, some people embrace it without reservation as a breakthrough that will open up the solar system, if not the galaxy, while others reject it as being clearly infeasible, if not in violation of the laws of physics. Reality, though, can be a little more complex. http://interstellar-news.blogspot.com/2014/08/alternative-propulsion-concepts-power.html