The symposium was far-reaching, with presentations including “Modular Aneutronic Fusion Engine for an Alpha Centauri Mission” and “To Humbly Go ... Breaking Previous Patterns of Colonization.” The meat of the conference was hard science: the physics and engineering of propulsion.
After years of being all talk, a Japanese probe launched last year became the first to use solar sails for propulsion, making it to Venus in just over six months. James Benford, an entrepreneur who founded the company Microwave Sciences, gave one of the most focused talks of the conference, addressing the economics of microwave-driven sails. Because microwave ovens are cheap, he said, we could assemble an array of thousands of microwave ovens into an array to push sails. This was a great example of the reverse spin-off argument: It’s more likely that Earth-bound developments will make things in space feasible than that astronaut ice cream will take over the nation’s stomachs.
These two most obvious paths—solar sails and nuclear rockets—are methods that, if we spent a lot of money and time on developing them, would definitely work moderately well. But neither will ever be that good. The stars are just too far. What we really need is something radically different, a game-changer. For that, I turned to Kramer’s exotic physics session.