It turns out that "relative efficiencies" from an energy standpoint is not the relevant consideration, by two or three orders of magnitude. Fuel costs for laun

It turns out that "relative efficiencies" from an energy standpoint is not the relevant consideration, by two or three orders of magnitude. Fuel costs for launch vehicles are a negligible fraction of the total cost to fly. Musk is working the rest of the problem by simplifying the design, designing for manufacturability, using off-optimum technologies, building everything under one roof, and so on.