The Space Shuttle was supposed to be reusable and cheap, too.  Originally, there were supposed to be 100 flights per shuttle, or about 400 for the program. There were 135, and two shuttles blew up and were replaced.  Turnaround time was supposed to be about two weeks; in practice it took months.  Each launch ended up costing about $600 million.<p>Space-X says they hope to reuse maybe 75% of a booster.   Boosters probably go back to the plant to be rebuilt, not to the pad to be launched again.<p>Rockets have been mass produced before.  Thousands of ICBMs were produced on assembly lines.<p>The tyranny of the rocket equation still applies.  Spacecraft are almost all fuel mass (85-95%), and can&#x27;t be built with the robustness level of commercial aircraft, which are only 40% fuel at takeoff.  Fuels can&#x27;t get any better; liquid hydrogen&#x2F;liquid oxygen is as good as it gets.  Unless and until we get fission or fusion propulsion, space launches will be a marginal technology.<p>The Apollo program originally included a nuclear-powered upper stage. It&#x27;s too bad that never launched.  Nuclear rocket engines have been built and ground tested, but they&#x27;re rather messy.