me again. Space transport: I like the two-stage-to-orbit solution for humans, with the booster stage piloted. The maths works well. I don't know about scramjets etc for the booster, but a few rockets would do, with an aero fuselage to take off and land. Using current airline technology mostly. Safe. Cheap.
If the second stage isn't reusable as a second stage (or if eg just the engines are) that's okay too. Things like tanks are useful in orbit, hell anything, any mass, is useful there. SSTO is pride, not economics (assuming at least a low-to-medium demand). But there ain't a company anywhere that's going to put up the dosh if NASA and the US insists on being the best... Another I like is tether systems, but not yet. The low-orbit rotating tethers with hypersonic collection (the tip of a rotating tether, whose overall CoG moves at orbital speeds, collects the spacecraft-to-be at mach 10 or so in the upper atmosphere) are a bit fraught, but doable with near-modern-day tech (modern economic materials ok, but patented!). A bit further on you might have a tether that reaches the ground... so a rope falls down from space, you grab on, and it yanks you up to orbit! Yeah!!! And light gas guns for cargo, perhaps with a mag assist. A two-ton payload gas-gun would cost $4bn to $6bn to build, then about $6,000 per ton launched, excluding capital costs. Figures are mine, about 5 years old. I suspect there are those who could do better, but aren't saying. I suppose you could even put one on the Ecuadorean plains, pointing up to the mountains near Quito, and have the needed 300km runup and low-gee for passengers (if it's on the equator you can schedule shots much better, eg every 30 minutes). Personal transport: Cars are okay, but I hate driving unless it's too fast for transport purposes. Suppose we have a mix of trains and cars - even the "Stephenson's Rocket" trials thought of carrying personal carriages on trains. If there was power and computer control available then people's individual cars could travel on the same lines as trains, but without needing an engine - or a schedule - or a train - or a driver - or a driving lcence - ar road accidents. Great when you're pissed and just want to say "Home George" (as a kid we actually had a chauffeur called George Cole, but I called him "Coley", not George). The macho Tim's of this world could also have fuel tanks on their cars, so thay could go where they liked (and if there was a strike, or the power failed, it wouldn't matter that much. Redundancy. Also you could get to places not on the regular network). Expensive in infrastructure terms, especially in the US. In the EU it might be better, as there are more railways already. But not cheap.
