Laws of Physics (Score 3, Informative)

SST's get re-studied every decade or so. Boeing and Douglas (remember them) last took their turn in the 80's, courtesy NASA funds. Gulfstream and one of the Russian design houses got far down the road toward a supersonic bizjet in the 90s. Now it is Japan's turn. They all run into the same laws of physics, and the same laws of economics. Until there's a breakthrough in engines, structures, fuels, or aerodynamics (or perhaps all four), don't look for an SST anytime in the next decade or two. An SST could be built today, even without breakthroughs, but it wouldn't make anybody any money. The laws of physics guarantee that the planes are exotic (skin temperature hot enough to boil water), thirsty (inefficient supersonic wing lift), and noisy (sonic boom = flight routes over land very restricted). These factors all add up to expensive tickets, and the market studies (including the one called Concorde) all show that the market isn't there. And that's not even beginning to take environmental concerns into account, such as high-altitude ozone depletion and of course greenhouse gas emissions.