Russia and China tested hypersonic weapons. But the hypersonic flight is not only missiles. The hypersonic aircraft can jump out from the atmosphere and pull satellites behind it. When the aircraft starts to return the satellite will release and the sling effect will push it higher. And there its transport engines starts. The scramjet or hypersonic ramjet is an engine that can accelerate aircraft to the speed of Mach 12+. The difference between scramjet and the rocket engine is that scramjet takes oxygen that it needs from the atmosphere. Hypersonic scramjets are straight tubes where is combustion chamber. When incoming air hits that point it will start to heat. And the only problem with the scramjet engine is where the nozzle of fuel injection is put in the tube. The best way is to inject the fuel at the front of the tube. The scramjet engine would be ecological because the best fuel for that system is hydrogen. But the problem is that the speed when scramjet is begin operationally