Silver Bullet: If it works, the HTV-3X will be the first reusable scramjet-powered plane. It will be able to take off from a runway, fly at speeds of up to Mach 6, land safely, and then do it again.
The Hypersonic Age is Near
Recent breakthroughs in scramjet engines could mean two-hour flights from New York to Tokyo. They could also mean missiles capable of striking any continent in a moment's notice. No wonder the race to develop them is as fierce as ever.
To put things in context, the world's fastest jet, the Air Force's SR-71 Blackbird spy plane, set a speed record of Mach 3.3 in 1990 when it flew from Los Angeles to Washington, D.C., in just over an hour. That's about the limit for jet engines; the fastest fighter planes barely crack Mach 1.6. Scramjets, on the other hand, can theoretically fly as fast as Mach 15—nearly 10,000 mph.
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