"We... believe that a hypersonic airplane could be a reality in the not too distant future."
Dr. Steven Walker, DARPA Tactical Technology Office
In the twenty-first century, speed seems to be of paramount importance. As well as improving the simple but inefficient turbine-based engine systems that drive rockets and planes, scientists have developed Supersonic Combustion Ramjet engines (scramjet) to allow much faster travel.
Scramjets improve on ordinary engines by eliminating the need to carry a fuel oxidant. Instead, they use oxygen from the atmosphere to burn the onboard fuel, making them lighter, more efficient, and extremely fast. Scramjets have long been a theoretical possibility, but in 2002 scientists at the University of Queensland, Australia, and at the U.K. defense company QinetiQ successfully completed the first flight of a scramjet vehicle. Although the test simply demonstrated the technology and not a practical engine system, the vehicle reached Mach 7, which is more...