MACH 9.7 PLUS

Flight Journal, Apr 2005 by Pace, Steve

ON NOVEMBER 16, 2004, the 12-foot-long X-43A soared well past Mach number 9.7 (7,200mph)-the fastest speed ever attained by an air vehicle with an air-breathing engine.

Following separation from the pylon under the right wing of the mother plane and ignition of the booster rocket at about 40,000 feet above the Pacific Ocean, the first stage of the Pegasus propelled the X-43A to a speed of about Mach 4.0 before it separated for its historic flight to nearly 10 times the speed of sound. After an approximate 10-minute flight, the scramjet-powered X-43A hit nearly Mach 9.8 at an altitude of about 110,000 feet (20.8 miles). It was the third and last flight in NASA's Hyper-X program.

An earlier flight on March 27, 2004, saw X-43A hit a maximum speed of Mach 6.83 (about 5,065mph). Prior to the Hyper-X program, the fastest air vehicle powered by an air-breathing engine was Lockheed's SR-71 Blackbird; it regularly flew at Mach 3.2 (about 2,375mph). A future air vehicle powered by a scramjet engine traveling at Mach 10.0 (7,400mph) could travel from Los Angeles to New York in about 20 minutes.

This monumental event also marked the last flight of the NASA B-52B mother plane that air-launched many types of air vehicles, including the X-15A/X-15A-2 series of rocket-powered aircraft that first exceeded four, five and six times the speed of sound in the 1960s.

-Steve Pace