It reached Mach 10!!!
At a post-flight news conference Tuesday, mission managers said they had only begun to look at the data, but they believed the aircraft reached a speed of about 6,600 miles (10,621 kilometers) per hour, or about Mach 10.
The flight took place over the Pacific Ocean off the coast of Southern California, in restricted U.S. Naval airspace.
The black X-43A, fastened to a larger, white booster rocket, was carried to 40,000 feet (13,157 meters) strapped to the right wing of a B-52, which took off from NASA's Dryden Flight Research Center in Edwards, California.
The B-52 released the booster rocket, which dropped for several seconds with the X-43A attached to its nose, then ignited and ascended to 110,000 feet (36,184 meters). At that point, the scramjet engine fired and the booster rocket dropped away.
As planned, the test flight lasted only a couple of minutes and ended when the aircraft ran out of fuel. It eventually crashed harmlessly into the ocean.
The test flight was originally scheduled for Monday, but technical glitches forced NASA to postpone it for 24 hours.
Tuesday's flight was the last of three test flights in NASA's eight-year, $230 million Hyper-X program, designed to help develop a new generation of spacecraft that could fly into low Earth orbit at a fraction of the current cost.
Wait a second... did they say Hyper-X program??? Now I know where Kingston got there performance line name from!