powered flight, the X-43A became a glider and made a controlled glide to a splashdown in the ocean about 800 miles (1,290 kilometers) offshore. It will not be recovered. Although brief, the flight produced an enormous amount of data compared to the milliseconds of data that all Mach 10 ground tests have produced, Voland said. "They only add up to a second or so, maybe," he said. The flight was the last in a $230 million-plus program to test a technology most likely to be initially used to power missiles or in military aircraft, such as bombers that could reach any target on Earth within two hours of takeoff. Scramjets may also provide an alternative to rockets for space launches. Sitz said he believes the technology eventually can also be used for commercial passenger flights. "We're just going to have to wait a while," he said. Unlike conventional jet engines which use rotating fan blades to compress air for combustion, the X-43A has no such rotating engine parts. Instead it uses the underside of the aircraft's forebody to compress air for mixing with hydrogen fuel. The airflow through the engine remains supersonic. The X-43A launched Tuesday was the last of three built for NASA's Hyper-X program. The first X-43A flight failed in 2001 when the booster rocket veered off course and was destroyed. The second X-43A successfully flew in March, reaching Mach 6.83 _ nearly 5,000 mph (8,000 kph)_ and setting a new world speed record for a plane powered by an air-breathing engine. That was more than double the top speed of the jet-powered SR-71 Blackbird spyplane, which at slightly more than Mach 3 is the fastest air-breathing, manned aircraft. Not having to carry oxygen is one of the advantages scramjets hold over rockets. Rockets achieve the same kind of high speeds but the weight of oxygen tanks or other oxidizers reduces the amount of payload they can carry.
