Hypersonic 

Per Space.com:
NASA has set Saturday, March 27, as the tentative date for the re-flight of its experimental Hyper-X craft, the flight vehicle designated as the X-43A. The unpiloted vehicle, part aircraft and part spacecraft, will be dropped high over the Pacific Ocean from the wing of a B-52 aircraft.
The X-43A tops a modified Pegasus booster that will propel the craft to test altitude. Once released from the Pegasus, the experimental craft is to briefly fly under its own power at seven times the speed of sound – roughly 5,000 miles per hour, or about one and one-half miles per second.
Air-breathing/scramjet engine technology embodied in the X-43A promises to increase payload capacity for future vehicles, including hypersonic aircraft (faster than Mach 5) and reusable space launchers.
A first try to fly the X-43A ended in failure on June 2, 2001. The vehicle spun out of control and had to be destroyed by range safety control. A mishap board later found that the failure was the result of inaccuracies in computer and wind-tunnel tests, based on insufficient design information about the vehicle itself.

:: :: 09:04 :: David :: [permalink] ::