If successful, NASA's third and last X-43A "scramjet" will fly at 7,000 mph for 10 or 11 seconds high over the Pacific Ocean off California and then, like the two other X-43As, plunge into a watery grave.
The first X-43A flight failed in June 2001 when the booster rocket used to accelerate it to flight speed veered off course and had to be destroyed. The second flight last March was a success, reaching Mach 6.83 — nearly 5,000 mph _and setting a new world speed record for a plane powered by an air-breathing engine.
Just 12 feet long and 5 feet wide, the X-43A is mounted on the nose of a Pegasus rocket that will be carried aloft to 40,000 feet by NASA's B-52 research aircraft and released. The Pegasus rocket will ignite and carry the X-43A to an altitude of 110,000 feet and a speed of about Mach 10, then release it for its brief powered flight.
The X-43A will then become a glider and perform maneuvers until it splashes down into the ocean.
That will be the end of the X-43A project, which has cost more than $230 million and has no immediate follow-on program.
Unlike rockets, scramjets wouldn't have to carry heavy oxidizer necessary to allow fuel to burn because they can scoop oxygen out of the atmosphere.
And ramjets, which operate from Mach 3 to Mach 6, have to use rotating blades to compress airflow down to subsonic speeds prior to combustion, while scramjets have few or no moving parts and airflow remains supersonic through combustion.
On the X-43A, the craft's underside actually functions as part of the engine, compressing the air for mixing with hydrogen gas and blasting it out the rear.
Imagine, if you will, a time in the near future. You hop on board of a craft in New York. Your destination is Tokyo. A normal flight on a Boeing 777 will be 12 hours and 35 minutes at an average flight speed of 550mph, average altitude of 40000 feet. That is 750 minutes at about 9.2 miles per minute for about 6900 miles.
Okay, now imagine the same trip on a hypersonic jet. Going 7000mph, the same trip will take about 60 minutes (116.7 miles per minute into 6900 miles). That's pretty damn impressive, once they get the technology done right.
However, it still irks me that they are not recovering these gliding aircraft. $230 million, while cheap by Nasa standards, is still nothing to sneeze at when there are complaints of government waste going on. If the thing can glide, glide it back in to a desert landing somewhere. Put a parachute on it, or floats, and pick it up in the ocean. Re-use the damn thing, if possible. Doesn't need to be littering up the ocean.
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