The X-43 will attempt to fly at Mach 10. Watch flight live on NASA TV (broadcast or internet). Right now pre-flight operations are underway with B-52 take-off scheduled for 3:0 PM PST followed by launch approx one hour later.
I saw some short news item on TV that the X-43 flew today and hit "almost" Mach 10, about 7,000 MPH. They showed a photo of a contrail moving very rapidly across the sky, but I couldn't make out the small vehicle. Even at 90,000 feet plus, it must have been glowing cherry red. Not too shabby for an air-breathing jet aircraft, not a rocket. I'm curious. Do these SCRAMJETs (supersonic combustion ramjets) use external combustion? I gather that some exotic jet designs don't keep their flame inside a pipe, but eject fuel from the aircraft into an external concavity on the side of the aircraft where combustion is confined by the supersonic airflow past it. Kind of like a jet engine made of air itself.
If anyone wonders what these speeds mean, you could get on a plane in London and be in in Australia two hours later. New Yorkers could go spend the afternoon in Tokyo and be back in time for bed. Everwhere on Earth within commuting distance of everywhere else. Rapid transit.
