This rather unconvincing video shows a current project of DARPA’s, in which a jet is accelerated first by regular propulsion, then ramjets, then scramjets — eventually pushing the vehicle to a ridiculous mach 6. That’s somewhere around 1700-2000 meters per second, or ~4000MPH. That’s if they can keep the thing from breaking apart. Wikipedia tells us that “while very short suborbital scramjet test flights have been performed, no flown scramjet has ever been designed to survive a flight test.” That’s not very promising.
I say unconvincing because first of all, they don’t make mach 6 look very exciting. Also, the people watching look bored. And the patriotic music pretty much overwhelms the narration. If this is the same amount of care they’re planning on putting into this hypersonic craft, that thing is going to break up before they get it on the runway.
The idea is that these things could carry 12000 pounds of payload over huge distances extremely quickly. Like across the Pacific in two hours. I mean, that’s obviously the application of a fast airplane. But I wonder if they’ve considered that if they just load this sucker up with ball bearings or something and drop them out, they’ve essentially created a flying railgun. Scrap metal hitting a target at 4000MPH? Yeah, possibly destructive.
Anyway, the video is years old but it’s news because they’re planning a test flight for April. The landing site is actually just a place in the ocean they’re going to let it crash, so I don’t think we’ll be seeing these things overhead any time soon. But it’s good to keep abreast of developments like this in case you see one; otherwise you might think it’s a UFO.