Yesterday, the Air Force conducted a third test flight of its X-51a "Waverider" hypersonic cruise missile, hoping for 300 seconds worth of sustained scramjet-powered flight at over Mach 5. It could have gone worse, but not by much: a faulty control fin caused the vehicle to break apart and crash into the ocean just over 30 seconds after launch.
This is (or rather, was supposed to be) the third test for the Waverider and its experimental scramjet engine. The first test back in 2010 went pretty well, with a flight lasting over three minutes. The second test, last March, suffered from engine trouble and was considered a failure. A redesigned fuel injection system that was supposed to solve that problem was in place yesterday, but it never even got to turn on.
According to the Air Force, a fault was identified with one of the X-51A's tail fins 16 seconds after the vehicle separated from its B-52 mothership. It was too late to stop the test at this point, and 15 seconds later the X-51A separated from its booster rocket and immediately lost control, broke apart and crashed into the middle of the Pacific. In pieces.
I guess on the upside, this failure can't be blamed on the engine. On the other hand, the Air Force only has one of these things left, and (at this point) doesn't seem too keen on building more. If everything can be made to work, the fantasy behind the X-51A is that it'll lead to a new sort of hyperonic cruise missile that can smack targets anywhere in the world in minutes. And don't forget about DARPA's Mach 20 glider, which is much faster, and so far, significantly more reliable.
Via Danger Room