X-51A WaveRider hypersonic mission doomed by bum missile fin
 

The latest attempt to go past Mach 5 with the X51A has finished badly again, as a broken fin caused the missile to lose control before its air-breathing "scramjet'" motor could even kick in. It happened just after the booster rocket phase, which accelerates the craft to at least Mach 4, a high enough velocity for the hypersonic scramjet to work. The craft ended up in the Pacific shortly afterwards instead, and this latest affair may end up dunking the entire $300 million program. The Air Force initiative is already short on funding, and the previous two tries were equally dismal failures -- meaning a fourth missile, already built, may end up a museum piece.

http://www.engadget.com/2012/08/16/x...sonic-mission/