In its fourth and final test, the X-51A WaveRider pulled off three and a half minutes of flight under the power of its supersonic combustion ramjet (Scramjet), the longest such flight ever. The WaveRider, developed by Boeing, DARPA, and the Air Force, is designed to test the feasibility of Scramjet-powered flight. A Scramjet utilized the atmosphere’s oxygen, the air compression from its own forward motion, a less fuel than a traditional rocket to propel a craft to hypersonic speeds — in this case Mach 5.1. It’s called the “WaveRider” because part of the reason it’s able to stay aloft is that it literally rides its own shockwaves.
The last test of the X-51 didn’t go so well, crashing down early into the Pacific after just 15 seconds….