Boeing has announced that the second flight of the X-51 hypersonic waverider is planned for the week of 13 June. The first flight of the revolutionary scramjet, on 26 May, 2010, was hailed as a technological leap.
The X-51 was the first hypersonic vehicle to fly using conventional hydrocarbon gas instead of more exotic fuels. The vehicle was able to actively circulate fuel to dissipate heat, a major concern of hypersonic flight. The scramjet engine burned for 140s, half its intended burn, before an engine seal failure.