BBC NEWS | Science/Nature | Nasa's Mach 7 technologyHmmmm Scramjets!!! The future of air transport!! Hypersonic aircraft will be cool, if they can work out a way of making sure we don't all turn to jelly inside the damn thing!! didn't realise they only start to work after Mach 6!!! have to be propelled to that speed before the scramjet kicks in and fires it up to Mach 8!!!