X-43 Hyper-XNASA X 43 Hyper X airplane model. NASA established a multi year experimental hypersonic ground and flight test program called Hyper X. The program sought to demonstrate "air breathing" engine technologies that promise to increase payload capacity or reduce vehicle size for the same payload for future hypersonic aircraft and or reusable space launch vehicles. Payload capacity was to be increased by discarding the heavy oxygen tanks that rockets must