Testing their way toward hydrogen-powered hypersonic flight

Combine the cleanliness of hydrogen combustion with the desire to travel at speeds of at least fi ve times the speed of sound, and you've got Destinus, the Swiss startup that wants to build Mach 5 airliners and sell them to airlines to begin passenger service in the 2030s. In late February 2023, the company plans to fly a hydrogenpowered aircraft for the first time when the unoccupied subscale test aircraft Jungfrau takes off from an airport near Munich, with a crew monitoring it from the ground. During previous test flights, Jungfrau was propelled by a conventional turbojet, but this time, its engine will mix compressed air with kerosene for combustion, and once airborne receive an additional burst of thrust through an afterburner that injects gaseous hydrogen into the nozzle jet stream.