How close is a hydrogen hypersonic commercial aircraft?

Abstract

There is a growing interest in hydrogen hypersonic commercial aircraft, which is claimed could permit travel from Sydney to London in less than 1½ hours with reduced environmental and economic costs compared to current subsonic airliners fueled with conventional hydrocarbon jet fuels. As here discussed, this development faces many technical hurdles, from thermal management to materials for extreme environments, from maneuverability to communication, and from sonic boom noise to efficient propulsion over a range of Mach from 0 to 10 and above. The development of this disruptive modality of air travel is constricted by resource availability to tackle these numerous technological challenges. Ultimately, the success will depend on social, political, and economic aspects, from the relevance of mass vs. elite air travel, the developments in the global economy, the synergies with military hypersonic propulsion, and the commitment toward general hydrogen aviation employing hydrogen for subsonic airliners.