Following the recent successful test of Boom Supersonic’s demonstrator aircraft, Kshitij Sabnis, a SEMS academic who works on high-speed experimental aerodynamics, discusses in The Conversation how a possible resurgence in supersonic civil aviation might impact the environment.

The article has received considerable attention from the readership of The Conversation and The New Daily, having been read more than 17,000 times in the past month since publication.

In the article, Kshitij describes recent innovations in exploiting a phenomenon called “Mach cutoff” to reduce noise impacts of aircraft, which may allow supersonic planes to fly over land and thus increase chances of their commercial viability. He explains how the shock waves generated at supersonic speeds substantially increase the drag force on a plane which, in turn, increases the fuel burnt and emissions generated.

However, given that supersonic aircraft will likely only account for a small percentage of worldwide fleets, Kshitij argues that the negative emissions impact may potentially be outweighed by the benefits of aerodynamics and propulsion research (such as alternative fuel sources) through producing technologies that transfer to subsonic aircraft. He also highlights the importance of looking beyond carbon emissions by considering contrails - thin clouds of water vapour which may have a far greater impact than carbon emissions but about which relatively little is known, particularly at the high altitudes favoured by supersonic planes.

Kshitij concludes by noting that the environmental impact of supersonic aviation is a complex issue, with many unknown factors that will become evident through crucial research as the industry develops in the coming years.