MIT’s Laboratory for Aviation and the Environment is beginning a new research effort on the environmental impacts of a potential future fleet of supersonic aircraft. The research effort, funded by NASA, aims to advance scientific understanding of the role of high altitude emissions in atmospheric chemistry, ozone depletion, and climate change, and provide information on what measures could be taken to mitigate the environmental impact of supersonic aircraft.

Environmental questions about the impact of supersonic aircaft emissions on the ozone layer contribued to the U.S. Government’s 1971 decision to cut funding for the development of a supersonic civil transport. The use of advanced engine designs with improved emissions characeristics is expected to mitigate the environmental impact, but the potential for adverse climate and ozone impacts remains an area of concern.

The research team plans to quantify ozone and climate impacts associated with the rollout of a fleet of advanced supersonic NASA N+2 generation aircraft. State-of-the-art atmospheric modeling will be applied to estimate both absolute impacts and sensitivities to parameters including fleet size, aircraft performance and emissions, fuel properties, and route selection. The models applied will comprise a suite of flexible and powerful rapid design and assessment tools allowing further investigation of the environmental impacts of supersonic aircraft.

In order to achieve these objectives, LAE has gathered a team with internationally-recognized expertise in atmospheric science, climate science, aviation’s environmental impacts, aviation economics, gas turbines and combustion. Assessing the ozone and climate impacts of supersonic aircraft requires an integrated approach that involves interactions among several component models. For this study, the researchers will develop tools to represent the effects of supersonic, stratospheric flight and implement efficient methods to assess model sensitivities to design parameters. This will include drawing on experience modeling and implementing stratospheric chemistry in the GEOS-Chem UCX atmospheric model to further advance understanding of the impact of aircraft flying in the stratosphere, and experience in estimating global aviation emissions and emissions from biofuel combustion.

The impact of supersonic cruise aircraft will depend on the routes and schedules of those aircraft. The researchers will identify a set of physically and economically feasible routes based on insights from fleet assignment models, in which aircraft are assigned to routes so as to maximize network profitability. Scenarios will be developed for changes in fleet assignments in which proportions of flights are replaced with supersonic aircraft, as well as scenarios in which supersonic aircraft serve as a supplement to the subsonic fleet.

Areas of scientific and technical investigation will include the potential for ozone depletion from high altitude emissions, the effects of any ozone depletion on human ultraviolet radiation exposure – which increases risk of skin cancer – and the impact of supersonic flights on the climate, including effects on high altitude condensation trails (contrails). Measures to mitigate environmental impacts including changing cruise altitude and routing, and the use of biofuels or cryogenic fuels such as LNG, will also be investigated.

LAE Director Professor Steven Barrett will be the Principal Investigator (email sbarrett@mit.edu), with MIT Professors Susan Solomon, Ron Prinn, Qiqi Wang and Ian Waitz serving as Co-Investigators. LAE Research Scientist Dr. Ray Speth (email speth@mit.edu) will coordinate the effort.  Other LAE personnel involved include Irene Dedoussi, Seb Eastham, Fabio Caiazzo and Dr. Robert Malina.