Conceptual design methodology for estimating chemical emissions and analysing pollutant dispersion in suborbital flight carriers

Suborbital flights are highly versatile and offer several opportunities to make rapid progress in various scientific fields and to develop new business activities. Concurrently, the growing concern over the environmental impact of the aviation sector highlights the need to assess and analyse the chemical emissions and their impacts on both climate change and local air quality. This thesis aims to bridge these two aspects, exploring the potential of suborbital flights while also evaluating their environmental implications. It focuses on the carrier of an A-to-A suborbital flight, namely White Knight Two, with Grottaglie as the reference spaceport. The first part concentrates on the assessment of the chemical emission of both proportional and non-proportional species during the ICAO Landing and Takeoff (LTO) cycle and along the nominal trajectory, described by ASTOS simulation, applying the Boeing Fuel Flow Method 2. These data are then compared and validated against a certified dataset reported in the literature. The research proceeds with an investigation on methods for assessing local air quality. It begins with an in-depth literature review of analytical dispersion models, as well as commercial software and tools. This is followed by the implementation of a simplified Gaussian Plume model to evaluate NOx concentrations during the landing and takeoff cycle, which is then validated using experimental data from existing studies. A comparison is then made between the resulting NOx concentrations produced by the WK2 carrier and those of the Boeing 747 LCF Dreamlifter, which operates regular flights at the reference airport. The aim is to show the public that WK2 and SS2 flights do not affect air quality more than the commercial flights already in operation. The final part is intended to serve as a starting point for future studies that may focus on assessing local air quality around the airport. These studies could take into account typical daily traffic at the spaceport, along with all the nearby emission sources, in order to accurately evaluate the long-term impact of aviation activities on the surrounding population.