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.