Since its establishment, the space sector has pursued the development of technologies required to further expand space exploration activities with an almost complete focus on performance achievement. With the projected increase in the frequency of access to space, it is of utmost importance to evaluate and develop minimization strategies for the environmental impact since the earliest design stages. This work aims at extending the applicability of NOx estimation methods developed for the aviation sector to a Single Stage To Orbit vehicle. This implies an adaptation of already existing formulations to cover propellants (different from Jet-A1 kerosene) and different propulsive technologies and speed regimes, ranging from subsonic to supersonic and hypersonic.