An upgraded environmental index for the SST fragmentation service

In Rossi et al. (JSSE, 2022) an index, named Fragmentation Environmental Index (FEI), able to quantify and visualize the medium term effects on the environment of a fragmentation in Low Earth Orbit (LEO) was derived. The main effort with FEI was to devise a simple analytical index to catch, also visually, the impact of an in-orbit fragmentation on the space environment and its evolution in a given time frame, typically limited to several months after the event. By parametrizing the performances of typical optical and radar sensors, an improvement of the original FEI is proposed with the adoption of specific weighting functions quantifying the observability of the fragments as a function of their size and orbital regions. The theoretical development of the new index is described along with the road to its validation which is currently undergoing through a test campaign.