Ricerc@Sapienza

In the recent years, an increasing interest towards enhanced and more frequent operations at high altitudes has been demonstrated both by aerospace industry and academics. In particular, many institutions and companies are developing the so-called HAPS (High Altitude Platform Stations, [1] - [3] ), high altitude balloons provided with low-thrust propulsion systems able to maintain their position over a target. These vehicles are provided with power generation systems and are able to perform long-term missions of weeks or even months. On the other hand, suborbital commercial missions are close to their starting point for both touristic and short-term scientific operations [4] , [5]. The mentioned new-generation vehicles require to maintain a certain level of reliability in the tracking and surveillance systems to assure their compatibility with the "conventional"air space operations of commercial aircraft and the needed safety levels for the conducted operations, with particular regards to manned missions.