Friday 9 April, the Italian SST Operations Center (ISOC), jointly operated by the Poggio Renatico (FE) Aerospace Operations Command – SSA Center (COA-CSSA) and the Experimental Flight Department – Aero-Space Engineering Group (RSV-GIAS) of Pratica di Mare (RM), in coordination with the Space Operations Command (COS) of the Defense Staff, monitored the evolution of a potential event with a high probability of collision between two class space objects ” large ”in low orbit, non-maneuverable. The space objects involved in the event were a US weather satellite, no longer operational, called OPS 6182 launched in 1978, and a stage of a Russian launcher, called SL-8 R / B launched in 1981. Both objects were at a altitude of about 770-780 km.
From a preliminary analysis carried out by the ISOC, the Time of Closest Approach (TCA), i.e. the prediction of the instant of the potential collision, was estimated for April 9 at 17:18 UTC (19:18 Italian time), with a minimum distance between the two objects of the order of 20 meters and a probability of collision of about 20%. Furthermore, thanks to the simulation models and algorithms implemented in ISOC, it has been estimated that a fragmentation of the two objects resulting from their possible collision would have generated at least 400 objects with a diameter greater than 20 cm and a total number of fragments greater than 4. millions, potentially representing a further significant danger to all operating satellites in low orbit.
The event of possible collision was observed detected thanks to the screening carried out in the context of the European Union cooperation on Space Surveillance and Tracking (EU SST), in which Italy has participated since 2015 (EUSST Consortium) thanks to a national collaboration between ASI, INAF and the Ministry of Defense. The Consortium, in fact, provides registered users with the services of Conjunction Analysis, Re-entry Analysis and Fragmentation Analysis, in order to limit the proliferation of space debris and to contribute to the safeguarding of both European and national space infrastructures, vehicles and services. In this context, the ISOC represents the national Operational Center of reference and is able to coordinate the use of various national sensors (radar, optical and laser) for measuring the orbits of space objects of interest. In detail, the event was followed thanks to the Italian radar sensors MFDR-LR and BIRALES, which were used by the ISOC in collaboration with the Interoforze Poligono del Salto di Quirra and the National Institute of Astro-Physics, sensors that they detected the two objects still intact during the steps following the TCA.