Debris monitoring observatory network (DEMON): A high coverage infrastructure for space debris monitoring

The most common methodologies for space debris identification and monitoring involve radar measures, laser ranging and finally optical observations. Although representing the only passive method for debris tracking, optical observations are constrained to reduced time windows, when targets are crossing the penumbra annular region and the observatory is in darkness. On this purpose, an increased amount of optical data can only be assured by a multiplicity of observing stations extending the coverage of the monitoring system. The Sapienza Space Systems and Space Surveillance Laboratory (S5LAB) Research Team at Sapienza - University of Rome has established the Debris Monitoring Observatory Network (DEMON), an international network of optical observatories addressed at debris surveillance. The first six DEMON observatories are owned by S5LAB and located in Rome and surroundings. The two observatories developed by the S5LAB research team in the framework of the Equatorial Observatory (EQUO) project managed by the Italian Space Agency are part of the SSON and located at the Broglio Space Center in Malindi, Kenya, and allow to provide coverage to the equatorial orbital region. Finally, five optical observatories located in Bologna (Italy), Ann Arbor (Michigan, USA), Cerro Tololo (Chile) and Bern (Switzerland) and a radar located in Bonn (Germany) are collaborating with the S5LAB research team as part of the DEMON. Such a spread dislocation of the observing sites allows to increase the accuracy of the obtainable orbital parameters. Moreover, the network observatories distribution allows to increase the European space surveillance capabilities, both allowing to achieve data from sites featuring different meteorological conditions, and to obtain less sparse measurements from longer orbit arcs, facilitating the orbit determination procedure. The whole network has been tested with several observation campaigns, including the Tiangong-1 re-entry campaign performed in support to the Inter-Agency space Debris Committee (IADC). The heterogeneous capabilities of the different observatories represent an advantage for acquiring a wider set of debris monitoring data with different techniques. Indeed, two observing modalities can be applied: a direct tracking can be performed by following the target during its pass over the ground station or the debris track can be recorded while the telescope is performing a sidereal tracking. A strong synergy between our institution and the Italian specialized industry has also revealed to be very productive in the context of the network establishment. The present paper will describe the DEMON infrastructure and the opportunities, improvements and future perspectives for research institutions or space industry of this wide observatories network will be discussed.