Performance of a network of stations dedicated to optical survey and associated services for space safety

The optical survey of the low Earth orbit is now a reality to provide a large amount of data for cataloguing purpose and to ensure space safety. A concept of multi-telescope observation station (MTOS) was developed and deployed by Aldoria with currently three operational stations. Each station is equipped of four telescopes, each one offering a large field of view and scanning a circular band of the sky to catch all objects travelling above the station and illmuminated by the Sun. Astrometric and photometric measurements are produced for catalogued and uncatalogued space objects ensuring to Aldoria an autonomy in catalogue building and maintenance.

In this paper, we introduce the concept of MTOS and the operational observation modes they provide. Moreover, we describe the complete production chain developed by Aldoria since the scheduling to the catalogue update. We provide the performances related to the data produced by this kind of individual station in term of volume and accuracy. Currently three stations are deployed but a larger network is scheduled. The deployment strategy, based on an optimization of the site location to observe objects on every orbit in LEO, will be discussed. Through its network of MTOS, Aldoria has a growing catalogue of space objects mainly covering the LEO region but also MEO and GEO. The current and future catalogue will be described.

Moreover, the SSA data platform of Aldoria is hosting the catalogue but also services for space safety. The space object characterisation service is based on patern-of-life analysis allowing to identify satellite during each phase of their life (orbit raising, station-keeping, decommissioning) or any change (longitude drift, change or orbital plane). The collision risk assessment service performs conjunction screening, computation of the risk and collision avoidance manoeuvre design if required. Both are event-driven services, triggered each time the catalogue is updated ensuring a very high reactivity.

The SSA data platform is natively multi-source. It is able to collect and process data coming from the Aldoria network but also any other third-party supplier able to push data through an Aldoria’s API. Source like the 18 SDS catalogue are integrated. It allows to perform a systematic cross-checking of the data at all the data levels (TDM, OPM, CDM) ensuring a greater confidence in the data but also to detect early an anomaly due for example to a manoeuvre.