Beam-park experiments at FGAN

The space debris situation is highly dynamic due to some on orbit break-ups and other debris producing events per year. This necessitates frequent observation campaigns e.g. with ground based sensors. FGAN (Research Establishment for Applied Science) conducted in the framework of study contracts from ESA several observation campaigns during the last years. FGAN's L-band monopulse radar of their TIRA System (Tracking and Imaging Radar) was used to detect space objects (larger than 2 cm at 1000 km range) in LEO (Low Earth Orbit) passing the parked radar beam (Beam-park experiment; BPE). During 24-h periods complete small circles in right ascension were observed at altitudes ranging from about 300-2000 km. This paper summarizes the most recent observation campaigns in October 2000, October 2001, and April 2002. The analysis results demonstrate the changes in the debris population over time. The results are also compared with predictions by ESA's MASTER/PROOF'99 model. The radar cross section (RCS) of detected objects is determined and converted to object size using NASA's Size Estimation Model (SEM). These data can be used to verify e.g. the orbital size distribution assessed by space debris environmental models. RCS data of some detected larger space objects are compared with data published in the US Space Command (USSPACECOM) RCS-catalogue. The comparability of these data is discussed. Using radars in BPEs side lobe detections might happen. Since they falsify the statistics their identification and treatment is discussed.