The ISON international campaigns for monitoring of faint high altitude objects

The research of the space debris fragments at high orbits is one of the main directions of the International Scientific Optical Network (ISON) activities. Therefore the dedicated ISON subsystem for high altitude faint space debris observations is arranged with the aim of detection and continuous tracking of as large number of unknown high altitude faint objects as possible. The subsystem includes the number of large telescopes that are able to detect the objects down to 20m-21m and the middle-size telescopes for the observations of the space objects of 15m-18m. The 1-m ZIMLAT in Zimmerwald, Switzerland, 1.5-m AZT-33IK in Mondy, Siberia, 64-cm AT- 64 in Nauchniy, Crimea, 60-cm RK-600 in Mayaki near Odessa, Ukraine, 60-cm Zeiss-600 in Maidanak, Uzbekistan, 70-cm AZT-8 in Gissar, Tajikistan are regularly participating in ISON observing campaigns in collaboration with 1-m Zeiss-1000 ESA space debris telescope in Teide, Canaries islands. 2.6-m ZTSh in Nauchniy, Crimea, 2-m Zeiss-2000 in Terskol, North Caucasus, 1-m Zeiss-1000 in Simeiz, Crimea, 1-m Zeiss-1000 in Arkhyz, North Caucasus are joining during few nights per month. The 60-cm Zeiss-600 in Arkhyz, 70-cm AZT-8 in Evpatoria, Crimea, 60-cm Zeiss-600 in Tarija, Bolivia, 80-cm RK-800 in Mayaki, 80-cm K-800 in Terskol, 50-cm in Ussuriysk, Far East will be added to the subsystem during 2008. The observing campaigns are coordinates by the Center on space debris data collection, processing and analysis of the KIAM RAS in cooperation with the AIUB space debris team. 353 faint objects are discovered in GEO region surveys during the last 3 years (about 100000 measurements were collected for this time), including objects with high AMR. Results are publishing monthly by KIAM in High Geocentric Orbit Space Debris Circular. We will discuss the most interesting of obtained results. Many of discovered fragments are associated with space debris clouds appeared as a result of known or suspected fragmentations occurred in GEO region. Orbital analysis performed for the tracked objects of such clouds proved their suspected origin. Surprisingly, many of faint objects have a high area-to-mass ratio value. This results in a very strong evolution of their orbits under influence of solar radiation pressure. In order to obtain deterministic picture of the real number of such objects each newly discovered one should be tracked continuously. Otherwise it quickly becomes lost and it is not always possible to correlate later discovered objects with the earlier tracked and lost ones. Other peculiarity of the high altitude objects is their high brightness variability in many cases. Sometimes the object discovered with 22-cm class telescope becomes hard if possible at all to track with the largest instruments involved into the ISON activity. That is why so important to establish regular surveys with the middle-class instruments (0.6-1 m) which should permit to discover finally all objects becoming brighter than 18m. Significant efforts in both directions (continuous tracking and surveys) are made by the ISON.