Space weather conditions and spacecraft anomalies in different orbits

摘要

A large database of anomalies, registered by 220 satellites in different orbits over the period 1971 – 1994, has been compiled. For the first time, data of 49 Russian Kosmos satellites have been included in a statistical analysis. The database also contains a large set of daily and hourly space weather parameters. A series of statistical analyses made it possible to quantify, for different satellite orbits, space weather conditions in the days characterized by anomaly occurrences. In particular, very intense fluxes (>1000 particles cm s sr (pfu) at energy >10 MeV) of solar protons are linked to anomalies registered by satellites in high-altitude (>15,000 km) near-polar (inclination >55°) orbits typical for navigation satellites such as those used in the GPS network, NAVSTAR, etc. (the rate of anomalies increases by a factor of ∼20) and to a much smaller extent to anomalies in geostationary orbits (the rate increases by a factor of ∼4). The efficiency in producing anomalies is found to be negligible for proton fluences <100 pfu at energies >10 MeV. Elevated fluxes of energetic (>2 MeV) electrons >10 cm d sr are observed by GOES on days with satellite anomalies occurring at geostationary (GOES, SCATHA, METEOSAT, MARECS A, etc.) and low-altitude (<1500 km) near-polar (>55°) orbits (Kosmos, SAMPEX, etc.). These elevated fluxes are not observed on days of anomalies registered in high-altitude near-polar orbits. Direct and indirect connections between anomaly occurrence and geomagnetic perturbations are also discussed.