11 research outputs found
Space weather and space anomalies
A large database of anomalies, registered by
220 satellites in different orbits over the period 1971â1994
has been compiled. For the first time, data from 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 on the days characterized
by anomaly occurrences. In particular, very intense
fluxes (>1000 pfu at energy >10MeV) 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 ~20), and to a much smaller extent to anomalies in
geostationary orbits, (they increase by a factor ~4). Direct
and indirect connections between anomaly occurrence and
geomagnetic perturbations are also discussed
Different space weather effects in anomalies of the high and low orbital satellites
Preliminary results of the EU INTAS Project 00810, which aims to improve the methods of safeguarding satellites in the Earth's
magnetosphere from the negative effects of the space environment, are presented. Anomaly data from the ââKosmosââ series satellites
in the period 1971â1999 are combined in one database, together with similar information on other spacecraft. This database contains,
beyond the anomaly information, various characteristics of the space weather: geomagnetic activity indices (Ap, AE and Dst),
fluxes and fluences of electrons and protons at different energies, high energy cosmic ray variations and other solar, interplanetary
and solar wind data. A comparative analysis of the distribution of each of these parameters relative to satellite anomalies was carried
out for the total number of anomalies (about 6000 events), and separately for high (~5000 events) and low (about 800 events) altitude
orbit satellites. No relation was found between low and high altitude satellite anomalies. Daily numbers of satellite anomalies,
averaged by a superposed epoch method around sudden storm commencements and proton event onsets for high (>1500 km) and
low (<1500 km) altitude orbits revealed a big difference in a behavior. Satellites were divided on several groups according to the
orbital characteristics (altitude and inclination). The relation of satellite anomalies to the environmental parameters was found
to be different for various orbits that should be taken into account under developing of the anomaly frequency models.
© 2004 COSPAR. Published by Elsevier Ltd. All rights reserved