The Cluster Mission after 13 Years -Operations beyond its Design Limits

摘要

The four Cluster spacecraft were designed in the early 1990s for a 3 years mission through the Earth's magnetosphere. The fleet is still going strong after more than 13 years in orbit: the science data volume is unchanged high. This paper provides the overview about the degradation of the on-board resources, fuel, batteries and electrical power. The focus is on the operations with low power in routine and eclipse operations without batteries. The various strategies and achievements of Flight Dynamics are summarized together with the impact of the orbit evolution due to natural forces. The migrations activities in the ground segment are briefly addressed to complete the picture. The successful implementation of these strategies gives the opportunity to extend the Cluster mission at least for four more years.