Cluster 1, 2, 3, 4, 5, 6, 7, 8

Cluster [ESA]

Cluster is an magnetospheric research project, consisting of a constellation of four identical satellites. Part of the first Cornerstone Mission in the European Space Agency's long-term space science programme, the Cluster II satellites were built to replace the original Cluster mission, which was aborted after Ariane-5G's maiden flight in June 1996 failed to launch the satellites. The mission's objective is to research the Earth's magnetosphere and its interaction with the solar winds, via four identical satellites flying in formation which take simultaneous measurements to provide the most detailed three-dimensional study of changes and processes taking place in near-Earth space. The four satellites were launched in 2000 on two Soyuz-U Fregat rockets.

Astrium was lead industrial contractor for the development and manufacture of the Cluster II satellites, heading a team of European aerospace indsutry partners from 14 European countries.

Each satellite features 11 instruments:

• FGM: Fluxgate Magnetometer
• EDI: Electron Drift Instrument
• ASPOC: Active Spacecraft Potential Control experiment
• STAFF: Spatio-Temporal Analysis of Field Fluctuation experiment
• EFW: Electric Field and Wave experiment
• DWP: Digital Wave Processing experiment
• WHISPER: Waves of High frequency and Sounder for Probing of Electron density by Relaxation experiment
• WBD: Wide Band Data instrument
• PEACE: Plasma Electron And Current Experiment
• CIS: Cluster Ion Spectrometry experiment
• RAPID: Research with Adaptive Particle Imaging Detectors

The Cluster scientific mission is extended until September 2024, when one of the four satellites will re-enter the Earth atmosphere. Two years of post-operations and monitoring of the spacecraft will follow, until re-entry of the last spacecraft in September 2026.