THE five THEMIS scientific satellites (launch February 2007) Florida USA, join the spacefleet of Sun-Earth connection explorers – four from the ESA Cluster mission and two from the CNSA/ESA Double Star mission.

For the first time, about half of the magnetosphere and its environment will be monitored simultaneously by state-of the-art scientific instrumentation, thanks to these three missions.

The main scientific objective of THEMIS (Time History of Events and Macroscale Interactions during Substorms) is to find what triggers magnetic substorms. This phenomenon corresponds to periods of time during which violent changes happen within the Earth's magnetic environment or magnetosphere.

The main scientific objective of THEMIS (Time History of Events and Macroscale Interactions during Substorms) is to find what triggers magnetic substorms. This phenomenon corresponds to periods of time during which violent changes happen within the Earth's magnetic environment or magnetosphere.