What is the purpose of the US Space Agency's Themis Mission, which was recently in the news?

1. Themis (Time History of Events and Macroscale Interactions during Substorms) is a NASA mission consisting of five identical probes launched in 2007. 2. Its primary purpose is to study the origin of magnetospheric substorms, which are responsible for the aurora (the colourful display of high latitude skies). 3. The mission investigates the chain of events leading to the auroral displays. 4. It is not focused on life on Mars, satellites of Saturn, or stellar explosions.