What is NASA’s THEMIS Mission?
THEMIS is an acronym for Time History of Events and Macroscale Interactions during Substorms. THEMIS is NASA’s first five identical-satellite mission, launched as a constellation on Feb. 17, 2007, to resolve the tantalizing mystery of what causes the spectacular sudden brightening of the Northern Lights or the auroral borealis — the fiery skies over Earth’s North Pole. These lights are the visible manifestations of sudden large energy releases (called substorms) in near-Earth space, out to half the way to the moon. THEMIS will answer the 30-year-old question: Where and when do substorms start?
