Stereo: The challenges

The goal of the Solar-Terrestrial Relations Observatory (STEREO) mission is to advance understanding og the three-dimensional structure of the Sun's corona and especially the of the origin of coronal mass ejections (CMEs), their evolutions inthe interplanterary medium, and the dynamic couplingn between CMEs and the Earth environment, CMEs, the most energic eruptions on the Sun, are the primary cause of major geomagnetic storms and are believed to be responsible for the largest solar energetic particles events. They may also be a critical element in the operation of the solar dynamo, because they appear to remove dynamo-generated magnetic flux from the Sun. The STEREO mission will study CMEs and the Sun's coronal structure using two spacecraft orbiting the Sun, one drifting ahead of the Earth and one behind. STEREO will obtain simultaneous extreme ultraviolet and visible image pairs along with simultaneous measurements of fields and particles, at gradually increasing angular separations over the course of the mission. The STEREO spacecraft will be outfitted with two instrument suites and two instruments: IMPACT ( In situ Measurements of Particles and CME Transients); SECCHI (Sun-Earth Connection Coronal and Heliospheric Investigation); Plastic (Plasma and Suprathermal Ion Composition); and SWAVES (STEREO/WAVES). STEREO Phase C/D confirmation occured in March 2002; the dual observatories will be launched on a single Delta II from Cape Canaveral in November 2005. This presentation focuses on the goals and approach of the Mission.