About the STEREO Mission

STEREO (Solar TErrestrial RElations Observatory) is the third mission in NASA's Solar Terrestrial Probes program (STP). This two-year mission will employ two nearly identical space-based observatories - one ahead of Earth in its orbit, the other trailing behind - to provide the first-ever stereoscopic measurements to study the Sun and the nature of its coronal mass ejections, or CMEs.

STEREO's scientific objectives are to:

• Understand the causes and mechanisms of coronal mass ejection (CME) initiation.
• Characterize the propagation of CMEs through the heliosphere.
• Discover the mechanisms and sites of energetic particle acceleration in the low corona and the interplanetary medium.
• Improve the determination of the structure of the ambient solar wind.

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• Why STEREO?
• Mission Concept
• Mission Design
• Report of the Science Definition Team for the Stereo Mission (1.8MB PDF)