STEREO (Solar TErrestrial RElations Observatory) was launched in 2006, employing 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. The STEREO Behind spacecraft was lost in 2014, but the STEREO Ahead spacecraft continues to operate and make important science observations of the Sun. Its unique vantage point for observing the Sun-Earth system makes its data an important resource for space weather forecasting. The STEREO STEREO Ahead data is routinely used by NOAA’s Space Weather Prediction Center (SWPC), NASA’s Moon to Mars Space Weather Analysis Office, and scientists and space weather prediction services worldwide.
