This image shows a coronal mass ejection (CME) from May 20, 2011 as taken by STEREO with an artist's concept of a STEREO spacecraft superimposed on it.

October 25, 2011 marks five years since the launch of the Solar TErrestrial RElations Observatory (STEREO) twin spacecraft. Over the last five years, each STEREO spacecraft, one preceding the Earth and one following the Earth, has moved to a position in their orbit of almost exact opposite sides of the sun providing us with a full 360 degree view of the sun starting on February 6, 2011. In the coming months/years, the two satellites will keep moving further away from Earth, lining up on the far side of the sun in 2015 and continuing on their journey until they are once again back close to Earth in 2019. Credit: NASA/SDO/Holly Zell › Link to associated news item