Solar Terrestrial Relations Observatory (STEREO)

The NASA Solar TErrestrial RElations Observatory (STEREO) mission consists of two identical spacecraft which were placed in two different orbits around the Sun. STEREO Ahead was placed slightly closer to the Sun than Earth and STEREO Behind slightly further away than Earth. This causes them to respectively pull farther ahead of and fall gradually behind Earth's orbit and thus exposing the farside of the Sun. On the site you will find data from the SECCHI instrument: the extreme ultraviolet imager (EUVI) camera showing the Sun in the 195 Ångström wavelength and two white-light coronagraphs: COR1 and COR2.

Communications with STEREO Behind were lost on October 1, 2014, due to multiple hardware anomalies affecting control of the spacecraft orientation. There is currently no real-time data available from STEREO Behind. Should communications be reestablished in the future we will feature any data coming from STEREO Behind on this page.

Where are STEREO A and B right now?