Solar Terrestrial Relations Observatory

Solar Terrestrial Relations Observatory (STEREO), two U.S. spacecraft that were designed to observe the Sun from separate locations in space and thus provide a stereoscopic view of solar activities. The STEREO mission was launched on Oct. 25, 2006, by a Delta II rocket from Cape Canaveral, Fla. The Moon’s gravity was used to pitch the satellites into different places along Earth’s orbit, where one would orbit the Sun ahead of Earth and the other following...