Herschel was launched on May 2009 and, with a main mirror (refined in Finland by Opteon Ltd.) 3.5 m across, it is the largest, most powerful infrared telescope ever flown in space. It has been studying previously invisible cool regions of gas and dust in the cosmos, and providing new insights into the origin and evolution of stars and galaxies.
Herschel has made extraordinary discoveries across a wide range of topics, from starburst galaxies in the distant Universe to newly forming planetary systems orbiting nearby young stars. ESA engineers believe that almost all of the liquid helium has now gone and in early May it will be propelled into its long-term stable parking orbit around the Sun.
Read more (ESA)