Herschel space telescope reaches end of life

BBC : The European Space Agency’s (ESA’s) Herschel Space Observatory was launched in 2009 to observe the formation and evolution of stars and galaxies, the chemical composition of bodies in our solar system, and molecular chemistry of objects throughout the universe. The instruments onboard require extremely low temperatures, but the 2000 L of helium refrigerant Herschel carried at launch will run out in the next few weeks, almost exactly when originally predicted. The telescope was placed at Earth’s second Lagrangian point âmdash;a point 1.5 million km from Earth, where the gravitational forces of Earth and of the Sun balance in the two bodies’ rotating reference frameâmdash;to keep the spacecraft in Earth’s shadow. Its 3.5-m single-piece mirror, the largest ever launched, was able to observe light in the far-IR and submillimeter wavelengths. When the helium supply runs out, the instruments will quickly warm beyond the point of usability. At that point, ESA will put the satellite into a slow-drifting orbit around the Sun.