London: Europe's Herschel space observatory - the largest infrared telescope ever launched - has stopped working after exhausting its supply of liquid helium coolant, ending more than three years of pioneering observations of the cool Universe.
Instruments on The European Space Agency's (ESA) billion-euro flagship observatory have warmed to levels that mean it has closed its eyes on the Universe. The mission began with over 2300 litres of liquid helium, which has been slowly evaporating since the final top-up the day before Herschel's launch on May 14, 2009, ESA said.
The liquid helium was essential to cool the observatory's instruments to close to absolute zero, allowing Herschel to make highly sensitive observations of the cold Universe until now. The confirmation that the helium is finally exhausted came on Monday at the beginning of the spacecraft's daily communication session with its ground station in Western Australia, with a clear rise in temperatures measured in all of Herschel's instruments....more
05:25 PM, Apr 30, 2013