Herschel space telescope finishes mission

Europe's flagship space telescope has stopped working.

The billion-euro Herschel observatory has run out of the liquid helium needed to keep its instruments and detectors at their ultra-low functioning temperature, BBC reports.

This equipment has now warmed, meaning the telescope cannot see the sky.
Herschel, which was sensitive to far-infrared and sub-millimetre light, was launched in 2009 to study the birth of stars and the evolution of galaxies.

Its 3.5m mirror and three state-of-the-art instruments made it the most powerful observatory of its kind ever put in space.
The end of operations is not a surprise. Astronomers always knew the helium store onboard would be a time-limiting factor.
The "blind" satellite is currently located about 1.5 million km from Earth on the planet's "night side".

Controllers at the European Space Agency's (Esa) operations centre in Darmstadt, Germany, will run some final tests on the spacecraft in the coming weeks before putting it in a slow drift around the Sun.

"We will push it out into a heliocentric orbit and passivate it," said Micha Schmidt, the Herschel spacecraft operations manager.
"We will switch off the transponder and the spacecraft will go silent."

Herschel should not come anywhere near the Earth again for several hundred years.