The telescope's lifespan is governed by a tank of coolant on board.
When the coolant runs out, the telescope doesn't work.
Estimations of the amount of coolant left predicted an end of observations by the end of March 2013.
It continued to operate until 29 April 2013, when it was announced that Herschel had run out of coolant.
The observatory needed the coolant to stay sufficiently cold to observe far infrared light it was designed to see
Originally posted by sparky31
ok i,m going to take a guess this has already been posted but i couldn,t find anything on it.
just surprised in this day and age when you spend a billion euros on it you would think it would last longer than 4 years........really the state europes in the now then then this 1 adventure probably is the 1 and only time it will happen cause no1s every going to see it justified spending that money again for such a short time when people all over europe are struggling to survive.edit on Mon Apr 29 2013 by DontTreadOnMe because: added telescope to title
The event was not unexpected: 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 14 May 2009.
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 today.