EU–(ENEWSPF)–29 April 2013. ESA’s Herschel space observatory has exhausted its supply of liquid helium coolant, ending more than three years of pioneering observations of the cool Universe.
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…






