Space is not cold enough for Herschel to detect the faintest infrared signals. European Space Agency officials said on April 29, 2013 that Herschel Space Observatory run out of liquid helium coolant. But Herschel kept going 'till Monday, June 17th. During this time, controllers were able to perform tests they wouldn't dare to do on a "live" telescope. Launched in 2009, Herschel was expected to last two years, but it performed for four years. Herschel's last commands were to fire a rocket and propel itself into a distant orbit. Then turn off its radio.