Herschel: ESA’s supercool heat seeker
Everything about ESA’s Herschel Space Observatory was big. The satellite was about 7 metres high and 4.3 metres wide, with a mass of 3.25 tonnes. Its telescope had a main mirror that measured 3.5 metres across, the largest ever built for a scientific spacecraft.
The observatory was named after another scientific giant, the German amateur astronomer and musician William Herschel, who discovered the planet Uranus in 1781. 19 years later, he also discovered a form of invisible light that scientists know as "infrared radiation". We often just call it "heat".
Herschel was used to study the ‘cold’ Universe. Its supercool 'eyes' were able to see through dust clouds to study star forming regions and galactic centres, as well as detect hidden stars and planets. It was also able to seek out distant galaxies in order to throw new light on how they formed, billions of years ago.
Herschel’s groundbreaking scientific mission ended on 29 April 2013, when its supply of helium coolant ran dry. However, the satellite continued to be used for orbital tests until the final command to shut it down was sent on 17 June.
Last update: 16 October 2013