|Back to Press Kit|
|28 April 2010|
Herschel is the largest astronomical telescope ever launched. Its 3.5 m-diameter primary mirror is giving astronomers their best view yet of the Universe at far-infrared and submillimetre wavelengths.
The mission builds upon the legacy of ESA’s Infrared Space Observatory and subsequent infrared missions such as NASA’s Spitzer and JAXA’s Akari.
The telescope is named after the German–British astronomer William Herschel. In 1800 he discovered infrared radiation while studying the Sun. He also discovered Uranus, the seventh planet in the Solar System, and surveyed the sky.
The Herschel mission has an unprecedented view of the cold Universe, bridging the gap in the spectrum between what can be observed from the ground and earlier space missions of this kind. Infrared radiation can penetrate the gas and dust clouds that hide objects from optical telescopes, allowing astronomers to see deep into star-forming regions, galactic centres and planetary systems.
Cooler objects, such as tiny stars and molecular clouds, and even galaxies enshrouded in dust (which barely emit optical light) are visible in the infrared. It can even detect emissions from dust itself. Observing in the infrared provides us with a complementary view of the Universe.
But why go into space to do this? The simple reason is that Earth’s atmosphere blocks most infrared wavelengths. In addition, the atmosphere produces its own infrared radiation. So, observing in the infrared from the ground is like trying to view stars on a cloudy day.
Herschel was launched together with ESA’s Planck satellite. Since operations began, the two missions have been studying different aspects of the cold cosmos.
The total cost of the Herschel mission is about €1100 million. This includes the spacecraft and its scientific payload, the launch and the mission and science operations.
Herschel was launched on an Ariane 5 ECA from Europe’s Spaceport in Kourou, French Guiana, on 14 May 2009. It was launched together with ESA’s Planck spacecraft.
Herschel is a tall ‘tube’. The most obvious feature is the 3.5 m-diameter primary mirror that sits on top of the cryostat and is protected by a sunshade from direct sunlight. The mirror focuses infrared light, via a smaller secondary mirror, down into the focal plane inside the cryostat. This sits under the mirror and provides cooling of the scientific instrument package to within a fraction of absolute zero. The sunshade and is also partially covered with solar cells to provide the power required to operate the space telescope
Below the cryostat is the service module. It contains the essential computers and other systems that allow the spacecraft and its instruments to function, and also allow handling and compression of the raw scientific data.
In order to achieve its scientific objectives, Herschel’s detectors have to operate at very low and stable temperatures. So the spacecraft cools the detectors close to absolute zero (–273ºC), ranging from –265ºC to only a few tenths of a degree above absolute zero.
Approximately 3400 kg at launch. This included 2300 litres of liquid helium that is used to cool the instruments to their operating temperatures.
Herschel is 7.4 m high and 4.0 m in width.
The prime contractor is Thales Alenia Space (Cannes, France). It leads a consortium of industrial partners with Astrium (Friedrichshafen, Germany) responsible for the Extended Payload Module (EPLM) and Thales Alenia Space (Turin, Italy) responsible for the Service Module (SVM). There is also a host of subcontractors spread throughout Europe.
Photodetector Array Camera and Spectrometer (PACS)
Principal Investigator (PI):: Albrecht Poglitsch, Max Planck Institute for Extraterrestrial Physics (Garching, Germany).
PACS was designed and built by a consortium of scientists and institutes – under their own funding – from Germany (country of the PI), Belgium (country of the co-PI), Austria, France, Italy and Spain. They are all led by the PI.
Spectral and Photometric Imaging Receiver (SPIRE)
Principal Investigator: Matthew Griffin, Cardiff University (Wales, UK).
SPIRE was designed and built by a consortium of scientists and institutes – under their own funding – from the United Kingdom (country of the PI), France (country of the co-PI), Canada, China, Italy, Spain, Sweden and USA. They are all led by the PI.
Heterodyne Instrument for the Far Infrared (HIFI)
Principal Investigator: Frank Helmich, SRON Netherlands Institute for Space Research (Groningen, The Netherlands).
HIFI was designed and built by a consortium of scientists and institutes – under their own funding – from the Netherlands (country of the PI), France, Germany and USA (countries of the co-PIs), and from Canada, Ireland, Italy, Poland, Russia, Spain, Sweden, Switzerland and Taiwan. They are all led by the PI.
Herschel Project Scientist: Göran Pilbratt
Copyright 2000 - 2012 © European Space Agency. All rights reserved.