The European Space Agency’s (ESA) Herschel Space Observatory will be the largest ever infrared space observatory. It will collect radiation from some of the coldest and most distant objects in the Universe. The UK has led the development of one of the three instruments on board. Herschel will observe previously unexplored wavelengths of light in the far infrared region of the electromagnetic spectrum to examine the formation of galaxies and stars.
Stars form inside big clouds of gas and dust, which act as a thick fog when viewed using visible light. Herschel is sensitive in the far infrared so astronomers will be able to see through these clouds to witness what is going on inside.
Herschel's major objectives will be discovering how the first galaxies formed and evolved to give rise to present day galaxies like our own. It will also investigate the continuing formation of stars in our galaxy today. Herschel will observe clouds of gas and dust where new stars are being born, disks out of which planets may form and cometary atmospheres packed with complex organic molecules.
Herschel has a 3.5 m telescope, much bigger than on any previous far infrared satellite. It can therefore collect more light and produce better images.
For more information, visit ESA’s Herschel mission homepage.
Mission facts
- Herschel was originally named FIRST (Far Infrared and Sub-millimetre Telescope) but was renamed in honour of the pioneering astronomers William and Caroline Herschel.
- Herschel will be launched on an Ariane 5 rocket together with ESA's Planck spacecraft. The two spacecraft will separate after launch.
- Prior to launch, all the instruments will be installed in the spacecraft and thoroughly tested as part of the complete system. The complete Herschel satellite will then undergo further tests at the ESA technology centre ESTEC, in the Netherlands, where it will be put in a test chamber to simulate the space environment. Finally Hershel will be transported to Kourou in French Guiana in preparation for the launch.
Technology
The Herschel spacecraft is approximately 7.5 m high and 4 x 4 m in overall cross section. Its launch mass is a hefty 3.3 tonnes.
With a diameter of 3.5 m, Herschel will have the largest mirror ever built for use in space.
The spacecraft comprises two modules. The power supply, computers and communication systems and the pointing system are housed in a service module. The payload module consists of the telescope, a sunshade with solar panels and three scientific instruments contained inside a large liquid helium tank or ‘cryostat’.
In order to make measurements at infrared and sub-millimetre wavelengths, parts of the instruments have to be cooled to as near absolute zero (-273.15 °C) as possible. The instruments and their common mounting structure are contained within the cryostat. More than 2,000 litres of liquid helium will be used during the mission to keep everything cold.
UK involvement
A key component of the satellite is being led by the UK. The SPIRE (Spectral and Photometric Imaging Receiver) instrument has been developed by an international consortium. It is led by a Principal Investigator from Cardiff University.
The assembly and testing of SPIRE has taken place at the STFC Rutherford Appleton Laboratory (RAL) in Oxfordshire. The instrument was delivered for installation in the Herschel satellite in April 2007. Other UK institutes involved in SPIRE are Imperial College London, University College London’s Mullard Space Science Laboratory and the UK Astronomy Technology Centre, Edinburgh.
UK companies involved in the mission include AEA Technology, Analyticon, BOC Edwards, Datasat, MT Satellite Products and System International.
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