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Credits: ESA (Image by AOES Medialab)

This artist's impression shows the Planck satellite and a sketch of the microwave radiation being collected and focused by the telescope’s primary and secondary mirrors.

The radiation is then directed to the focal planes of the two instruments (LFI Low Frequency Instrument and the HFI High Frequency Instrument). LFI is designed to convert the lower energy microwaves into electrical voltages, rather like a transistor radio. HFI works by converting the higher energy microwaves to heat, which is then measured by a tiny electrical thermometer.

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Credits: ESA (Image by C. Carreau)

The routine observations of Planck are planned to last 15 months, allowing two complete surveys of the sky.

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Credits: ESA (Image by AOES Medialab)

Artist's impression of Planck

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Credits: ESA (Image by AOES Medialab)

This artist's impression shows the focal plane unit of the Planck telescope.

Planck's instruments will operate at a few degrees above absolute zero. To achieve this, a series of cooling stages are required. Without any additional cooling, the spacecraft itself can passively cool to around 50 K (about -223ºC).

For the Low Frequency Instrument (LFI) the focal plane is cooled to around 20 K (about -253ºC). The signals received in the instrument horns are amplified and passed through waveguides to a back-end unit (which is at around 300 K, or about 27ºC) where the signals are processed.

The High Frequency Instrument (HFI) unit is more compact and sits entirely within the LFI housing at about 18 K (about -255ºC). The bolometers (devices for measuring incident electromagnetic radiation) are then stage cooled to just 0.1 K (-273.14ºC) with the detected signals again processed in a warmer back-end readout and data processing unit.

Isolating the various components and cooling only small volumes to the coldest temperatures the optimum efficiencies and mission achieve lifetime.

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Credits: ESA - S. Corvaja

Planck satellite on display at Thales Alenia Space in Cannes, France, on 1 February 2007. Thales Alenia Space is the Prime Contractor for building the satellite.

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Credits: ESA

The Planck satellite at ESA's European Space Research and Technology Centre (ESTEC) in Noordwijk, the Netherlands. The picture was taken on 31 March 2008 as Planck was being prepared for fine balance tests inside the Large Space Simulator.