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Planck at a glance

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ESA's microwave observatory

Named after the German Nobel laureate Max Planck (1858-1947), ESA's Planck mission is the first European space observatory whose main goal is the study of the Cosmic Microwave Background (CMB) – the relic radiation from the Big Bang.

Observing at microwave wavelengths, ESA's Planck observatory is the third space mission of its kind. The first two, COBE and WMAP, were American. Planck is measuring tiny fluctuations in the CMB with unprecedented accuracy, providing the sharpest picture ever of the early Universe — when the cosmos was only 380 000 years old. This will allow cosmologists to zero-in on theories that describe the Universe's birth and evolution.

Planck is measuring the fluctuations of the CMB with an accuracy set by fundamental astrophysical limits. In other words, it may be impossible to ever take better images of this radiation than those obtained from Planck.

The spacecraft is equipped with a powerful telescope and two instruments operating at radio to sub-millimetre wavelengths. A sophisticated cryogenic system keeps their detectors at temperatures close to absolute zero.

Planck will measure the fluctuations of the CMB with an accuracy set by fundamental astrophysical limits.

Launch: 14 May 2009 on board an Ariane 5 from ESA's Spaceport in Kourou, French Guiana. The launch took place at 15:12 CEST. Planck was launched along with Herschel, ESA's infrared space observatory.

Status: In operation.

Journey: Planck was launched with ESA's Herschel infrared space observatory. Herschel separated from the upper stage of the launcher 26 minutes after launch and Planck followed 2.5 minutes later. The two spacecraft now operate independently. The upper stage set both spacecraft onto a trajectory that led them to orbits around the second Lagrangian point (L2), situated about 1.5 million km from Earth in the direction opposite to the Sun.

Orbit: Planck operates from a Lissajous orbit around L2, the second Lagrangian point of the Sun-Earth system, with an amplitude of 400 000 km. L2 is located 1.5 million km from Earth.

Telescope and instruments: Planck carries a 1.9x1.5-m telescope, with an effective aperture of 1.5 m. It focuses radiation from the sky onto two arrays of sensitive radio detectors, those of the Low Frequency Instrument and those of the High Frequency Instrument. Together they measure the temperature of the CMB over the sky, searching for regions very slightly warmer or colder than the average.

A sophisticated cryogenic system keeps the instrument's detectors at temperatures close to absolute zero.

Wavelength coverage: Planck observes in nine wavelength bands, from one centimetre to one third of a millimetre, corresponding to a range of wavelengths from microwaves to the very-far-infrared.

Launch mass: About 1.9 tonnes.

Dimensions: Approximately 4.2 m high and 4.2 m wide.

Ground station:ESA's deep space antenna in New Norcia.

Planned lifetime: Routine observations are planned to last until November 2011, allowing the whole sky to be surveyed four times. After this, the LFI instrument will continue operating for an additional year, providing more information to help astronomers interpret the CMB data.

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