Planck scanning the sky

Status: In operation

Objective
Mapping the relic radiation from the Big Bang with improved sensitivity and resolution, and testing theories on the birth and evolution of the Universe.

Mission
Planck is ESA’s time machine, looking back to the dawn of time close to the Big Bang, about 13.7 billion years ago. Planck will analyse, with the highest accuracy ever achieved, the remnants of the radiation that filled the Universe immediately after the Big Bang – observed today as the Cosmic Microwave Background (CMB).

The results willhelp astronomers in deciding which theories on the birth and evolution of the Universe are correct, for example, did the Universe start its life with a rapid period of expansion?

But first, Planck must detect and understand the foreground emissions that lie between us and the Universe’s first light. Planck’s first scientific data and results were released in January 2011, and the first cosmological results are expected in early 2013.

Simulation of cosmic ray background, as Planck would see it

What’s special?
Planck is Europe's first mission to study the relic radiation from the Big Bang.

The temperature of this CMB radiation has already been measured as approximately 2.7 K, but Planck will provide even more precise measurements with an accuracy set by fundamental astrophysical limits. In other words, it will be impossible to ever take better images of this radiation than those obtained from Planck.

Scientists also know from previous observations that slightly hotter or colder patches – anisotropies – appear in the sky, different by one part in 100 000. These differences in temperature are the imprints left in the CMB by the primeval 'seeds' of today's huge concentrations of matter – galaxies and galaxy clusters, for example. Planck's high sensitivity will result in the best ever map of anisotropies in the CMB, enabling scientists to learn more about the evolution of structure in the Universe.

To complete these highly sensitive measurements, 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. Planck’s detectors are cooled to temperatures very close to the absolute zero, otherwise their own emission of heat will spoil the measurements.

Planck on display

Spacecraft
The Planck spacecraft is approximately 4.2 m high and 4.2 m wide. The primary mirror is 1.5 m and is accompanied by two science instruments: the Low Frequency Instrument (LFI), which operates between 30 and 70 GHz, and the High Frequency Instrument (HFI), which operates between 100 and 857 GHz.

HFI completed its survey in January 2012. LFI continues to operate.

Journey
Planck launched on 14 May 2009 on an Ariane 5 from ESA’s Spaceport in Kourou, French Guiana. It shared a ride into orbit with ESA's Herschel spacecraft. The two spacecraft now operate independently.

Planck operates from a Lissajous orbit around the second Lagrangian point of the Sun–Earth system (L2), a virtual point located 1.5 million km from Earth in the direction opposite to the Sun.

Planck's cruise to L2

History
Planck was formerly called COBRAS/SAMBA (Cosmic Background Radiation Anisotropy Satellite and Satellite for Measurement of Background Anisotropies), since the mission grew out of a pair of proposals with similar objectives.

It was renamed on approval of the mission in 1996 in honour of the German scientist Max Planck (1858-1947) who won the Nobel Prize for Physics in 1918.

ESA's Planck observatory follows NASA’s Cosmic Background Explorer, COBE, and the Wilkinson Microwave Anisotropy Probe, WMAP.

Partnerships
The Prime Contractor for the Planck satellite was Alcatel Alenia Space (Cannes, France), which lead a consortium of industrial partners with the Alcatel Alenia Space industry branch in Torino, Italy, responsible for the Service Module. ESA and the Danish National Space Centre (Copenhagen, Denmark, funded by the Danish Natural Science Research Council) were responsible for the provision of Planck’s telescope mirrors, manufactured by EADS Astrium (Friedrichshafen, Germany).

The Low Frequency Instrument was designed and built by a Consortium (led by the Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF) in Bologna, Italy) of scientists and Institutes from Italy, Finland, the United Kingdom, Spain, the United States, Germany, The Netherlands, Switzerland, Norway, Sweden and Denmark.

The High Frequency Instrument (HFI) was designed and built by a Consortium (led by the Institut d'Astrophysique Spatiale (CNRS) in Orsay, France) of scientists and Institutes from France, the United States, the United Kingdom, Canada, Italy, Spain, Ireland, Germany, The Netherlands, Denmark and Switzerland.

Many funding agencies contributed to the LFI and HFI instruments hardware; the major ones are: CNES (F), ASI (I), NASA (USA), PPARC (UK), Tekes (FIN), Ministerio de Educación y Ciencia (Spain), and ESA.