Planck is an ESA mission and Europe's first mission to study the relic radiation from the Big Bang. Launched in tandem with ESA's Herschel space telescope on the 14th May 2009; it has now mapped the structure of the Cosmic Microwave Background radiation, receiving it's final deactivation command on the 23rd October 2013, however the results will continue to be analysed over the next few years. Ever since the detection of small fluctuations in the temperature of this radiation, astronomers have used the fluctuations to understand both the origin of the Universe and the formation of galaxies.
Plank is equipped with a powerful telescope and two instruments operating at radio to sub-millimetre wavelengths. The detail and sensitivity of the measurements Planck will provide will help determine fundamental parameters relating to the origin and evolution of the universe.
In order to achieve its scientific objectives, Planck's detectors have to operate at very low and stable temperatures. The spacecraft is therefore equipped with the means of cooling the detectors to levels close to absolute zero. RAL Space has provided thermal analysis for the design of the system, as well as the cooling stage that reduces the temperature from 20K to 4K, using a Joule-Thomson system.