A&A special feature: Pre-launch status of the Planck mission

This A&A issue features 13 articles describing the pre-flight status of the European Space Agency Planck mission, launched together with the Herschel satellite on 14 May 2009. The Planck mission is designed to image the anisotropies of the cosmic background radiation field over the whole sky, with unprecedented sensitivity and angular resolution, as well as a wide frequency range. As a byproduct of that main goal, it will simultaneously address a wide range of galactic and extragalactic science. The mission involves more than four hundred scientists, who are currently working on data processing, calibration, and data analysis.
The satellite is scheduled to continuously acquire high-quality science data until the end of 2011. An early release of the compact source catalogue will be delivered in January 2011, together with a small set of science papers related to foreground astrophysical sources. The first major cosmology results will be delivered in December 2012.
In this special feature, the telescope’s optical system and the design, ground calibration, and performance of the Planck lowand high-frequency instruments are described in detail.