Planck Early Results: The Planck mission
  The European Space Agency's Planck satellite was launched on 14 May 2009, and
has been surveying the sky stably and continuously since 13 August 2009. Its
performance is well in line with expectations, and it will continue to gather
scientific data until the end of its cryogenic lifetime. We give an overview of
the history of Planck in its first year of operations, and describe some of the
key performance aspects of the satellite. This paper is part of a package
submitted in conjunction with Planck's Early Release Compact Source Catalogue,
the first data product based on Planck to be released publicly. The package
describes the scientific performance of the Planck payload, and presents
results on a variety of astrophysical topics related to the sources included in
the Catalogue, as well as selected topics on diffuse emission.
