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The analysis of the data which will be provided by the Planck Surveyor is a serious scientific challenge. Taking the raw sky intensities measured by the satellite and producing meaningful astrophysical results requires a number of careful steps.

Given that Planck is not expected to be launched until 2007, all the analysis tools must be tested on simulated data. Aside from the cosmic microwave background (CMB) radiation itself, the both Galacitc and extra-Galactic forgrounds must be included in any simulations of the microwave sky. The sky at this stage is represented as the sum of the various, physically distinct components, but it is more general (and also intuitive) to treat it as a pixel map. Pixelisation of the sky is non-trivial, and a number of different methods have been suggested. Given a model microwave sky, the orbital parameters of the satellite and the response of its various detectors combine to determine the time-ordered data that would be sent back to Earth. These satellite simulations are non-trivial, as the beam shapes and orientation of the feed horns are complex.

The data returned by the Planck satellite cannot be used to do meaningful science, at least in their raw form. Firstly, they must undergo destriping -- low frequency instrumental noise induces stripes in the sky maps -- to generate a realistic image of the microwave sky. Such a map is essentially astronomical, as all observational inputs have been removed as far as possible. The next step is component separation -- the Galactic foregrounds, high-redshift galaxies and clusters, and of course the CMB must be distinguished from each other -- to get data that is essentially astrophysical. This is the end point of the data analysis, in so far as there will be a catalogue of point sources, a picture of Galactic dust emission, up to 10,000 clusters detected via the Sunyaev-Zel'dovich effect, and a high-resolution map of the CMB.

The primary aim of the Planck mission is to obtain an all-sky CMB map at a resolution of tens of arcminutes. Such a data-set can then be used to constrain a number of cosmological parameters to within a few per cent -- at least an order of magnitude more accurate than current measurements.