  An harmonic-space maximum-entropy method (MEM) is presented for separating
the emission from different physical components in all-sky observations by the
forthcoming Planck satellite. The analysis is performed at full Planck
resolution, with a pixel size of 1.7 arcmin, which corresponds to a maximum
multipole of around 6000. The simulated Planck data include emission from the
CMB, the kinetic and thermal Sunyaev-Zel'dovich (SZ) effects from galaxy
clusters, as well as Galactic dust, free-free and synchrotron emission. Our
simulations also assume homogeneous, uncorrelated pixel noise, although this is
not a requirement of the method. We find that the MEM technique produces
faithful reconstructions of the main input components over the whole sky,
without the need to perform a Galactic cut. The CMB power spectrum is
accurately recovered up to a multipole of around 2000. The algorithm is
parallelised so that the entire reconstruction can be performed in around 6 hr
using 30 R10000 processors on an SGI Origin 2000 supercomputer and requires 14
Gb of memory.
