![]() NASA played a role in the development of this mission and contributes to the analysis of scientific data. From August 2009, Planck was the coldest known object in space, until its active coolant supply was exhausted in January 2012. Planck 's passive and active cooling systems allow its instruments to maintain a temperature of −273.05 ☌ (−459.49 ☏), or 0.1 ☌ above absolute zero. The cosmic microwave background spectrum peaks at a frequency of 160.2 GHz. Both instruments can detect both the total intensity and polarization of photons, and together cover a frequency range of nearly 830 GHz (from 30 to 857 GHz). The spacecraft carries two instruments: the Low Frequency Instrument (LFI) and the High Frequency Instrument (HFI). ![]() The dominant foreground radiation depends on frequency, but could include synchrotron radiation from the Milky Way at low frequencies, and dust at high frequencies. It is expected that most Planck measurements have been limited by how well foregrounds can be subtracted, rather than by the detector performance or length of the mission, a particularly important factor for the polarization measurements. It also observed in nine frequency bands rather than WMAP's five, with the goal of improving the astrophysical foreground models. Planck had a higher resolution and sensitivity than WMAP, allowing it to probe the power spectrum of the CMB to much smaller scales (×3).
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