<i>Planck</i>pre-launch status: Low Frequency Instrument calibration and expected scientific performance

We present the calibration and scientific performance parameters of the <i>Planck<i/> Low Frequency Instrument (LFI) measured during the ground cryogenic test campaign. These parameters characterise the instrument response and constitute our optimal pre-launch knowledge of the LFI scientific performance. The LFI shows excellent 1/<i>f<i/> stability and rejection of instrumental systematic effects; its measured noise performance shows that LFI is the most sensitive instrument of its kind. The calibration parameters will be updated during flight operations until the end of the mission.