Planck LFI-only mission extension

Abstract

The main reason for the extension of the Planck mission beyond the lifetime of the 0.1-K dilution cooler is to obtain further data which will improve our understanding of systematic effects. In the present report, we justify the continuation of the current scanning strategy in order to obtain a sixth survey, allowing for better sensitivity and further “jackknife” (survey difference) tests. The fifth survey is already improving the estimates of the polarisation leakage for two of the LFI horns, and this improvement will continue with the sixth survey during the extension. In addition, we confirm the “deep rings” scanning strategy to improve mapping of the beams using radio sources, specifically Jupiter and the Crab Nebula. We propose to maintain the current spin rate: no other changes are foreseen, except the possibility to increase the sampling of some house-keeping data.