Integration of Planck's Two Instruments
22 November 2006On Monday 20 November, the focal plane units of the two Planck instruments HFI and LFI were integrated into a single assembly. The High Frequency Instrument (HFI) focal plane unit was inserted into the dedicated opening in the centre of the Low Frequency Instrument (LFI) focal plane unit.
At this time, the HFI was already assembled with its cryogenic cooling pipework in a dedicated support structure, whilst the LFI focal plane unit was already connected to the back end electronics by a set of waveguides. In this complicated configuration, the two instruments were integrated into a single assembly.
The complex integration was conducted by a team of four engineers of AAS-I (former Laben). It took about four hours to perform the integration, during which the two instruments were at many instances as close as 1millimetre from each other at different locations. The descent of HFI into LFI was precisely controlled to the millimetre to prevent any contact between the two instruments. The successful integration now gives way to the mating and alignment of the combined HFI/LFI instruments with the Planck telescope integrated on the flight model spacecraft.