Integration of the Planck flight model solar array
26 November 2008This is the final entry in the Planck Test Campaign journal series, which ran from September 2005 to November 2008. The journal covered the main activities during Planck's extensive spacecraft and instrument test campaigns. It was followed by the Planck Launch Campaign journal series, which ran from February 2009 until just before launch in May 2009 (see link in right-hand menu).With the successful integration of the inner part of the flight model solar array to the Planck spacecraft on 25 November 2008 the project reaches another milestone.
Since mid-June 2008 the Planck spacecraft has been in the FOCAL-5 vacuum chamber at the Centre Spatial de Liège (CSL) for the Thermal Balance and Thermal Vacuum (TBTV) test campaign. During these tests, the qualification model (QM) of the spacecraft's solar array was used rather then the actual flight model as it allowed to simulate in the best way the flight conditions. It was equipped with heaters for the test campaign to simulate the thermal conditions of the solar array during operations.
Following the successful completion of the TBTV campaign (see also the previous journal entry, linked from the right-hand menu) the spacecraft was removed from the vacuum chamber.
On 3 November Planck was transferred from the FOCAL-5 clean room to the FOCAL-X clean room, where it was initially placed on the multi-purpose trolley (MPT). The extra height of the FOCAL-X room was needed to allow the spacecraft to be hoisted vertically by crane to the height required for the integration activities.
For the solar array integration the spacecraft was transferred onto the Planck Vertical Integration Stand (VIS), which allows the spacecraft to be hoisted straight up in a vertical position. At this point the inner part of QM solar array was removed. By end October the flight model (FM) solar array arrived at the CSL facilities, after transport from Thales Alenia Space in Cannes where it had undergone final preparations and a flasher test. Integration of the inner part of the array with the spacecraft was completed on 25 November 2009.
Another important activity was performed prior to the integration of the FM solar array: the spacecraft alignment measurements (Figure 3). These measurements were performed with the spacecraft in vertical position and verified the mechanical stability of the spacecraft by accurately determining relative and absolute positions of different spacecraft elements.
With the inner part of the FM solar array integrated, the Planck FM spacecraft will soon be returned to the FOCAL-5 chamber for storage during the end-of-year holidays.
Early next year, after all final checks at CSL, the spacecraft will be prepared for shipment to the launch site in Kourou, French Guiana. There the Planck spacecraft will meet up with the Herschel spacecraft for a combined launch on board an Ariane 5 ECA rocket. During the final preparations for launch in Kourou the outer part of Planck's FM solar array will be integrated.