Ground Segment

Geographical distribution of the Planck Ground Segment

The Planck Ground Segment consists of four geographically distributed centres.

The Mission Operations Centre

The mission operations centre (MOC), located at ESA’s operations centre in Darmstadt (Germany), was responsible for all aspects of flight control and of the health and safety of the Planck spacecraft, including both instruments. It planned and executed all necessary satellite activities, including instrument commanding requests by the instrument operations centres.

The European Space Operations Centre in Darmstadt, Germany, home of the Planck Mission Operations Centre.

MOC communicated with the satellite using ESA’s 35-m antenna located in New Norcia (Australia), or that in Cebreros (Spain), over a daily 3-h period, during which it uplinked a scheduled activity timeline which was autonomously executed by the satellite, and downlinked the science and housekeeping (HK) data acquired by the satellite during the past 24 h. The downlinked data were transferred from the antenna to the MOC over a period of typically 8 h; at MOC they were put onto a data server from where they were retrieved by the two data processing centres.

The Planck Science Office

The European Space Astronomy Centre in Villanueva de la Cañada, Madrid, Spain, site of the Planck Science Office.

The Planck Science Office (PSO) is located at ESA’s European Space Astronomy Centre in Villanueva de la Cañada surroundings (Madrid, Spain).

Its main responsibilities include:

• coordinating scientific operations of the Planck instruments;

• designing, planning and executing the Planck observation strategy;

• providing MOC with a detailed pointing plan with a periodicity of about one month;

• creating and updating the specifications of the Planck Legacy Archive (PLA) developed by the Science Archives Team at ESAC;

• testing and operating the PLA.

The LFI instrument operations and data-processing centre

The LFI instrument operations and data processing centre, located at the Osservatorio Astronomico di Trieste (Italy), is responsible for the operation of the LFI instrument, and the processing of the data acquired by LFI into the final scientific products of the mission.

The HFI instrument operations and data-processing centre

The HFI instrument operations and data processing centres, located, respectively, at the Institut d’Astrophysique Spatiale in Orsay (France) and at the Institut d’Astrophysique de Paris (France), are similarly responsible for the operation of the HFI instrument, and (with several other institutes in France and the UK) for the processing of the data acquired by HFI into the final scientific products of the mission.

Data flow in the Planck Ground Segment

The PSO sent the Pre-Programmed Pointing Lists (PPL) to the MOC. The Flight Dynamics team at ESOC adapted them into Augmented Pre-Programmed Pointing Lists (APPL) taking into account ground station scheduling, Operational Day (OD) boundaries and other issues.

General schematics of European Space Agency Science Ground Segments, showing how ESA Ground Segments are generally organized.

Specific schematics of the Planck Science Ground Segment, showing how the specific Planck Science Ground Segment worked.

MOC sent pointing and instrument commands to the spacecraft, and received the house-keeping telemetry and science data through the ground stations (for Planck, mostly the New Norcia and Cebreros ones).

Science data were then transferred to both data processing centres (DPCs), which processed the data and sent quality reports to PSO.

Science products (timelines, maps, etc) have been regularly exchanged between DPCs in order to assist with calibration, systematics, and scientific issues.

More information about the Planck Ground Segment may be found in Planck-PreLaunch-XI.