August 23, 2016


The Institut d'Astrophysique Spatiale set up, in collaboration with CNES, a European Centre for Soho instrument operation access. MEDOC (Multi-Experiment Data and Operations Centre) operates as an auxiliary centre to the main operations centre at NASA's Goddard Space Flight Center.
MEDOC allows the European solar community to fully participate in the Soho operational phase, by contributing to the observation programme scheduling, by using the amenities available to analyze the data, or by accessing the Soho archive.
The MEDOC service is linked through a dedicated high-speed link to the NASA Center and receives in real time the Soho data stream, as well as the auxiliary data required for the permanent update of the Soho programme scheduling and execution. MEDOC welcomes the teams that control the Soho instruments as well as other solar reseachers. They can come to MEDOC where they have access to its workstations and specialized software programmes. They also have a remote access to the Soho Archive (the "Sun's data base") and can even make a remote processing on the MEDOC workstations.
MEDOC set up one-month specific campaigns, during which the daily operations responsibility is delegated to MEDOC. Those campaigns aim especially to exploit the co-operation with the large ground-based European observatories such as Tenerife (Canary Islands), Pic du Midi, Nançay Radioheliograph, etc.

Archiving Operations

MEDOC is also the European Archiving Centre for all Soho instrument data. It was conceived for remote access to data information (catalogue consultation) as well as data files themselves. Every Internet user has a free access to various images acquired by the Soho instruments.
MEDOC benefited from the following supports: CNES, the CNRS, Conseil Régional d'Ile-de-France, Département de l'Essonne, Paris Sud University (XI).

The MEDOC system, which was partially re-organized in 1999 to optimize the equipment and minimize housekeeping costs, is composed of the following sub-systems:

  1. the sub-system dedicated to operations:
    • for telemetry reception and real-time or delayed-time delivery
    • for telecommand upload
  2. mission archive
  3. long-term archive
  4. analyze server
  5. the sub-system managing the access to the public network and web/ftp servers
  6. different peripherals
  7. network
  8. infrastructure and hosting facilities.

The task allocation between the IAS and CNES is as follows: the IAS, project leader, is responsible for the PI, EOF, ESA, and Soho Working Team (constituted of the PIs) interfaces. CNES is responsible for communications between the Orsay site and the EOF as well as for long-term archiving. In Operations mode, the IAS relies on the scientists involved in the SOHO instruments as PI, CoI, etc.

As MEDOC promotes multi-instrument use, its manager reports its progress to a Scientific Committee (created in July 1995 and whose last meeting took place on 15 April 1998 in Orsay), a Steering Committee and, if necessary, the SWT. It reports to the IAS for all material questions (budget and logistics).