The Data Preservation and Long Term Archiving function ensures the storage of the essential mission data. It is fulfilled by the Long Term Archive element in the form of operational service provision.
The Long Term Archive (LTA) service is defined to cover the following main functions:
- Data Ingestion and safe storage
- Data Query, Retrieval and delivery on an Archive Interface delivery Point (AIP)
- Data curation and archive Integrity
- Performance Monitoring and Reporting
- Implementation and operations of the AIP, ensuring its availability for consumers and handling of cache policy
The LTA interface includes all the features necessary to support the above LTA functionalities. In particular, all the features to query the stored data, query performance information for monitoring purposes and to retrieve the selected data. The LTA interface allows precise query capabilities for standard EO oriented metadata, with a detailed definition of the indexed fields for each data type.
The LTA service scope is common to all missions: The functional scope of the LTA and the associated interfaces are defined in order to be Sentinel-generic and fulfil the archiving needs for any Copernicus mission. Multiple LTAs service instances are however necessary in the GS architecture to ensure geographical redundancy with separated safe storage for all Sentinel missions. The same LTA may serve one single Copernicus mission or several Copernicus missions, depending on its capacity and cost efficiencies. The content of each LTA (in terms of Sentinel mission and data types) and the overall data flow configuration (data flows between the various Sentinel production services and the various LTA services) is defined and maintained by ESA as part of the E2E operations management. Each LTA operates autonomously with respect to the other LTAs. However, the LTAs monitor their own completeness, and any missing products are downloaded from one of the other LTAs in case it is no longer available on the PRIP. An E2E view is also gathered through the E2E operations monitoring and the traceability service.