Hesperides, the data garden

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Since a few years, my colleagues from THEIA project and from the data campus at CNES, started designing a new processing and distribution center, named Hysope-II. This centre was initially set up for products related to hydrology. It includes a processing center, a catalog, and a distribution center (hydroweb.next). It was developed in the framework of the SWOT mission downstream project, and aims to provide users with all the data that can help analyse hydrology data.

But the tools developed on this occasion quickly proved their worth, and little by little we became convinced that they were perfectly suited to the setting up of the new CNES production center for THEIA. Indeed, it is necessary to replace the current MUSCATE, whose technologies and processing capabilities are no longer state-of-the-art, despite the million products already published.

Rather than calling it MUSCATE-NG, my colleagues have poetically voted to name it « Hesperides », after the mythical garden where Hercules, tasked with picking well-guarded golden apples, distinguished himself by his cunning. The golden apples of the garden will be our beautiful continental surface remote sensing data, and we’ll do our utmost to make it as easy as possible for you to access them. It’s up to CNES to do the work of Hercules, not up to data users.

Hesperides description

Hespérides will consist of three workshops, based on developments from Hysope-II:

• Hymotep will be the production workshop, based on a processing orchestrator developed for the SWOT mission: Chronos.
• Hygor will be the database manager
• Hydra will oversee the entire system

These workshops already exist, as for Hysope-II, they are already producing France in near real time, with the following processors: MAJA (Sentinel-2 surface reflectances), LIS (snow cover) and Surfwater (water surfaces).Their adaptation to Hesperides therefore mainly consists of configuring them for the specific features of THEIA production.

Hesperides does not provide a data access center, as the distribution and access will be handled by hydroweb.next and the GeoDataHub, which are also being developed.

While it used to take months to integrate a new chain into MUSCATE, it has now been demonstrated that it only takes a few weeks to configure Hymotep to put a new chain into production. This should make it possible to finally put into production some of the chains that have been prepared for years in THEIA’s CES.

Finally, the Hesperides garden will be hosted in fertile ground, with the new CNES TREX computing centre and its datalake, which should increase the computing power dedicated to THEIA at CNES by almost tenfold. Hesperides is scheduled to start mass production in the second quarter of 2024.

What should we process ?

As new possibilities open up, two questions will quickly arise:

• which areas of the world are we going to cover?
• with which processors?

To determine this, two processes will take place in parallel :

• consolidating the assessment of our processing capacities, and determining the priorities of the CNES, which is funding this infra-structure
• gathering the needs of THEIA users (French public remote sensing community). THEIA will be issuing a call for projects at the end of the summer. You will be able to put forward your areas of interest and ask for processing lines to be put into production. So you can already start thinking about your requests to be submitted after the holidays.

We already know that the processors will be able to rely on Sentinel-2 L2A data produced with MAJA, and on the Sentinel-1 data, ortho-rectified on Sentinel-2 tile grid with S1-Tiling processor.

Of course, despite their sharp increase, resources will remain limited, and we probably won’t be able to meet all requests. That said, before calling on Hercules and Atlas, don’t hesitate to submit your ideas and requirements.