Virtual European Solar & Planetary Access (VESPA) 2022: Sustainability

VESPA (Virtual European Solar and Planetary Access) has focused for 10 years on adapting Virtual Observatory (VO) techniques to handle Planetary Science data [1] [2]. The objective of this activity is to build a contributory data distribution system both to access and publish data with minimum fuss. This system is responsive to the new paradigm of Open Science and FAIR access to the data, and is optimized to publish data from public-funded programmes with limited resources.

VESPA’s architecture was defined during the previous Europlanet-2020-RI program, incorporating concepts and standards from various areas: astronomy, Earth observation, space physics, heliophysics, etc. It relies on the VO infrastructure: data services are installed in any location but are declared in a system of harvested registries with identifiers, end-point (URL), mention of supported access protocols, and a rough description of content. Such services are interoperable via clients and tools, which also provide visualization and analysis functions.

The activity in Europlanet-2024-RI focuses on expanding this environment, enforcing sustainability, and opening new possibilities to improve data handling – such as workflows, cloud-based computation, and readiness for exploitation through Machine Learning techniques.

Data access. VESPA uses a specific access protocol called EPN-TAP, associated with a metadata vocabulary providing uniform description of datasets in the field. At the time of writing EPN-TAP is in the final stage of becoming a Recommendation of the International Virtual Observatory Alliance (IVOA) [3].

EPN-TAP is compliant with the general TAP protocol, allowing usage of existing VO tools and communication protocols with data services pertaining to Solar System studies. Some VO tools (TOPCAT, Aladin, CASSIS) are also adapted to improve handling of such data, e.g. visualisation of footprints (spatial or temporal), reflected light, or spectral cubes on planetary surfaces. In parallel, OGC-compliant definitions of planetary coordinate reference systems will facilitate the use of GIS tools in Planetary Science.

The VESPA portal, intended as a discovery tool to browse the EPN-TAP services, is being redesigned to improve the user experience (new version expected to be released for the conference). Other, more specific access modes (via script, web services, Jupyter notebook, VO tools, etc) are also available.

Data services. 67 EPN-TAP data services are currently searchable from the VESPA portal, and about 20 are in development phase. Contributions from space agencies have increased significantly this year, with now 25+ million files in ESA’s PSA, and 60 datasets from the NASA PDS PPI node (declared in the IVOA registry but not yet reviewed for the portal). New services include atmospheric modelling from GCM (Venus and Mars), surface and asteroid spectra, radio observations, solar databases, and tables from published articles at CDS/VizieR. Larger data infrastructures with EPN-TAP interface (AMDA, SSHADE, PVOL) also develop their content and capacities, e.g. this year band lists have been implemented in SSHADE, and support for long time series in AMDA. An implementation workshop associated to a call for data services from the community was held in Nov 2021, and two more workshops are scheduled in the course of the programme.

Service implementation support. The standard procedure to implement services has been greatly enhanced with new releases of DaCHS (a VO data server by Heidelberg University) and TOPCAT (a VO tool for tabular data by the University of Bristol). Both tools fully support the current version of EPN-TAP and greatly facilitate the set-up of new data services: DaCHS includes a predefinition of standard EPN-TAP parameters (with units and UCDs), while TOPCAT includes an EPN-TAP validator. A Docker version of DaCHS is available for assessment purposes. Existing data services have been reviewed for compliance, and most of them have been upgraded to benefit from the latest developments. In many cases, their content has been extended with new data and functions.

Service access. The recent upgrade also addresses low-level technical aspects, e.g. related to declaration in the IVOA registry. Most EPN-TAP services are now declared in compliance with recent evolutions of the VO, and are findable independently from the portal.

Sustainability. Definition files of all services are stored in a unique gitlab for preservation and maintenance by several VESPA teams. Gitlab authentication is granted by GÉANT/eduTEAMS. This is a simple and efficient way to share the technical expertise among services and teams, and to improve sustainability.

Implementation of data services on EOSC (the recent European Open Science Cloud) was assessed during the VESPA-cloud project supported by EOSC-Hub, through its 2nd Early Adopter Program (2020-21). EPN-TAP services can be deployed on EOSC inside Virtual Machines or Docker containers, from the same gitlab installation used to preserve the services. This will provide a workaround to services temporary unavailability, for performing cloud-based computation on data services, and a solution for data providers who are not able or not willing to host a VESPA server for a long period of time.

Coming data services. Data produced by other WP in Europlanet-2024 will distribute their results using the VESPA infrastructure: other VAs (SPIDER, GMap, ML), NA2 (telescope network and other pro-am projects), and TAs (lab experiments and field studies). VESPA is of course also available to distribute data from other H2020 programmes in the field. An interface with space agency archives will make use of the recent PDS4 dictionary for EPN-TAP (in addition to the existing EPN-TAP interface on ESA’s PSA).

Prospects. Detailed examples of recent VESPA developments are provided in this session and related ones. The focus will shift again next year to new data services, with the finalization of several projects, in particular related to the Moon, Mercury, and exoplanets. A workflow platform will also be connected to perform run-on-demand (the OPUS system also used by the ESCAPE H2020 programme) and cloud-based activity will expand.

 

The Europlanet-2024 Research Infrastructure project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreements No 871149.

 [1] Erard et al 2018, Planet. Space Sci. 150, 65-85. 10.1016/j.pss.2017.05.013. ArXiv 1705.09727  

 [2] Erard et al. 2020, Data Science Journal 19, 22. doi: 10.5334/dsj-2020-022.

 [3] https://ivoa.net/documents/EPNTAP/