ESA UNCLASSIFIED – For ESA Official Use Only

The overall system architecture for the Copernicus Space Component (CSC) and its evolution have been defined on the basis of user requirements coordinated by the European Commission. The Long-Term Scenario (LTS) describes the main elements of this architecture and is maintained and evolved in an iterative process in close interaction with the European Commission (COM), EUMETSAT and EU Member States and Copernicus Participating States.

ESA needs to guarantee the continuity of the on-going operations with the maximum level of performances for the flying Copernicus Sentinels while facing the technical and financial challenges to adapt to the evolutions of the CSC architecture.

The CSC Ground Segment (GS) is based on a service-based architecture and a clear set of operations management principles (management and architectural) hereafter referred as the ESA Earth Observation Framework (EOF).

The EOF encompasses all the activities necessary to successfully deliver the expected level of CSC operations entrusted to ESA (i.e. establishment and maintenance of the new baseline, procurement actions, operations management, reporting, etc.).

The EOF-CSC is documented throughout a complete package describing and specifying the applicable operational concepts as well as the architecture and procurement approach adopted for establishing and evolving the CSC operations baseline (in particular with respects to the future Expansion Missions, associated with the necessary cost information to size the proposed approach and potential trade-offs).

The EOF-CSC implementation is based on a service architecture with well-identified components that exchange data through Internet respecting defined interfaces. A service presents a simple interface to its consumer that abstracts away the underlying complexity. Combined with deployments on public cloud infrastructure, the service approach shall offer large adaptability to evolution of the operational scenarios in particular for what regards scalability.

Since the transformation process which started in 2019, the operational CSC Mission and Data management activities have been transferred to cloud based environments (in anticipation of the enlargement of the Copernicus Sentinel missions and in response to the ever-increasing demand for Copernicus data) and the service-oriented approach has been strengthened to enhance competitiveness, prevent industrial and technical lock-in and introduce the necessary operational flexibility and transparency to allow the adaptation of the Copernicus Space Component operational activities managed by ESA to future challenges.

Within this context, this document contains the specifications of the EOF for the CSC operational activities entrusted to ESA by the European Commission. The specifications establish the traceability with the current baseline of requirements issued by the European Commission. This document is planned to undergo regular revisions in accordance with possible evolutions of the LTS scenario and the Copernicus Contribution Agreement.

2.1 Background

The Copernicus Space Component has been established as one of the largest and most proficient Earth Observation infrastructure in the world. With nine high-performance satellites put in orbit the system has evolved at a breath-taking pace.

The CSC operations have generated more than 90 PBytes of data. Central to the programme, the current CSC fuels the operational Copernicus Services but also provides a reliable and growing data stream for numerous new applications and services.

The current CSC has also triggered large application oriented technological developments, such as in the domain of Big Data management, as exemplified by the Data and Information Access Services (DIAS) and further evolved in the Copernicus Data Space Ecosystem (CDSE).

The intense use and increased awareness for the potential of Copernicus have generated great expectations for an evolved Copernicus system.

User and observation requirements have been identified, structured and prioritized in a continuous reflection process led by the EC. Future missions have been defined in the context of four observational capability families:

•Microwave Imaging Family,

•Optical Imaging Family,

•Topographic Measurement Family

•Spectroscopic Atmosphere Measurement Family.

Two sets of missions have emerged, that correspond respectively to the enlargement of the present measurements through the introduction of new missions (the Copernicus Expansion missions) and to a more progressive improvement of the current measurement capabilities, mostly by means of new generation of similar instrumentation compared to the ones currently deployed (the Next Generation Sentinel missions).

The CSC operations entrusted to ESA for Sentinel-1, -2, -3 A&B and Sentinel-5P deliver outstanding results, with more than 800 PB of delivered Sentinel data to registered users around the globe (2025/06).

Figure 1: Dissemination Statistics (May 2025)

The ESA and EUMETSAT encompass all the activities necessary to successfully deliver the expected level of entrusted CSC operations and reflect the primary goal of securing the entry into operations of the Sentinels Missions, with their unprecedented data volume and user uptake.

The ESA CSC operational activities encompass the Space Segment operations with the necessary post-launch spacecraft maintenance activities, the Flight Operations Segment services to ensure the spacecraft operations and the Mission and Data Management further addressed hereafter.

In particular, the ESA EO Framework for the CSC encompass the following families of services providing for the overall EOF-CSC needs:

•Operations management services

oOverall configuration management

oEnd-to-end system & performance monitoring

oSecurity monitoring

oUser support services: helpdesk, training, tools, communication

•Space segment and Flight Operations services: spacecraft operations and post-launch spacecraft engineering support for satellite maintenance and contingency management.

•Mission services

oMission planning services: instrument sensing & satellite downlinks operations planning & optimization.

oAcquisition services: satellite data acquisition services (e.g. X-Band, Ka-Band, relay satellite).

oPrecise orbit determination service

•Data services

oProduction and routine quality control services, encompassing different processing strategies including systematic production and reprocessing services

oLong Term Archive services, ensuring preservation of the essential mission data

oData Access services: data distribution & user interface allowing access to any mission Data Sharing Units User Level Data and complementary services for data analytics, on-demand processing, AI, etc.

oCalibration & Validation services: monitoring of instrument performance and data quality, calibration and validation, and external cal/val data provision.

oAlgorithms and data processors maintenance and evolution services

oSupport to international agreement with data access services

oAuxiliary data provision services

oData traceability services

The ESA EO Framework for the CSC also includes the implementation and operations of the interfaces with services identified through specific agreements, deriving from the collaborative programme component or upon EC request. In particular these interfaces cover:

•Support to collaborative local acquisition stations

•Provision of a network of data access relays

•Coordination of interfaces for data and information provision from other sources and from Copernicus Services.

The operational experience gathered over the past decade of operations has demonstrated that sizing and performance are largely dependent on the user demand. Consequently, a refined approach was introduced with the Copernicus Ground Segment Transformation, in the period 2020-2022, for the management of the CSC operations. This approach is reflected in the baseline presented in this document. While ensuring a robust and highly performing solution, it introduces wider flexibility wherever the CSC operations may be impacted by the user scenario.

2.2 Scope

The ESA EO Framework documentation for the CSC is made of the following set of documents:

●The EOF-CSC Operations Concept document

●The EOF-CSC specifications defining the scope of the ESA Copernicus Space Component operational management, its associated performance and the traceability to the EC requirements (this document)

●The EOF-CSC Architecture document describing the main functional blocks and their interfaces in particular for what concern the external interfaces,

●The System Technical Budget document, providing an estimate of the expected operational load and generally operations context sizing,

●The risk folder,

●The cost models of EOF-CSC services operations establishing the key parameters driving the operations costs,

●The High Level Roadmap, establishing the objectives for the future evolution.

The EOF-CSC documentation seeks to:

The data warehouse in charge of the provision of third-party mission data on behalf of Copernicus Services is not subject to this document even if it may benefit from the projects and services developed as part of the EOF-CSC.

2.3 Applicable and Reference documents

2.3.1 Applicable documents

[AD- 4] Copernicus Ground Segment – Functional Requirements for the acquisition, generation and archiving of Sentinel data, Revision 1.3, 1st April 2019

2.3.2 Reference documents

[RD-1][RD-EOF-GLO] ESA EO Framework (EOF) – CSC – Glossary [ESA-EOPG-EOPGC-TN-13]

[RD-2] [RD-EOF-OCD] ESA EO Framework (EOF) – CSC –Operations Concept [ESA-EOPG-EOPGC-TN-19]

[RD-3] [RD-EOF-DASP] ESA EO Operations Framework (EOF) – CSC – Copernicus Sentinel Data Access Services Portfolio [ESA-EOPG-EOPGC-TN-57]

2.4 Acronyms and Definitions

Acronyms are expanded on first use. The full list of acronyms and definition of terminology is provided in [RD-EOF-GLO].

Considering the nominal plan of evolution, the overall operational load has doubled in the current period and will more than double again in the next period. An even bigger challenge for the future CSC operations lies in the non-linear increase of the required data management effort since future operations shall ensure access to all data for all missions since the start of operations (2014).

The “ESA EO Framework (EOF)” application within the Copernicus Space Component (CSC) (i.e. all the activities to be put in place and to be performed by ESA in order to deliver the required CSC operations in the period 2022 – 2027) is therefore facing the challenges to:

3.1 EOF-CSC operational Scenario Assumptions

The operational scenario and associated specifications are based on the Long-Term Scenario [AD- 6].

According to the LTS, the CSC operations continue after 2027 for the Sentinel-1, Sentinel-2, Sentinel-3 and Sentinel-5P missions, with remaining Sentinel-1, Sentinel-2, Sentinel-3 recurrent satellite units to be onboarded in the EOF-CSC. .

For the sake of this document, the reference periods for the CSC operations are 2014-2021 (referred as the Previous Period), the 2022-2027 period (referred as the Present Period) and the 2028-2034 period (referred as the Next Period).

The following key operational assumptions in line with the LTS considered for the sake of this document are recalled hereafter:

•The CSC operations managed under ESA responsibility after 2027 will be a continuity of the operational responsibilities for currently flying missions.

•A maximum of 3 Sentinel satellite units for the same mission will be simultaneously in operated during the period covering the commissioning phase of the 3rd unit.

•A maximum of 2 Sentinel satellite units for the same mission will be simultaneously in routine operations.

The specifications defined in this document are applicable to the EOF-CSC activities to be performed up to Q1 2028. Nevertheless, they provide the basis for the Sentinel Expansion mission operations to be performed after Q1 2028 (with the exception of CO2M operations planned to start in the Present Period ), to be further consolidated in future versions of this document as necessary.

3.2 Key Sentinel missions characteristics

The following table recalls the main characteristics of the Sentinel missions to be operated in the Present Period. The main characteristics of the Copernicus Expansion missions will be included in a future version of this document in line with the consolidation of the space segment design activities.

Copernicus Sentinel missions characteristics

3.3 Documentation Tree and context

The “Concept for the Cooperation of ESA and EUMETSAT regarding Copernicus Evolutions” ([AD- 5]) addresses the ESA and EUMETSAT involvement and coordination for the Copernicus missions. Based on the successful experience of developing, upgrading and managing complex systems together the respective activities are organised to maximise efficiency, mitigate risks while removing potential ambiguity from the cooperation.

The following figure provides the context for the agreements.

Figure 2: Copernicus EOF Document hierarchy

In

Figure 2 the arrangement in series of levels reflects the cascading of responsibilities and tasks. This cascading is established to coherently manage with the maximum efficiency the activities that need to be coordinated avoiding to the maximum extend unnecessary overlaps between the operational activities.

The overall documentation tree is illustrated in the figure below.

Figure 3: Copernicus Documentation Tree for ESA EO Framework baseline

As illustrated in the graph below, the CSC ESA EO Framework documentation is refined at mission level as necessary and represents the basis for deriving the industrial operational baseline associated to the operational services procurements organised by ESA and to the management of the operational services delivery.

Figure 4 : Copernicus EOF Documentation structure

Specifications for the implementation of the various services contributing to the EOF, including operations and procurement specifications are logically organised by the following categories of services:

●Flight operations

●Observation Strategy implementation

●Operational Management services

●Mission services

●Data services.

Figure 5: Copernicus EOF Specifications Logic

4.1 ESA EO Framework CSC Baseline Requirements

Table 2 Sentinels family, development and (high level) operational roles

The following requirements are considered for the period 2021 - 2027. ESA activities related to ESA programme and not part of the Copernicus Contribution Agreement are not covered by this document (e.g. collaborative Ground Segment).

4.2 ESA EO Framework CSC Implementation

Considering the complexity of the overall operational management and the large number of services and actors contributing to the end-to-end operations, the overall coordination across services and entities is of paramount importance and it relies on specific procedures and teams ensuring this coordination.

In particular, whenever trade-offs have to be established between the available level of resources and the operations performances, The EOF-CSC shall always guarantee the mission data safeguard and the maximum achievable production quality while balancing the system configuration against timeliness.

In the frame of the EOF-CSC, a cloud provider is considered a well-established public provider whenever access to the cloud service is clearly available without discrimination to any potential customer with a public price list, and the provided cloud services are well-recognised and established.

4.3 ESA EO Framework Architecture

4.4 ESA EO Framework Security Services

The EOF-CSC security implements the security management of the EOF-CSC for all prevention, detection, response and maintenance activities. It is composed of the different EOF-CSC services security measures complemented by a central security management function for end-to-end auditing, risk assessment, and security incident handling.

The EOF-CSC ESA Project Specific Security Officer (PSSO) acts as a central EOF-CSC security reference for the EOF-CSC operations, performing the risk assessment of the EOF-CSC operations, defining the reference guidelines for all the EOF-CSC services and managing the EOF-CSC services security auditing.

4.5 ESA EO Framework Procurements

A framework is considered whenever a unique procurement action may lead to several independent contracts covering the needs of the specific procurement action.

The provision of scalable services is serving the potential adaptation to the evolution of the operational scenario, in particular wherever the service may be impacted by evolution of the user scenario. The EOF-CSC shall adapt the performances of the services to the available resources as well as manage priorities between the different interfaces. Under no circumstances, overconsumption of resources shall occur.

In order to illustrate the above, in a scenario for which the cost of the service is impacted by the number of user requests and associated data download, the service provider is responsible for the strategy to limit any consumption of the bandwidth that would exceed the provisioned value.

Scalability shall be managed as part of the service and rely on well-established cost models. Whenever the demand exceeds the capacity the situation will be reported and further allocation may be authorised.

The following description introduces the operational scalability scenario and the interaction between the main programme stakeholders for the management of such scalability.

The operational scenario requires the interaction between the main programme stakeholders and involves the following actors:

-COM as stakeholder for the EOF-CSC CSC operations

-Industry, as service provider for the EOF-CSC operations (multiple service providers are expected)

-User, as EOF-CSC final user, interacting with the service provider

The following diagram illustrates the end-to-end process from the establishment of the available CSC operations resources, to the configuration of the operational parameters in line with the resources, the resulting user experience and the potential role of industry (as service provider) to enhance the user experience.

The CSC operations resources are established by the European Commission as part of the overall delegation process. The EOF-CSC is designed to be able to adapt the CSC operations services capacity and performance according to the available resources, through the configuration of key operational parameters. These key operational parameters are those driving the operations cost and the EOF-CSC strategy (in terms of design, procurement and implementation) allows tuning them with minimum impact to the operations implementation.

The available EOF-CSC operational resources are translated into a set of operational parameters establishing the performance of the free and open services provided by the Copernicus Programme.

The Industrial service provider may offer additional services to users, complementing or extending the free services supported by Copernicus (e.g. ad-hoc performance, tailored data access services, etc.).

Figure 6: Adaptation of operational configuration for free and open services to the available CSC resources

4.6 Network and GÉANT access

4.7 ESA EO Operational Framework Support to User and Third-Party Operations

4.7.1 Data acquisition

Listening ground stations or user ground stations are defined as X-Band user ground stations in geographical overlap with the EOF-CSC Sentinel-1 X-Band ground stations.

The European Commission is authorising such access and defines the procedure for the corresponding requests.

4.7.2 Data distribution

The EOF-CSC supports data distribution to all users according to the free and open data policy. Categories of users are established by the European Commission for statistical analysis of data uptake, and in some instances, may be used to provide prioritised quota for access (e.g. Core Copernicus Services). Extended support is also provided for authorised entities as follows.

oCopernicus Core Services and Downstream Services

oPublic institutions

oNational users

oInternational partners

oScientific users and value adding industry

oOperational Meteorological users

oClimate Change users

oMission Calibration and Validation users

Collaborative Users shall have free on-line access to the systematically generated core user data, and reprocessed data through an on-line data access points with access rights configuration restricted to authorised entities.

International Users, shall have free on-line access to the systematically generated core user data through an on-line data access point with access rights configuration restricted to authorised entities.

The European Commission is authorising the International access while the Collaborative access is conceived for privileged access to the EU/ESA member states and further supported directly by the ESA programme. The load of the Collaborative data access on Copernicus core operations shall not exceed the equivalent of one user retrieving all data once.

4.7.3 Data access synergetic services

Whereas the data access provides open and free-of-charge data access to all users for data download, the experience in the 2014-2020 MMF with the DIAS initiative demonstrated that ease of user exploitation of the Sentinel data can be considerably enhanced through the provision of compute resources and further customer facing value adding applications local to the data holdings. By supporting the presence of such third-party interfaces, the EOF-CSC operations provide an anchor tenancy that may contribute to the development of sustainable applications with even opportune or competitive reductions of data access operational costs. It is noted that the support to complementary applications is performed within the limit of the core operation performances on best effort basis.

●Copernicus Services Information

●Copernicus Contributing Mission data

●In-situ data

●Other earth observation or socio-economic data, ….

●Programming environments

●Interoperable interfaces

●Specialised tools

●Market place,.…

The observation scenario defines the target utilisation of the instrument operations (typically in terms of coverage, observation revisit and frequency) to fulfil the mission objectives and the user needs collected by the European Commission. The EOF-CSC converts the observation scenario into a satellite tasking and downlink activities. The associated operations specifications are defined in this section.

The Flight Operations Segment (FOS) Services encompasses the services required for operating the satellite and ensure the satellite safety, including in particular the following services:

▪Satellite commanding, monitoring and control service

▪Telecommand security

▪Backup control service

▪Debris monitoring service

▪Collision avoidance service

▪Flight dynamics service

The ESA - EUMETSAT Coordinated Flight Operation Services are documented in the Contribution Agreements for the period 2022 - 2027.

The ESA-EUMETSAT Coordinated Operation Management Services are documented in the contribution agreements for the period 2022 – 2027.

7.1 EOF-CSC End to end performance monitoring services

7.2 EOF-CSC Operations Coordination services

The orchestration of the operations provided by the various services involved in the EOF-CSC requires a careful management, ensuring e.g. that any anomalies across services are timely identified, that all affected services are duly notified and investigations pursued with the necessary contribution of multiple services whenever required. The Operations Coordination Services, in conjunction with the end-to-end monitoring, shall aim at ensuring the proper coordination between the operations performed by the various services.

7.3 Benchmarking services

The EOF-CSC shall include the functions for assessing the quality, from a user perspective, of the operational services available to users as well as a measure of comparison against similar services operated by other providers.

The service performance as reported and monitored by the services provider shall be in line with the applicable Service Level Agreements. However, the performances experienced by the user at the access points may differ among users depending on a number of user parameters such as e.g. its connectivity or its effectiveness on using the available interfaces, and may differ from the quality experienced on access points offered by other providers.

The outcomes of the benchmarking services shall be used wherever relevant to identify limitations in the services available to users leading potentially to the design of improved data accessibility solutions.

The benchmarking activity shall make use of the public service interface and shall not depend on any service internal design knowledge, any service internal interface or any service monitoring interface.

This implies that the obtained results shall be made available in support to internal and external auditing (e.g. from the benchmarked service providers)

This means that external benchmarking shall be included, addressing prominent target sites that provide similar data access services.

Examples include decontamination from underperformances of the measuring network and/or by the effect related to the diversity of the network providers.

7.4 Traceability services

The EOF-CSC is in charge of the operational Sentinel data production. The free and open Copernicus data policy allows potential third parties to easily setup a production chain or a distribution service in parallel to the EOF-CSC services. These complementary services support the development of applications and are encouraged; however, the EOF-CSC services cannot be held responsible for the outcome of such production. In addition, for security issues and proper management of the operations the need to maintain the knowledge of the products generated by the core services is necessary. Traditionally such service was partially implemented by maintaining the baseline of the archive content and of the disseminated production. The increase of on-demand production operations, the increasing number of processor versions, the cleaning of the archive for obsolete baselines and the possibility to transfer core services as the result of industrial competition is complexifying the operation of such service based on individual EOF-CSC service monitoring and reporting. This scenario leads to the need for a dedicated traceability service as part of the EOF-CSC operations.

The traceability service shall implement the following requirements.

The term “trace” is used to represent the information used to identify the user level data. User level data are often made of large repository of files that can be grouped into a unique package. The traceability service may provide several levels of identification.

7.5 Reference system services

The mission specific observation scenarios are converted into an instrument tasking and a satellite downlink plan as part of the mission planning service operations, in line with the satellite operational capacity and constraints (e.g. instrument duty cycle, maximum satellite downlink time, available downlink resources, etc.) and the available ground resources.

8.1 Mission planning services

The mission planning service may be considered as the origin of the operational data flow, feeding the satellite with the necessary commanding activities to perform the desired observations and ultimately generate the associated production and data delivery flows.

The mission planning has also to consider the constraints that may be derived from the acquisition service operations (Interferences between satellites, unavailability of stations, deconflicting between sentinels, ...).

For missions without a systematic or continuous instrument operations, users may need the information on the foreseen detailed observation scenario (i.e. list of the planned data takes, with associated time, duration and instrument mode).

As an example, such a situation may occur to temporarily replace an X-Band station in case of long term unavailability preventing data loss.

For the S1-type of mission, the instrument duty cycle is shorter than the complete orbit and planned instrument activities may not be optimally tasked to respond to unexpected needs from the Copernicus Emergency Service and the International Charter for Major Disaster, requiring an ad-hoc modification of the existing planning.

Authorisation shall be provided by the EC.

8.2 Data acquisition services

For Sentinel-1,-2,-3,5P, the downlink operations rely on a set of available acquisition resources (corresponding typically to the visibility of several X-Band stations and the available EDRS downlink sessions in case it is supported by the operated satellite) to implement the instrument tasking and downlink plan, which are procured through open competition and adjusted in capacity (e.g. by adding additional X-Band stations) in line with the evolution of downlink needs.

Optimisation may consider different kind of criteria including overall downlink capacity, fulfilment of sensing scenarios downlink timeliness, operational robustness, operations complexity, overall cost…).

8.2.1 The X-Band acquisition services

8.2.2 The Ka-Band acquisition services

8.2.3 EDRS acquisition services

For missions embarking an optical communication payload (currently S1 and S2 missions), data downlink can be performed through Ka-Band via the EDRS Service, complementing the X-Band downlink capability.

8.3 Precise orbit determination services

This specification applies for missions requiring precise orbit information for the operational generation of user level data. The type of orbit information and the associated timeliness are mission dependent.

Specifications for the implementation of the various data services are logically organised by the following categories of services:

9.1 Data Preservation Services

Preservation of historical Level-1/2 is subject to trade-off between the resources available and the needed time for generation and availability at the user end. The decision shall be documented user level data type by user level data type.

9.2 Production services

The production services are in charge of converting the raw data from the satellite into user level data. The production services encompass the systematic production, triggered by the availability of new data, and the data reprocessing. Large scale reprocessing is managed according to campaigns authorised with specific requirements to provide harmonised datasets with latest achievable quality. On-demand processing is addressed as part of the Data Access services.

The use of ESA provided CFI elements for the generation of the L0/L1/L2 guarantees to Copernicus user a harmonised quality regardless of the potential changes in the production service provider and also in case of multiple simultaneous service providers.

The production service shall not interrupt the data delivery, the quality report and quality disclaimer are available for retrieval by end users.

9.3 Data Calibration and Validation services

The Calibration and Validation services ensure the calibration and the validation of the user Level-1 and Level-2 data as defined in [RD-3].

These activities encompass the monitoring of the instrument performance and the expert quality assessment of user level data.

9.4 Algorithms and data processors services

The algorithms and data processors services ensure the maintenance and evolutions of the mission/instrument specific scientific algorithms to convert the satellite data stream into instrument and geophysical measurements, as well as the maintenance and evolutions of the operational software implementing these algorithms for the purpose of generating engineering and user level data in line with the mission specificities and user needs.

A regular frequency of 2 processor releases per year is foreseen to introduce algorithm evolutions, improvements and minor corrections. Additional versions may be released in case of major / urgent changes to be introduced.

9.5 Data access services

By its nature, the Data Access Services operations load and performance may be impacted by the diversity and unpredictable evolution of the user scenario in terms of data access needs and access profile (e.g. request for partial or complete user level data, etc.). The sizing of the user scenario is not only difficult to predict on average (e.g. average download volume, average active users, etc.) but presents also a high variability along time (e.g. high peaks related to sudden retrieval requests for user level data on areas impacted by catastrophic events, development of new operations or services that may require access to complete time series…).

In line with the Copernicus Regulation, the EOF-CSC shall offer a full, open and free-of-charge data access to all users, optimising the available operations resources and cost efficiency. This requires establishing an equilibrium between the resources allocated to the fast access infrastructure (e.g. volume of on-line data, available bandwidth…) and in an on-demand scenario the production capacity (e.g. computing infrastructure and feeding links…). As a matter of example, maintaining all user level data available on-line at its native resolution and compression, may not be as cost efficient as allowing for rolling-out past user level data with time and offering the possibility to retrieve them from off-line systems or even following on-demand reprocessing. Whatever would be the selected approach at any point in time, an unlimited demand cannot be satisfied with limited resources and operations shall be protected to prevent the unfair usage of the operational services (e.g. the sudden request for accessing the complete historical production would create such surge on an open system that it could overflow its capacity and block the nominal services for all other users). The protections against such a scenario need to be considered as a nominal function of the data access system (e.g. quotas, queuing of demands, …).

Possible security restrictions are defined by the European Commission and may apply on some user level data. Restriction may apply only on availability timeliness.

The term “fair access” is meant here to ensure that under all operational conditions all users are offered with an equivalent access priority.

The richness of the information contained in the Sentinel user level data is such that the same user level data may be used for multiple applications requiring different components of the same user level data. The classical definition concept, with a fixed packaging and sizing, has demonstrated to be rigid for the large Sentinel volume, with users forced to download the full user level data regardless of the subset of information that would be needed for subsequent applications.

Transformations are mainly aiming at reducing the data transfer from the data access service to the end user. Transformation may be fast extraction of user level data subset.

While the concept of user level data definition is essential to describe and characterise the user level data content (including all necessary quality annotations), a flexible organisation of the information contained would further support the development of user applications.

The timeliness of user level data availability to users depends on the user typology and on the data age. Fresh Sentinel user level data are made available to the Copernicus Services with committed timeliness and to other user typologies with target timeliness. Historical user level data are available with target timeliness to all user typologies. The migration from recent to historical user level data class may be driven by the attainment of a configurable user level data aging, which may be adjusted depending on the demand and on the available overall system resources (e.g. on-line retention time for immediate access to data may be adjusted according to the available resources).

Timeliness corresponds to the time span between data sensing by the satellite to the availability of the corresponding user level data for user download.

9.6 Data support services

●User front-desk services

●Training and support services

●Data access tools

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9.7 Traceability to Functional Requirements for the acquisition, generation and archiving of Sentinel data

9.8 Traceability to functional requirements for the Copernicus Distribution Services

The EC requirements to ESA Specification Traceability is established with the “Functional Requirements for the Copernicus Distribution Services and the Data and Information Access Services (DIAS)” Document, Final Version, 06 December 2016.

EC requirements are available under the format of tables and free text addressing the different functions or entities. Tables related to the EOF-CSC scope have been extracted and extended to allow for traceability indications and commenting. Free text similar to requirements have been extracted and is presented in a complementary table to ease future reference. It is noted that the DIAS is not part of the reference EOF-CSC scope and therefore corresponding requirements have not been extracted.