Without a 'ground segment' − the complex combination of hardware and software on Earth used to fly a satellite in space − it would be impossible to operate any mission. A ground segment is a complex 'system of systems', comprising many elements that must function together perfectly. For spacecraft flown from ESA's ESOC mission control centre, the ground segments are based on a generic infrastructure that is reused, in so far as possible, across missions, and adapted to meet mission or 'family of mission'-specific requirements and configuration needs.
Unique reference environment
Supported by European industry, ESA's ground systems engineers design and develop individual software and hardware elements used in ground segments that can perform satellite control, mission planning, simulations, training and ground station control and management.
At ESOC, the Ground Segment Reference Facility (GSRF) provides a unique reference environment where all these software and hardware systems can be integrated and tested throughout their life cycle, in isolation as well as in various test chains up to a complete end-to-end ground segment.
The 'representativeness' of such an environment, including the representativeness of the test scenarios with respect to use cases, is critical. The deployment of automation wherever possible provides efficiency gains to achieve the highest quality in mission operations infrastructure at minimum cost.
In addition to contributing to the high quality of ground segments at ESOC, teams at the GSRF provide system-level licensability and security tests in order to support European industry.
Integration and testing service
Already available to our industrial partners to investigate complex problems and replicate operational issues in a safe environment, the GSRF aims at offering 'integration and testing as a service' (I&TaaS) to the space community. This means providing a multi-disciplinary team-sharing platform, cross fertilising between technical domains, users and industry.
GSRF: Representative environment
'Mission representativeness' − along the concept “test as you fly” − is ensured by the use of operational configurations, captured from a mission's operational environment.
This configuration is made context-independent and stored centrally under configuration control. After being checked out from a central repository, the configuration can be adapted to the new context and deployed in its final location, ensuring coherency across various mission operations infrastructure systems constituting the chain to be tested. This is achieved by the preservation of the interfaces of each system and the capability to configure multiple systems in one go.
Mission-representative test chains
The GSRF comprises a full spectrum of systems constituting a ground segment and the simulated space segment.
Representative test chains range from simpler chains (mission control systems, network interface systems, ground stations and spacecraft models) to a chain containing the full ground segment (mission control system, network interface system, network delay simulator, signal processing and conversion, antenna and spacecraft simulator). The use of different test tools like Tevalis to test specific cases, together with spacecraft simulators, offers a wide range of possible test scenarios.
Operationally representative test scenarios
The test cases used in this environment have been developed based on real operation scenarios relying on real experiences at mission control. These operational scenarios have been made generic so to be adaptive to any mission-specific configuration and making them portable from one mission to another. This makes these test cases valid across different test chains, for different system versions and ready to support different mission configurations.
The GSRF-provided environment promotes cross-fertilisation among engineering domains, and between engineering and operations, where experts can share their knowledge, experience, efforts and expectations among a multi-disciplinary team.
The GSRF's automated end-to-end test cases precisely replicate user actions by mimicking the actions of the user at the human-machine interface. The automated test cases have been developed in order to be widely reusable by making them modular (they are based on building blocks) and parametrised. The set of automated test cases is rather extensive: 12 hours continuous testing can be automatically executed overnight on different versions of the mission operations infrastructure.
The GSRF conducts research and development (R&D) studies needed to explore and validate new concepts, to demonstrate the suitability and the maturity of new technologies and to harmonise and converge the various integration and testing processes and environments.
The primary goal is to further automate systems deployment and configuration and to enable continuous integration and testing.
In addition, advanced test automation capabilities will include automated problem root-cause analysis and forecasting, as well as security and licensability testing. The GSRF is also evolving toward a future ground segment architecture based on new major developments, in particular the EGS-CC-based monitoring and control systems.
The objective is to develop an 'End-to-end (E2E) Reference Environment' spanning all segments of a mission, providing E2E demonstration and validation of capabilities required to meet present and future mission objectives. The GSRF aims to continually enhance collaboration with European industry, national space agencies and a diverse range of organisations and partners in the spacecraft operations community.
ESA/ESOC Darmstadt, Germany
Tel: +49 (0)6151-90-2204