Welcome to HASDEL!

HASDEL (Hardware Software Dependability for Launchers) is an ESA project (contract ESTEC 4000107221/13/NL/JK), conducted by a consortium coordinated by Airbus Defence and Space with FBK and RWTH, aiming at analysing the specific needs of launcher systems in the domain of RAMS (Reliability, Availability, Maintainability and Safety) analysis and at extending the COMPASS (Correctness, Modelling and Performance of Aerospace Systems) toolset with these specific needs (see COMPASS project) Compared to satellites, launchers and space transportation vehicles are characterized by some very specific features:

• High level of criticality
• Hard real time requirements

Functional complexity in addition to the complexity implied by the RAMS requirement (e.g. management of redundancies) and by the real time requirements (e.g. the favouring of time triggered designs instead of asynchronous ones). The COMPASS project, funded by ESA, had the objective to support RAMS analysis for satellites. The COMPASS project was motivated by the observation that with the current development methodologies, there is no single view of the system that links all aspects relevant to all involved engineering disciplines in a coherent manner:

• Hardware and software (i.e., co-engineering)
• Performability and dependability
• Reliability, availability, maintainability and safety engineering (RAMS)

The project goal was to develop a coherent and multi-disciplinary approach that supports the early design phases by developing systems at an architecture level. Thus it mainly targets the “requirement engineering” and “analysis” functions of system engineering, but also tackles the “design and configuration” and “verification” phases. More concretely, the first step was to design a specification language that offers convenient ways to describe nominal hardware and software operation, hybridity, (probabilistic) faults and their propagation, error recovery, and degraded modes of operation. A system specification is hierarchically organized into components which interact through connections via ports allowing for both message (event) and continuous (data) communication, and which can be reconfigured dynamically. The specification formalism is inspired by the Architecture Analysis and Design Language (AADL) and its Error Model Annex. It is named System-Level Integrated Modelling (SLIM) Language. In the next step, a formal semantics was developed that allows precisely characterizing the complete set of nominal and non-nominal behaviours of a given system model, and that opens up the possibility to apply a wealth of formal methods for various kinds of verification and validation (V&V) activities. The latter are supported by an integrated toolset that supports:

• Requirements validation
• Functional verification
• Safety and Dependability Analysis
• Performability Analysis
• Fault Detection, Identification and Recovery Analysis

So the Hardware Software Dependability for Launchers project had the main objective of adapting the COMPASS toolset to the specific launcher system needs.