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.