Papers by Kjeld Hjortnaes
Virtual Spacecraft Reference Facility
ESA Roadmap for IMA Spin-In to Spacecraft Avionics
ESASP, Aug 1, 2012
Time and Space Partitioning in Spacecraft Avionics
This paper will describe the benefits of incorporating software time and space partitioning (TSP)... more This paper will describe the benefits of incorporating software time and space partitioning (TSP), based upon the aeronautic IMA concept, into the spacecraft avionics architecture to manage the growth of mission functions implemented in the on-board software. The paper addresses how TSP can be used to safely integrate applications of different criticality and security classifications, and how incremental validation is supported to control the impact of software modifications to the system.
From Software Crisis to System Solution
Virtual Spacecraft Reference Facility
DASIA 2004 - Data Systems In Aerospace, Jun 1, 2004
From Software Crisis to System Solution
DASIA 2004 - Data Systems In Aerospace, Jun 1, 2004
Software Validation Facilities
An Efficient Approach to Software Validation

Proceedings of the 12th international workshop on Real-time Ada - IRTAW '03, 2003
Business and mission critical real-time systems need to be fully predictable, in order that their... more Business and mission critical real-time systems need to be fully predictable, in order that their behaviour is known before deployment, even in the presence of faults. The Open Ravenscar Real Time Kernel (ORK) is a small size with reduced complexity kernel designed to be used in this type of applications. This kernel was implemented to be fully compliant with the Ravenscar profile, which defines a subset of the tasking features of Ada which can be used to implement a small and reliable kernel. Critical Software has recently conducted an evaluation on this kernel as well as started a new project to provide a monitoring tool for ORK, thus further enhancing the already existing range of hard real-time verification and validation tools. This paper summarizes the objectives and results of the ORK evaluation and presents the main goals and functionalities of the monitoring tool.
Calculating the WCET of mission-critical satellite applications is a challenging issue. The Europ... more Calculating the WCET of mission-critical satellite applications is a challenging issue. The European Space Agency is currently undertaking the CryoSat mission, consisting of a radar altimetry satellite to be launched in 2005. This paper describes the challenges and the first experimental results of calculating the WCET of the Control and Data Management Unit (CDMU) subsystem of the satellite. This subsystem constitutes the central control unit of all the on-board data handling, as well as the attitude and orbit control system of the satellite, and must guarantee predictable behavior.
ESA Roadmap for IMA Spin-In to Spacecraft Avionics
Calculating the WCET of mission-critical satellite applications is a challenging issue. The Europ... more Calculating the WCET of mission-critical satellite applications is a challenging issue. The European Space Agency is currently undertaking the CryoSat mission, consisting of a radar altimetry satellite to be launched in 2005. This paper describes the challenges and the first experimental results of calculating the WCET of the Control and Data Management Unit (CDMU) subsystem of the satellite. This subsystem constitutes the central control unit of all the on-board data handling, as well as the attitude and orbit control system of the satellite, and must guarantee predictable behavior.

Space technology is no longer used only for much specialised research activities or for sophistic... more Space technology is no longer used only for much specialised research activities or for sophisticated manned space missions. Modern society relies more and more on space technology and applications for every day activities. Worldwide telecommunications, Earth observation, navigation and remote sensing are only a few examples of space applications on which we rely daily. The European driven global navigation system Galileo and its associated applications, e.g. air traffic management, vessel and car navigation, will significantly expand the already stringent safety requirements for space based applications Apart from their usefulness and practical applications, every single piece of onboard software deployed into the space represents an enormous investment. With a long lifetime operation and being extremely difficult to maintain and upgrade, at least when comparing with "mainstream" software development, the importance of ensuring their correctness before deployment is immen...
The plasma and wave experiment on Vega-1 and Vega-2
A Vega spacecraft instrument which explores the electrostatic and electromagnetic wave spectra wi... more A Vega spacecraft instrument which explores the electrostatic and electromagnetic wave spectra with a dipolar probe from dc up to 300 kHz and measures the plasma density and temperature with a set of two Langmuir probes is presented. The primary objectives of the experiment are: to measure the density of the solar wind just before it is influenced by cometary constituents, thereby establishing a reference for understanding the subsequent solar wind-comet interaction; to observe the mass loading of the solar wind by cometary ions either directly or through the associated wave instabilities; to obtain plasma density and temperature profiles, as well as wave frequency spectra during the cometary transit; and to search for the signature of collision-free shocks and contact surface.

Independent Software Verification and Validation (ISVV) is an established practice in European sp... more Independent Software Verification and Validation (ISVV) is an established practice in European space projects. An organisation independent of the software supplier and the prime performs verification and validation of software requirements, design, and code. The purpose is to identify faults as early as possible and to create confidence in the software scrutinised. This paper presents a consolidated, coherent, and cost effective ISVV process and a prototype ISVV facility developed in the context of an ESA project, for use across the space industry in Europe. It discusses the motivation for ISVV (including the importance of independence), as well as the purpose and contents of the various ISVV activities. The activities of the defined process are: Management, Criticality Analysis, Technical Specification Analysis, Design Analysis, Code Analysis, and Validation. The process itself is being validated by applying it to elements of the on board software of the European Robotic Arm.
Time and Space Partitioning in Spacecraft Avionics
2009 Third IEEE International Conference on Space Mission Challenges for Information Technology, 2009
This paper will describe the benefits of incorporating software time and space partitioning (TSP)... more This paper will describe the benefits of incorporating software time and space partitioning (TSP), based upon the aeronautic IMA concept, into the spacecraft avionics architecture to manage the growth of mission functions implemented in the on-board software. The paper addresses how TSP can be used to safely integrate applications of different criticality and security classifications, and how incremental validation is supported to control the impact of software modifications to the system.
Software Validation Facilities
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Papers by Kjeld Hjortnaes