Modelling and Simulation of Spacecraft Hardware based on Machine Learning Techniques

Research and development projects involving complex systems are often executed in a collaboration between engineers and scientists of various institutions. In such a collaboration, different parts of the system are developed by different companies located in different physical locations. Whenever this happens, testing the system and its components is difficult, since the adjacent hardware required to test the communication channels may not be available on site. This is further problematic in the space industry, because replicating a spacecraft hardware is expensive and arises other technical difficulties as every hardware is a prototype. A solution to this problem is to use a hardware emulator application in the development cycle of the OBSW which can reflect the true hardware behaviour and can be shared easily between the distributed development teams. However, precise low-level hardware emulators are very tedious to build and require deep domain knowledge. A noble alternative solution to this problem is to learn a black-box model from the temporal data-space of the candidate hardware using a ML algorithm which can reflect the realistic hardware behaviour. RNN based models with the LSTM and GRU memory units are excellent in learning sequences and are able to capture long-range dependencies in the temporal dataset. In this study, different LSTM and GRU models are applied to the task of modelling a physical hardware system. Input and output signals from the real hardware are used to train the RNN models following a supervised learning method. The obtained result show that both types of RNN models are capable of simulating the realistic hardware behaviour with a considerable accuracy. The performance of the well configured GRU model is seen to be slightly better than that of the equivalent LSTM model. Nevertheless, the signals predicted by both RNN models showed more than 90% resemblance to the actual signals obtained from the hardware in their frequency spectrum

PaTaS: Quality Assurance for Model-driven Software Development

The quality of software products in safety critical applications, extensively found within the space domain, is a key success factor but also a major cost driver. To ensure high quality of the software product, quality assurance processes with quality models and metrics are applied. With these tools and processes, product assurance managers and software developers are able to quantify the quality of the software under development. Within the ESA-funded study PaTaS (Product Assurance with TASTE Study), a product quality model with software and model metrics was developed and implemented in an end-to-end model-driven software development (MDSD) life cycle demonstrator. The goal of this study was to identify applicable concepts to maintain quality and dependability levels when MDSD is applied. This requires the definition of connected model and software quality indicators. These indicators were integrated into ESA’s reference software product quality model (ECSS-Q-HB-80-04A). The resulting adapted quality model got incorporated in a model-driven software development life cycle demonstrator. To evaluate this demonstrator and the integrated quality indicators in a realistic development scenario, mission-critical parts of the command and data handling subsystem of a satellite mission were modelled and subsequently coded. The aim of the activity was to demonstrate the effect of the end-to-end life cycle in combination with the developed quality model on the final onboard software product. In this paper we present the result of the study. The focus is on the quality model for MDSD and new quality metrics for models, which can be embedded in an end-to-end model-driven product development life cycle

PaTaS - Quality Assurance in Model-Driven Software Engineering for Spacecraft

Within PATAS (Product Assurance with TASTE Study), a product quality model with software and model metrics is developed and implemented in an end-to-end model-driven software engineering (MDSE) lifecycle demonstrator, based on TASTE. The goal of this study is to find applicable concepts to maintain quality and dependability levels, when MDSE is applied. This requires the definition of connected model and software quality indicators. These indicators are identified and integrated with ESA's reference software product quality model (ECSS-Q-HB-80-04A). The resulting quality model is integrated in a model-based software development lifecycle demonstrator, based on TASTE. To evaluate this demonstrator and the integrated quality indicators, mission-critical parts of the command and data handling subsystem of a satellite mission are modelled and subsequently coded, simulating a realistic development scenario as use case. The aim of the activity is to demonstrate the effect of the end-to-end lifecycle in combination with the developed quality model on the final onboard software product. The final results will set the baseline for recommendations to improve Quality Assurance in MDSE at ESA. In this talk, we present the on-going study and its latest results

Tasking Modeling Language: A toolset for model-based engineering of data-driven software systems

The interdisciplinary process of space systems engineering poses challenges for the development of the on-board software. The software integrates components from different domains and organizations and has to fulfill requirements, such as robustness, reliability, and real-time capability. Model-based methods not only help to give a comprehensive overview, but also improve productivity by allowing artifacts to be generated from the model automatically. However, general-purpose modeling languages, such as the Systems Modeling Language~(SysML), are not always adequate because of their ambiguity resulting from their generic nature. Furthermore, sensor data handling, analysis, and processing of data in on-board software requires focus on the system’s data flow and event mechanism. To achieve this, we developed the Tasking Modeling Language~(TML) which allows system engineers to model complex event-driven software systems in a simplified way and to generate software from the model. Type and consistency checks on the formal level help to reduce errors early in the engineering process. TML is focused on data-driven systems and its models are designed to be extended and customized to specific mission requirements. This paper describes the architecture of TML in detail, explains the base technology, the methodology, and the developed domain specific languages~(DSLs). It evaluates the design approach of the software via a case study and presents advantages as well as challenges faced

The BECCAL Experiment Design and Control Software

This paper presents the software responsible for the design and execution of the experiments in the Bose-Einstein Condensate and Cold Atom Laboratory (BECCAL) mission, an experiment with ultra-cold and condensed atoms on the International Space Station. The software consists of two parts: the experiment control software and the experiment design tools. The first corresponds to the software running on the payload and is in charge of controlling and executing the experiments, while the latter are the tools used by the scientists to create the experiment definition that will be later uploaded to the instrument to be executed. To overcome the challenge of developing software with such complexity, it was decided to follow a model-driven development approach. Several domain-specific languages (DSLs) have been created to allow scientists to describe their experiments in a domain-specific way. These descriptions are then uploaded and executed by different interpreters onboard. The paper details the architecture of the experiment control software and the different modules that compose it, as well as the developed languages and tools used to describe new experiments. The paper also discusses and evaluates some important aspects of the software, such as how resilient it is to failures, as well as the advantages and disadvantages of the selected approach compared to other approaches used in similar missions. The developed software will also be used for the MAIUS-2/3 missions

A Dual-Species Atom Interferometer Payload for Operation on Sounding Rockets

We report on the design and the construction of a sounding rocket payload capable of performing atom interferometry with Bose-Einstein condensates of 41 K and 87 Rb. The apparatus is designed to be launched in two consecutive missions with a VSB-30 sounding rocket and is qualified to withstand the expected vibrational loads of 1.8 g root-mean-square in a frequency range between 20–2000 Hz and the expected static loads during ascent and re-entry of 25 g. We present a modular design of the scientific payload comprising a physics package, a laser system, an electronics system and a battery module. A dedicated on-board software provides a largely automated process of predefined experiments. To operate the payload safely in laboratory and flight mode, a thermal control system and ground support equipment has been implemented and will be presented. The payload presented here represents a cornerstone for future applications of matter wave interferometry with ultracold atoms on satellites

Final Presentation of PATAS - Quality Assurance in Model-Driven Software Engineering for Spacecraft

Within (Product Assurance with TASTE Study), a product quality model with software and model metrics had been developed and implemented in an end-to-end model-driven software engineering (MDSE) lifecycle demonstrator, based on TASTE. In this talk, we will present the condensed results of the study. This includes an applicable quality model with correlated model metrics for MDSE, the elaboration of the demonstrator implementation and qualitative as well as quantitative results of the use-case implementation. The goal of this study was to find applicable concepts to maintain quality and dependability levels, when MDSE is applied. This requires the definition of connected model and software quality indicators. These indicators are identified and integrated with ESAs reference software product quality model (ECSS-Q-HB-80-04A). Figure 1 displays the new quality model, which had been integrated in a model-based software development lifecycle demonstrator, based on TASTE. To evaluate this demonstrator and the integrated quality indicators, mission-critical parts of the command and data handling subsystem of a satellite mission had been modelled and subsequently coded, simulating a realistic development scenario as use case. The aim of the activity was to demonstrate the effect of the end-to-end lifecycle in combination with the developed quality model on the final onboard software product. The final results shall set the baseline for recommendations to improve Quality Assurance in MDSE at ESA

ScOSA on the Way to Orbit: Reconfigurable High-Performance Computing for Spacecraft

The German Aerospace Center (DLR) is developing ScOSA (Scalable On-board Computing for Space Avionics) as a distributed on-board computing architecture for future space missions. The ScOSA architecture consists of commercial off-the-shelf (COTS) and radiation-tolerant nodes interconnected by a SpaceWire network. The system software provides services to enable parallel computing and system reconfiguration. This allows ScOSA to adapt to node errors and failures that COTS hardware is susceptible to in the space environment. In the ongoing ScOSA Flight Experiment project, a ScOSA system consisting of eight Xilinx Zynq systems-on-chip with dual-core ARM-based processors and a LEON3 radiation-tolerant processor is being built for launch on DLR's next CubeSat in late 2024. In this flight experiment, not only all 18 cores but also the programmable logic will be used for high performance on-board data processing. This paper presents the current hardware and software architecture of ScOSA. The scalability of ScOSA is highlighted from both hardware and software perspectives. We present benchmark results of the ScOSA system and experiments of the ScOSA system software on ESA's OPS-SAT in orbit in combination with a machine learning application for image classification

A Dual-Species Atom Interferometer Payload for Operation on Sounding Rockets

We report on the design and the construction of a sounding rocket payload capable of performing atom interferometry with Bose-Einstein condensates of K and Rb. The apparatus is designed to be launched in two consecutive missions with a VSB-30 sounding rocket and is qualified to withstand the expected vibrational loads of 1.8 g root-mean-square in a frequency range between 20-2000 Hz and the expected static loads during ascent and re-entry of 25 g. We present a modular design of the scientific payload comprising a physics package, a laser system, an electronics system and a battery module. A dedicated on-board software provides a largely automated process of predefined experiments. To operate the payload safely in laboratory and flight mode, a thermal control system and ground support equipment has been implemented and will be presented. The payload presented here represents a cornerstone for future applications of matter wave interferometry with ultracold atoms on satellites