Matra Marconi Space Research Articles

Structural analysis of a cryogen-free refrigerator for space

Future X-ray observatories in space, such as European Space Agency's (ESA) X-ray evolving universe spectroscopy (XEUS) mission, will require cooling to the region 10–100 mK to enable the utilisation of advanced cryogenic photon detectors in cryogenic spectrometer instruments. Such missions are envisaged to be completely cryogen-free, replacing the traditional superfluid liquid helium cryostat with a space worthy mechanically cooled system. As part of the Mullard Space Science Laboratory's (MSSL) adiabatic demagnetisation refrigerator (ADR) development programme, we have investigated the construction of a flight cryostat containing a 10 mK ADR (the MSSL double ADR (dADR)) that can be cooled by a single Astrium (formally Matra Marconi Space (MMS)) 4 K mechanical cooler. A proto-type dADR has been constructed and will be flight proven as part of a sounding rocket payload, where the dADR system will be used to cool an array of superconducting tunnel junction (STJ) detectors at the focus of an X-ray telescope.

On the way towards a truly integrated European space company

Space has always been a field of interest for pioneers and visionaries. Hence, it is not really surprising that the space industry is once again setting examples: last May the former MatraMarconi Space and the space activities of Dasa/Dornier, all companies with a great heritage in the space community were merged to form ‘Astrium N. V.’, the spearhead of European space industry integration.

Institutional Aspects of a Global Navigation Satellite System

This, and the following three papers, where first presented at GNSS 99, the Second European Symposium on Global Navigation Satellite Systems held in Genoa, Italy from 5th to 8th October 1999.Galileo is being developed as the European contribution to the next generation of navigation satellites to replace GNSS1. Sponsored by the European Union, Galileo will be a civil, internationally controlled and operated system that will secure the long-term availability of satellite-based navigation services for multi-modal purposes throughout the European region and beyond. Galileo will be designed to support a wide variety of applications. These include professional navigation, position reference, safety, emergency, tracking, sport/leisure and governmental. Such services may be open to all, for safety-of-life applications, or for commercial users. In the case of safety and commercial applications in particular, it is imperative that the appropriate institutional control and regulatory framework is in place for purposes of safety and economic regulation. To ensure that the various parties understand their obligations and liabilities, clear legal instruments must be put in place to support the organisational framework. It is planned to attract private investment to fund elements of system development and operation through Private/Public Partnership arrangements. At present there is no institutional, regulatory or legal framework that will enable the early impetus to Galileo development to be maintained. This presents a challenge that Europe must address without delay. It has been the subject of several European Commission studies in the past twelve months. In a complementary activity under contract to the European Space Agency (ESA), a European industry consortium comprising Alcatel, Alenia, DASA and Matra Marconi Space was tasked to complete the preliminary design of the space and ground segments by the Autumn of 1999. One task of this study, led by Matra Marconi Space, relates to a study of the impact of institutional, regulatory and legal issues on the organisation and development of Galileo. This paper describes the studies undertaken into these issues within the overall Galileo development programme.

The LEOSTAR platform design and validation

Matra Marconi Space (MMS) has designed a new generation of platforms for Low Earth Orbit small satellites: the LEOSTAR family. The key characteristics of the LEOSTAR platform, namely manoeuvring capability, pointing accuracy, high performance localisation, spacecraft stability and enhanced autonomy, make it perfectly adapted to high performance Observation missions. After an overview of the LEOSTAR concept, this paper presents the main performances of the LEOSTAR platform as fully confirmed and validated by the avionics tests campaign.

The LEOSTAR ™ solution for high performance Earth observation missions

Matra Marconi Space (MMS) has completed in 98 the development and validation of the generic avionics for its new LEOSTAR™ platform. The key characteristics of the LEOSTAR™ platform, namely maneuvering capability, pointing accuracy, high performance localization, spacecraft stability and enhanced autonomy, make it perfectly adapted to Observation missions. After an overview of the LEOSTAR™ concept, this paper presents the main performances of the LEOSTAR™ platform as fully confirmed and validated by the avionics tests campaign.

Cryogenic testing of several parts of the meteosat second generation payload

The first Meteosat Second Generation (MSG) satellite is planned to be launched in 2000. As the first generation of the Meteosat satellites, it is mainly an Infra-Red and Visible Imager. The cooling of the experiment is provided by a passive radiator facing the deep cold space. In the frame of this program, CSL is in charge of the testing of four different parts of the payload, with different thermal environments and cooling systems. For SFIM-ODS REOSC, the I/R detectors are calibrated at 85 and 95 K, before and after cycling them from 333 down to 70 K. The visible detectors are calibrated at 248 K and cycled from 333 down to 228 K. They are cooled by conduction. For Fokker Space b.v., the Passive Cooler Assembly, including the sunshield and the two-stage radiator, is tested with regards to its mechanical stability and thermal performances. As in space, it is cooled radiatively by means of a helium plate. The main specifications for this plate are a total hemispherical emittance greater than 0.95 at 20 K, and a temperature lower than 25 K with a heat load of 200 W. Liquid nitrogen shrouds surround the set-up. For Matra Marconi Space, the Passive Cooler Assembly and the detectors are calibrated at their nominal temperature. The cooling power is provided by the same helium plate simulating the deep cold space. Again for Matra Marconi Space, the whole payload, called SEVIRI, is thermally and optically calibrated. Up to 19 temperature regulated channels are used, and the space is once again simulated by the helium plate. Three of these tests have already been performed successfully. From the facility point of view, we present here the relevant testing philosophies used to meet the specifications, the related problems, solutions and results.

Matra Marconi Space

Provides an independent account of the Matra Marconi Space company’s range of engineering activities. Its technologies include earth observation, communications, science, transportation and manned systems.

Corporate mergers—the Matra Marconi space experience

Mergers and acquisitions are a recognised part of the corporate landscape in late 20th century Europe. In a market that is in creasingly global, especially for the high technology industries companies have Been forced to join forces; downsize or die. This is the case for Europe's space industry, as much as any other. One company that has direct knowledge of corporate mergers and acquisitions is Matra Marconi Space an Anglo French joint venture of some seven years experience. Here its Deputy Chief Executive Officer, Nicholas Franks describes the challenges and the ultimate advantages of a merger between companies from different nations and provides an insight into how the putative cultural divide can be bridged.

Effects of the space environment on the calibration and performance of remote sensing instruments

The trend towards increasing accuracy and longer lifetime, for remote sensing instruments in low-Earth orbit, necessitates a good understanding and careful evaluation of the effects of the space environment. A description of the spacecraft environment for polar orbits at altitudes between 500 and 1500 km, is presented along with some of the potential hazards to spacecraft and instruments. Examples of instruments where the space environment is known to degrade the calibration, such as the Global Ozone Monitoring Experiment (GOME) on ERS, are discussed. In addition, the importance of the effects of radiation induced interference, due to single-effect cause by heavy ions and protons, will be evaluated in light of the probable increased usage of CCD and photodiode arrays. Predictions of the effects of the space environment on the complex geometries, found on the ERS satellite, have been made using Systema, a concurrent engineering tool, developed by Matra Marconi Space Systems.

STEP mission and system design

STEP (satellite test of the equivalence principle) is a candidate mission, in the discipline area of `fundamental physics', for the third medium-size project (M3) of ESA's long-term science programme `Horizon 2000'. A phase A study of the spacecraft and mission has been carried out by an industrial consortium led by Alenia Spazio, with Matra Marconi Space and Dornier Satellitensysteme as subcontractors. The concept that was studied was for an autonomous ESA mission with a payload provided by principal investigators. The model payload includes four equivalence principle accelerometers, a spin-coupling accelerometer and a gradiometer. A helium cryostat provides the required cryogenic temperatures for the payload. Spacecraft and warm payload equipment are accommodated on two platforms surrounding the cryostat. STEP will be launched with a Lockheed Martin LMLV-2 launch vehicle directly into its Sun-synchronous operational orbit at 400 km.

A smallsát approach to large missions

The paper reviews potential Earth observation applications of small satellites using the LEOSTAR platform under development at Matra Marconi Space. This platform is able to support both optical and radar missions thanks to its relatively large payload capability (up to 500 kg) in the small satellite class. This allows users to consider payloads in a large variety of masses for experimental or operational missions, which can be grouped in payload complements coherent for achieving complex missions. The platform is proposed on a generic basis and can be customized to match new Earth observation mission requirements, in a way similar to the buses used for geostationary communication satellites. The costs in each satellite class are reduced as the platforms become a nearly recurrent part, thus making space affordable to a wider community. After a description of the capabilities of the LEOSTAR platform, the paper illustrates a number of planned Earth observation missions which will use it. The description of the missions includes that of the instrumentation and of the end application.

Quasi-optical antennas for radiometric remote-sensing

Millimetre- and submillimetre-wave radiometers are employed for remote-sensing of the Earth's atmosphere. They must operate in several widely-spaced frequency bands which together might exceed the fundamental bandwidth of a waveguide. A wholly independent radiometer for each band would be inefficient and considerable savings in space and weight can be achieved if all bands are received via a single aperture antenna and then separated by an optical demultiplexer, the arrangement comprising a `quasi-optical' antenna. This paper discusses the requirements for, and the design of, quasi-optical antennas for radiometric remote-sensing and illustrates this with particular reference to the Advanced Microwave Sounding Unit AMSU-B, which was designed and built by Matra Marconi Space UK for the UK Meteorological Office and is due to be placed in orbit on a satellite.

Usages et formations de sigles, une application dans l'industrie spatiale

This study of acronyms belongs in the area of descriptive linguistics which deals with the written language and its interaction with speech, and with the bringing into play of linguistic economy. It also belongs in the the area of natural language processing through the development of tools and methods for the recognition of non- lexical forms in a corpus of technical reports. The analysis of the Matra Marconi Space corpus points out variants of the developped forms of one acronym and acronym redundancy in phrases. Thus the categorization of the phenomena we observed should be used for the constitution of electronic dictionaries.

A use of case-based reasoning technique in building expert systems

Matra Marconi Space France and Aramiihs (Action de Recherche et Application Matra Irit en Interaction Homme Système) laboratory have used and evaluated Case Based Reasoning (CBR) techniques in two projects: • - The first project is about the development of a system dedicated to help satellites AIT/AIV (Assembly Integration and Test/Validation) test engineers to cope with incidents occurring during test activities. The project is funded by the EGSE System Section of ESTEC (European Space Research and Technology Centre.). • - The second project is related to the building of a knowledge-based system for diagnosis assistance in AIT/AIV activities of Ariane4 Vehicle Equipment Bay (VEB). The project is financed by internal funding of MMS-F. In the two projects, CBR technique is neither used the same way nor with the same purpose. In the first project, CBR technique is used to find out or suggest the cause of an anomaly when an incident appears. Confronted with the occurrence of an incident, the system will refer to its characteristics (test context, symptoms…) that are considered as relevant to retrieve previous similar incidents. In the second project, CBR technique is combined with Rule Based Reasoning and Model Based Reasoning ones to form the reasoning core of a Hybrid Knowledge Based System. When an incident occurs, the system proposes to test engineers a diagnosis approach based on the combination of different knowledge (coded into rule, cases and models). Aramiihs is a research unit where engineers from MMS and researchers from the IRIT (Institut de Recherche en Informatique de Toulouse) CNRS (Centre National de la Recherche Scientifique) collaborate on problems concerning new types of man-system interaction.

PREVISE: A knowledge-based system to support the preparation and verification of space operations procedures

This paper presents the Previse system for preparing and verifying operations procedures, developed in the frame of a project conducted by Matra Marconi Space for the European Space Agency ESA/ESTEC. This knowledge-based system supports an evolutive procedures language (syntax and vocabulary). It improves the efficiency of procedures preparation by providing powerful editing facilities, by checking the validity of the syntax used by procedures writers, and by automating the formatting task. It also provides a set of verification mechanisms allowing to detect different types of semantic errors in procedures.

Matra Marconi Space Leading Europe into Space

MATRAMarconi Space is the first fully integrated European space company (51 % Matra, 49 % GEC Marconi). It employs a staff of 3200 – 2000 in France and 1200 in Great Britain — spread over five sites. In 1992, it achieved a turnover of 5.6 billion francs ($1.05 billion).

Thermal conductivity of several fibre-reinforced composites between 2 K and 300 K

Future X-ray observatories in space, such as European Space Agency's (ESA) X-ray evolving universe spectroscopy (XEUS) mission, will require cooling to the region 10–100 mK to enable the utilisation of advanced cryogenic photon detectors in cryogenic spectrometer instruments. Such missions are envisaged to be completely cryogen-free, replacing the traditional superfluid liquid helium cryostat with a space worthy mechanically cooled system. As part of the Mullard Space Science Laboratory's (MSSL) adiabatic demagnetisation refrigerator (ADR) development programme, we have investigated the construction of a flight cryostat containing a 10 mK ADR (the MSSL double ADR (dADR)) that can be cooled by a single Astrium (formally Matra Marconi Space (MMS)) 4 K mechanical cooler. A proto-type dADR has been constructed and will be flight proven as part of a sounding rocket payload, where the dADR system will be used to cool an array of superconducting tunnel junction (STJ) detectors at the focus of an X-ray telescope.

Line-of-sight Jitter Of SELEX Optical Terminals,Analysis And Verification Activities

The Semi-Conductor Laser Inter-Satellite Link Experiment (SILEX) is a very innovative program of the European Space Agency. Two optical terminals, PASTEL and OPALE, respectively on the SPOT4 satellite (low Earth orbit) developed by MATRA MARCONI SPACE under CNES contract, and on the ARTEMIS satellite (geostationary) developed by ALENIA under ESA contract, must be pointed to each other to within 2 microradians in the communication phase. To achieve this very high accuracy pointing, the Pointing, Acquisition and Tracking (PAT) system of each terminal provides high bandwidth (above 100 Hz), fine control capabilities so as to decrease the pointing jitter induced by host spacecraft disturbances. In this frequency band, the spacecraft and the optical terminal are no more rigid bodies, and the coupling of structural modes is a performance driver that requires detailed analysis and verification tests. The aim of the paper is to describe the activities carried out at MATRA MARCONI SPACE to predict and verify on the ground the high frequency line-of-sight pointing performances of the SILEX terminals, essentially focusing on the case of PASTEL. Due to the complexity of the problem (flexible bodies in a high frequency range, large angle azimuth/elevation motions of PASTEL, PAT control loop, on-board disturbing environment...), the pointing verification logic was built on a combined tests/analyses approach. A series of modal tests have been performed at terminal level, completed by a microvibration test on the SPOT4/PASTEL assembly. Their exploitation has led to Finite Element Model update, and definition of worst case transmissibility envelopes. In addition, the detailed characterisation of the main on-board disturbance sources (SPOT4 Reaction Wheels and Oblique Viewing Mirror mechanism) has provided the Transactions on the Built Environment vol 19, © 1996 WIT Press, www.witpress.com, ISSN 1743-3509

Relational Approach To Fault Diagnosis BasedOn A Functional Model

Matra Marconi Space has been developing operational expert systems for spacecraft fault diagnosis using hybrid approaches, including techniques related to model based approach and fault trees. Keeping in mind the operational constraints of exhaustivity and efficiency that guided the initial choices, the reasoning paradigms developed are now refined, to improve the solutions reached. The paper describes some of the techniques implemented so far, and proposes extensions to the relational approach to automated diagnosis, in order to include more of the available knowledge to refine the representation of influences, by distinguishing certain and possible influences, and through a gradation of the uncertainty introduced.

Towards Intelligent Assistants For SpaceOperations And Logistics

This paper describes the Intelligent Support to Logistics concept (ISL), that is emerging at MATRA MARCONI SPACE thanks to software tools of the OPSWARE family. These tools provide support for project and mission planning/scheduling, operations procedures elaboration/validation/execution, generation and browsing of operations manuals, monitoring/trend analysis and reporting, failure diagnosis. They are based on advanced software engineering techniques, including AI techniques. Several instances of these tools have been fielded with a very significant pay-off, both at MMS and at external customers' sites (ESA, CNES, ARIANESPACE).