european space agency agence spatiale europeenne

The European Space Agency was formed out of, and L'Agence Spatia/e Europeenne est issue des deux took over the rights and obligations of, the two earlier Organisations spatia/es europeennes qui I'ont precedee European Space Organisations: the European Space - I'Organisation europeenne de recherches spatiales Research Organisation (ESRO) and the European (CERS) et I'Organisation europeenne pour la mise au Organisation for the Development and Construction of point et la construction de lanceurs d'engins spatiaux Space Vehicle Launchers (ELDO). The Member States (CECLES) - dont elle a repris les droits et obligations. are Austria, Belgium, Denmark, France, Germany, Les Etats membres en sont: l'Allemagne, l'Autriche, la Ireland, Italy, Netherlands, Norway, Spain, Sweden, Belgique, le Danemark, I'Espagne, la France, I'lrlande, Switzerland and the United Kingdom. Finland is an l'Italie, la Norvege, les Pays-Bas, le Royaume-Uni, la Associate Member of the Agency. Canada is a Suede et la Suisse. La Finlande est membre associe de Cooperating State. I'Agence. Le Canada beneficie d 'un statut d'Etat cooperant.

In the words of the Convention: The purpose of the Agen­ Selon les termes de la Convention: L'Agence a pour mis­ cy shall be to provide for and to promote, for exclusively sion d 'assurer et de developper, a des fins exc/usivement peaceful purposes, co-operation among European paci/iques, la cooperation entre Etats europeens dans States in space research and technology and their space les domaines de la recherche et de la technologie applications, with a view to their being used for scientific spatia/es et de leurs applications spatiales, en vue de purposes and for operational space applications leur utilisation a des fins scientifiques et pour des systems. systemes spatiaux operationnels d'applications:

(a) by elaborating and implementing a long-term Euro­ (a) en elaborant et en met/ant en oeuvre une politique pean space policy, by recommending space objec­ spatia/e europeenne a long terme, en recomman­ tives to the Member States, and by concerting the dant aux Etats membres des objectifs en matiere policies of the Member States with respect to other spatia/e et en concertant les politiques des Etats national and international organisations and in­ membres a I'egard d'autres organisations et institu­ stitutions; tions nationales et internationales; (b) by elaborating and implementing activities and pro­ (b) en elaborant et en mettant en oeuvre des activites et grammes in the space field ; des programmes dans le domaine spatial; (c) by co-ordinating the European space programme (c) en coordonnant le programme spatial europeen et and national programmes, and by integrating the lat­ les programmes nationaux, et en integrant ces der­ ter progressively and as completely as possible into niers progressivement et aussi completement que the European space programme, in particular as possible dans le programme spatial europeen, regards the development of applications satellites; notamment en ce qui concerne le developpement (d) by elaborating and implementing the industrial de satellite d 'applications. policy appropriate to its programme and by recom­ (d) en elaborant et en mettant en oeuvre la politique in­ mending a coherent industrial policy to the Member dustrielle appropriee a son programme et en recom­ States. mandant aux Etats membres une politique industrielle coMrente.

The Agency is directed by a Council composed of L'Agence est dirigee par un Conseil, compose de representatives of Member States. The Director General representants des Etats membres. Le Directeur general is the chief executive of the Agency and its legal est le fonctionnaire executif superieur de l'Agence et la representative. represente dans tous ses actes.

The Directorate of the Agency consists of the Director Le Directoire de I'Agence est compose du Directeur General; the Inspector General; the Director of Scientific general; de I'lnspecteur general; du Directeur des Pro­ Programmes; the Director of the Earth Observation and grammes scientifiques; du Directeur des Programmes Microgravity Programme; the Director of the Telecom­ d 'Observation de la Terre et de Microgravite; du munications Programme; the Director of Space Transpor­ Directeur du Programme de Telecommunications; du tation Systems; the Director of the Space Station and Directeur des Systemes de Transport spatial; du Platforms Programme; the Director of ESTEC; the Direc­ Directeur du Programme Station spatiale et Plates­ tor of Operations and the Director of Administration. formes; du Directeur de I'ESTEC, du Directeur des Operations et du Directeur de I 'Administration.

The ESA HEADQUARTERS are in Paris. Le SIEGE de I'ESA est a Paris.

The major establishments of ESA are: Les principaux Etablissements de I'ESA sont:

THE EUROPEAN SPACE RESEARCH AND LE CENTRE EUROPEEN DE RECHERCHE ET DE TECHNOLOGY CENTRE (ESTEC), Noordwijk, TECHNOLOGIE SPATlALES (ESTEC), Noordwijk, Netherlands. Pays-Bas.

THE EUROPEAN SPACE OPERATIONS CENTRE LE CENTRE EUROPEEN D'OPERATlONS SPATlALES (ESOC) , Darmstadt, Germany (ESOC), Darmstadt. Allemagne.

ESRIN , Frascati, Italy. ESRIN, Frascati, /talie

Chairman of the Council: Mr H. Grage. President du Conseil: M H. Grage.

Director General: Prof. R. Lust. Directeur general: Prof. R. LOst. no. 60 november 1989 contents/sommaire

Ulysses - Preparations for the Voyage over the Solar Poles Resumed K.-P' Wenze/ & R.G. Marsden 9

Aristoteles - A European Solid-Earth Mission G. Mecke 15

Eureca Flight Operations J. van Casteren & P. Ferri 25

Flight Opportunities for Small Payloads J. Feuste/-Buech/ & H.A. Pfeffer 34

Front cover: Ulysses spacecraft under test at ESTEC (see page 8) Testing of Space Fuel Cells at ESTEC M. Schautz & G. Dud/ey 39

Editorial/Circulation Office ESA Publications Division Computer Simulation of Space Mechanisms clo ESTEC, PO Box 299, Noordwijk N. Cable 46 2200 AG The Netherlands

Publication Manager Bruce Battrick ESA Support for the Italian SAX Astronomy Satellite Mission Editors P. Ma/dari, G. Manarini & L. M. Pa/enzona 55 Bruce Battrick, Duc Guyenne

Assistant Editor Erica Rolfe The European Centre for Space Law - A New Branch of Layout Space Studies Opens at European Level Carel Haakman K. Madders 59

Montage Keith Briddon, Paul Berkhout ESA's Olympus Satellite and Distance-Learning in Europe Advertising - The Creation of a European Users' Association (Eurostep) Brigitte Kaldeich J. Chap/in 63

In Brief 68 The ESA Bulletin is published by the European Space Agency. Individual articles may be reprinted provided that the credit line reads 'Reprinted from the ESA Bulletin' plus Focus Earth 76 date of issue. Signed articles reprinted must bear the author's name. Advertisements are accepted in good faith : the Agency accepts Publications 78 no responsibility for their content or claims.

Copyright © 1989 European Space Agency Printed in The Netherlands Programmes under Development and Operations ISSN 0376-4265 Programmes en cours de realisation et d'exploitation 81

european space agency agence spatiale europeenne • bulletin 60

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3 • bulletin 60 Dornier - Milestones in Space.

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7 • bulletin 60

8 ulysses

Ulysses - Preparations for the Voyage over the Solar Poles Resumed

K.-P. Wenzel & R.G. Marsden Solar and Heliospheric Science Division, ESA Space Science Department, ESTEC, Noordwijk, The Netherlands

Introduction be staffed by a joint team of ESA and NASA The past year has seen a number of positive personnel, will be located at the Jet developments affecting the much-delayed Propulsion Laboratory (JPL), in Pasadena, Ulysses project. Among these, the California. resumption of NASA's Shuttle operations in the autumn of 1988, and the successful Ulysses' scientific payload consists of nine launches of the Magellan and Galileo instruments that are provided by institutes planetary missions earlier this year, were from both ESA Member States and the perhaps the most significant external factors. United States. In addition, the spacecraft's telecommunications system will be used to On ESA's side, reintegration of the scientific conduct radio-science investigations. payload and spacecraft recertification was started in early 1989, after a spacecraft storage period lasting nearly three years The Ulysses mission The primary scientific objective of the Ulysses mission is to explore the inner The joint ESA-NASA Ulysses mission is finally scheduled to start its heliosphere over the full range of solar long-awaited interplanetary voyage in October next year. This will latitudes. The heliosphere is the vast region make Ulysses the first spacecraft to perform an exploration of the of space extending outwards from the solar inner heliosphere covering the full range of heliographic latitudes, corona. It is dominated by the magnetised including the solar-polar regions. Following a period of storage stream of ionised gas, or plasma, that flows after the Shuttle 'Challenger' accident, activities were resumed this radially away in all directions from our star. year to recertify the spacecraft and its scientific payload for flight. This flow, which is called the 'solar wind', is the only large-scale astrophysical plasma that is available for in-situ study, just as the Sun is (the second such period in the history of the the only star close enough for its surface Ulysses programme). These activities will structure to be resolved. Observations of the continue until the.beginning of 1990, when Sun and the heliosphere are used as a basis the spacecraft should be ready for shipment for deciding what is possible in other astro­ to the launch site. physical settings.

The launch campaign at Cape Canaveral will Our knowledge of the heliospheric plasma start in May 1990, leading up to the Shuttle environment to date is based largely on the launch in early October 1990. vast number of observations made during the past three decades by spacecraft Within the overall programme, ESA is operating close to the plane of the ecliptic responsible for the development of the (the plane in which the Earth orbits the Sun). spacecraft and its in-orbit operation. NASA is If further progress is to be made in under­ responsible for the provision of the launcher standing the physics of the heliosphere, and all launch services, for provision of the a comprehensive database of in-situ spacecraft's electrical power source (a Radio­ measurements made at all solar latitudes is isotope Thermoelectric Generator, or RTG) , required . for tracking and data acquisition support by the Deep-Space Network, and for processing To obtain such a database is the and distribution of the scientific data. Six steps on the way to fundamental goal of Ulysses' unique the first circumnavigation exploratory mission. Specific topics to be of the solar poles The Mission Operations Centre, which is to addressed are (Fig. 1):

9 ., bulletin 60

- the three-dimensional structure of the major constraint on the mission, namely that solar wind and heliospheric magnetic field launch opportunities occur only once every - solar radio bursts and heliospheric plasma 13 months. waves - solar hard X-rays The Ulysses launch vehicle - the propagation and acceleration of solar Since the start .of the Ulysses project in 1977, energetic particles there have been many versions of the launch - the propagation and deceleration of vehicle. Although NASA's Space Transport­ galactic cosmic rays ation System (STS) has remained as the - the distribution of interplanetary/interstellar baseline for achieving a circular orbit around neutral gas and cosmic dust the Earth , there have been many variants of - the origin of cosmic gamma-ray bursts. the Upper Stage needed to propel the spacecraft towards Jupiter. Direct ballistic injection of a spacecraft into a solar polar orbit requires a launch energy far Following the Challenger accident in 1986

Figure 1. Schematic of various solar-, Interplanetary- and galactic-science topics that will be investigated by the Ulysses mission

in excess of the capabilities of currently­ and the resulting delay in the launch of available launch vehicles. In order to achieve Ulysses until 1990, NASA made a major such an orbit, Ulysses will first make a close review of Shuttle safety policy. One outcome flyby of Jupiter, during which the planet's was that a liquid-fuelled Centaur Upper immense gravitational pull will act as a sling­ Stage was considered to be too dangerous shot to propel the spacecraft out of the to be carried by the Shuttle. It was therefore ecliptie plane and send it arcing back decided to revert once again to a US Air towards the Sun (Fig. 2). Force Inertial Upper Stage (IUS) . This two­ stage solid motor will be augmented by the After the encounter, Ulysses will be travelling PAM-S boost motor, which is a variant of the in an elliptical orbit in a plane almost at right­ well-proven PAM-D Payload Assist Module angles to the ecliptic, climbing slowly in solar (Fig. 3). latitude. The first high-latitude pass will be over the Sun's southern pole, followed one Although the IUS and PAM have both been year later by the second (northern) polar flown previously with the STS, they have pass. never been used in combination. Their main role has been for the injection of fairly Although enabling the spacecraft to get what heavy payloads into geostationary orbit. amounts to a free ride on a natural booster, Consequently, although the combined weight the Jupiter swing-by manoeuvre places a of the spacecraft and the PAM-S is such that

10 ulysses

the IUS sees a normal load, the situation for The FM recertification programme includes a PAM-S is very different. Instead of the 1 ton rigorous series of system-level electrical tests of a typical PAM payload, the Ulysses and a number of mechanical checks. The spacecraft weighs only 370 kg . As a result, first Integrated System Test (1ST) was the PAM-S imparts an acceleration in excess successfully completed at Friedrichshafen in of 11 g, rather than the usual 4- 5 g mid-September. experienced by other payloads. Since the low payload weight and high acceleration are Thereafter, the complete spacecraft started both outside the existing PAM database, what it is hoped will be its last series of considerable analysis and some testing has Earth-bound journeys. From Dornier, Ulysses been needed to prove this motor's suitability was transported to IABG near Munich, where for the Ulysses mission. it was successfully demonstrated that the spacecraft's low magnetic levels have Project status and plans remained unchanged since its initial As a consequence of the delay resulting integration in 1983.

Figure 2. Ulysses trajectory viewed from 15° above the ecliptic plane. The blue segments show regions in which the heliographic latitude of the spacecraft exceeds 70°. Dots are plotted along the Ulysses trajectory at 100 d intervals

from the Challenger accident, the Ulysses On 5 October, the spacecraft arrived at spacecraft was put into storage at the Prime ESTEC in Noordwijk (NL), where it will Contractor's site (Dornier) in Friedrichshafen undergo its final recertification tests, including 01'1. Germany). The majority of the scientific cold thermal-vacuum exposure, a second 1ST, instruments were returned to the investigator spin balance testing, and a number of other teams. This year has seen a significant mechanical tests. Between these activities, increase in hardware-related activities. Mission Operation System (MOS) tests will be slotted in, designed to demonstrate Starting in January, following the refurbish­ the readiness of the ground system for the ment of memory modules in the spacecraft's in-orbit operation, and to train the (totally data-handling subsystem and a number of new) spacecraft operations team . experiments, the Qualification Model (QM) spacecraft was built up using flight-spare The ESOC (Darmstadt) Spacecraft units. It was then subjected to system-level Operations Team that was dissolved in 1986 electrical tests. These tests, conducted at has been reformed, and will transfer to JPL Dornier, served to check out the flight-spare in early 1990 to take its place as part of the hardware, while at the same time providing joint ESA-NASA Mission Operations Team . training for the (largely new) assembly, This will include a Ulysses Science integration and test team, prior to starting Coordination Office. Flight Model (FM) spacecraft integration.

11 • bulletin 60

Figure 3. Artist's Impression of Ulysses and the large Upper Stage after deployment from the Space Shuttle. The Upper Stage consists of the two­ stage IUS (large diameter) coupled to the PAM-S boost motor (small diameter). Prominent features of the spacecraft are the parabolic high-gain antenna and the RTG. The launch support structure, which Is attached to the IUS adapter, carries RTG COOling lines

Some adjustments in mission operations planning have been necessary due to the Why 'Ulysses'? long launch delay. The flight-control computer system has had to be replaced, for Why is the first space mission to example, necessitating the conversion of circumnavigate the poles of the Sun spacecraft and payload control software. called 'Ulysses'? A Spacecraft Pre-Shipment Review will be held in February 1990, followed by a buffer When the project was started in the period, which will lead to resumption of the mid-1970s, it was called the 'Out-of­ launch campaign at Cape Canaveral in Ecliptic' mission, and later became the May 1990. 'International Solar Polar Mission' (ISPM). It was renamed 'Ulysses' in Acknowledgement 1984, at the suggestion of one of the The authors acknowledge the contribution Scientific Investigators, Prof. B. Bertotti provided by D. Eaton, Ulysses ESA Project of the University of Pavia (Italy). MM~m • The story is told in Dante's 'Inferno' Further Reading that Ulysses, the Greek hero of the Other articles on the Ulysses mission Trojan War and King of Ithaca, that have appeared in earlier ESA becoming restless for further publications include: adventure, wanted to set off for - The International Solar-Polar Mission another voyage to explore beyond the - Its Scientific Investigations, known world, which at that time K.-P' Wenzel , R.G. Marsden & B. Battrick, ESA Publication SP-1050, ended at Gibraltar, July 1983. 'to venture the uncharted distances .. .. - The ISPM Mission: Science of the uninhabited world behind the Objectives and Mission Overview, Sun .... to follow after knowledge and K.-P' Wenzel & R.G . Marsden, excellence.' ESA Journal No. 2, 1983.

- Ulysses - The Voyage Must Wait, 'Ulysses' therefore seems to be an apt R.G. Marsden & K.- P' Wenzel , name for man's first adventure over ESA Bulletin No. 48, November 1986. the solar poles.

12

G bulletin 60

14 aristoteles

Aristoteles - A European Solid-Earth Mission

G.Mecke Earth-Observation Preparatory Programme, ESA Directorate of Earth Observation and Microgravity Programmes, ESTEC, Noordwijk, The Netherlands

Scientific rationale and objectives dynamics at great depths was not fully Progress in the Earth-sciences over the past recognised. two decades has, as in many other areas of science, been considerable. Since the In the past two decades, however, the mid-1960s, for instance, geology has been concept of and evidence for plate tectonics revolutionised by the theory of plate and sea-floor spreading has revolutionised tectonics. Most of today's knowledge about our understanding of how the Earth works. It the structure and dynamics of the Earth has is now commonly accepted that many of the been obtained by interpreting data from processes that shape the Earth's surface are related to processes very deep in its interior. Geodynamics is therefore now a highly The Aristoteles mission is a European solid-Earth-sciences interdisciplinary and complex research field , programme dedicated to precise global measurement of the involving increasingly refined stu.dies of the Earth's gravity field with unprecedented accuracy. As part of Earth's lithospheric dynamics, rotation (polar ESA's Earth-Observation Programme, this satellite mission will be motion, length-of-day), surface geometry, an ideal tool for gathering gravity-field , magnetic-field and other gravity field, magnetic field, and sea level. data on a global scale, quickly and at reasonable cost. It will contribute both directly and indirectly to a significant improvement Space techniques provide a powerful means not only in our geophysical, geodetic, and oceanographic know­ of studying the links between these quantities ledge, but also that in many other disciplines and applications on a global scale, and can therefore con­ (Fig. 1). tribute substantially to our achieving a better knowledge as to how this complex system Contacts with the scientific community and bilateral discussions works. with ESA Delegations have shown considerable interest in the Aristoteles Programme in Europe and in the United States, as well Geopotential field research as in other countries. Discussions with NASA on possible American Possibly the most essential prerequisite for participation in the mission are currently in progress. our understanding of the structure, dynamics and evolution of planet Earth is precise determination of its gravity and magnetic measurements of its geopotential fields, of fields. Both have been measured and seismic activity and of the irregularities mapped in the past in a general way, but observed in its rotation parameters. These not in sufficient detail and, more importantly, observations will also be used in the coming not homogeneously on a global scale. years to develop a strategy for solving the many unanswered questions in the inter­ The primary needs for improved high­ disciplinary science of 'geodynamics'. resolution geopotential data (down to about 100 km) are in: Geodynamics is concerned with the physical - solid-Earth geophysics forces and processes that affect the Earth's - physical oceanography core, mantle and crust; it also embraces the - climatology and global change. interactions of the solid Earth with the atmosphere and the oceans. Until recently, Solid-Earth geophysics such processes were treated as independent The structure of the gravity field , as • Applications and Research from each other, and the close connection measured on the Earth's surface or in near­ Involving Space Techniques Observing The Earth fields between topographic features, geological Earth space, directly reflects irregularities in from Low Earth orbit structures and natural-resource distribution the mass distribution within the planet's Spacecraft. on the Earth's surface and its structure and interior. Any changes in this mass distribution

15 • bulletin 60

due to internal and external forces become interrelation Detween oceanic variables and apparent as time variations in the gravity climate. field. Since all geodetic observations, from levelling to inertial navigation systems, are Climatology and global change affected by motions of matter on the Earth's Another example of the need for establishing surface, detailed knowledge of the gravity a high-accuracy reference surface for the field is of fundamental importance for such World 's ceans is the study of secular sea­ discipines as geodesy, geophysics, and level rise. The monitoring of sea-level change oceanography. is an integral part of the study of global change, particularly if combined with surface­ Physical oceanography temperature and ocean water-body The sea surface differs from the classical temperature surveys, and monitoring of the reference surface, the geoid, because of ice volumes of the World 's glaciers and ice currents, wind stress, and salinity and sheets. temperature variations. In physical oceanography, an understanding of the Positioning geodesy departure of the actual sea surface (as In view of the dynamic nature of planet

Figure 1. Gravlty- measurement accuracy requirements and ., en Arlstoteles' capabilities ., 30 Oceanic 100 ..J ", Lithospere " a.~ ":::E E ~ en ca 24 ARISTOTELES 80 ..J ca BASELINE n .,c: "Zw ":::E E :::E " 0 60 0 ~ .,c: 18 Z Oceanography Continental w > ~ :I: U a. Lithosphere a. '0 L£. a: 40 ";:) -.e 12 0 u 0 en U <') W Cl 0 " c: ;:) E 6 20 ~ :::J ::::i 11> a. 11> :::E ~ " 1000 100 10

HORIZONTAL RESOLUTION IN KM

measured, for example, by a satellite Earth , we can no longer maintain the altimeter) from a unique zero reference level, traditional assumption of regarding the shape provides the basis for observing ocean­ of the Earth as constant. In fact, observed circulation features down to the very small phenomena, such as tectonic plate motion, scales of interest. internal heat convection, polar motion and climatic changes are all providing evidence The global homogeneous determination of that the Earth is far from a static system. the Earth's gravity field by Aristoteles will Powerful energy sources in its interior provide data of sufficient quality to permit the continually manifest themselves through World Ocean Circulation Experiment (WOCE) major catastrophic events on its surface. to measure all the components of ocean circulation, to substantially refine the models, The list of scientific objectives would be and to infer the nature of ocean/atmosphere incomplete if it were not to include the study interaction. of lithospheric dynamics by means of precise measurements of points on the Earth's The temporal variations in ocean-surface surface and their motions. Aristoteles, though topography are an important aspect of primarily a geopotential field mission, has the physical oceanography. In particular, ability to conduct such studies as a changes in the ocean surface's shape relate secondary mission objective, which would be directly to different driving forces and to of benefit in: changes in the ocean/atmosphere environ­ ment. The El Nino Southern Oscillation - geodesy: connection of dynamic and phenomenon is a good example of the inertial reference systems

16 aristoteles

- geodynamics: monitoring of deformations It was at this point that the ESA Member in seismic areas and monitoring of States approved preparatory activities for a volcanic activity mission called 'Aristoteles' as part of the - offshore operations: positioning of Agency's Earth-Observation Preparatory exploration sites and oil platforms. Programme (EOPP). These activities were to be based on the conclusions of the Matera Workshop and included both system-level Programme background studies and complementary technology and ESA has been working with industry and the data (pre)-processing tasks. scientific community since the mid-eighties on developing a number of conceptual Scientific Working Groups were created in mission designs in preparation for Aristoteles. 1988 to provide ESA with advice on both the As part of the Agency's Earth-Observation gravity- and magnetic-field mission aspects. Preparatory Programme (EOPP), a system The data-processing needs have also been concept for the measurement of anomalies in carefully considered. the Earth's gravity field has been developed that confirms the basic technical feasibility of System requirements and constraints the approach. A first laboratory model of the In accordance with the primary mission highly sensitive accelerometer required for objective as defined at the Matera Workshop, the gravity-gradient determination has been Aristoteles is tailored to the prime require­ manufactured and tested, and software ment of determining the Earth's gravity field simulators modelling the data processing that to an accuracy of 5 mgal (resolution of will be needed have already been developed 100 km x 100 km at the Earth's surface). and are now being used for system studies. The spacecraft concept (drag-free or non­ The ESA 'SESAME ' (Solid-Earth Science and drag-free) and orbital altitude, the mission Application Mission for Europe) Workshop in duration, as well as the sensitivity, sampling 1986 resulted in a recommendation, based rate and configuration of both the accel­ on a single-satellite or a dual-satellite erometers and the GRADIO instrument, have concept, for a mission that would combine to be selected such that this overall gravity-gradiometer and magnetometer requirement is fulfilled . There are also measurements at low orbital altitude (about stringent requirements on: the matching of 200 km) with a high-altitude (about 7000 km) the accelerometers (scale-factors); internal Point-Positioning Mission (PPM). The use of alignment of the GRADIO instrument and satellite-to-satellite tracking systems was matching of its geometrical centre with the recommended for both concepts, and it was spacecraft centre of mass; precise attitude also suggested that ESA should explore the knowledge; low-disturbance accelerations; possibility of a joint venture with NASA for and low variations in angular rates and the two-satellite concept. parasitic accelerations (including variations due to changes in the spacecraft's internal Following these recommendations, studies mass distribution). were performed on the possible flight of instruments like 'PRARE' (Precise Range And Optional mission elements Range-rate Equipment) for precise tracking, For the magnetic-field measurements, an and 'GRADIO' (a gradiometer consisting of a accuracy of 2-5 nT at a horizontal resolution set of accelerometers for gravity-gradient of 100 km x 100 km is projected. Measure­ measurements) on the American GRM ments from low orbital altitude (about satellites. These studies showed a clear 200 km) to study anomalies in the Earth's preference for the single-satellite concept for lithospheric magnetic field have the highest both scientific and cost reasons. priority; measurements from higher altitudes to study the magnetic fields surrounding the A subsequent joint ESA/NASA Workshop Earth and that of its core have a lower held in Matera, Italy, in 1987 also recom­ priority. mended the single-satellite concept, with a gradiometer as the baseline payload. The accommodation of a magnetometer Secondary objectives included l1)agnetic-field aboard Aristoteles requires that the satellite's measurements and a Global Point Positioning magnetic field at the instrument location be System (GPS) as desirable extensions of that compatible with the overall accuracy baseline. The Matera Workshop also specified. A magnetically clean satellite and welcomed any possible ESA/NASA the accommodation of the magnetometer on cooperation and recommended the setting a boom of considerable length are the rather up of an international data-user team . costly consequences. In the case of a vector

17 G bulletin 60

Figure 2. Aristoteles mission scenario (for the case of an Ariane dual launch with an ERS-type satellite)

ARISTOTELES

Injection

• Launch with ERS-type Satellite • Sun synchronous, circular Orbit • Altitude: 780 km • Inclination: 98S

Preoperational Drift Phase

• Inclination: 96.330 • Duration: 8 months

1fTiTi~*'-----l-+-- ERS-type Satellite

--H-- ARISTOTELES Satellite

18 aristoteles

ERS-type Satellite

Point Positioning Mission

• Inclination: 98.1 0 • Duration: 3 years

Optional Ascent to 700 km

• Descent to 300 km • Duration: 22 days

7 to 10 Microwave ~ Tracking Stations for Orbit Determination (Further Stations for Point Positioning)

• Descent to 200 km • Duration: 2 weeks

Main Ground Station: Kiruna

Geopotential Field Mission

• Sun synchronous, circular Orbit • Inclination: 96.330 • Duration: 6 months

19 • bulletin 60

magnetometer, very accurate attitude environment, flight-profile, onboard-memory, reconstitution is also required. satellite-autonomy, and last but not least, development-schedule requ irements. For the Point-Positioning Mission (PPM) , a relative positioning accuracy goal of Results of preparatory work 5-10 cm is specified for baselines of Based on the requirements and constraints 100-1000 km . A mission duration of three mentioned above, system-level studies (so­ years is required at an orbital altitude of called 'Pre-Phase-A' and 'Phase-A' studies) about 700 km . The MTS*!PRARE system have been conducted on the Aristoteles needed to provide the required a-posteriori mission for ESA since 1987 by a European orbit reconstitution for the gravity mission can industrial consortium led by Dornier System be used to perform the point-positioning (D) . All studies have been performed in close measu rements. contact with the scientific community interested in the solid Earth . The inclusion of a GPS receiver system would provide a backup for the PRARE orbit­ At satellite level, the so-called 'drag-free' and determination system, and would comp­ 'non-drag-free' concepts have been traded­ lement the gravity-field measurements at long off. In the drag-free case, the GRADIO wavelengths. instrument is suspended inside the satellite such that the external (non-gravity) distur­ The baseline and all optional mission bances are filtered out by the spacecraft variations call for global coverage, and hence body. In the non-drag-free case, the demand a quasi-polar orbit. It is further instrument is mounted directly onto the required that at least 90% of the payload satellite structure and therefore senses all data generated on board the spacecraft be external accelerations in addition to the available to the scientists. Care must gravity signal. therefore be taken to ensure that the accommodation of any secondary instrument The drag-free concept foresaw the use of a does not jeopardise the primary mission three-dimensional GRADIO, employing either objective. This may prove difficult in the case eight accelerometers in a cubic arrangement, of the boom-mounted magnetometer, which or six accelerometers at the corners of an may adversely interact with the environment octahedron. All three axes of each accel­ and the GRADIO instrument, and thereby erometer would yield highly sensitive pose accommodation problems. measurements. All components of the gravity gradient tensor could be determined with Neither the accommodation of a GPS, nor such a drag-free concept, leading to a the inclusion of the PPM appear to pose gravity-field anomaly reconstruction accuracy major problems, provided that in the latter of better than 4 mgal for a mission duration case sufficient additional propellant can be of three months and an orbital altitude of included. 180 km .

Financial aspects The studies of the non-drag-free concept In addition to the scientific and technical resulted in the use of a planar GRADIO requirements resulting from the pre-defined mounted at right angles to the satellite's flight mission objectives, there is also the need to direction. The GRADIO in this case consists minimise the overall cost of the programme. of four accelerometers with highly sensitive Since the launch costs represent a measurement axes perpendicular to, and a considarable fraction of the total, a dual less sensitive axis in the direction of, flight. launch on an Ariane-4 vehicle or an APEX This concept allows two of the three diagonal flight on one of the Ariane-5 qualification components of the gravity-gradient tensor to flights is anticipated. be determined. System performance simulations showed a gravity-field anomaly Another important cost element lies in the reconstruction accuracy of better than 5 mgal satellite operations. These costs will be for a mission duration of six months at an minimised by using only one telemetry and altitude of about 200 km . telecommand (TTC) station, namely Kiruna in Sweden, and by sharing this station's The system-performance simulations operation with another ESA polar-orbiting assumed an instrument accuracy of 0.01 EU** 'MTS = Microwave Tracking satellite. for measurement of the diagonal compon­ System ents of the gravity-gradient tensor. The These additional constraints lead to further GRADIO instrument and the satellite design "1 EU = 1 Ebtvbs Unit = 10-9 sec-2 stringent mass/volume, design load! are expected to meet this performance.

20 aristoteles

Overall, the non-drag-free concept was and misalignments, there are additional solar shown to meet the primary mission objective, cells on the Sun-facing side of the satellite to be technically feasible and to comply with body. Field-of-view requirements mean that the imposed cost and schedule constraints. the nc and other antennas have to be The more sophisticated drag-free concept, mounted at the tips of the solar-array wings. on the other hand, would yield a somewhat The satellite electronics are mounted in two improved gravity reconstruction accuracy, but side pods on the spacecraft (Earth and anti­ was judged to involve greater risk, to be Earth faces). more expensive, and to require a consid­ erably longer development period. The non­ The GRADIO accelerometers, the main drag-free concept was therefore chosen as Aristoteles payload instruments, use the baseline for further study. electrostatically suspended proof masses, which are kept motionless with regard to the The constraint of a dual launch imposes an instrument frame by closed-loop control. . injection orbit quite different from the final orbit needed for the gravity mission, and leads to a nine-month pre-operational phase at a high altitude. Parts of the optional missions like magnetic-field and point­ Deployed positioning measurements could be Solar Array Wing performed during this phase. A series of manoeuvres then transfers the satellite into the low-altitude, Sun-synchronous, near Gradiometer Gradiometer Electronics dawn-dusk orbit needed for the six-month gravity-determination mission, during which Solar Array on Spacecraft Body measurements of the Earth's crustal magnetic field could also be performed. After this Flight ~~~~~~H+~~~~~~ ~---~ -----11~~ phase, the satellite's orbit can be re-adjusted I Direction for further point-positioning and magnetic­ Magnetometer field measurements if so desired. 16 Hydrazine Tanks Aristoteles must be kept within an altitude Side Pods carrying Equipment Launcher Interface bandwidth of a few kilometres during the low-orbit phase in order to counteract decay due to aerodynamic drag. This aspect, and the limited contact with the single nc station (about once per day), means that the satellite itself and its operations scenario must be highly reliable, with a considerable degree of autonomy. These accelerometers are a critical element Figure 3. Aristoteles A number of MTS/PRARE ground stations of the mission, and pre-development of an payload configuration, are necessary to determine the spacecraft's accelerometer specifically tailored to showing the GRADIO instrument at the centre of orbit, especially during the gravity mission Aristoteles' needs was therefore initiated in the spacecraft, directed phase, with an accuracy compatible with the 1988. The French company ONERA, perpendicular to the flight requirements for orbit maintenance. These supported by a European industrial team, direction, and the and additional MTS/PRARE stations can be has already manufactured and successfully (optional) magnetometer on a boom at the front. used for the precise a-posteriori orbit tested a complete laboratory model (Fig . 4) . Hydrazine propellant in the determination necessary for the evaluation of symmetrically arranged the GRADIO data and for point positioning. In the data-processing area, two software tanks makes up half of the packages have been prepared in 1988/89 satellite's launch mass The gradiometer is mounted in the centre of that simulate the generation of GRADIO the satellite with its plane perpendicular to output data and their processing for recovery the flight direction. The propellant tanks are of the gravity-gradient tensor. While one of arranged symmetrically to the gradiometer in the packages involves important simplif­ order to reduce the self-gravity effect. ications regarding instrument and satellite characteristics, the other represents a more The spacecraft flys with the two deployable elaborate model that includes the impacts of solar-array wings edge-on to the aero­ moving parts, aerodynamic interactions, and dynamic flow. To reduce the overall area of all stages of the data-processing chain. Both the solar-array wings, and thereby limit software packages are currently being used aerodynamic disturbances from lateral winds for system-sensitivity analyses.

21 G bulletin 60

implications. Operational aspects, especially those related to overall mission analysis, satellite autonomy, and possible tracking systems, will also be further scrutinised.

The pre-development efforts on the GRADIO accelerometers are continuing, with further optimisation of the electrical and mechanical designs, the manufacture of another laboratory model, and additional ground testing. The present industrial team is preparing for the transition towards a possible project consortium for later phases.

Conclusion The present baseline mission concept for Aristoteles will greatly expand our knowledge and understanding of the physical forces affecting our planet's core, mantle and outer crust. The data obtained will benefit all solid­ Figure 4. Laboratory model Future plans Earth disciplines, as well as studies of of the GRADIO The Aristoteles concept described above has environmental problems (including man's accelerometer, and its already been presented to and endorsed by disturbing effect on the sensitive equilibrium proof mass and electrode plates the scientific community on a number of of environmental processes), and satellite occasions. While the mission's preparation navigation. The mission concept that has has advanced significantly during the last been arrived at, and which has the two years, a number of key questions still endorsement of the European scientific need to be addressed before a detailed community, has been shown to be design can be established. Further system­ technically feasible and consistent with the performance evaluations and system trade­ schedule and cost constraints applicable. It offs are required for the primary gravity also allows the accommodation of additional mission. Design alternatives at subsystem mission elements such as magnetic-field and level are being investigated and evaluated point-positioning measurements. with regard to their merits for improved system performance using upgraded data­ Final programme approval for the Aristoteles simulation software. mission is expected in 1990, commensurate with a possible launch in the mid-nineties. During the past year, a number of bilateral discussions have taken place on the Acknowledgement Aristoteles mission, as an optional Agency This article is based on a paper entitled programme, between the ESA Executive and 'Aristoteles - Status of Overall System Member-State Delegations. As a result, Italy Definition and Preparatory Activities of the is willing to take the lead in this programme Programme' by R. Bonnefoy and G. Mecke and to contribute a major share. In addition, (ESTEC) , presented at the 'Italian Workshop important support has already been on the European Solid-Earth Mission indicated from a number of other European Aristoteles', Trevi, Italy, 30- 31 May 1989. countries. The author wishes to thank all those both A final decision on the payload complement within and outside ESA , who have contrib­ to be flown on Aristoteles will be taken in the uted directly or indirectly to this article, and near future, based on more detailed invest­ the groups at Dornier, in Friedrichshafen (D) , igations of the impacts of the optional and ONERA, in Chatillon (F) , for material payloads on the primary mission. Accom­ used in its preparation. ~ modation of a GPS receiver and a magnetometer in the context of a possible ESA/NASA cooperation is one such question that is still to be resolved.

Several launch opportunities in the mid­ nineties, including an APEX flight on an Ariane-5 launch, are being investigated in terms of technical, cost and schedule

22 YlSit to A Fragile World.

The imposing energy generated by tropical topography, and stimulate fresh insights into the storm Xina reflects the complex, yet imperfectly circulation and behavior of ocean currents like El Nifio. understood dynamics of the earth's ecosphere. Earth observation satellite ERS-l, developed Because a startling array of conditions must be met under the aegis of the European Space Agency, will before such a disturbance can fulfill its vital role in provide a powerful new source of oceanographic planetary housekeeping. Everything from relative and weather data to scientists worldwide. condensation in the upper atmosphere to slight Alcatel Espace's contribution: Synthetic aperture temperature fluctuations in ocean currents can radar and a host of other remote-sensing influence its strength and course. technologies based on our experience on numerous To gain a better perspective on such scientific payloads, including SPOT. phenomena, and our common ecology generally, Alcatel Espace is proud to work with ESA, CNES Alcatel Espace is now contributing to two boldly and NASA on such meaningful projects as Topex / innovative new satellite programs due to enter Poseidon and ERS-l. And tomorrow, we hope, on service within the next thirty-six months. CNES's tum-of the-century program "BEST" (Tropical Topex / Poseidon, a joint collaborative venture System Energy Index). Each symbolizes the important between NASA and France's national space benefits to be derived through sustained intemational agency CNES, will use an unprecedentedly cooperative efforts. And each will generate data sophisticated radar altimetry system developed by essential to more sensitive management of our Alcatel Espace to measure sea-surface planet's fragile environment.

ESPACE

11 avenue Dubonnet 92407 Courbevoie Cede x, France Tel. : (3 31 ) 49044710 Fox : (3 31 ) 49044798

23 • bulletin 60

TYPE B

1000 KG 1000 KG

B.5 M 3 B.5 M 3

POWER (CONTINUOUS) 1000 W BOO W

THERMAL CONTROL ACTIVE/PASSI VE PASSIVE

CONTINUOUS ONBOARD PAYLOAD DATA ACQUISITION 1 KBIT/S 45 KBI T/S

ATIITUDE POINTING - DIRECTION TO SUN CELESTIAL - ACCURACY + /- 1° +/- 1° ARCMIN - STABILITY +/- 0.5° +/- 1 AR CMIN/H - RECONSTITUTION + /- 0.5° +/- 5 ARCSEC

ORBIT ALTITUDE/ INCLINATION - 500 KM/2B.5° - 500 KMl28.5°

MICROGRAVITY 5 CONSTRAINT < 10 - G AT 1 HZ NA

IN·ORBIT OPERATIONAL

24 eureca flight operations

Eureca Flight Operations

J. van Casteren & P. Ferri Operations Department, European Space Operations Centre (ESOC), Darmstadt, W. Germany

Introduction Payload The Eureca platform, which will be launched The payload for the first flight can be and retrieved by the NASA Space Shuttle, classified into four main elements: the will stay in space for between si x and nine microgravity core payload, the microgravity months on successive missions. Hydrazine add-on payload, the space-science thrusters will be used for coarse attitude experiments, and the space-technology control and orbit manoeuvres. During experiments. experiment operations, attitude control will be provided by nitrogen thrusters to guarantee The core payload itself consists of five low acceleration disturbance levels. As some facilities, all of wh ich have been developed payloads will generate large amounts of heat, under ESA contract: an active freon cooling system will be used - the Automatic Mono-ellipsoid Mirror to transport this excess energy to space Furnace (AMF) radiators. - the Solution-Growth Facility (SGF) - the Protein-Crystallisation Facility (PCF) - the Multi-Furnace Assembly (MFA) , and The European Retrievable Carrier (Eureca) is a multipurpose, - the Exobiological Radiation Assembly reusable space platform to be launched by the Agency for the first (ERA). time in 1991 . Its prime role is to provide opportunities for conducting experiments at very low gravity levels, namely about These facilities provide in-orbit 'laboratories' one ten-thousandth of that prevailing on Earth. The first mission, in which to process samples of metals, designated Eureca-A1 , will carry the largest ever payload supported solutions, biological tissues, and proteins. by an ESA spacecraft. European scientists from eight ESA Member States will conduct a total of 37 different experiments in the five facil ities during the Flight operations will be conducted from the 1991 flight. Operations Control Centre (OCC) at ESOC, in Darmstadt, where the satellite and ground­ The two micro-gravity add-on instruments: segment monitoring and control system - the High-Precision Thermostat (HPT) , and is being implemented on a dedicated - the Surface-Forces Adhesion Experiment computer, the Eureca Dedicated Computer (SFA) System (EDCS). Special software has been developed to support the new concepts of will also exploit the unique microgravity packet telemetry and telecommanding to be conditions that will be offered by the used with the platform. platform. Each of these instruments is dedicated to one specific experiment. Eureca's flight operations will involve a variety of new and challenging tasks, as the plat­ Since Eureca offers a wide spectrum of form is guided through the deployment, capabilities in terms of payload accom­ operational and retrieval phases of the flight, modation, and the core payload does not ensuring at the same time that the fifteen fully exploit the full resources available instruments that will make up the fi rst pay­ (particularly in terms of mass capability, load operate safely together. The hundreds of electrical power and onboard data storage) , different experiment runs to be conducted several additional instruments can be flown each have various needs and constraints, on the platform. These will include several and must also share the necessarily limited experiments in the space-science field : resources available on-board. - the Solar Spectrum Experiment (SOSP)

25 G bulletin 60

- the Solar Variation Experiment (SOVA) also a consequence of the Shuttle launch - the Occultation Radiometer (ORA) and retrieval. - the Wide-Angle Telescope for Cosmic and Hard X-ray Transients (WATCH) The main mission phases are 'deployment', - the Time-band Capture Cell Experiment 'operation/experimentation', 'dormant' and (TICCE) 'retrieval' (Fig. 2) . After Eureca's launch and deployment by the Shuttle, just three days and in the space-technology field: will be needed to execute a complex series - the Radio-frequency Ionisation Thruster of operations, including system activation, Assembly (RITA) transfer of the platform to its 200 km higher - the Inter-Orbit Communication Experiment operating orbit, and subsystem checkout and (IOC), and commissioning, before committing the - the Advanced Solar Gallium-Arsenide platform to payload operations. Array (ASGA). The nominal operations phase will last Mission profile 180 days, during which all the platform A microgravity mission's success is based on services necessary to support payload the retrieval from space of processed operations, e.g. power, cooling, attitude material samples for complete ground-based control and data handling, will be

Figure 2. The Eureca-A1 mission profile

analysis. There are three options for this: one continuously available. The dormant phase is to retrieve only the samples (e.g. using a will bridge the gap between the nominal end re-entry capsule and parachute descent); a of this experimentation phase and the start of second is to retrieve the entire payload (as in the retrieval phase. Depending on the the case of sounding rockets) . With Eureca, resources available, some payloads may the whole spacecraft will be retrieved, allowing continue to operate during this phase, re-use of the carrier and its facilities for up to although no active cooling will then be four additional missions after servicing. available.

The choice of retrieving the 4 ton spacecraft From the platform-operations and mission­ has two predictable consequences: selection success points of view, the retrieval phase is of a low Earth orbit, for reasons of fuel the most critical of the mission. To increase economy, and use of NASA's Space Shuttle contact between the platform and the for launch and retrieval, this being the most ground, the deployment and retrieval practical 'soft' means currently available for phases will be supported by three ESA bringing a large spacecraft back to Earth . ground stations: Maspalomas on Gran The orbital inclination of 28.5° for Eureca is Canaria, Perth in Western Australia, and

26 eureca flight operations

Kourou in French Guiana. During the satellite Olympus as a data-relay station for experimentation and dormant phases of the telemetry and telecommands. This exper­ mission, operations will be supported only by iment could improve the total visibility time the primary ground station at Maspalomas. between oee and platform to about 200 min per day, while the longest non-coverage Operations concept period remains about 18 h, similar to when Maspalomas has been chosen as the only Maspalomas is used. If the loe primary ground station because of the experiment performs adequately, and relatively favourable pattern of contact on board and ground-segment constraints periods available from there. Figure 3 shows and resources permit, this possibility will that Eureca will pass over Maspalomas for certainly be exploited. five or six consecutive orbits. Between two consecutive sequences of passes, i.e. once The extremely limited periods of visibility per day, the platform will be invisible to the have a dramatic effect on the flight­ ground control system for a period of 16 to operations concept for Eureca. Real-time 18 h (by comparison, use of an equatorial interaction between the oee and the station results in two to three passes during platform, i.e. the sending of telecommands consecutive orbits, with a half-day repetition for immediate execution, will be minimal. cycle) . A so-called 'Master Schedule' will therefore be stored on board the platform containing a Each station pass will last less than 10 min, list of time-tagged telecommands, each of and passes within the same pass sequence which will be executed at a specified time to will be approximately 90 min apart. Overall, perform the requisite payload and platform the platform will only be visible from the operations. The oee will prepare and uplink ground for about 3% of the mission's up to 1000 telecommands for entry into the duration. In the event of a malfunctioning of Master Schedule on a daily basis. the primary ground station in Maspalomas, a back-up station will be available in Perth, Scientific and housekeeping telemetry will Western Australia. also be stored onboard and transmitted to ground at high data rates during the short The loe experiment onboard Eureca can contact periods. Figure 3. Eureca's ground use ESA's geostationary communications track and station coverage

~.Or------~----~----~----~----~----~----~----~--~

NOTE: DASHESlINTERVALS CORRESPOND TO 1 MINUTE EACH -~.0+-~--~----~--~----~-----+--+--+----~--~~----~----4-----4---~ -180.0 -150.0 -120.0 -~.O -~.O -30.0 0.0 30.0 ~.O ~.O 120.0 150.0 180.0

27 • bulletin 60

Each individual operation, such as the All of Eureca's microgravity-payload activation of an instrument or the changing of operations will be supported by the its operating mode, will be conducted in two Microgravity Users Support Centre (MUSC), parts, by two different persons. The Mission being set up near Cologne in West Germany. Planner will first prepare the sequence of Scientists conducting experiments using any telecommands needed to execute the of the platform's microgravity facilities will use operation off-line, checking that it does not this Centre to plan and to test their exper­ conflict with the overall platform resources iments, send telecommand requests, and budget, and specifying the precise times at receive and analyse their scientific data. which the commands must be executed. The Spacecraft Controller will then uplink this Mission planning telecommand file, selecting the appropriate During the so-called 'experimentation phase', telemetry transfer from the ground station , a continuous 1000 W electrical supply will be and supervising the EDCS operations. available to the payload. However, if all fifteen Eureca experiments were to be activated The experiment representatives will be able simultaneously, the power needed would be to communicate with the OCC via the public well over 2000 W. An appropriate experiment data switching networks, using commercially operating schedule has therefore to be available software (Fig . 4) . This channel of established to resolve this conflict, while still communication will be used both for sending meeting the scientific objectives of the requests for execution or modification of individual experiments. Figure 4. Ground segment for the routine phase of payload operations (command requests) , and Eureca-A1 mission for the reception of such data as telemetry Apart from these electrical limitations, other operations and orbit and attitude information. significant on board constraints to be managed are cooling capacity, application programs usage and the average rate of data generation. The latter is limited by the platform's on board data-storage capacity and the availability of ground station passes to downlink stored telemetry data. The infreq­ uent data up- and down-linking possibilities will also affect minimum experiment turn­ around times in those cases where analysis of data from one experiment is needed prior to the initiation of another.

A baseline mission plan for all payload operations will therefore be established and approved prior to launch. The aim will be to utilise well over 90% of the available power, since the 180 d mission duration will be extremely tight for satisfying all experiment requirements. Changes to the mission plan will, however, still be possible during the flight itself.

To assist with the mission planning, Eureca's computer system has a specially designed 'Mission Planning Aid'. This will be used prior to the mission to develop the baseline payload-operations plan. During the mission , in addition to its role for mission plan maintenance, it will be used to plan the detailed operation sequences for quasi­ automatic telecommand generation.

OECNET IFTAM ,DECNET IFTAM OECNET IFTAM Telecommanding MUSC USER USER The nominal payload operations will be USERS 2 N conducted by translating the pre-mission­ defined plan into sequences of time-tagged telecommands. The complete sequence will be directed to the Master Schedule of

28 eureca flight operations

Any 'exception telemetry packet' that has been stored onboard will be transmitted to the ground station when dumping of the on board memory is initiated at the beginning of each pass. From there, it will be routed to the OCC, together with the real-time telemetry data. When an exception telemetry packet is received at the OCC, the EDCS will generate both an audible and a visible alarm, thereby alerting the spacecraft controller immediately.

The traditional recovery procedures used for geostationary satellites cannot be used in the case of Eureca, because the time available for real -time commanding during a normal station pass will not be sufficient to perform even the simplest failure analysis and recovery procedure. The first step will therefore be to collect as much information on the anomaly as possible, by commanding the platform to generate additional telemetry data (extended telemetry packets) at drastically higher rates than under nominal conditions.

If the quick-look analysis shows that the autonomous onboard recovery actions have not been successful, the spacecraft controller can suspend all subsequent pre-planned required accuracy limits (based on the Figure 7. Solar panel of the autonomous command activities, by measurements of the on board optical Eureca carrier under test commanding the platform in real time into a sensors) is a substantial challenge for the at ESTEC standard safe configuration, to await further ESOC ground segment. The daily nature of recovery actions during subsequent passes. the orbit-determination and prediction The Flight Control Team can then analyse the calculations, and the criticality of the failure flagged in the telemetry data, prepare uplinking of the orbital model parameters, commands for failure recovery, and re-plan call for a departure from the traditional future operations during the period when approach of offline flight-dynamics Eureca is out of contact with the ground computing. In Eureca's case, close and station. frequent interaction between the flight­ dynamics computer and the real-time Orbit determination and prediction operations computer (EDCS) becomes Another important new aspect of the Eureca necessary. Most of the routine tasks like orbit flight operations, also stemming from the low determination, orbit prediction and orbital orbit chosen for the mission, is the need for model parameter generation are executed more accurate orbit determination and automatically when the tracking data from prediction. Spacecraft in low Earth orbits are the last pass of the daily pass sequence in fact subject to high and highly variable have been received. The daily frequency and perturbing forces (primarily aerodynamic), the time-criticality of these tasks also affect which reduce the precision of orbit the reliability requirements on the flight­ predictions. Furthermore, the short duration dynamics computer system, which has to of the ground contacts makes the prediction guarantee both a low probability of, and fast accuracy of the pass-start and pass-end recovery from, failure. times extremely critical : a few seconds become very significant in the context of a Retrieval pass lasting only a few minutes. The initial manoeuvring activities will begin approximately one month before the The need for daily updating of the precise actual retrieval, due to fuel-economy orbital data to be transmitted to the on board considerations. To avoid the need for an orbital-modelling software used by ~ureca's active orbital-plane correction manoeuvre to Attitude and Orbit Control Subsystem (AOCS) make Eureca's orbital plane coincide with to maintain the platform's attitude within the that of the Space Shuttle at time of retrieval,

31 • bulletin 60

a passive method has been selected which The challenges of the mission stem from the involves manoeuvring the platform to an complications of: the low Earth orbit; the orbital altitude where the rate of orbital limited periods of direct contact with the precession aligns its orbit at the right platform via the ground station(s); the large moment with that of the Shuttle. number of experiments being carried; the deployment and retrieval by NASA's Space In order to be retrieved by the Space Shuttle, Shuttle; the degree of platform autonomy Eureca is obliged to manoeuvre itself into a required; and the implementation of the strictly bounded 'control box' on an orbit packet telemetry and telecommand concept about 200 km below its normal operating for the first time. altitude. This retrieval phase proper will last 72 h, starting with NASA's authorisation for The wealth of relevant operational experience the Shuttle to 'go for descent', and that will be gained in the preparation and terminating with the berthing and securing of execution of the Eureca platform's flight the Eureca platform in the Shuttle's cargo operations will undoubtedly be of substantial bay using the craft's Remote Manipulator benefit to the Agency in the context of its System. Although three operational ground future Columbus operations, as part of the stations will be in use during this critical International Space-Station (Freedom) phase, there will still be substantial waiting project. G time for tracking and command uplinking opportu nities.

NASA plans require that future Shuttle retrievals will have to be accomplished within 48 h rather than 72 h, calling for a further increase in Eureca's onboard autonomy. Significant improvements are promised in the future with the availability of a Global Positioning System (G PS), which will provide the on board AOCS with accurate positional information at any point in the orbit. The use of data-relay satellites to increase communications coverage will also help to accelerate retrieval operations.

Conclusions The most important new aspects of the Eureca-A1 mission and the novel supporting flight-control concept have been described.

Related Articles

The Eureca Design Concept, by W. Nellessen ESA Bulletin No. 47, August 1986

The Eureca Concept and its Importance in Preparing for the Columbus Programme, by R.D. Andresen & W. Nellessen ESA Bulletin No. 52, November 1987

New Ground Data Processing System to Support the Agency's Future Satellite Missions, by K. Debatin ESA Bulletin No. 53, February 1988

A New Generation of Spacecraft Control System - SCOS, by C. Mazza & J.F. Kaufeler ESA Bulletin No. 56, November 1988

Precise Orbit Determination at ESOC, by J. Dow et al. ESA Bulletin No. 50, May 1987

32 SIEMENS

ONE MORE ACHIEVEMENT OF SIEMENS TELECOMUNICAZIONI IN SPACE PROGRAMMES 1st ON BOARD PARAMETRIC AMPLIFIER On January 17th, 1976 a parametric amplifier 1976 was flown for the first time on board a telecom­ munications satellite (CTS - HERMES). So far Siemens Telecomunicazioni paramps have cu- mulated a total of 1.3 million operating hours without failure (CTS, OTS 2, ANIK S, ECS 1, ECS 2, ECS 4, ECS 5, TELECOM 1A, TELECOM 1 S, TELECOM 1C).

1st ON BOARD 147 Mb/s BURST MODE QPSK COHERENT DEMODULATOR* 1990 Planned for launch in mid-1990, ITALSAT will be the first regenerative telecommunications satellite. Its 9 demodulators, developed and "manufactured by Siemens Telecomunicazioni, represent a further step towards exploitation of Satellite Telecommunications. Siemens Telecomunicazioni (formerly GTE Telecomunicazioni) have given important contributions to many space programs for more than 15 years, leading to a total backlog of more than 20 satellites. Presently we are involved in: DFS, TELE-X, OLYMPUS, ITALSAT, EUTELSAT 11.

Siemens Telecomunicazioni Headquarters and Marketing 20093 Cologno Monzese (Milano) V.le Europa, 46 - Italy ·Work under SES contract for ASI. Tel. (02) 25131 - Telex 330346 - Telefax (02) 2536135 ~ bulletin 60

Flight Opportunities for Small Payloads

J. Feustel-Buechl Director, Space Transportation Systems, ESA, Paris

H.A. Pfeffer Future Launcher Office, Directorate of Space Transportation Systems, ESA, Paris

Organisation of the Workshop - microsatellites and micropayloads; The Frascati Workshop responded to a real - small satellites and technologies; need for an exchange of views in Europe on - recoverable systems and payloads; the subject of flight opportunities for small payloads, as was evidenced by the large - existing and planned launch services and number of requests received for participation. opportunities. They came mainly from the space industry (payload and satellite manufacturers, Thirty-three short presentations were made, and the Workshop concluded with a discussion and synthesis session. The A first Workshop was organised by the Agency earlier this year, at corresponding papers are included in the ESRIN in Frascati (Italy), on the topic of 'Flight Opportunities for Proceedings, together with a number of Small Payloads'. The Proceedings of the meeting have already been written contributions that, although relevant, published (as ESA Special Publicatibn SP-298*). This article is could not be presented due to lack of time. intended to bring the main results of the dialogue that took place to the attention of the wider scientific/technological community. Outcome of the Workshop • Available from ESA At the Concluding Session, the Session Publications Division. suppliers of launch services, etc.} and, to a Chairmen presented a synthesis of the lesser extent, from the user community presentations and of the comments made; (scientists from various disciplines, this was followed by a general discussion universities, and payload-development involving all participants. The outcome of this institutes). As the number of participants that discussion can be summarised as follows: could be accommodated at ESRIN was strictly limited, the Agency had the difficult User requirements task of making a selection. Nevertheless, 150 User requirements exist, but they are still of a delegates (listed in the Proceedings) were preliminary nature. They need to be better ultimately able to attend, representing about defined and grouped by type of mission 90 space research institutes and industrial and/or sectors of activity. 'Genuine users' concerns. were not sufficiently well represented at this first Workshop; further user-specific ESA's management was strongly represented workshops would be advisable. at the Workshop, with the Agency's Director General, Prof. Reimar LOst, its Directors of ESA has subsequently organised an the Scientific Programme, Prof. Roger Bonnet, 'Information and discussion meeting on flight of the Earth Observation and Microgravity opportunities for small experiments in the Programme, Or. Philip Goldsmith , of Space domains of Space Science and Earth Transportation Systems, Mr Jbrg Feustel­ Observation' at its Paris Headquarters (25 to BOechl , and the Agency's Inspector General, 27 September 1989). Prof. Massimo Trella, all present. Microsatellites The Workshop Programme was divided into Microsatellites and micropayloads have five main sessions: masses of up to 50 kg . They have been - user requirements for small orbiting found to be of major interest for basic payloads; scientific investigations, for technological

34 small payloads

Opening comments by ESA's Director General, Prof. Reimar Liist

When the European Space Research Organisation more and more difficult to implement small (ESRO) began its scientific satellite activities in the projects. early 1960s, the satellites being built weighed between 80 and 300 kg (ESRO-1, ESRO-2, HEOS, It is for this reason that I have asked that this etc.). These were what we would term small Workshop on Flight Opportunities for Small spacecraft by today's standards. However, at that Payloads, the first of its kind, be organised by ESA. time they seemed large to us, and we were proud I believe its timing is opportune because the of these spacecraft as they demonstrated that accident to the US Space Shuttle in January 1986 European scientists, industry and inter­ brought all small-payloads activities that were governmental organisations could indeed work routinely being implemented on the Shuttle to a together and achieve results beyond the reach of dramatic halt. We are happy that in the meantime individual entities working alone. the Shuttle has successfully returned to operational status, but the policies now implemented have led Since these exciting beginnings, Europe's space to a significant reduction in flight opportunities for activities have steadily increased, as witnessed by small payloads. This sequence of events has, on the growth of ESRO and its transformation into the other hand, stimulated the user community into ESA. We have completed several more scientific searching for other opportunities and has fostered satellites, designed applications satellites for the development of alternative launch solutions. communications and meteorology, produced the Ariane launcher family, built the reusable space In particular, I believe that our own large space laboratory Spacelab, as well as undertaking many transportation systems (Ariane-4 and, later, other programmes. Ariane-5) should allow for the possibility of carrying auxiliary payloads, albeit without inconveniencing The ESA Council, at its Meeting at Ministerial Level the main passenger and without causing undue in The Hague, in November 1987, endorsed a complications for the auxiliary passenger. The further growth of ESA's programmes and ambitions: solving of this problem calls for creative and we now serve to consolidate the presence of imaginative solutions. One such effort I would like Europe in all major fields of space activities, and to highlight here is that by Arianespace and ESA to we are aiming at achieving European autonomy in develop the Ariane Structure for Auxiliary manned space flight. Passengers (ASAP) and the Ariane Technology Experiment Platform (ARTEP), which will soon allow Single payloads of up to 20 tons in low Earth orbit a series of small payloads to be flown. These are no longer cause for surprise, and one might be activities are represented in the Workshop tempted to believe that a satellite weighing in at programme. less than 500 kg is too small to be worthy of our attention . However, we must never lose sight of the However, it is likely that not all user wishes can be fact that large space projects are only possible satisfied in an optimal manner using the means thanks to the experience accumulated from many presently available. This Workshop is therefore also much smaller projects, carned out by enthusiastic intended to allow all participants to state their young students and experienced space scientists needs, and those having solutions to present them . alike. Indeed, the short response time possible in It will be our task to take the needs and ideas small space projects allows the testing of new presented into account and define what additional ideas, the opening of promising new areas of developments should be undertaken. research , and the education and training of our next generation of space engineers and scientists, I am confident that, by this means, an already without which our ambitious plans would not be coherent European space programme can be achievable. further improved so as to cover the whole spectrum of space activities, from the multitude of In addition, what we today perceive as small still small and creative projects up to the large space appears large to those just entering the field. I can infrastructure that will allow Europe to take its place therefore well understand the occasional frustration amongst the major space powers. I have seen growing in recent years in the space community based on the impression that, while the I invite you all to make your wishes and also your larger multinational projects appear to attract most criticisms known, and thereby contribute to a of the public funding and attention, it is becoming successful Workshop.

35 (9 bulletin 60

Figure 1. The 'Ariane activities, and for educational purposes. Structure for Auxiliary Typical examples can be found in the papers Payloads', ASAP. The presented by speakers from Amsat and the interfaces allowing the attachment of up to four Universities of Berlin, Bremen and Surrey. microsatellites are clearly The development cost of microsatellites, said, visible. The ASAP is 4m in in most cases, to be less than $US 1 million, diameter should provide an incentive for other organisations to adopt this type of carrier.

Microsatellites can be developed relatively quickly and should benefit from regular inexpensive flight opportunities. With this in Figure 2. Implementation mind, Arianespace and ESA presented two of the ASAP platform inside the Ariane fairing complementary concepts: the Ariane Structure for Auxiliary Payloads (ASAP) and the Ariane Technology Experiment Platform (ARTEP). Thanks to these launch structures, up to three flight opportunities per year for several experiments or microsatellites can be offered on Ariane under particularly attractive financial conditions. These concepts are shown in Figures 1, 2 and 3. Ariane Fairing Users recommended that the ASAP and ARTEP facilities should be accessible at the Ariane Main lowest possible cost and should offer Payload (SPOT) sufficient flexibility for late changes. It was also suggested that they should be offered free of charge to Universities when the payloads to be flown serve an educational purpose. Microsatellite Minisatellites With masses varying between 150 and ASAP 600 kg, there does not, at present, appear to be a systematic solution that would allow inexpensive, minisatellite launches at sufficiently regular intervals. The availability of a dedicated small launcher (such as the Amroc, Conestoga, Littleo, Pegasus and Figure 3. The 'Ariane Scout 2, presented at the Workshop) would Technology Experiment Platform', ARTEP, can be be a good solution from the technical point used whenever dual of view. Studies have also begun on the satellite launches are means of using the incremental payload carried out by Ariane capabilities of Ariane-4 to accommodate such satellites. A typical example is shown in Figure 4.

Recoverable satellites Recoverable satellites are considered Cl.~~;:- +--, ARTEP essential to enable progress to be made in microgravity research pending the availability of larger platforms. They might also continue to be used even when the future in-orbit infrastructure is operational. By their very nature, recoverable satellites cannot be considered 'small', and designs with masses of between 600 and 2000 kg were ARTEP presented. Further studies are required to Platform after identify the most promising solutions, i.e. release those that can be available sufficiently early to be of relevance for the scientific

36 small payloads

Long Fairing

AOCS-COMP ACOE IRES-E

Figure 4. A possibility for accommodating a Figure 5. The 'Raumkurier', a proposed recoverable satellite (diameter, minisatellite 'Ministar' on an Ariane-4 approx.2m) community. Typical concepts are shown in Figures 5, 6 and 7. Standard Interface Main Engine

Launch opportun ities

A high-inclination, low Earth orbit (LEO) is Cold Gas System the most desirable one for both micro- and minisatellites. Such an orbit is not, however, HydrazIOe Tank often provided by Ariane. The only solution at present appears to be to use a dedicated launcher. ElectroniCs Batteries Whilst users have the resources to cover the recurrent costs of their mission, they do not have the funding needed for front-end development for specific carriers or systems, which should therefore be provided by the national or international agencies. Solar Array A4 550 lm AS GTO

The development of small payloads is of real Figure 6. The 'Ariane Capsule', a proposed recoverable satellite, and its possible interest only if the total duration of such a accommodation on an Ariane-4 and an Ariane-5 programme, from inception until the first results are obtained, is less than three years. Users then require frequent launch or flight opportunities at an affordable cost (say, not more than 50% of the cost of the payload) and with simplified launch procedures.

Several plans and concepts for small launchers were presented. Of these, the US privately developed and air-launched Pegasus is closest to a first flight. Since the Workshop, Arianespace has announced its interest in marketing this launch service in Europe. Small-launcher proposals being elaborated in Europe are the Littleo and Scout 2, shown in Figures 8 and 9, respectively.

Recommendations The above findings were summed up by ESA in the form of five specific recommendations: - User requ irements should be better Figure 7. The 'Carina', a proposed recoverable capsule (diameter approx. 1.3m) defined in order to ensure that and its possible accommodation on a small launcher

37 G bulletin 60

Figure 8. The proposed 'Littleo' small launcher Dimensions Payload Envelope

Overall height 2lm Cylinder diameter 1.Sm All-up launch weight 67t Cylinder height 1.lSm Cone height 1.0m

Figure 9. The proposed 'Scout 2' small launcher, which could be derived from the normal Scout vehicle Scout Scout 2

--- PAYLOAD CAPABILITY (kg) SAN MARCO WALLOPS VANDENBERC SAN MARCO •WALLOPS VANDENBERC CIRCULAR ORBIT ALTITUDE 27B km 257 241 196 525 495 415 555 km 218 205 165 451 426 555 1110 km 155 145 114 551 512 254

consolidated solutions can be found. developed. In order to provide European - The use of microsatellite support users with a maximum of launch structures such as ASAP and ARTEP opportunities, the market should be should be encouraged. Only in this way opened to all potential launch service can they offer a mature and readily suppliers. Such suppliers were therefore available flight opportunity with the invited to inform the Agency of the status required flexibility and accessibility and at of their programmes. an economical price. - Whilst there is obviously a need for In summary, the great interest shown in the minisatellites, there is, at present, no Workshop, the large number who wanted to obvious solution to the launch problem. attend , and the relevance of the comments Both users and industry are therefore made, all confirm that there is indeed a encouraged to look into possible serious demand for the fl ight of small solutions. payloads and that a considerable effort must - There is a definite, and urgent, need for a be made to provide such flight opportunities. recoverable satellite, but it would appear ESA has a leading role to play in promoting that Europe has room for only one activities in this field ; it has, in fact, already design. Further consultation between awarded study contracts on this subject and users, national agencies and ESA is has commenced further studies immediately necessary if a suitable solution - from both after the Workshop. ~ the points of view of both early availability and affordability - is to be found. - There is a distinct growth in the number of small launch vehicles being planned or

38 fuel-cell testing

Testing of Space Fuel Cells at ESTEC

M. Schautz & G. Dudley Energy Storage Section, Electrical Systems Department, ESTEC, Noordwijk, The Netherlands

Introduction requires high power levels (about 4 kW) for One may ask 'Why do we need fuel cells intermediate time periods (1 -2 weeks) , during when conventional batteries have fulfilled all much of which the deployment of solar ESA spacecraft energy storage needs so panels would be impracticable. To satisfy this far? '. To answer this, one has to look at the power demand in an application where mass particular needs of the different classes of is particularly critical, a hydrogen-oxygen fuel space applications. cell is by far the most attractive solution. It also has the advantage of producing a Orbital spacecraft rely on rechargeable (i.e. valuable byproduct, water, which can be 'secondary') batteries to supply electrical exploited by the crew. Fuel cells have been power during periods of eclipse or peak used on all manned American space power demand. For the remainder of the missions since the Gemini Programme. time, energy is provided directly by the solar In the more distant future, fuel ceJls may also be attractive as part of the energy-storage Fuel cells are expected to play an important role in ESA's future system of large manned orbital platforms. In manned space programmes, starting with the Hermes spaceplane. this application, the hydrogen and oxygen Although very similar to conventional batteries in principle, in used by the fuel cell during periods of practice fuel cells are much more complicated, requiring such eclipse would be regenerated by electrolysis ancillary devices as pumps and heat exchangers for their operation. of the water produced during periods of In order to be able to evaluate and eventually space-quality fuel-cell sunlight using power from the solar arrays. hardware, a Fuel-Cell Test Facility (FCTF) has been built at ESTEC Such 'regenerative fuel-cell systems' are as an annex to the existing European Space-Battery Test Centre currently under study. Compared with other (ESBTC), and is due to become operational in early 1990. power systems, they offer not only the bonus The technology and types of tests required are discussed here and of integration into the crew's environment and an outline is given of the planned design for the FCTF and its life-support system , but also the possibility of capabilities. supplying hydrogen + oxygen propellant for thruster motors.

arrays, both to power the spacecraft's What is a fuel cell? payload and to recharge its batteries, for A fuel cell , like a primary battery, is an periods of between 2 and 15 years electrochemical device in which the energy depending on the mission requirements. The of a chemical reaction is converted directly vast majority of past and present ESA into electricity. The only difference is that in a spacecraft operate in this way. battery the reactants are totally contained with in each individual cell , whereas in a fuel Launchers, such as the Ariane series, need cell they (in our case hydrogen as fuel and electrical power only for relatively short oxygen as oxidant) are stored outside the periods (tens of minutes). Consequently, 'reactor' and fed to it as and when required. they have relied on non-rechargeable Unlike a battery, a fuel cell has non-consum­ (i.e. 'primary') batteries, such as silver-zinc able and inert electrodes, which act as cejls, which can provide several times as reaction site and catalyst. Just as a battery is much stored energy per unit mass as made up of a number of cells linked rechargeable batteries during a single together, so in a fuel -cell system a number of discharge. individual fuel cells are connected in series. Unfortunately, the resulting unit is still usually Hermes, the European spaceplane, is referred to as a 'fuel cell' rather than a 'fuel­ different from both of the above in that it battery', which would be more logical.

39 • bulletin 60

The theoretical gravimetric energy density separate electrodes. Hydrogen is oxidised on obtainable from a battery or fuel cell is the anode (-), whilst oxygen is reduced on proportional to the free energy of the the cathode (+). To provide electrical power chemical reaction ('couple') that is exploited, to the consumer (load), electrons have to divided by the total mass of the reactants. In move through the external connections and practice, this is much reduced by the mass the same amount of charge in the form of of necessary 'inactive' components (casing, ions has to move through the electrolyte connectors, etc). Of the possible reactions (potassium hydroxide dissolved in water) to that can be harnessed electrochemically, that allow the energy conversion on the between hydrogen and oxygen offers one of electrodes. At the reaction sites on the the highest theoretical energy densities. anode, water is formed, which must Since both reactants are gases under normal subsequently be removed from the system . conditions, it is necessary in the interests of compactness to store them cryogenically as Fuel cells in practice liquids. Clearly, then, a fuel-cell configuration We have discussed how similar batteries and is required. fuel cells are in principle. In practice, however, there are major differences. There are five major classes of hydrogen­ Whereas the thermal control for a battery oxygen fuel-cell technology, each can usually be passive, that of the fuel-cell characterised by the use of a different system requires coolant circulation pumps electrolyte and operation in a different and heat exchangers. Two alternative temperature range: electrolyte and thermal-management schemes may be used. In the 'mobile­ Electrolyte Operating temperature (0C) electrolyte' fuel cell, the electrolyte is also used as the heat-transfer medium and is Aqueous alkaline electrolyte ambient to 120 pumped through the cells and heat Proton exchange membranes 60 to 120 exchanger. In the 'immobile-electrolyte' fuel Acidic electrolyte 100 to 300 cell , the electrolyte solution is immobilised in Molten salts 300 to 800 a matrix such as asbestos, and water (or Solid oxides 600 to 1000 another coolant liquid) is pumped through the cell stack and heat exchanger.

Some fuel-cell plants that have to operate in H2 (absorbed) a completely closed environment, like those for submarines or spacecraft, need devices l ANODE to separate liquids and gases. This is particularly difficult in zero-gravity, where one cannot rely on differences in density for fluid separation. Instead, special 'membrane separators' or 'mechanical cyclones' are needed.

A battery is usually a very simple device with no moving parts, whereas a fuel-cell system is more like a small chemical plant and CATHODE • t therefore requires a sophisticated control ---... 1202 system. When one adds to this the stringent reliability and safety requirements of manned space missions, the chemical-engineering aspects of the system become critically Figure 1. Electro-chemical Only the first two of these have been used important. reaction in an alkaline so far in space programmes. Since the first hydrogen-oxygen fuel cell type is the baseline for Hermes, only fuel In order to test the electro-chemistry of a cells of this class will be considered further in practical fuel cell , all the peripheral this article. components needed to manage the various fluids must be provided. A fuel-cell test When fuel cells with an alkaline electrolyte bench is therefore very much more and hydrogen and oxygen as reactants are complicated than one used to test batteries. used, the reactions shown in Figure 1 The available area in the existing European (somewhat simplified) take place. The Space Battery Test Centre (ESBTC) at ESTEC electrochemical process is based on is insufficient to accommodate fuel -cell tests simultaneous oxidation and reduction on and this, together with the safety concerns

40 fuel-cell testing

about the use of large quantities of hydrogen disturbing the tests. All gases, as well as and oxygen on site, led to a decision towards closed-loop cooling water, are routed to the the end of 1986 to build a dedicated Fuel­ test benches through underfloor channels. Cell Test Facility as an annex to the ESBTC, some distance from the main complex. Types of fuel cell to be tested Development of the fuel-cell power plant for the Hermes spaceplane calls for the The Fuel-Cell Test Facility (FCTF) evaluation of a number of different types and Figure 2 shows the layout of the FCTF sizes of fuel cells, ranging from single cells building, which was completed in May this rated at about 100 W, to complete modules year. Much attention has been paid to the delivering up to 10 kW of electrical power potential hazards of working with large (Fig. 3) : quantities of hydrogen and oxygen. - single cells (1 anode, 1 cathode) in frames

Figure 2_ Layout of the FCTF building GAS STORAGE ARE A

OXYGE N

00000

STORAGE AREA

D PLANT ROOM TEST BENCHES CONTROL ROOM & ~ I' AIR LOCK AIR CONDITIONING D D TEST LABORATORY

1-----i======~--~. ~======~ . ~ ~ .~j 1~'------27M ------~

The control room is separated from the test - small cell stacks: up to 1 kW of electrical laboratory by a strong wall. The gas storage output area is outside the facility and the hydrogen - large cell stacks: more than 1 kW of and oxygen lines coming into the test room electrical output would be shut off automatically in the event - complete modules including peripheral of fire, mains failure, excessive gas flow in the equipment. li nes, or abnormal pressures. In the event of hydrogen leakage within the laboratory, gas This wide range cannot be covered with one detectors near the ceiling would trigger the size of test bench and therefore two small operation of emergency (explosion-proof) benches (100 W to 1 kW) and one large one extraction fans in the roof and shut off the (1 kW to 10 kW) are to be installed initially. hydrogen and oxygen supplies as soon as The small benches will be capable of testing any detector registers a concentration greater two fuel cells of similar type simultaneously. than 10% of the lower explosive limit (LEL) in air. At 20% LEL, all mains power would be There is sufficient space to implement a turned off and emergency (explosion-proof) further large test bench in the laboratory at a lighting activated. All critical detectors are fed later date. The necessary ventilation and gas by an uninterruptable power supply. and cooling-water supplies are already provided. This location may eventually be Hydrogen and oxygen as reactants, and used for testing regenerative fuel -cell nitrogen (for flushing purposes during test systems. In principle, all types of low­ shutdown and emergencies), are to be temperature hydrogen-oxygen fuel cells can stored in 16-cylinder pallets outside the be tested. laboratory. Each gas-storage system consists of two sets of pallets, with an automatic Both immobile and mobile KOH fuel cells switchover between them. This will allow have been evaluated for the Hermes empty pallets to be replaced without Programme. Although in the one case water

41 • bulletin 60

Figure 3. Laboratory-scale fuel-cell stacks from Elenco (left) and Siemens (right)

and in the other KOH electrolyte is pumped The fuel-cell coolant may be the electrolyte, through fuel-cell stack and heat exchanger, KOH (as shown in the diagram), or water the design of the test benches allows testing (in the case of immobile-electrolyte systems). of both types of fuel cells without changing The coolant circuit consists of a tank equip­ equipment. ped with a heater for start-up purposes, a pump with controllable flow rate and, in the In the future, fuel cells with proton-exchange case of the large test bench, a heat membranes may become important for exchanger (KOH-cooler) with variable bypass space projects. The test-bench design valve. The gas-space in the tank is filled and therefore allows for their testing also. flushed with nitrogen maintained at the fuel­ cell operating or 'reference' pressure. Test benches Each test bench is enclosed by a steel frame The pressures of the hydrogen and oxygen (3 m x 1.2 m in plan , and 3 m high) clad reactants with respect to the reference with removable transparent plastic panels. A pressure are generally quite critical , so fume-extraction hood provides continuous pressure-change controllers are specially low-rate ventilation. High-rate ventilation that designed to maintain the required is switched on automatically if reactant differentials under all normal and, as far as leakage is detected will ensure rapid possible, fault conditions. Reactant gases are evacuation of any potentially hazardous metered to enable fuel -cell efficiency to be gases. Detection of hydrogen in a calculated. On shutdown of the system, concentration of more than 20% LEL, or either planned or automatically as a result of failure of the fume-extraction fan, will result in a fault, the reactant gases are replaced by automatic shutting down of the test. nitrogen. Purge lines are provided at the fuel­ cell outlet side for each reactant. These The main components of a single test bench operate at two rates: an adjustable, slow, rate and the associated fluid interconnections are to provide for elimination of accumulated shown (in simplified form) in Figure 4. At the impurity gases, and a fast rate to allow heart of each bench is the pressure flushing with nitrogen during shutdown. container in which the fuel cell under test can be mounted. This allows tests to be Controllable-flow-rate gas pumps are carried out at pressures of up to 7 bar on provided for fuel cells that require reactant fuel cells not equipped with their own circulation for water removal. Condensing pressure containment. This pressure is heat exchangers in the reactant gas loops usually the same as that of the electrolyte or allow for water-product removal. They are coolant loop, but it can be controlled equipped with level-measuring devices. The independently, for example for testing fuel condensers are preceded by traps that cells that require a higher external pressure collect any electrolyte/coolant that gets into to maintain stack compression. The Hermes the gas streams as a result of fuel-cell leaks. fuel cells will be operated at higher than Such leaks can also lead to the release of ambient pressure because efficiency reactant gases into the pressure container increases with reactant pressure. and, via bubbles in the electrolyte or coolant,

42 fuel-cell testing

--1- -~------1--- ,

I,

I,

I,

I,

I, I

CONTROL AND DATA ACQUISITION SYSTEM ELECTRIC LOAD

into the coolant tank. To prevent possible to be used. One channel will be dedicated to Figure 4. Block diagram of accumulation of explosive gas mixtures in transmitting the status of the FCTF the fuel-cell-stack test unit these vessels, both are continuously purged laboratory's safety system and of the gas with nitrogen and are equipped with storage, so that any faults or impending gas hydrogen and oxygen detectors that shortages can be monitored directly in the automatically cause a test to shut down and ESBTC. an increase in purge rate when any leakage is detected. Just as battery tests are protected by a so­ called 'Battery Protection Unit', designed to The fuel-cell loading will be simulated with an isolate a battery in case of loss of control electronic load capable of operating under from the decentralised test bay, failure of test set current, set resistance or (via a computer hardware or of the battery under test, so fuel ­ feedback loop) set power. For safety reasons cell tests will be protected by 'Fuel-Cell this, together with the fuel-cell circuit-breaker, Protection Units' designed to ensure safe will be situated outside the test bench. automatic shutdown. Since the actions required are much more complicated and Fuel-cell test control may vary depending on the type of fuel cell Although the test equipment in the FCTF will under test, these will be implemented using differ considerably from that in the existing high-reliability, programmable-logic Battery Test Centre, as much existing battery controllers. test control hardware and software as possible will be reused. Routine operations All test-bench controls that need to be will be entrusted to the same contractor team operated during a test (as distinct from (Serco) that has been running the Battery during test set-up) are computer-controlled. Test Centre at ESTEC since 1985. Consequently, it will not be necessary for the laboratory to be manned continuously. Video 'Decentralised' test bays, already developed links with the ESBTC will be provided for and in operation in the ESBTC, will be used remote surveillance. for test control and data logging (based on HP-300 series computers and HP-3852A The FCTF's role for Hermes and other mUlti-programmers). They will be located in future pogrammes the FCTF test room , but will be linked to the Since the main aim of the development effort ESBTC data-processing computer (HP-1000) for Hermes is to produce a weight- and via a fibre-optic link. volume-optimised fuel -cell power plant unit rated at 4 kW, complete with peripheral Test data will be transmitted in the same components, it will be necessary to carry out formats as battery test data, allowing the tests using progressively fewer of the test­ same data-processing and archiving software bench peripherals as the design effort

43 o bulletin 60

matures. Ultimately, the qualification tests manufacturing plant. In the longer term, it is might only require gas supplies, heat expected that the FCTF's flexible design, exchanger, electronic load, water collection wide range of operating conditions, and the and purge connections in addition to a part possibility of carrying out continuous 24 h of the test control system . per day testing should make it attractive for other future ·fuel -cell and electrolyser testing , Test durations will vary from a few hours both for ESA programmes and for external (excluding equipment set-up time) to several customers. months. Short-term tests will be sufficient to establish the primary characteristics of the Acknowledgments cells, such as current/voltage characteristics, The considerable efforts of ESTEC Technical influence of temperature and pressure of Facilities Section staff in the design and operation, and design limitations (maximum realisation of the FCTF building, and the temperature, pressure or flow rate) . Failure valuable contributions of our colleagues in modes can also be simulated. Medium­ the Energy-Storage Section in the duration tests, lasting of the order of one preparation of test-control hardware and week, will be required to demonstrate the software, are gratefully acknowledged. ~

Figure 5. Exterior of the new FCTF

thermal management of stacks and the water-removal properties of electrodes. Long­ term tests (endurance tests) are, however, the most important and will need to be run for about six months. Here, the test control system will allow simulation of any required load profiles. Only these tests can measure the true degradation rates of materials and components (especially electrodes).

In this article, emphasis has been placed throughout on the Hermes spaceplane as the first programme requiring fuel cells and without which the FCTF would not have been built. It is hoped that the new facility will be able to make a substantial contribution to the very large effort that will be needed to achieve a European space-qualified fuel-cell

44 When an earth-observation or telecommunications satellite is placed in orbit, there is no room for uncertainty, error or failure, however small. Crouzet is on hand to meet this fail-safe requirement by offering a comprehensive range of services to space agencies and contractors. For the vital functions of satellites, launchers, interplanetary space probes and orbital infrastructure, Crouzet offers all the services you can expect from a high-calibre partner. In data handling, processing and storage and software engineering for example, Crouzet participates at a very early stage in subsystem conceptual design. For power conditioning systems, we are particularly involved in energy conversion, protection and monitoring. In addition, Crouzet has solid experience of wide-band analog signal processing for effective signal detection, extraction and processing. And we also design tailor-made instruments to meet specific mission requirements. In 25 years, Crouzet has played an active part in 60 space programmes, involving the supply of more than 700 items of equipment. Today, the company is collaborating in all the major programmes of this decade. Crouzet meets the requirements of a demanding world.

Crouzet SA - Division Aerospatial 26027 Valence Cedex - France Tel. 75.79.85.11 - Telex 345807 F Crouzet ® (9 bulletin 60

Computer Simulation of Space Mechanisms

N. Cable Structures and Mechanisms Division, Mechanical Systems Department, ESTEC, Noordwijk, The Netherlands

Mechanisms another. A body in space can move along or From the placing of a filter in an optical about three perpendicular axes, in its beam, to the deployment of a solar array or so-called 'six degrees of freedom' (Fig . 1). communications antenna, mechanisms are A mechanism is a chain of such bodies the means by which pieces of spacecraft linked in a particular way. It is the nature of hardware are moved from one point to the joints between the parts that allow or, just as importantly, restrict these motions that gives mechanisms their distinctive Computers can now be used routinely and inexpensively to characteristics; in fact, they would otherwise generate a model of a working mechanism that emulates the actually be structures. The way in which they mechanical properties of the real thing , even responding to driving move and the paths that they follow depend and resistive forces and torques in a realistic manner. To be able to upon their geometry, and how quickly and observe the behaviour of his machine in action 'on the drawing with what energy upon their mass-properties board ' has long been the designer's dream. This article discusses and their internal and external resistances. current computer technology that makes this feasible, and assesses its impact on the current approach to mechanism design. Man has long observed things in action and tried to understand how they work; so it follows that the traditional approach to mechanism design has been one of making models and seeing how they behave. Being able to feel the model literally put men in touch with the machine. But this method relies upon analysis and interpretation before appropriate modifications can be implemented, and the drawback with the models is that they possess latent properties that are not all known or even evident. Prompted by the apple fall ing on Newton's head, the theory enabling the dynamic )ehaviour of any given configuration to be predicted, albeit laboriously, was worked out +Y and refined three centuries ago, and is still valid for the mechanisms referred to here.

Starting with only a rough idea of what is needed, the designer will often modify an existing design which was made for a 'similar' task, rather than start from scratch. Whilst there is good reason to use exi sting designs where they are close to what is required , some properties may well be undesirable or even intolerable. For space equipment, much effort is expended merely trying to eliminate unwanted properties that should have been avoided from the outset, Figure 1. The six degrees of freedom of a body and costly re-development and re·qualific· in space ation are needed when they come to light

46 computer simulation of space mechanisms

too late. The prerequisite is knowing and form , to which we can relate much better, we describing in sufficient detail the functions can 'play' with the model much as we would and characteristics that are required of the on a test-bench, but with the significant mechanism and , if possible, those that are advantage of being able to extract undesirable. Only by checking against a information on its behaviour at any point detailed description of what is wanted can a without recourse to cumbersome proper assessment of any candidate design instrumentation. be made. Being synthetic, the key feature of a computer model is that all its properties are Computer simulation known. Al'though this imposes the burden of The advent of the computer meant that defining them in the first place, as long as enormous series of calculations could be the code provides correct results, the done rapidly, and more aspects of observed effects are directly attributable t6 mechanism behaviour could be ascertained those properties. We can modify the design more quickly, but this still provided only static almost instantaneously, knowing that the and fragmented insights. To many engineers, effects observed are due to the change the output from earlier computer programs alone - and not, for example, to the was indigestible, arriving in the form of reassembly of the mechanism which can tabulated figures in forbiddingly large stacks result in changes even if nothing has been of paper. Although undoubtedly an advance, deliberately altered. Moreover, the it was a cumbersome means of finding out mechanism model may be run indefinitely what was going on . without wearing out.

Computer programs have been common­ A truly empirical approach is thus possible, place for some time for structrural and with rapid learning and convergence to thermal design, but their needs have not optimal designs. Often the designer has no been as demanding as for mechanisms, and exact data, but from his experience he only recently has the complete process of knows the ranges in which the parameters calculation for mechanisms been coded in will lie. Using the tools of computer unified software. The breakthrough has simulation, he can experiment with the awaited the development of fast processors, different values and determine the sensitivity interactive graphics software and fast high­ of his design to a particular property. The resolution display systems, enabling the speed with which this can be done is of writing of application programs for the enormous value for education, which is a visualisation of mechanisms in operation. most exciting and significant aspect of Now, at last, we can synthesise models from computer modelling. It is also valuable for scratch, and see what they look like and early refinement of requirements, which are what they do, without having to wait months often established with large errors or margins for manufacture, assembly and test. In this to cover uncertainties.

Translational Revolute Cylindrical Universal Joint Joint Joint Joint

Figure 2. Mechanism joint Spherical Planar Rack-and-Pinion representations in ADAMS Joint Joint Joint Joint (Courtesy of TEDAS, W. Germany)

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Finally, the graphical outputs of the programs When all of this is taken into account, it are understandable to non-specialists, there­ becomes clear that only a commercially by assisting the designer in communicating mature package will suffice. To do the job directly outside his realm. properly needs dedication and specialisation beyond that which is justifiable in most 'It always works on paper' manufacturing companies, and suppliers of There will always be a balance between the commercial packages necessarily take on the theoretical and the practical, since ultimately responsibility for this work. Even with these a piece of real equipment has to be made. commercial packages, there are still However, that balance is changing problems, but the suppliers are usually able significantly as the theoretical approach to carry out the necessary refinements on a gains more of the capabilities once only continuing basis in close contact with the available in the practical, enhanced by its user community. own particular advantages. The practical work will in future have to be concentrated Of paramount concern to the user is the on those problems that can only be solved credibility of the results, especially in the by practical means. It is pertinent to mention absence of any alternative means of here that two-thirds of the phenomena that confirmation. Distinguishing between influence the reliability of the mechanism lie mechanism behaviour and problems with the outside the design area, in the activities program may be difficult, especially if the associated with manufacture, assembly, test user does not recognise the characteristics and operation. So the practical engineering displayed. Limitations in numerical integration is not diminished however good the design, are one source of problems, which must be and attention to detail, provision of required overcome by careful selection of the tolerances, correct manufacture, lubrication, integration step size. Experience in use of the assembly, test and operation must all receive software, together with cross-checks by other the appropriate effort. methods, quickly builds up confidence in the model's ability to provide meaningful results.

Software Dynamic modellers While there is nothing magical about doing The typical dynamic modeller will : provide a the necessary calculations, and many people library of joints, such as hinges, spherical, think they can easily write a program for this universal, sliding, rack and pinion, screw and purpose, it is frequently found to be much gear joints; request definition of the parts in more complicated than at first thought. terms of geometry and mass properties; Starting with a simple set of calculations request the nature of the results required, covering a specific need, complexity such as time- and displacement-histories; increases with the attempt to broaden it into automatically formulate and solve the a fully universal code. Besides the equations of motion to give displacements, prerequisite of giving accurate results over velocities and accelerations, and then pass the full range, it is essential that the program the results to a post- processor for formatting be free from errors that could interfere with into graphs; and construct diagrams of the the results, and lead to loss of confidence. incremental positions and show them as an Essential to the usefulness and speed of animation (Figs. 3-6). the technique is visual feedback, so that interfacing with appropriate geometrical For particular non-standard phenomena, modellers is necessary. user-written subroutines can usually be inserted by exploiting the open architecture To ensure that the engineer feels it is worth­ of the software. The use of a common while to use the tool, it must be possible for computer language and of standard data him to communicate easily with the computer structures will ensure that interfacing with code. Ease of describing the mechanism and other useful packages, such as solid­ receiving the results, and understanding what modellers and mesh-generators, is possible. to do to get them, is not just desirable, but a legitimate right on the part of the user. There Currently, one of the industry-leaders in must be clear, comprehensive and detailed mechanism modelling is a software package documentation so that users other than the called 'ADAMS' (Automatic Dynamic Analysis author can obtain meaningful results, and of Mechanical Systems). It originated in good technical support to help solve the response to mechanism-specific needs, and user's problems as they arise. 'User­ hence is formulated in a particularly suitable friendliness' is an apt description of a real fashion for mechanisms work. It is used at need in this context. ESTEC for studies of satellite antenna and

48 computer simulation of space mechanisms

Figure 3. EUCLID solid model of the Spin-and­ Eject Mechanism

4 AXIS OF ROTATION

Figure 4. ADAMS dynamic­ simulation model of the Spin-and-Eject Mechanism

MOVING RING STOPS --PZ:I ~~~::r---r=::::::::==+::====Z

CLUSTER: RADIAL BOOM DEPL - HINGE VELOCITY [R AD/ SEC VS SEC) 4

2

o

- 2

Figure 5. Velocity/time trace from a boom­ deployment Simulation, - 4 showing the distinct 0 2 4 6 B 10 stages of initial motion, Line X Axis Y Axis and oscillations following Type Style Req* Camp Type Reqf Camp Run file first and second hinge TIME 21 ANG3 VEL 1 12 locking

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Figure 6. Sequence from a simulation of a truss boom deployment

Figure 7. EUCLID solid model of the tiermes Robot Arm (HERA)

boom deployment, docking systems, separation and jettisoning activities, and elsewhere for the design and development of automobile steering and suspension systems Yaw f and for aircraft landing-gear.

Many solid- and surface-modelling packages claim to provide mechanism-analysis Pich f modules. Generally speaking, these need to be treated with caution , as the capability is often limited to kinematics, based upon the Yaw 2 geometrical data needed anyway for the representation of the discrete bodies, and possibly time-derivatives of the displacements to give so-called 'dynamic responses '. Pich 2 Without the ability to handle forces and torques, the software cannot show if the assembly will actually work as a machine. For example, the dimensions defined by the user will not necessarily be those of a motor with sufficient torque to overcome the resistances in the system, but the dynamic simulation model will show this (Fig. 7). Pich 3 A deceptively simple but informative example is a ball bouncing on a surface. Only a true

50 computer simulation of space mechanisms

dynamic modeller can represent this Where kinematics alone are required, there is process; the geometric modellers would a wide range of linkage-analysis software show the ball passing straight through the available, both independent from and integral surface. with solid-modelling packages, but this does not give dynamic information. Features Most of the software has been based on Computing environments rigid-body descriptions that are valid for Many people may be concerned that the use many machine parts. For large space of such codes means expensive hardware deployables, however, the structural investment or redundancy of their existing properties of the linked bodies contribute equipment. Generally, however, the packages significantly to the dynamic behaviour from are written in universally used languages that release, through deployment, to the end of can run on a wide range of mainframe travel and thereafter. computers as well as many mini- and micro­ computers. Typically, AOAMS is written in Recent work at ESTEC on incorporating Fortran and uses a Tektronix display format flexibility into dynamic models has provided for basic interactive graphics. The use of a valuable insight into the interaction between three-dimensional graphics workstation

deployables and the spacecraft (Fig. 8). enables instantaneous manipulation of the Figure 8. Simulation used Phenomena like friction and backlash have model and animated sequencing of the to determine optimum also been described in subroutine form for simulation, giving a clear view of the deployment of antennas and reactions on use with dynamic models, while the mechanism in motion. spacecraft characteristics of transmissions such as gears, harmonic and cyclo drives are being With the rapidly improving ratio between studied for formulation into usable modules. price and performance, especially in the field Other items, such as bearings, should join of graphics workstations, the cost­ the list in the future. effectiveness of mechanism simulation is improving all the time. Even on a micro­ One of the Agency's aims is to categorise the computer, without the full advantages of different features and to construct a library of 3-D graphics, useful results can be obtained. models, the exercise itself being used to A company possessing no appropriate check whether this is appropriate or possible, computer can take advantage of the software and as a further opportunity to gain insight by using a computer bureau, or by placing a into fundamental mechanism behaviour as contract with the software supplier. well as the specific techniques of describing the model and presenting the results. In one Engineering implications particular package, by coupling the Justified concern is often expressed about mechanism equations package to a finite­ the credibility of the results obtained from element code, the stresses developed in the software simulations, but with the advances links of a mechanism in motion have been in graphics, much of the doubt can be displayed as colour shadings on the dispelled by seeing the machinery in component surface. operation and examining the perfomance

51 (9 bulletin 60

results taken at points of interest. There is distorted equipment. Mechanism simulation nothing mysterious about the software; it is provides the answer in that the whole test­ just doing the calculations that the designer item and support-rig assembly can be would do, but fast enough to display the simulated, including the effects of gravity, action. As to the rejoinder There's no with the ground-test performance being used substitute for a test!', if not done correctly to generate confidence in the model. tests can lead to a false sense of security, as Removal of the gravity and test-rig influences many additional indeterminate influences from the model would then leave the orbital exist in a test rig which directly affect the situation, which could be tested as many performance of the item under observation, times as necessary to predict system not to mention the effects of gravity. The behaviour over the full range of interest (Fig . 9) .

Since the ultimate need was for items of equipment for building into a spacecraft, it has been commonplace to expect hardware as the end product of research and develop­ ment contracts also. In future, however, dynamic models will be more valid as deliverable items instead of development hardware, especially as initial demonstrations of designs.

Financial implications A common reaction to a computer-based approach is that it is 'so expensive', but in the wider context of global- rather than task­ level considerations, the contrary is usually true. The older, isolated methods whose results must be further treated to arrive at a clear understanding are labour-intensive, and computing costs are diminishing progres­ sively, while labour costs continue to rise. The argument that the tool would only be used from time to time, and hence is not justified, fails to take into account the technique's potential influence over the greater part of the whole design process for all mechanisms, no matter how small.

While the obvious candidates for dynamic simulation are the large deployable appendages like solar arrays, antennas and booms, the development costs of 'simple' on­ board mechanisms show that these too would benefit from its use. Enormous sums can be saved by avoiding costly and lengthy prototype manufacture and test, which may only bring to light those unwanted character­ Figure 9. Deployment logical way forward is a reasoned balance istics. Mechanism simulation should be seen testing of a solar array in a between the old and the new. as an integral part of the overall design-to­ gravity-compensation rig , test process. Since proficiency and effective­ involving many additional mechanisms, and hence a Optimising system design for performance, ness are directly related to practice, the more typical candidate for with mechanisms just strong enough for it is used, the greater will be the benefits. dynamic simulation orbital operation, but not ground conditions, leads to problems of demonstration. The Social implications deployable structures now being planned are Questions are often raised about the social becoming so large that testing on the ground implications of such software, but dynamic will either be impossible, or will at best modelling by computer is only a tool to help produce dubious results due to the reactions the engineer do his job more effectively, not from the rigs needed to support the gravity- to replace him. There has still to be a critical

52 computer simulation of space mechanisms

mind to set up, assess and modify the mechanism, evaluate the results, and know how to alter the parameters to achieve the REQUIREMENTS desired result.

These tools mean that more design activity and improvement of understanding is now IDEAS possible in a shorter time than before, J leading to an overall improvement in quality. Moreover, in its educational role, computer simulation allows invaluable risk-free experimentation, making engineers more CONCEPTS effective more rapidly. It is true that the hardware fabrication and test work should be reduced , but then saving of manpower and materials must be the aim of any DESIGN commercially-minded organisation.

Conclusions MANUFACTURE The time is ripe for pursuing this approach to establish confidence in the software and remove the few remaining problems, so that we can be ready to simulate the behaviour of ASSEMBLY mechanism chains too large and too delicate to be deployed or operated in Earth's gravity, but which cannot be strengthened just for th is purpose as they would then be too heavy for launch. Mechanism simulation is TEST becoming a significant contributor to good design and confidence in the equipment we place in orbit. OPERATION

Acknowledgement I wish to thank P Dobson and P Pearson for advice in the realm of computers and Figure 10. Extent to which software, F. Panin for diagrams of ADAMS dynamic simulation can models and results, J. Pang and affect the whole process of mechanism making H. de Zeeuw for diagrams of EUCLID models and results, and all those who have, in their various ways, stimulated my interest in this subject. ~

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54 esa supports sax mission

ESA Support for the Italian SAX Astronomy Satellite Mission

P. Maldari ESA Directorate of Operations, ESOC, Darmstadt, West Germany

G. Manarini Agenzia Spati ale Italiana (ASI ), Rom e, Italy

L.M. Palenzona ESA Technical Directorate, ESTEC, Noordwijk, The Netherlands

Introduction ::5 5° and an initial altitude of 600 km by an The SAX mission was conceived in the early Atlas Centaur launcher in the last quarter of 1980s to perform a systematic and 1993. The nominal mission lifetime will be comprehensive observation of celestial X- ray two years, with a design goal of four years. sources in the 0.1-200 keV energy range, with particular emphasis on spectral and The main industrial contractors are Aeritalia timing measurements. It is being carried out for space-segment definition, and Telespazio in collaboration with several Italian scientific for the ground segment, under the institutes, the Netherlands Organisation fo r management of AS!. Space Research (SRON) in Utrecht, and ESA Space Science Department's Astrophysics Scientific mission Division. In addition to the satellite itself, a The scientific objectives of the SAX mission ground segment consisting of an Operations are: Control Centre, Ground Station, Scientific - imaging with moderate angular resolution Data Centre and Communications Network is and broad band spectroscopy over the also under development. energy range 0.5-10 keV; continuous cyclotron line spectroscopy The SAX satellite (Fig . 1) will be injected into over the energy range 3- 200 keV; a circular equatorial orbit with an inclination time-variability studies of bright-source energy spectra over time scales ranging from milliseconds to months; In 1979, the Italian Government established a National Space systematic observation of the long-term Programme (PSN) based on a plan that was to be updated every variability of X-ray sources, by means of five years. The Interministerial Committee for Economic Planning periodic surveys of preselected regions of (Cl PE) initially entrusted the overall management and administration the sky (minimum intensity equivalent to a of the Programme to the Italian National Research Council (CNR), 1 mCrab source). and later to the Italian Space Agency (ASI) when it was formed in June 1988. To achieve these mission objectives, a scientific payload has been designed wh ich A collaborative link between ESA and PSN , established at the consists of a nest of four X-ray concentrators outset of the Italian space endeavour, also involved a consultancy (C/S), a large-area phoswich detector system agreement whereby ESA would assist PSN (now ASI) with technical (PDS) , a high-pressure gas-sci ntillation and management issues*. One of the projects for which ESA is proportional counter (HP-GSPC) , and two currently providing support is the SAX X-ray astronomy satellite, wide-field X-ray cameras (WFC) developed by designed to make systematic and comprehensive observations of SRON (Fig. 2) . celestial X-ray sources, with special emphasis on spectral and timing measurements. Three of the four concentrators, the Medium­ Energy X-ray Grazing Telescopes (MECS) , will Th is article outlines ESA's contributions to the various SAX mission be sensitive to medium-energy X-rays in the elements, which involve the Agency 's latest standards and range 1-10 keV . The other, the Low-Energy technologies. X-ray Grazing Telescope (LECS), developed by ESA Space Science Department, will be • The overall ESA consultancy to the Italian space programme was described in the sensitive to relatively low-ene rgy X-rays in the August 1989 issue of ESA Bulletin (No. 59, pp. 81-87) . range 0.15- 10 keV.

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Figure 2. The SAX payload layout MEDIUM-ENERGY CONCENTRATORS SOLAR ARRAY (MECS)

PHOSWICH DETECTOR SYSTEM (PDS)

GAS­ OPTICAL BENCH SCINTILLATION PROPORTIONAL WIDE-FIELD COUNTER CAMERAS (WFC) (HP-GSPC) UPPER PLATFORM LOW-ENERGY CONCENTRATOR (LECS)

LAUNCH VEHICLE INTERFACE (SEPARATION PLANE)

SHADE STRUCTURE TOP COVER

LATERAL ENCLOSURE

PAYLOAD MODULE CONCENTRATOR BRACKETS

OPTICAL BENCH

GSPC FLOOR

STRUTS

CONCENTRATOR TUBES

SERVICE MODULE UPPER PLATFORM

STRUTS

SHEAR PANEL

SIDE PANEL

THRUST CONE

LOWER PLATFORM

Figure 3. The three primary modules of the SAX spacecraft

56 esa supports sax mission

The SAX space segment - the On- Board Data-Handling/Data­ In the design of the 1200 kg SAX satellite Management Subsystem (OBDH/DMS), (Fig , 3) , two main modules can be identified: which is based on ESA-standard concepts the Payload Module and the Service and guidelines for spacecraft data­ Module, handling subsystems,

The payload Module, consisting of a stable Three more subsystems, developed by carbon-fibre optical bench , will carry all the Aeritalia, namely the Structure Subsystem scientific instruments and associated control (SS) , the Thermal Control Subsystem (TCS) electronics, The Service Module will house and the Harness Subsystem (HS), complete the subsystems required for the operation of the satellite system design, the satellite and the various scientific instruments, namely: Mission communications and flight operations - the Electrical Power Subsystem (EPS), The interface between the space and ground developed by FIAR, the main function of segments is provided by the RF link between which is to supply the satellite's electronic the satellite and the ground station, All equipment with a constant voltage the satellite data will be packetised in (regulated bus) of 29 V (both in sunlight accordance with the ESA Packet Telemetry and eclipse) ; Standard before transmission to the ground, This will allow a relationship to be established - the Solar-Array Subsystem (SAS) , onboard the spacecraft between the various developed by Fokker, consisting of six data sources and the channels used for data solar panels, designed to generate transmission, thereby allowing priorities to be 1700 W of electrical power at end of life; established from the ground for the processing of data from particular satellite - the Attitude-Control Subsystem (ACS), sources, This feature offers important developed by Fokker/Aeritalia, to provide advantages for the operation of low-orbiting attitude control and stabilisation for the satellites like SAX, which have short-visibility satellite in all three axes; passes over the ground station lasting just 5 to 8 mins and thereby require intensive - the Telemetry, Tracking and Command ground-based operational activities during Subsystem (TTCS) , developed by Selenia the pass, Spazio based on ESA standards, which will provide the necessary interfacing The SAX ground segment between the satellite and the radio­ The baseline communications scenario for frequency (RF) link with the ground, ESA­ the SAX mission is shown in Figure 4, standard packet telemetry will be used ; together with the basic elements of the

INTELSAT RELAY SATELLITE

- SAX MAIN GROUND STATION

• SAX STATION DATA RELAY ~ITALY STATION Figure 4. Overall SAX communications scenario

57 .. bulletin 60

ground segment. They are a Ground Station - spacecraft and ground-segment control; (GS) to be located in the equatorial region - telemetry processing, display and (Kenya for nominal operations, with Kourou archiving; as a back-up), and an Operations Control - command generation and verification; Centre (OCC) and a Science Data Centre - tracking initialisation, processing and orbit (COS) to be sited in Italy. determination.

The SAX Ground Station, equipped with an Conclusion 11 m diameter antenna, will benefit from The scientific objectives of the SAX mission technology developed by ESA in cooperation are unique and as such represent a with European industry, in particular for: challenge for the scientific community - the Telemetry Processing Subsystem, worldwide. With ESA's help, the design of the which will reassemble the telemetry mission elements has based on advanced packets after decommutation, catalogue engineering concepts and state of the art them according to on-board data source, technology. and store them ready for transmission to the OCC; The good collaboration established between - the Tracking Subsystem, which will allow ESA and ASI at all levels during the SAX the satellite's range (distance between project's development will therefore be a ground station and satellite) and the rate substantial benefit in the mission's of change of this range (range rate), to be implementation. Moreover, it will serve to determined. foster further cooperation between the two agencies in the future. G The prime functions of the Operations Control Centre (OCC) include (Fig. 5): - establishment of operational plans and Figure 5. SAX data flow associated observation scheduling;

TEMPORARY STORAGE TO TT&C STATION ~ FROM TT&C STATION .IDUSER . - USER .~~-

ON-LINE FilES SHF: SHORT HISTORY FilE CHF: COMMAND HISTORY FilE RRD : REFORMATTED ROW DATA 1--- FROM COS ATTITUDE ORBIT RANGING STATION •TO COS I ~ , SCIENTIFIC SCIENTIFIC DATA CENTRE DATA CENTRE

58 ecsl

The European Centre for Space Law - A New Branch of Space Studies Opens at European Level

K. Madders Legal Affairs Department, ESA, Paris

ESA's initiative outside communities, describing it as being: In 1988, the Agency's Legal Adviser, 'in the best traditions of the Agency ... for Mr Gabriel Lafferranderie, took the initiative of ESA and its predecessor, the European proposing a European Centre for Space Law Space Research Organisation, ESRO, have a (ECSL) as a means of strengthening Europe's long history of utilising the technical and space-law research profile. This idea elicited intellectual resources at their disposal to a very encouraging response, both from foster space-related communities where only delegates to ESA's International Relations isolated groups existed before'. Moreover, the Advisory Committee (IRAC) and from leading ECSL can, like the Agency itself, 'contribute figures in the space industry, the legal to inter-disciplinary dialogue' among lawyers, profession and the academic sector. As a engineers, economists and scientists. result, the Agency called an exploratory meeting for October 1988. Organisation The proposed Charter, adopted at the May meeting, provides for a General Meeting of For some years now, space activities have been racing forward, Members, and the establishment of a Board. leaving the legal means to govern them effectively far behind. The Centre is, however, only at an early The study of, and research into, space-law issues are also lagging stage of development. It has no juridical beh ind present-day events. While large projects like Hermes and the personality, and detailed rules and Columbus Programme, for example, are posing legal questions on a procedures are thus deliberately avoided at new scale, the complexities of regulating trans-national aspects of present. A more detailed Charter will be telecommunications satellites in Europe still remain to be adopted once the Centre's work is more addressed in a coherent manner. advanced.

ESA/ECSL activities Participants from all over Europe, repres­ ESA has recognised the importance of the enting the areas of both research and ECSL and has been a leading supporter in technology, met and unanimously endorsed its development. The Agency has further the need for a space-law research body. shown this support in two major projects They set up a Preparatory Group to establish laying the ground work for the establishment the basic elements of the ECSL. of an effective framework for research and exchanges of views and information by: The fruits of the Group's labours, including a draft ECSL Charter, were then presented to - Opening up and expanding an existing some 70 interested persons at a meeting internal ESA electronic database dedicated to the inauguration of the Centre, (ESALEX) including ESA/ESRO law and which took place at ESA Headquarters in Europe-wide space-law bibliographical Paris on 12 May 1989. The ECSL.:s operations references. This will serve legal academics formally began on that date. and practitioners across Europe via ESA's Information Retrieval Service (IRS, based in Frascati, Italy). A bridge between interested - Publishing a newsletter, the ECSL News, communities of which three issues a year are foreseen. Opening the May meeting, ESA's Director (Two issues have already appeared, and General, Prof. Reimar LOst, characterised the copies are available from ESA Public­ wider significance of the Agency's role in ations Division. Issue No. 2 contains the setting up the ECSL as a partnership with current ECSL Charter).

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depends mainly on the willingness of individual ECSL members to supply bibliographical data and materials on space law and regulation to a common pool that all can access electronically via a desk-top computer and modem.

Progress has been good in th is regard so far, and the ECSL Board has taken organisational steps to further the process. Once established (passwords should be available to ECSL members in early 1990), this resource will provide an important means to enable the Centre to become, in the words of ECSL News, 'Europe's powerhouse of ideas on space law.'

ECSL research projects Another major function of the ECSL is to assist or execute research projects that can analyse the existing state of the law in its technical and policy context, and refine ideas even to the stage of formulating law-making proposals. Encouragement to do just this has already come from Mr H.J. Allgeier of the European Commission who, speaking at the Second Aerospace Conference EAC'89 'Progress in Space Transportation' in Bonn (22- 24 May 1989), said: 'The Commission ECSL national members (e.g . the Institute of ... welcomes ESA's initiative to create a Air and Space Law of Cologne University European centre for space law, and will and the University of Leiden Institute for Air participate in its activities. This could form and Space Law) provided inputs to both the basis of Community action in the projects. ESALEX's efficacy in particular harmonisation of legislation '.

The ECSL Board

The following Members were elected to the - Mr Jean-Denis Dupuy, Board at the ECSL inaugural meeting on Industry (Spot Image) 12 May 1989: - Mrs Marie Helen Pichler, Industry (Astra-SES) - Prof. Karl-Heinz Bockstiegel, - Mrs Tanja Zwaan, Director Cologne University Institute for Air University of Leiden International Institute and Space Law of Air and Space Law - Dr. Michel Bourely, (representing student interests) President International Institute for Space Law Ex Officio Members: - Prof. Francis Lyall, - Chairman: Mr Gabriel Lafferranderie University of Aberdeen (ESA Legal Adviser) - Prof. Claudio Zanghi, - Operations Manager for ECSL University of Rome Secretariat: Mr Kevin Madders (ESA, - Prof. Ingrid Detter de Lupis, DA/LA) Stockholm Institute for Research in International Law Secretariat: - Dr. Bess Reijnen, - ECSL Secretary: Mr Mathias Spude (FRG) University of Utrecht Institute of Public (responsible for day-to-day administration International Law of the Centre) - Dr. Ralph Kroner, - ESA Administrative Support: Private Practioner (Nolst Trenite) Mrs Eva Vermeer (ESA, DA/LA)

60 ecsl

Figure 1. Inaugural meeting of the ECSL, at ESA's Paris Headquarters, on 12 May. From left to right: Prof. I. Oetter de Lupis, Or B. Reijnen, Prof. K.-H. Bockstiegel, Prof. R. Liist, Mr G. Lafferranderie, and Mr G. van Reeth

Subjects currently being considered for in, an ESA Member State, and who are not ECSL space-law workshops are: employed by non-European firms or other entities. In cases of doubt, the ECSL Board - The protection of satellite data derived will decide on the basis of an applicant's from Earth-observation satellites. circumstances.

- The regime for intellectual property rights Membership application forms and further in space on European space objects. information are available from :

- Coordination mechanisms to use Earth­ Mrs Eva Vermeer observation data more effectively in taking ECSL measures to protect the biosphere. 8-10 rue Mario Nikis 73858 Paris 15 A Colloquium on Space Stations and the France Law on 7-8 November 1989 at CNES Headquarters in Paris is being supported by ESA within the framework of its ECSL activities.

Above and beyond these types of research activities, though, a further task of the Centre is to stimulate the work of individual researchers (where possible through cross­ frontier collaboration). A number of bursaries will be available to doctoral students and other researchers in fields targetted for inquiry by the ECSL Board.

Funding for such bursaries comes from ESA and donations to the ECSL Fund by indiv­ idual members. After only a short period, over 14000 French francs have been received from such members, in addition to a 10000 French franc donation by the Agency.

Membership and further information The ECSL is a European organisation. Membership is open to interested persons within any ESA Member State territory who are nationals of, or are permanently resident

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62 distance learning via olympus

ESA's Olympus Satellite and Distance­ Learning in Europe - The Creation of a European Users' Association (Eurostep)

J. Chaplin ESA Directorate of Telecommunications, ESTEC, Noordwijk, The Netherlands

Background Preparatory Committee gladly accepted th is The earlier article in ESA Bulletin No. 56 offer, realising that this implied that Leiden described how so-called 'distance-learning' would become the seat for the new users' - education by satellite link or other means association . The LUF also obtained support to remote users - had been identified as an for the project both from the university and ideal application for future broadcast and from the town of Leiden , which was crucial at telecommunication satellites. The Olympus this early stage. broadcast payload, covering all of Western Europe as well as states further east, is The fUll -time Executive Secretary was able to particularly appropriate. give invaluable help to the committee, in particular on the legal aspects of establishing In early 1988, individual distance-learning the association. projects had begun, with over 3000 h of satellite time available annually free-of-charge Eurostep Articles of Association from ESA. Since then the three high-power The formation of an association requ ires 'Articles of Association' and a list of 'Founder Members'. The potential users of Olympus This article, continuing the story that appeared in the ESA Bulletin readily provided the latter and, at the in November 1988, describes progress in preparation for using the Olympus Utilisation Conference in _Vienna in Olympus satellite fo r distance-learning, in particular the establish­ April 1989, draft articles were tabled and ment of a Users' Association, called 'Eurostep'. adopted. In May 1989, under Dutch law, Eurostep was born.

broadcast satellites TDF-1 (France), TV-Sat It must be stated immediately that Eurostep (Germany) and Olympus itself have been does not intend to limit its scope just to successfully launched, the start of trans­ Olympus, which obviously provides its missions is imminent, and a new users' seminal opportunity. This principle is association has been created. enshrined in Article 3, which explains that the objectives of Eurostep are: to promote the At Avignon in April 1988, a meeting of use of satellite communications in education, distance-learning institutions formed a Prep­ to create opportunities for members, to aratory Committee to establish a satellite manage and coordinate these affairs, and users' association. The original name STEP generally to act in the interests of its (Satellites in Training and Educational members. Programmes) was quickly amended to 'Eurostep', to reflect the pan-European nature Article 4 provides for institutional and of the project. individual membership of Eurostep. Institutions that are already satellite users are The creation of Eurostep eligible for full membership, while those that After Avignon, the work of the Preparatory intend to become users are awarded Committee was greatly assisted by the associate membership. An individual Leidse Universiteit Fonds (LUF), the assoc­ member is a person interested in Eurostep iation of the alumni of Leiden University, activities without implying institutional which has recently endowed a Chair in involvement. Individual members have no distance-learning. The LUF offered to provide voting rights. salaried staff and accommodation for a small secretariat in Leiden. The Articles 5 and 6 explain how membership is

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decided and terminated, while Article 7 country, and at least si x different nationalities covers the obligations of members. will be represented .

Articles 8 to 15 define Eurostep's structure Article 2 anticipates that Eurostep will use and decision-making mechanisms. Eurostep Olympus at least in the daily periods consists of a General Assembly of full 02.00 - 05.00 h, 09.00 - 14.00 h, and members, which elects the majority of the 16.00 - 17.00 h (Central European Time) . This members of a Management Board, which in schedule may be reviewed after the first year, turn establishes and maintains a full -time and in any case occasional additional access Secretariat. A minority of further members of can be arranged. Eurostep accepts full the Board may be elected by the associate responsibil ities as a broadcaster, but wil l give members and, whilst Eurostep uses ESA advance notice of what is to be Olympus, a single representative will be transmitted. The provisions of the Council of appointed by ESA. The Board also has an Europe convention on transfrontier television Executive Committee which conducts the will be respected. routine business. Article 3 obliges Eurostep to make As this structure indicates, Eurostep is an arrangement for access to su itable uplink association of practical users of satellites. stations, but ESA's Redu ground station will of course be available. No charge will be The Eurostep/ESA Agreement made for service demonstrations carried by It is customary for the Agency to make Olympus, but ESA reserves the right to binding agreements with major users of its negotiate recovery of a proportion of the satellites. Accordingly an Agreement has operating cost of Olympus in the case of been drawn up between ESA and Eurostep, pilot or pre-operational services. which is expected to be ratified by a General Assembly in October 1989. Article 4 requires Eurostep to make regular reports on its activities to ESA , while retaining Article 1 of this Agreement gives Eurostep intellectual property rights. ESA may only exclusive access to the Olympus European disclose information so received after written DBS channel from a date to be agreed, approval. probably early in 1990. Eurostep will make the maximum possible use of the channel for Article 5 acknowledges that Olympus is an transmitting programmes selected by experimental satellite, and that the Agency is Eurostep according to agreed criteria (see not in any way liable following any Table 1). In keeping with the international malfunctioning of the system. nature of Olympus's exploitation, this Article also states that not more than one third of Article 6 foresees quarterly progress the Eurostep Board shall be from anyone meetings between ESA and Eurostep to review operations. Eurostep must use the satellite for at least 70% of the hours allocated to it. While using Olympus, the Table 1. The ESAlEUROSTEP Agreement Association is not allowed to make unnotified - Criteria for the Selection of Programmes major changes and Article 7 states that it General cannot pass on its rights and obligations to No si ngle member has more than 5% of total others. time Preference to Olympus participating states The Eurostep Operating Agreement After 2nd year, 20% of time allocated to new This ESA/Eurostep Agreement transfers the users. obligations of using Olympus, including those of a broadcaster, to Eurostep. In its turn, Project Requirem ents Eurostep passes on some of these Originality with new service concept obligations to its participating members by Multipoint reception by an identified audience means of an 'Operating Agreement' with group Clear specification of programme content each member actually taking advantage of Video production facilities identified the Olympus opportunity. Results of interest to all. The Operating Agreement defines the rights International Dimension and obligations of the member, and Coverage and appeal across Europe indemnifies Eurostep itself and its officers - Cooperation in planning/production/evaluation. against legal and operational difficulties, and unforeseen costs. Members must submit

64 distance learning via olympus

programme synopses and applications for Table 2. Eurostep Members with Olympus transmission time specific airtime to the transmit-scheduling commission 20 weeks in advance. Eurostep Organisations City Hours/year Programmes reserves the right to reject an unacceptable programme up to 15 days before the Training Commission Sheffield 162 Adult Education planned time of transmission. Open University Milton Keynes 12 Tertiary Education Birkbeck College London 104 Medici ne The technical standards to be used are Herriot-Watt University Edinburgh 50 Tertiary Education specified in detail in an annex to the Educational TV Assoc. York 50 Group Agreement. This avoids many of the SCET Glasgow 20 Mixed problems arising from a potential diversity of standards in material contributed by a large University College Dublin 120 Group number of sources. Fern Universiteit Hagen 78 Adult Educat ion Universities FilmlVideo London 150 Group British Medical TV Woking 150 Medicine Eurostep management of Olympus Univ. of Glasgow Glasgow 50 Language Learning distance-learning activities Satecosse Edinburgh 26 Language Learning Eurostep will manage the disparate distance- learning activities on at least the Olympus Brighton Poly1echnic Brighton 30 Language Learning DBS European channel. The Agency plans Centre for Int. Studies Exmouth 16 Group to negotiate a limited initial contract with TVE1 Centre Clwyd 36 Mixed Eurostep to cover the first few months' Univ. of East Anglia Norwich 35 Tertiary/Adult Educat. activities. The initial contract, expected to run Univ. of London London 144 Group until the end of 1989, will cover completion of Gwynedd County Council Uangefni 30 Mixed the setting-up of the Executive Secretariat, Oxford University Oxford 150 Language Learn ing the first few months of Olympus test Integrated Info. Syst. Athens 150 Mixed transmissions, and negotiation of the main Coventry Lanch. Poly. Coventry 50 Mixed contract. Royal Coil . Psychiatry London 24 Medici ne European Parl iament Lu xembourg 36 Adult Education The main contract will cover: the estab- lET Thessaloniki 50 Mixed lishment of information systems, the continuation of Olympus transmission University Coll ege London 70 Technology scheduling, liaison with established users in IASPA Brussels 12 Th e Arts six particular countries, and the general Univ. of Leiden Leiden 100 Medicine Post-Grad. Medic. School Exeter 50 Medicine marketing of Eurostep and the Olympus Vrije Univ. Brussel Brussels 40 Tertiary Educat. opportunity. Aston University Birm ingham 30 Adult Education

National user liaison merits a special mention Elec. Univ. Norway Stavanger 75 Adult Education here. Eurostep is dealing with users right TV-Inter Stockholm 50 Rel igion across Europe and face-to-face commun- Generalitat de Catalunya Barcelona 35 Culture ication between identified representatives was Internat. Space Univ. Boston 20 Adult Educati on felt to be essential. This representation was Escuola Univ. de EGB Tenerife 5 Culture first arranged in the UK and France, Cosejeria de Ed. (Anda.) Sevilla 12 Culture encouraged and funded by their national Univ. of Barcelona Barcelona 12 Mixed governments. ESA has now placed contracts Cent. Cult. Tajamar Madrid 26 Adult Education in Spain, Belgium and Italy, and Eurostep will Min. Education & Science Madrid 24 Language Learning continue this work, extending it to include Circulo de Bellas Artes Madrid 74 The Arts Ireland. Trans World Rad io Hilversum 175 Rel igious Educ. IBM La Hulpe 50 Product Training It is hoped that other countries will decide to support this project by subscribing to the so- Univ. of Navarre Pamplona 12 Culture called 'ESA PSDE Slice-3 Programme'. EON Leatherhead 25 Religiou s Edu c. Another option would be for Eurostep to gain Rights and Humanity London 28 Soci ology financial support from a European institution, Nat. Inst . for Higher Ed. Limerick 30 Umbrella Univ. of Paris VIII Pari s 5 Training Trainers and this route is being vigorously explored. VIDEOSCOP Nancy 12 Medici ne

Univ. of Montpellier Montpellier 90 Umbrella Pan-European cooperation in Eurostep CNDP Paris 113 Cul t. and Lang. By its very nature, Eurostep is a pan- AFT/IPT Rantigny 17 Transport European cooperative venture. It is coord- Univ. of Nantes Nantes 20 Training Trainers inating more than 70 individual projects Min. Affaires Etrangeres Paris 96 Culture (Table 2) , almost all of which are themselves Univ. P. et M. Curie Paris 45 Maths the fruit of international cooperation. Many of (cont'd)

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the project teams are made up of active Table 2. (cont'd) Eurostep Members with Olympus transmission time users from several countries, and they are also in contact with many interested potential Organisations City Hourslyear Programmes users, a number of whom are providing advisory support. Univ. of Poitiers Poitiers 15 Mixed Vlaams Theater Inst. Brussels 36 Culture Eurotransmed, a medical project from the Tekel Bilbao 20 Technology University of Leiden, is in contact with 30 CGER Brussels 36 Banking Dutch organisations and doctors, and a IFA Rome 8 Insurance Intellink Rome 100 Umbrella further 103 doctors and medical institutions in 17 other countries. The British Universities' Elemedia Pozzuoli 60 Technology Film and Video Council is in contact with Media Facilities Mechelen 30 Culture 252 organisations from 18 countries, CNED Rennes 15 Biotechnology including four East European states. The ENS Production St. Cloud 9 Mixed Vlaams Theater Instituut in Brussels is an CNDP-CRDP Nantes 7 Mixed international standing conference involving IFACE/Univ. Compeigne Paris 18 Management some 300 organisations in 20 European countries. LERSCO-CNRS Nantes 12 Sociology UFCV Lille 6 Perfume Hopital Lapeyronie Montpellier 6 Medical These three projects alone embrace a total of Agropolis Montpellier 12 Medical 555 participants in virtually every country in CELA Avignon 5 Lang. Learning Europe. It is already clear that the total CAVILAM Vichy 16 Lang. Learning number of participants in all projects far exceeds the 300 estimated in early 1988. CLEMI Paris 10 Culture There must be several thousand potential Unlv. of Nantes Nantes 6 Mi xed participant institutions and many thousands of private individuals who are interested.

Figure 2. The Headquarters of Eurostep, on the Rapenburg , in Leiden (NL), next to the Leidse Universiteit Fonds (WF) building (right)

66 distance learning via olympus

Figure 3. Typical Olympus DBS antenna coverage patterns, serving 4S-cm and gO-cm antennas (inner and outer contours, respectively)

RAI and BBC interest in distance­ Conclusion learning Distance-learning via Olympus is a project ESA has a long-standing agreement with the that involves practical cooperation spilling Italian broadcasting corporation RAI on the over the traditional boundaries of the use of the Olympus 'Italian' DBS channel. Agency's activities. The greatest problem of a Details of RAl's plans were released at the project of this scale is its management. Olympus Utilisation Conference held in Eurostep is the solution to this problem, but it Vienna in April this year (more details can be is as yet in an embryonic state and needs found in ESA Special Publication SP-292, p. care and attention. Here is a genuine case of 429). RAI is willing to cooperate with the pan-European cooperation which merits pan­ Olympus Users' Association , and intense use European multilateral funding. It is hoped of the channel for international education and that other institutions will follow ESA's training programmes is likely to be the example and give Eurostep their support. ~ outcome.

A similar agreement was signed in June this year with BBC Enterprises, which will use the Olympus European DBS channel daily in the peak evening hours from 17.00 h onwards. Education and training, and particularly language skills, is a major area of proposed programming development for Enterprises For further information about distance­ Services. The BBC's existing educational learning via Olympus and the Eurostep services, particularly English by radio and project, please contact the author or: TV, and its natural history and science output, are already being considered for Eurostep broadcasting via Olympus. Rapenburg 63 2311 GJ Leiden It is clear that two of the major established The Netherlands broadcasting corporations are planning a major move into distance-learning, which will Tel. (31) 71 277268 complement the programmes of the newer Fax (31) 71 140841 organisations cooperating within Eurostep.

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Hipparcos Update In late September, the two entrance aperture baffles were opened and Status on 26 October 1989 latched. All prime and redundant detectors have been checked out and After the successful launch of ESA's are performing nominally, as are the Hipparcos (High Precision Parallax refocussing and switching mirror Collecting Satellite) on 9 August, attempts mechani?ms. The star mapper data were to ignite the apogee boost motor of the entirely nominal , and attitude initialisation satellite to put it into its final geostationary based on star pattern recognition was In brief orbit were not successful. Following achieved on 8 October. Data is now several such attempts, experts met at being routinely acquired by the primary ESOC, ESA's Operations Centre at detection system , and the early stages of Darmstadt (D) , to plan a revised mission the payload calibration, including the for Hipparcos. telescope focussing, were completed at the end of October. Acquisition of the Hipparcos was launched into a highly nominal 'scanning law' (the mathematical elliptical transfer orbit, with a perigee of description of how the satellite scans the 210 km and an apogee of 36000 km . To sky) and the final stages of the payload reach a geostationary orbit, the calibration are planned for the first week spacecraft needed to be given additional of November. energy to inject it into the new circular orbit. This is done by firing the apogee In the revised mission, the satellite will boost motor - on Hipparcos, a solid remain in a highly elliptical orbit, instead powder Mage II ABM - when the of a circular orbit, and it will have an satellite is at the furthest position from orbital period of 10.5 h instead of 24 h. Earth. Orbital coverage will be carried out by a combination of the Odenwald (D) and Geostationary orbits are at an altitude of Perth (Australia) ground stations, giving about 36 000 km above the equator and about 63% coverage of the telemetered are difficult to achieve since they require data. Inclusion of a third ground station a high orbital speed. In such an orbit, (Kourou), wh ich should bring the data the satellite moves from west to east with coverage to about 80%, should be a period of about 24 h, staying in the finalised by mid-November. same place above the Earth. The satellite appears to hang in the sky at one point The nominal observing programme, and and is, therefore, always accessible from the implementation of the scanning law a single earth station. are being retained without modification.

Following the failure of the Hipparcos The most critical parameter in any apogee boost motor, plans for the assessment of the expected accuracy of revised operations of the Hipparcos the revised Hipparcos mission is still the satellite in its highly elliptical transfer orbit satellite lifetime, determined by the ""ere completed in late August and have degradation of the solar panels due to since been implemented. the high-energy proton rad iation environment in the elliptical transfer orbit. In early September, the orbit perigee was Additional operational difficulties are also raised to approximately 500 km, and the expected, due to the high rad iation three solar panels and the fill-in antenna background, the long occultation were successfully deployed. A week later, intervals, and the higher perturbing the unused hydrazine was drained from torques that will occur around perigee the satellite. The detection electronics passages. Estimates of the mission were activated , and data taken by both lifetime should be available in the near the image dissector tubes and the star future. mapper detectors have been analysed to study the effects of Cerenkov emission MAC. Perryman during the orbit. Hipparcos Project Scientist

The Hipparcos satellite under test in the Large Space Simulator at ESTEC, Noordwijk (NL)

68 in brief

IACG Meeting in Prague Global Scientific Networking Demonstrated The Inter-Agency Consultative Group for during the IACG Space Science (IACG) held its ninth annual meeting on 21 and 22 September During the ninth IACG meeting in 1989 in Prague, Czechoslovakia. The Prague, current possibilities for scientific IACG is a mUlti-agency international data transfer between East and West forum in which space science activities were demonstrated. A satellite link was are discussed to maximise opportunities set up between the meeting hotel in for multilateral scientific coordination on Prague and ESA's operations centre approved space science missions. The (ESOC) in Darmstadt, Germany. IACG member agencies are NASA, ESA, Intercosmos (representing 10 east block The temporary link, installed by ESOC 's countries), and the Japanese Institute of Computer Department with the full Space and Astronautical Science (ISAS) . cooperation of the Deutsche Bundespost and the Czechoslovakian PD, connected The IACG was formed in 1981 to the IACG delegates to the European coordinate the six space missions to Space Physics Analysis Network (SPAN) Halley's Comet: Vega-1 and -2 in Darmstadt and the European Space (Intercosmos); Suisei and Sakigake balloon and rocket experiments from up Information System (ESIS) in Frascati, (ISAS); Giotto (ESA) and ICE (NASA). In to 100 countries worldwide (SCOSTEP is Italy. The link itself consisted of a Dornier 1986, after the successful completion of the Scientific Committee on Solar­ personal earth station installed on the the coordination of the Halley missions, Terrestrial Physics). roof of the hotel in Prague, together with the IACG decided to adopt Solar­ network switches and personal Terrestrial Science as its next project for Since its formation the IACG has met computers. One of the computer screens inter-agency coordination. annually. The task of organising the was projected onto a larger screen on a meeting, and consequently the venue, wall in the meeting room. Starting in 1992, the four agencies will rotates among the four agencies. launch 12 spacecraft to make Heading the four delegations for the The IACG Data Analysis Working Group coordinated measurements of the Sun, 1989 meeting were: Prof. AA Galeev, demonstrated the capabilities of the the Earth 's environment and solar­ Director of the Space Research Institute network connection, concentrating on five terrestrial relationships, namely: of the USSR Academy of Sciences, who particular aspects. First, a simple mail - Geotail (ISAS/NASA) also chaired the meeting; Or J.K. message was sent to a colleague at the Wind (NASA) Alexander, NASA's Assistant Associate Geophysical Institute in Kyoto, Japan and Polar (NASA) Administrator for Space Science and a reply was received within two minutes. 4 Regatta spacecraft (Intercosmos) Applications; Prof. R.M. Bonnet, ESA's In the second demonstration the orbit of SOHO (ESA/NASA) Director of Scientific Programmes; and the recently launched Japanese satellite, 4 Cluster spacecraft (ESA/NASA) Prof. J. Nishimura, Director General of Akebono, was predicted using the ISAS. SCOSTEP's President, Prof. J.G. Satellite Situation Center of the National A further 26 spacecraft from the four Roederer, participated as an observer. Space Science Data Center in Greenbelt, agencies, which have already been or Maryland, USA. will be launched before 1992, will Topics discussed in Prague included complement the 12 'prime' missions. general principles and timeliness of data Near-real time data from a scientific exchange. The IACG recommended satellite were displayed as the third Coordinating the solar-terrestrial science standard data formats and common example. The data shown were from the missions through the IACG will : software tools. The delegates also X-ray instrument on the GOES - make available to participating reviewed the progress in setting up the geostationary satellite, and were obtained institutes in the IACG member states IACG Science Information System , an from the MAX91 database of the National the scientific data from the maximum inter-agency network wh ich is scheduled Oceanographic and Atmospheric number of instruments on these to be operational by 1992 to facilitate the Administration's database at Boulder, spacecraft exchange of science data from the Colorado. The plot, displayed in the - optimise the spacecraft orbits and coordinated missions. A practical meeting room , showed a solar flare that experiment operation times demonstration of current possibilities for had occurred on the Sun on the previous - further discussion and collaboration scientific data exchange was also given day. between scientists from all the (see next item). countries of the member agencies The NASA master directory was then through the organisation of IACG The next annual meeting of the IACG will called up and the Dynamics Explorer workshops and symposia. be hosted by ESA and will take place in (DE) database in the South West Spain in early November 1990. Research Institute in San Antonio was These activities will be complemented by accessed. Data from several instruments SCOSTEP's Solar Terrestrial Energy R. Reinhard on DE-1 were transmitted over the Program (STEP) , which includes the IACG Secretary G network and displayed on the screen in coordination of ground-based, aircraft, the meeting room.

69 G bulletin 60

Lastly, the database of the Coordinated Data Analysis Workshop-9 was accessed. XRAY and OPTICAL DATA BEGIN: 21 SEP 89 This database was assembled specifically ~ ;!W698 Sf .56ga for a workshop that was taking place ~ IN,5698 ~ 56!1l simultaneously at the Goddard Space 10-4 Flight Center in Greenbelt, Maryland, USA. A more detailed report will appear 10-S M in the next issue of the ESA Bulletin. ":-' ~ a.> E TR. Sanderson C

ESA Space Science Department IT> ~ B

Plot of X-ray data from the GOES geostationary orbiting satellite on 21 A September 1989, as received in Prague one day later. The plot shows an enhancement in the X-ray flux at 21/0000 2110300 21/0600 03:00 UT due to a solar flare

ESA Experiments on - Does life shorten as a consequence hope to learn more about the role of Soviet Biology Satellite of exposure to weightlessness? There gravity in the fundamental biological is evidence from experiments with processes. This will contribute new ESA has been cooperating with the insects that the answer is yes. Some insights into the evolution of life and Soviet Union on a second joint space phenomena observed in astronauts cellular processes. It will also help us biology mission. On 15 September 1989, could also be signs of accelerated better to perceive the opportunities space the Soviet Union launched Biokosmos-9, ageing. offers to human beings, as well as the with five ESA experiments on-board. The - Can seeds be kept in space and dangers to which they are exposed in its first cooperative venture was successfully germinated normally if they have been harsh environment. undertaken in October 1987, when two bombarded with highly energetic ESA experiments were carried on cosmic ions? Biokosmos-9 landed safely 14 days after Biokosmos-8. - Will isolated carrot cells be able to launch, on 29 September 1989 at build a new cell wall, divide, and 05 :30 h Moscow time. A recovery team The main objective of Biokosmos-9 eventually produce a new carrot plant at the landing site obtained the biological during its two-week voyage was to study without the guiding force of gravity? samples which were then flown back to the effects of microgravity and cosmic - Are there some plant mutants that are Moscow in specially designed containers. radiation on two primates, ten rodents more resistant to the space The samples were handed over to the and a variety of smaller organisms. environment than others? Are there experimenters approximately 20 h after combined effects of the full spectrum landing. G The Agency's experiments were selected of space radiation and microgravity? by a scientific and technical peer group following a European-wide call for Through these experiments, scientists proposals. They are concerned with the smaller organisms and were conducted jointly by 30 scientists from Norway, Denmark, Germany, Switzerland, Spain Ariane-S Vulcain Thrust and the USSR. Necessary ground Chamber Test Facilities equipment in Moscow and operational support were provided by ESA. Inaugurated An important milestone in the ESA's experiments were designed to development of the Vulcain engine that 0 investigate biological development and will power the Ariane-5 central stage was ti ageing, and sensitivity towards cosmic reached on 19 September 1989 with the ~ radiation. Questions the scientists would inauguration of the new P32 test facilities ~ ill like to answer as a result of this mission at Lampholdshausen (D) . In the presence ~ include: of the Vulcain engine project managers, () ~""""'.. - Can insect development, starting from MBB held a 17 sec test, during which a egg formation, occur normally in thrust level of 107 tons was reached. Vulcain thrust chamber under test at space conditions or is there a With this successful demonstration, the Lampoldshausen (D) dependency on gravity in the early new installation was declared fully stages of development as observed operational. previously?

70 in brief

. Three ESA Contracts Awarded to Spanish Industry The Agency's Operations Centre (ESOC) in Darmstadt recently awarded three contracts to the Spanish space firm Grupo de Mecanica del Vuelo SA (GMV). The subjects of the first two contracts are: Flight dynamics software support (1989-1994), and on-line orbit determination and manoeuvre calculation. The third is a frame contract for study tasks in the area of orbital mechanisms.

The accompanying photograph shows the signing of the contracts on 12 September 1989 by Mr K. Heftman (right), ESA's Director of Operations, and Pro!. J. Martfnez Garcfa, Executive President of GMV. •

ESA Co-sponsors Astronomy is evolving and developments range of new equipment and techniques, 'Astronomy and Space' in space exploration mean that new are still in their formative years. Modern research methods are available in every educational methods must take account ESA has combined efforts with the field. These changes prompt investigation of the new possibilities. This meeting, European Southern Observatory and the into the implications of space research accessible to a general audience, was Aniane Observatory to sponsor the latest for society in general, the human therefore convened to consider questions in a series of European meetings on presence in space and its philosophical in space-related education in Europe. 'Astronomy and Space' which took place implications. The next generation of on 20-23 September at Montpellier (F) . scientists, who will be using the wide Each day's programme focussed on a specific theme: 'People and Careers' examined problems such as mobility of researchers and students, transfer of First ESA Shuttle-Mission knowledge, language learning and Specialist familiarisation with scientific language.

ESA astronaut Claude Nicollier has been 'The Sky in the Third Millenium' selected as mission specialist for the considered how the highly sophisticated Space Shuttle mission, STS 46. This will instruments and equipment currently be Nicollier's first flight and he will also being conceived will affect the be the first ESA astronaut to fly as a community, scientific research , and mission specialist. programmes under way worldwide.

Nicollier, a Swiss national, has been 'Space for AII' invited speakers to present assigned to NASA since 1980 to receive selected examples of the uses of space mission specialist training under a special and what they can mean to the planet agreement between ESA and NASA. Earth. 'Life in Space' relived with American, Soviet and European The STS 46 mission objective is to deploy astronauts/cosmonauts the space ESA's Eureca Free-Flying Platform , a odyssey - from the moment man first space platform designed primarily for set foot on the moon through to current microgravity experiments. In addition, the developments involving the human STS 46 crew will demonstrate the Italian presence in space. Space Agency's Tethered Satellite. System (TSS) , designed for the deployment, An open day for amateur astronomers operation and retrieval of data-gathering was also held at the Aniane probes. The system provides constant Observatory. physical and electrical connection between the probe and the Shuttle.

71 • bulletin-~-- 60 l,f 5 '5 se~te~~er '96~

?l'Ofe55C "01 a ta.'

Mr D. Eaton (I ft and technicalities e ) explaining the in C f payload to M~ :.~ E;~O sounding-rocket Ambassador t yer, US p 0 ~',he N th apendorp (US E e erlands, Mr JT BondI' (far nOg ht Embassy) ' and Prof H, , ;.l SRO 's 0 Irector' Ge neral'

72 in brief

At work on an early ESRO sounding-rocket payload 25 years later - the 1989 sounding-rocket exhibition at ESTEC

25th Anniversary of Aboard were instruments from the Institut (formerly Head of ESRO Sou.nding ESRO's Sounding Rocket d'Astrophysique de Liege (F) and the Rockets Division). A firework display Programme Max-Planck Institute (MPI) in Garching formed a fitting climax to a day of slides, (D). One of the experimenters was films and reminiscing. To commemorate the 25th Anniversary Reimar LOst, now Director General of of the ESRO sounding-rocket ESA. An exhibition was open throughout the programme, a reunion of some 250 'ex­ week, with photographs, hars:Jware and rocketeers' was organised at ESTEC on Appropriately then, the speeches other mementos provided by the 'ex­ Friday 15 September. During the period preceding the evening's celebratory rocketeers'. Actual flight hardware, 1964 - 1972 the Sounding Rocket dinner included an address by Prof. supplied by BAe, Dornier and Contraves, Division launched a total of 183 rockets, LOst. An opening address by M. Le formed the centrepiece. carrying scientific payloads, from various Fevre, Director of ESTEC was followed launch ranges in Europe and Australia. by speeches from Prof. R. Bonnet, P. Colson The very first ESRO sounding rocket was Director of Scientific Programmes, and 'Ex-rocketeer' launched from Sardinia on 6 July 1964. Mr D. Eaton, Ulysses Project Manager

73 • bulletin 60 Noordwijk Space Expo Foundations Laid

In a ceremony to mark the start of construction of the 'Noordwijk Space Expo', The Netherlands' Deputy Prime Minister and Minister of Economic Affairs, Or RW. de Korte sank the first pile for the new Centre on 26 October. Minister de Korte, for many years a keen supporter of the European space endeavour, spoke during the ceremony of the Dutch Government's declared policy of 'broadening the social base of spaceflight' and the need 'to make the public more aware of the opportunities' that it holds.

The Noordwijk Space Expo (NSE) , a cooperative venture between the NSE Foundation and ESTEC, is expected to contribute substantially to these two goals. The Centre itself is located within the grounds of ESTEC and will have a dual role; in addition to housing a permanent 1600 m2 space exhibition - the future of space flight Director of ESTEC, on behalf of ESA, open to the public, it will also serve as - spin-offs from space exploration. and the Chairman of the Noordwijk an official visitors' centre for ESTEC. Its Space Expo Foundation, Or R.P. facilities include a 150-seat auditorium. An additional attraction will be live video Dessing (above, right). coverage of key events such as The Centre is scheduled to be opened launches and major satellite tests. At The Expo venture has been supported next summer. The exhibition will be open least 100 000 visitors are expected by more than 30 European aerospace to the public six days a week and will annually. companies within the ESA Member feature actual flight hardware, models States, the local authorities, the Province and audio-visual presentations on four Prior to the pile-driving ceremony, the of South Holland and the Dutch Ministry main themes: ' 'Development and Operating Agreement' of Economic Affairs. G - the history of space flight that will govern the running of Space - the European space endeavour Expo was signed by M M. Le Fevre,

74 in brief

Noordwijk Space Expo, due to open in the summer of 1990

Information System for the framework of the prototype, various Columbus Users advanced information-retrieval systems, expert systems and other media-oriented LATE NEWS The Columbus Promotion and Utilisation innovations are currently being studied Department of ESA's Space Station and and tested. In this context, the Columbus Intelsat-VI Launched by Platforms Directorate has developed a Pictures Databank (COPIDAB) has been Ariane prototype electronic information system set up. COPIDAB provides access to for the Columbus user communities. The photographs, videotapes, viewgraphs An Ariane-4 launch vehicle equipped system will be demonstrated to interested and slides of equipment and experiments with four liquid strap-on boosters users at 'Space Commerce '90 ', in from the three Spacelab flights. (known as version 44L) placed the Montreux, 26 - 28 March 1990. I ntel sat-V I F2 telecommunications If you would like to see a demonstration satellite safely into geostationary The Columbus Utilisation Information of CUIS or COPIDAB at Space transfer orbit in the early hours of System (CUIS) will enable users to Commerce '90, or would like further Saturday 28 October (European time). receive, process and exchange information, please contact Philippe information on Columbus utilisation. An Willekens or Marilynne Taylor, European I ntelsat-VI , Ariane's sole passenger on initial trial group of some 30 users has Space Agency, Paris; Tel: 33-1-42 73 88 this flight, is the largest telecom­ been selected from various international or 33-1 -42 73 20. munications satellite ever built. It is and national space agencies and destined to be integrated into European universities. The CUIS For general information on Space Intelsat's international communications prototype will handle all the Columbus Commerce 90 (an international network, and will be stationed at documentation needed by the users conference and exhibition on the 335°E. C during the familiarisation , mission commercial and industrial uses of outer preparation, and operational pha~es of space) please contact the permanent the Columbus Programme. secretariat: Space Commerce 90, Po. Box 97, CH-1820, Montreux, The system runs on any IBM -compatible Switzerland (Tel: 41 -21 963 23 54). C personal computer connected to a public network anywhere in the World. Within

75 The dry winter of 1988/89, monitored via NOAA Tiros-N space imagery. The central lowlands are affected by dense mist and fog , while the elevated areas are dry and clear. The many orange spots indicate areas of intense heat (e.g. the metal-working plants at Piombino and in the Trieste region), or forest fires. The smoke from these fires is clearly visible over the Gulf of Genoa, and over the Adriatic off the coast of Istria.

Image acquired and processed by DLR , Oberpfaffenhofen, FRG . Landsat Thematic Mapper (TM) image showing the snow-capped Sierra Nevada, the southernmost ski area in Europe. Granada lies in the foothills of Earthnet User Services the mountains, with fertile lowlands ESRIN extending to the west Via Galileo Galilei 00044 Frascati, Italy Image acquired and pre-processed by ESA/Earthnet. Image processing by , Tel. 39 6 9401218/210 Geospace, Beckel Satellitenbilddaten, Telex 616468 EURIME I Bad Ischl, Austria. • bulletin 60

ESA Journal

The following papers have been published in ESA Journal Vol. 13, No. 2:

HERMES - DEFI TECHNOLOGIQUE BARON F M ET AL

SATELLITE POWER SYSTEM TOPOLOGIES Publications O'SULLlVAN 0 ASSESSMENT OF ELECTROSTATIC CHARGING OF The documents listed have been issued SATELLITES IN THE GEOSTATIONARY ENVIRONMENT since the last publications announcement FREZET M ET AL in the Bulletin. Requests for copies should be made in accordance with the PLASMA-DEPOSITED MULTIPURPOSE Table and using the Order Form inside PROTECTIVE COATINGS FOR SPACE APPLICATIONS the back cover of this issue. KLEMBERG-SAPIEHA J E, WERTHEIMER M R & ZIMCIK 0 G - esa '"' ""0" 'P' l;.j' • ELECTRON BEAMS AND NON DESTRUCTIVE TESTING OF MATERIALS IN SPACE FRANCESCHI J L & CHAPUIS C

DETERMINATION OF THE GfT FIGURE OF MERIT ESA SP-294 (2 VOLS) 11 859 PAGES OF GROUND RECEIVING STATIONS FOR EUROPEAN SPACE POWER, PROC EUROPEAN METEOROLOGICAL SATELLITES BENIP SPACE POWER CONFERENCE, MADRID, SPAIN, 2-6 OCTOBER 1989 (AUGUST 1989) LANOEAU J (EO) ESA Special Publications ESA SP-300 11 77 PAGES CREW SAFETY AND RESCUE IN SPACE, AN ESA SP-291 11 312 PAGES AAAF, AIAA & ESA WORKSHOP HELD AT LE PROC 9TH ESA SYMPOSIUM ON EUROPEAN BOURGET, 7 JUNE 1989 (AUGUST 1989) ROCKET AND BALLOON PROGRAMMES AND OAVIO V & GUYENNE TO (EOS) RELATED RESEARCH , LAHNSTEIN, GERMANY, 3-7 APRIL 1989 (JUNE 1989) ESA Sp·l088 11 43 PAGES BURKE W R (EO) CATALOGUE OF ESA PUBLICATIONS IN 1988 (AUGUST 1989) ESA SP-293 11 549 PAGES COMPILED BY BA TTRICK B & DE ZWAAN F PROGRESS IN SPACE TRANSPORTATION, PROC 2ND EUROPEAN AEROSPACE CONFERENCE, ESA SP·ll0511135 PAGES BONN BAD-GODESBERG, GERMANY, 22-24 MAY LIFE SCIENCES RESEARCH IN SPACE (JULY 1989 (AUGUST 1989) 1989) GUYENNE T 0 & HUNT J J (EOS) OSER H & BA TTRICK B (EOS)

esa SP·291

""...... } tH"" .... ~<:.,1.,~ $-~ptf'.~r".N ·"...... I~..." .... l...L~ ~ ..1IJ ... 1~~S...,.. ~'''''~''''''''''''l~. Mt.c./UI(.Jr...,...,.) .~'

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78 publications

ESA SP-1113 11 69 PAGES ESA SP-1118 11 18 PAGES ESA BR-62 11 28 PAGES COMBUSTION EXPERIMENTS DURING KC-135 EXPERIMENT FACILITIES FOR MATERIALS AND COLUMBUS - A USER 'S INTRODUCTION PARABOLIC FLIGHTS (AUGUST 1989) FLUID SCIENCES EMBARKED ON EURECA-l (SEPTEMBER 1989) KALDEICH B (EO) (AUGUST 1989) LANOEAU J (EO) WALTER H U & RIESSELMANN (EO: OAVIO V) ESA SP-1114 11 169 PAGES IUE-ULDA ACCESS GUIDE NO 1 - DWARF ESA Newsheets NOVAE AND NOVA-LIKE STARS (SEPTEMBER ESA SP-1120 1152 PAGES 1989) EXPERIMENT FACILITIES FOR MATERIALS AND COMPILED BY LA OOUS C FLUID SCIENCES EMBARKED ON SPACELAB MICROGRAVITY NEWS FROM ESA 11 48 PAGES (AUGUST 1989) VOL 2, NO 2 (JULY 1989) ESA SP-1116 11 31 PAGES WAL TER H U (EO .· LONGOON N) OAVIO V (EO) FLIGHT EXPERIMENT HARDWARE FOR SOUNDING ROCKET INVESTIGATIONS - REACHING FOR THE SKIES 11 8 PAGES MATERIALS SCIENCE AND FLUID SCIENCES VOL liNO 2 (SEPTEMBER 1989) (AUGUST 1989) ESA Brochures LONGOON N & GUYENNE T 0 (EOS) WAL TER H U & MINSTER 0 (EO: HUNT J J) ECSl NEWS 11 4 PAGES ESA SP-ll17 11 138 PAGES ESA BR-60 11 25 PAGES BUllETIN OF THE EUROPEAN CENTRE FOR MISSION TO MARS - REPORT OF THE MARS FROM SMALL BEGINNINGS - THE STORY OF SPACE lAW (PUBLISHED TWICE A YEAR UNDER EXPLORATION STUDY TEAM (JULY 1989) ESRO 'S SOUNDING ROCKET PROGRAMME THE AUSPICES OF ESA), NO 2 (AUGUST 1989) CHICARRO A F, SCOON G E N & CORAOINI M (SEPTEMBER 1989) LONG DON N & GUYENNE T 0 (EOS) (EO: BA TTRICK B) EATON 0 NEWS & VIEWS 11 8 PAGES ESA-IRS NEWSlETIER VOl 14 NOS 213 (SEPTEMBER 1989)

ESA Scientific & Technical Reports

ESA STR-228 11 69 PAGES SATELLITE SYSTEMS INTEGRATED WITH THE TERRESTRIAL CEllULAR NETWORK FOR MOBilE COMMUNICATIONS (AUGUST 1989) DEL RE E (EO: BURKE W R) •

79 advertisement

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.~ Via Galileo Galilei ...... 00044-FRASCATI(ITALY) -..._ Tel.(39/6)94011 esa I -~ Twx. 610637 e'srin i european space agency Online Services programmes & operations

Programmes under Development and Operations/ Programmes en cours de realisation et d'exploitation

In Orbit / En orbite

1989 I 1990 I 199 I I 1992 I 1993 I 1994 I 1995 PROJECT JIFIt1Ajt1J1J1AjSIOINIDIJIFIt1Ajt1J1JIAjSIOINIOIJIFIt1Aj t1 J1J1AjSPINIDIJlFIt1Ajt1JIJIAjSI~NIDIJIFIt1Ajt1J1J1Ajsl~NIDI,llt1Ajt1JIJIAjsl~NIDIJIFIt1Ajt1J1JIAjsloINlo COMMENTS SCIENT PROG. IUE ...... MARECS·A LEASED TO tNMAASAT •...... •....•...... •.....•...... FOR 10 YEARS LEASED TO INMARSAT MARECS·B2 ...... FOR 10 yEARS

METEOSAT·3 ...... •...... •.•.•••.•.•..••.. LIFETIME 3 YEARS UlW Z;:;; METEOSAT·4 (MOP·l) ...... LIFETIME 5 YEARS Q;:;; \i:« 00: ECS·l ...... ------UFETIME 7 YEARS -Cl -'0 ~[ ECS·2 ...... ----- LIFETIME 7 YEARS ECS·4 ...... LIFETIME 7 YEARS

ECS·S ...... LIFETIME 7 YEARS

OLYMPUS·l ...... •...... ••...... LAUNCHED 12 JULY 1989

Under Development / En cours de realisation

1989 1990 199 I 1992 1993 1994 1995 PROJECT I I I I I I COMMENTS JlFIt1AIt1JIJIAjsl~NIDIJIFIt1Ajt1JIJIAjsloINI~JIFIt1A1t1JIJlAjsICiNIDIJIFIt1Ajt1J1JIAjsIDINIDIJIFIt1Ajt1J1JIAj sloINIDIJIFI t1Ajt1 JIJIAjslolNI~JIFI t1Ajt1J1"'AjsloINlo SPACE TELESCOPE ----~------+ ...... LIFETIME 11 YEARS w ~;:;; ULYSSES ############H########+ •••••••••••••••••••••••••••••••• ••••••••••••••••••••••••••• u.;:;; i=« ZO: »»»» LAUNCHES' SOHO MARCH 1995 wCl ~g~~~~~'6~~~~~ CLUSTER DEC 1995 HIPPARCOS ######+ •••••••••••••••••••••••••••••• ~~a.. ISO ...... LIFETIME 1 5 YEARS ui · DATA·RE.!-AY »»»»»»»»» ;:;;Cl SATELLITE (DRS) SYSTEM OPERATIONAL 1996 ;:;;0 og: > > > > > > > > > > > > > >~A'l«»/4 READY FOR LAUNCH END 1993 0 PSDE TECH . MISSION ff~Ul ERS·l ...... w~~ ARTH OBS. PREPAR. ~a:~ OCl« PROG. (EOPPl M p. I~O: oP· MOP·J MOP· 1 LAUNCHED !;:08 METEOSAT OPS.PROG. = ...... MARCH 1989 «;:;;a: IML·1 IML· w06o.. MICROGRAVITY

0. '" . EURECA ...... • ~58«0..0: ., PH 3 YEAR INITIAL DEVELOPMENT 3;aDQ.. COLUMBUS PHASE Z Qw ARIANE·2/3 ~2:+"'; :~' ~\i:;:;;"";:;; ARIANE-4 IJ~.IJ+~ ~~~J~~~~7 •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• OPERATIONAL UNTIL END 1998 c:~;i ",a.. Cl (/)0 ARIANE·S ...... FIRST FLIGHT APRIL 1995 Za: ~o.. 3 YEAR INITIAL HERMES DEVELOPMENT PHASE f- TECH. IN·ORBIT TECHNOL. SEVERAL DIFFERENT PROG. DEMO. PROG. (PH·1l .~,~ '1''''''' CARRIERS USED DEFINITION PHASE > PREPARATORY PHASE o MAIN DEVELOPMENT PHASE • STORAGE ~, HARDWARE DELIVERIES ~ INTEGRATION '" lAUNCHIREADY FOR lAUNCH • OPERATIONS • ADDITIONAL LIFE POSSIBLE + RETRIEVAL

81 (9 bulletin 60

Telescope Hubble sol etait satisfaisante. On est preoccupe que les marges de conception etaient par la grande complexite de la largement suffisantes. Le lancement du Telescope Hubble conception du sous-systeme d'orientation (HST) reste fixe au 26 mars 1990. Le et il faut travail/er encore cl eliminer les Les essais sur modeles de laboratoire de materiel de vol sera expedie, sur C5-A, points critiques de defail/ance toutes les unites du sous-systeme de Sunnyvale (Californie) au Centre prejudiciables aux missions dans le electrique ont bien progresse. spatial Kennedy (KSC) cl la mi-octobre. systeme electrique du satellite. La Le HST est complet, cl I'exception d'un fabrication des unites electriques du Les travaux de developpement de la instrument, la chambre de prises de modele de qualification sera engagee charge utile scientifique se deroulent de vues planetaire cl grand champ, par etapes au cours des prochains mois. fayon satisfaisante. Les quatre groupes demontee pour modification, qui sera 'instruments scientifiques' ont entame la remontee au KSC. La chambre de prises L'integration du module de charge utile fabrication de leurs modeles de vues pour objets de faible luminosite a commence en juillet et progresse d'identification et de qualification. La est veriMe tous les mois et ne montre rapidement. Les travaux sur un probleme definition du secteur sol progresse et les aucune modification de fonctionnement. de fuite du reservoir d'Mlium liquide ont premiers modules du logiciel qui sera La fabrication du deuxieme ensemble de suffisamment avance pour autoriser le utilise pour les essais d'instruments et reseaux solaires se poursuit, en soutien demarrage de la realisation du cryostat. pour les operations en vol ont satisfait de la mission d'entretien du HST qui doit La fabrication de la structure du module aux essais et ont ete receptionnes. avoir lieu cinq ans apres le lancement. de service est bien avancee et le sous­ systeme de commande cl reaction cl Le calendrier d 'ensemble du projet est hydrazine est sur le point d'etre livre. Le tres critique et tous les efforts sont faits ISO reservoir d'hydrazine, une nouvelle pour rattraper les retards. Bien que la realisation de Oowty (UK), a ete livre et date de lancement demeure la meme, il Les activites recentes liees cl I'on a procede cl des essais de timbrage ne reste qu'une faible marge de I'Observatoire sola ire dans I'infrarouge sur un deuxieme reservoir qui ont montrs manoeuvre et I'on studie actuellement la (ISO) ont eu pour objectif de figer la situation. conception du systeme et des sous­ systemes pour preparer la Revue de conception du systeme. Tous les aspects Formal acceptance of the first model of ISO's Olympus de la conception d'lSO, y compris les hydrazine reaction control system (left) operations en vol, ont ete examines par Le satellite 0lympus-1 a ete lance avec Recette formelle du premier modele du plusieurs groupes d'etude specialises. systeme de commande cl reaction cl hydrazine succes du Centre spatial Guyanais de Oebut juil/et, le Comite de revue est de I'ISO (cl gauche) Kourou, le 12 juil/et cl 00:14 h TU sur le parvenu cl la conclusion que la vol V32, le dernier des lanceurs Ariane 3. conception du module de charge utile Thruster block for ISO's orbit and attitude (en particulier le grand cryostat cl Mlium) correction (right) Les panneaux solaires ont ete deployes etait bonne, que I'integration mecanique une heure et demie apres le lancement du modele structurellthermique pouvait Bloc du propulseur pour la correction et le satellite a ete place sur orbite de demarrer et que la definition du secteur d'attitude et d'orbite de I'ISO (cl droite) derive gsostationnaire lorsque le moteur

82 programmes & operations

The Hubble Space Telescope (HST) remains scheduled for launch on 26 March 1990. Shipment of the flight hardware from Sunnyvale California to Kennedy Space Centre (KSC) by C5-A aircraft is planned for mid-October. The HST is complete except for one instrument, the Wide-Field Planetary Camera, which has been removed for reworking and will be re-installed at KSC. The Faint Object Camera is checked out each month and shows no change in performance. Work continues on the building of the second set of solar arrays to support the HST maintenance mission planned for five years after launch.

ISO

Recent activities on the Infrared Solar Observatory (ISO) have been geared to freezing the system and subsystem design in preparation for the System Design Review. All aspects of ISO 's design, including flight operations, were examined by a series of specialised review panels. In early July the Review Board approved the design of the payload module (essentially the large hel ium cryostat); the start of mechanical Development of the scientific payload is Installation de /'aile du g{merateur solaire de integration of the structural/thermal progressing well. All four scientific vol du Telescope Hubble chez Lockheed cl model; and the definition of the ground instrument groups have now started to Sunnyvale, California segment. The design of the very manufacture their engineering Installation of HST solar-array flight wing at complex attitude control subsystem is qualification models. Ground segment Lockheed's facility in Sunnyvale, California causing concern and further work is definition is proceeding well and the first required to ensure no mission-critical modules of the software that will be used single point failures remain in the for both instrument testing and flight was placed in geostationary drift orbit satellite's electrical system. Qualification operations have been tested and when the bi-propellant liquid apogee model electrical units will be released for accepted. engine was fired as planned some 36 manufacture in stages over the next few hours after lift-off. Platform SUb-system months. The overall project schedule is very commissioning tests were completed critical. Although the launch date is during the drift phase, and the station­ Payload module integration started in unchanged, little contingency remains acquisition manoeuvres to place the July and is proceeding rapidly. A and this situation is currently being satellite in its final orbital position at problem of leakage from the liquid reviewed. 19°W were successfully completed on helium tank has been reduced 4 August. sufficiently to allow development of the cryostat to begin. Manufacturing of the Preliminary tests have shown that all four service module structure is well Olympus payloads are working properly. A team advanced and the hydrazine thrust of ESA and British Aerospace engineers reaction control subsystem is about to be The 0lympus-1 spacecraft was are now engaged in payload delivered. The hydrazine tank, a new successfully launched from the Guiana commissioning and in-orbit testing from European development by Dowty (UK), Space Centre in Kourou on 12 July at the Redu ground station. Initial results has been delivered and a second tank 00: 14 h UT on V32, the last of the from these more detailed performance has been burst-tested, demonstrating Ariane-3 launchers. tests are good, and they are expected to generous design margins. All electrical be completed by mid-October, after subsystem units are in an advanced The solar arrays were deployed 1V2 which the satellite will be available to stage of breadboard testing . hours after launch , and the spacecraft users.

83 • bulletin 60 d 'apogee biliquide a ete mis a feu, poursuivent chez Marconi; la livraison est sondeur a haute resolution spectrale et comme prevu, environ 36 heures apres prevue pour octobre. les etudes de dissemination de donnees. le decollage. Les essais de recette du Les etudes de modelisation du sondeur sous-systeme de plate-forme ant ete EEMS (ERS-2) a ondes millimetriques et de I'imageur a acheves pendant la phase de derive et Une nouvelle proposition de programme, haute resolution dans le visible ant les manoeuvres d'acquisition de la concern ant le satellite europeen de commence respectivement en juin et en station, visant a placer le satellite dans surveillance de I'environnement (EEMS), juillet et les etudes de simulation du sa position orbitale definitive de 19°W, qui doit faire suite a ERS-1, devait etre sondeur a ondes millimetriques et du ant ete menees a bonne fin le 4 aout. presentee en septembre au Conseil petit ensemble optique sont en voie directeur du Programme d'observation d 'acMvement. Lorsque ces etudes Des essais preliminaires ant montre que de la Terre. La proposition EEMS parte seront terminees, le Conseil d 'Eumetsat les quatre charges utiles fonctionnaient notamment sur les instruments similaires choisira les options les plus correctement. Une equipe d'ingenieurs a ceux prevus sur ERS-1 et sur une interessantes. Pour que le lancement de J'ESA et de British Aerospace nouvelle experience de surveillance de puisse avoir lieu en 1998, I'etude de procede actuellement aux essais en I'ozone a I'echelle du globe (GOME). faisabilite de phase A doit demarrer orbite et aux essais de recette de la avant la fin 1990. charge utile a la station sol de Redu. Les premiers resultats de ces essais de Plate-forme polaire fonctionnement plus detailles sont bans EOPP La reunion de lancement pour I'etude de et I'on pense qu'ils seront termines pour phase A de la premiere mission la mi-octobre; apres cela, le satellite sera Aristoteles d'observation de la Terre sur orbite mis a la disposition des utilisateurs. Une etude supplementaire sur la mission polaire utilisant la plate-forme polaire de Aristoteles du Programme 'solide Columbus s'est tenue en juillet avec terrestre ', que le Conseil directeur du Dornier et les 12 sous-traitants ERS Programme d 'observation de la Terre 'instruments' charges de I'etude des avait approuvee en juin 1988, a demarre instruments candidats de I'installation du ERS-1 en mai. Elle parte sur la definition plus noyau. La Revue des resultats de qualification, poussee de la principale mission de tenue en juin 1989, a confirme que la mesure du champ gravifique qui utilisera Parallelement, un certain nombre situation d'ensemble du modele de un gradiometre, definition entamee au d'activites de soutien ant ete menees: qualification du satellite etait satisfaisante cours de la phase A, et I'analyse des - reunion des groupes de consultants et a renforce la conviction que le options additionnelles, notamment une scientifiques de I'ESA pour les detecteur actif a hyperfrequences (AMI) mission de localisation precise, un instruments MER IS, HRIS et A TLID et I'altimetre radar (RA) satisferaient aux magnetometre et un recepteur pour le - reunions de liaison avec les sept imperatifs de fonctionnement. systeme mondial de localisation. equipes retenues pour les instruments afin de lancer leurs etudes de En juin et en juillet. le modele Les aspects programmatiques, y compris phase A d 'identification de la charge utile un lancement paten tiel sur Ariane 502 en - reunions de liaison avec Eumetsat et entierement integree a passe les essais octobre 1995, sont a I'etude, I'objectif la NOAA, consacrees a la charge utile d'equilibrage thermique et les essais etant d'entamer en septembre 1990 une operationnelle thermiques sous vide dans la grande etude de definition du projet de phase B. - travaux relatifs a I'integration des installation de simulation solaire (LSS) de activites d'instrument du MIPAS dans I'ESTEC et la premiere evaluation de ces Un atelier consacre a la mission d'etude le cadre de I'etude de phase A essais a montre que le fonctionnement du solide terrestre 'Aristoteles ' s 'est tenu - poursuite des activites de etait satisfaisant. La charge utile a ete en mai a Trevi, italie. Cet atelier, preside developpement des technologies transportee chez Matra, a Toulouse, pour par le Ministre ita lien de la Recherche critiques. etre integree avec la plate-forme du scientifique et technologique a confirme modele de vol et pour subir des essais a nouveau l'interet scientifique et la Campagnes aeroportees de compatibilite electrique. La plate­ faisabilite technique de la mission de Deux campagnes aeroportees ant ete forme a deja satisfait aux premiers essais reference proposee. menees a bonne fin . Entre le 16 mai et en circuit ferme, commandes a distance le 15 jUl'/let, lors d 'une campagne avec le du Centre de contr61e de missions de Meteosat de deuxieme generation spectrometre imageur, un grand nombre I'ESOC. Deux etudes paralleles portant sur un de donnees ant ete recueillies au-dessus systeme de satellite stabilise par rotation de zones-cibles maritimes et terrestres. Para IIelemen t, I'integration du modele de ant ete lancees en juin par I'Aerospatiale En aout, un accord a ete conclu avec la vol de la charge utile se poursuit chez et British Aerospace. Des appels d 'offres NASA pour la collecte de donnees Fokker, apres livraison de I'altimetre ant ete envoyes en aout pour deux aeroportees au-dessus de sites d 'essais radar, du sous-systeme de traitement et autres etudes paralleles portant sur un terrestres, au moyen du SAR a triple de transmission des donnees des satellite a stabilisation trois axes. frequence et quadruple polarisation instruments et du radiometre infrarouge embarque sur un DC8 de la NASAlJPL. et hyperfrequences a balayage dans le Un certain nombre d'etudes Les donnees des deux campagnes sens de la trace au sol. L'integration et d 'instruments sont en cours. Des appels seront mises a la disposition d 'un grand les essais du modele de vol de I'AMI se d 'offres ant ete lances en aout pour le nombre de centres de recherche.

84 programmes & operations

· ERS additional options including a Precise­ their Phase-A studies Positioning Mission, a magnetometer and - interface meetings with Eumetsatl ERS-1 a Global Positioning System receiver. NOAA for the operational payload The Qualification Results Review held in - actions on integration of the MIPAS June confirmed the overall satisfactory The programmatic aspects, including the instrument activities within the status of the satellite engineering, and potential launch on Ariane 502 in Phase-A study this has further increased confidence that October 1995, are being reviewed, with - continuation of the critical technology the Active Microwave Instrument (AMI) a view to a Phase B project definition development activities. and the Radar Altimeter (RA) will fulfil study starting in September 1990. their performance requirements. Aircraft campaigns A workshop on the European Solid Earth Two aircraft campaigns have been The fully integrated Engineering Model Mission Aristoteles was held at Trevi, successfully completed. Between 16 May Payload completed thermal Italy in May. This workshop, chaired by and 15 July an imaging spectrometer balance/thermal vacuum testing in the the Italian Minister for Scientific and campaign collected extensive data over Large Solar Simulation (LSS) facility at Technological Research, reconfirmed the sea and land target areas. In August an ESTEC in June and July, and the initial scientific validity and technical feasibility agreement with NASA provided for test evaluation indicated satisfactory of the proposed baseline mission. airborne data collection over land test performance. The Payload has been sites, using the NASA/JPL three­ transported to Matra, Toulouse for Meteosat Second Generation frequency quad ri-polarised DC8 SAR integration with the Flight Model Platform Two parallel studies for a spin-stabilised facility. Data from both campaigns will be and electrical compatibility tests. The satellite were initiated in June with made available to a wide number of Platform has already successfully Aerospatiale and British Aerospace. research centres. completed the first closed-loop test, Invitations-to-tender for two further remotely controlled from the Mission parallel studies for a three-axis-stabilised Control Centre at ESOC. satellite were issued in August. Earthnet

In parallel, Flight Model payload A number of related instrument studies The satellite missions handled by integration is progressing at Fokker, are underway. Invitations-to-tender were Earthnet (Landsat, MOS-1, Tiros and following the delivery of the Radar issued in August for the High Spectral Spot) continue to perform nominally. The Altimeter, the Instrument Data-Handling Resolution Sounder and the Data Kiruna, Fucino, Maspalomas and Troms~ and Transmission Subsystem and the Dissemination studies; the Millimetre stations continue to process the data Along-track Scanning Infrared and Wave Sounder Modelling and High from these missions successfully. Microwave Radiometer. Resolution Visible Imager studies were initiated in June and July, respectively. A joint ESA-CEC project to process all The AMI Flight Model is still undergoing Studies on the Millimetre Wave Sounder the CZCS European data (acquisitions integration and testing at Marconi, with Simulation and Small Optical Package performed at Dundee, Lannion and delivery expected in October. are nearing completion. Maspalomas in the period 1978-1986) has been proposed. EEMS (ERS-2) Once all of the above studies have been A new programme proposal for a follow­ completed, the Eumetsat Council will The ESA-EEC agreement for Spot and on ERS-1 programme, the European select its preferred options. I n order to Landsat operations at Maspalomas has Enviroment Monitoring Satellite (EEMS), achieve a launch in 1998, the Phase A been extended to the end of 1990. will be presented to the Earth feasibility study must start before the end Observation Programme Board in of 1990. The ESA-Eurimage agreement for the September. The proposed EEMS commercial distribution of Landsat data instrument complement is similar to that Polar Platform hOlS been extended for two years. of ERS-1, with the addition of a new The kick-off meeting for the Phase A Global Ozone Monitoring Experiment study of the first Polar Orbit Earth Progress is continuing on the (GOME). Observation Mission using the Columbus establishment of the Earthnet ERS-1 Polar Platform was held in July with Central Facility and ground stations at Dornier (D) and the 12 instrument sub­ Fucino, Gatineau and Maspalomas. The EOPP contractors charged with the study of the German project for an Antarctic station is candidate Core Research Facility underway. Aristoteles instruments. An additional study on the Aristotoles Work on the French, German and British Solid Earth Mission, approved by the In parallel, a number of supporting Processing and Archiving Facilities (PAF) Earth Observation Programme Board in activities have been performed, continues. Contractual actions have been June 1988, was initiated in May of this including: initiated by the Italian Space Agency for year. The study includes the further - meeting of the ESA scientific the Italian PAF at Matera. Proposals are definition of the primary gravity consultancy groups for the MERIS, being prepared for the expansion of the measurement mission using the Gradio HRIS and ATLlD instruments ERS-1 Phase E activity to cover the instrument addressed during Phase A, - interface meetings with the seven operation of the PAFs and the promotion together with an investigation of selected instrument teams to initiate of ERS.

85 • bulletin 60

Earthnet manquer d 'ergo/s et sera retire de en octobre a d 'autres essais de I'orbite geostationnaire dans les compatibilite a I'ESOC. Les satellites dont les donm3es sont prochains mois. Son systeme imageur traitees par Earthnet (Landsat, MOS-1, est verifie regulierement et ne montre Eureca est actuellement inscrit au Tiros et Spot) continuent de fonctionner aucun signe de deterioration au bout de manifeste pour un lancement en mai normalement. Ce sont les stations de huit annees de fonctionnement en orbite. 1991 a vec le sa tellite captif ita lien . Kiruna, Fucino, Maspalomas et Troms~ qui assurent ce traitement. Programme operationnel Apres son lancement reussi et sa recette Station spatiale L 'ESA et la CCE ont propose de mener en orbite, le satellite MOP-1 a ete mis en en commun un projet relatif au traitement service le 19 juin 1989 et rebaptise internationalel de toutes les donnees europeennes du Meteosat-4. Les reserves d 'ergo/s sont CZCS (acquises a Dundee, Lannion et suffisantes pour les cinq annees de Columbus Maspalomas pendant la periode duree de vie prevues et le Apres que l'industrie ait ann once fin mai 1978-1986). fonctionnement est nominal. que la soumission de la proposition de phase CID du secteur spatial de L 'accord conclu entre la CEE et I'ESA MOP-2 a ete integre dans les locaux de Columbus serait repoussee a la fin aout, pour le traitement de donnees Spot et I'Aerospatiale a Cannes et les essais le Conseil directeur du Programme Landsat a Maspalomas a ele prolonge d 'ambiance ont debute. Le lancement Columbus et le Comite de la politique jusqu'a la fin 1990. est maintenant prevu pour avril 1990. Le industrielle (IPC) ont ete informes de ce troisieme modele, MOP-3, sera lance en glissement en juin lors de leurs reunions L 'accord ESA -Eurimage sur la distribution septembre 1993. respectives. Afin de ne pas retarder la commercia le des donnees Landsat a ete decision du Conseil de I'ESA, fixee a prolonge de deux ans. A la demande d 'Eumetsat, on prepare octobre 1989, des dispositions speciales une proposition de prolongation du ont ete arretees avec I'industrie en vue On poursuit la mise en place de programme au-dela de 1995. Elle portera de soumettre une proposition anticipee I'installation centrale ERS-1 d 'Earthnet et notamment sur le lancement et pour les options A et B de plate-forme des stations sol de Fucino, Gatineau et I'exploitation d 'un satellite polaire. La proposition officielle de phase Maspalomas. Le projet allemand de supplementaire. CID du secteur spatial de Columbus a station antarctique est en cours. ete soumise pendant la periode comprise entre le 31 aout et le 4 Les travaux sur les installations franr;aise, Eureca septembre. allemande et britannique de traitement et d 'archivage (PAF) se poursuivent. L 'integration de I'unite de vol d'Eureca La date de soumission de la proposition L 'Agence spatiale italienne a engage des chez MBBIERNO (Breme) se deroule de ayant ete modifiee, I'ESA a revise son procedures contractuelles pour la PAF far;on satisfaisante. Le systeme de planning d 'evaluation. L 'evaluation italienne de Matera. On prepare des micropu/sion par gaz froid et le systeme principale doit avoir lieu entre septembre propositions relatives a I'elargissement de transfert interorbital a hydrazine ont et novembre et, apres une serie initiale des activites de phase E d'ERS-1 pour satisfait aux essais d 'etancMite et de de negociations, ses conclusions couvrir I'exploitation des PAF et la timbrage. On se concentre main tenant devraient etre presentees a I'IPC en promotion d 'ERS. sur I'integration initiale et les essais de mars 1990. fonctionnement des sous-systemes electroniques, a I'exception du sous­ Le Comite ESA de la Revue des systeme de commande d 'orientation qui imperatifs preliminaires (PRR) de Meteosat ne sera pas disponible avant le debut de Columbus s'est reuni en juin pour I'annee prochaine. Sur les quinze examiner les resultats des revues Programme pre-operationnel instruments qui doivent etre integres complementaires de la PRR 1 qui se Depuis sa mise en service en aout 1988, dans la premiere mission, sept sont deja sont terminees au debut de I'annee. Le Meteosat-3 (P2) a assure les activites a Breme et les essais initiaux sont sur le Comite a conclu que l'acMvement de meteorologiques operationnelles, a tive point de commencer. ces revues complementaires mettait un de satellite principal, jusqu 'au 19 juin point final a la PRR 1 de Columbus. 1989, date a laquelle Meteosat-4 On travaille activement avec I'ESOC et la Apres reception de la documentation (MOP-1) a pris le relais. Cela a mis un NASA a la mise au point definitive des technique, qui fait partie de la terme a la mission de P2 qui a assure la accords d'interface et a la preparation proposition de phase CID, on a entame transition entre les programmes pre­ du planning des operations en vol. les preparatifs de la PRR 2 qui aura lieu operationne/s et operationne/s. Ce dans la deuxieme moiM de I'annee. satellite est actuellement parque 3°W en Le modele d'experience RF d'Eureca a renfort de Meteosat-4. 11 sera ete assemblee et mise a I'essai; elle est L 'equipe Columbus a egalement ulterieurement place a 50 0 W ou il actuellement au Centre spatial Johnson participe a la PRR d'Hermes en juin. comblera le vide cause par la defaillance de la NASA ou elle subit des essais de Aucun probleme important n 'a ete du satellite americain GOES-East. compatibilite avec la Navette dans le decele au cours de la revue en ce qui laboratoire d 'essais des sous-systemes concerne les exigences d 'interface entre Meteosat-2, lance en juin 1981, va electroniques. 11 est prevu de proceder I'avion spatial Hermes et le module

86 programmes & operations

Meteosat already at Bremen and initial testing is part of the CID proposal, preparation for about to commence. PRR 2 in the latter part of the year is Pre-operational Programme underway. Meteosat-3 (P2) was used as the primary Very active discussions are underway spacecraft for operational meteorological with ESOC and NASA to finalise interface Columbus also participated in the activities from the end of its agreements and to prepare the flight Hermes PRR in June. No major commissioning in August 1988 until 19 operation planning. problems were identified during the 19 June 1989 when operations were review with respect to the Hermes switched to Meteosat-4 (MOP-1). This The Eureca RF 'Suitcase' model has spaceplane/Columbus Free Flyer ended the role of P2 as a bridge been assembled and tested and is now interface requirements. A delta PRR between the Pre-operational and at NASA's Johnson Space Center for review is planned towards the end of the Operational Programmes. The spacecraft Shuttle compatibility testing in the year, after completion of the Hermes is now on stand-by at 3°W as back-up Electronic Systems Test Laboratory. spaceplane concept preliminary design for Meteosat-4. It will later be moved to Subsequent compatibility testing is review. 50 oW, where it will fill the gap caused by scheduled for October at ESOC. the failure of the American satellite In early July ESA was informed by NASA GOES-East. Eureca is currently manifested for launch that a critical internal NASA Space together with the Italian Tethered Satellite Station Freedom review had been M eteosat-2 , launched in June 1981 , is in May 1991. initiated in response to anticipated running low on fuel and will be removed budget cuts over the next few years. At from geostationary orbit in the next few the beginning of August NASA informed months. Its imaging system is exercised International Space the international partners about a periodically and shows no deterioration significant reduction of the International after eight years in orbit. Station/Columbus Space Station (Freedom) capabilities, at Following Industry's announcement at least in the early years of operation. ESA Operational Programme the end of May of a delay in submittal of has expressed its concerns to NASA, After successful launch and in-orbit the Columbus Space Segment Phase and consultations on how to resolve the commissioning, the MOP-1 spacecraft CID proposal to late August, the issues are in progress. was placed in service on 19 June 1989 Columbus Programme Board and the as Meteosat-4. The on-board fuel is Industrial Policy Committee (IPC) were A Multilateral Utilisation Study supported sufficient to support the five-year lifetime informed of the slippage at their by all International Space Station and performance is nominal. respective meetings in June. In order to (Freedom) partners will be completed in safeguard the October 1989 ESA September. The study team has MOP-2 has been integrated at the Council decision milestone, special elaborated a detailed list of candidate Aerospatiale facilities in Cannes, and advanced proposal-delivery payloads for all Space Station Modules, environmental testing has started. The arrangements related to the Polar including information on their resource launch is now scheduled for April 1990. Platform Options A and B offers were requirements. This information has The third model, MOP-3, will be agreed with Industry. The formal enabled the study team to perform an launched in September 1993. Columbus Space Segment Phase CID analysis of the integration and operation proposal was actually submitted over the of this complement. At the request of Eumetsat, a proposal period 31 August to 4 September. for extension of the programme beyond A hardware contract has been placed the end of 1995 is being prepared. This ESA's evaluation planning was revised with Industry for the development of a would include launch and operation of as a consequence of the changed Microgravity Measuring Assembly to be one more spacecraft. proposal delivery date. The main flown initially on Spacelab 0-2 and then evaluation is planned for the period developed further for use in both the September to November, and will be Attached and the Free-Flying Laboratory. followed by an initial negotiation round, Phase-A Studies for additional common Eureca with the aim of presenting the laboratory equipment (such as coolers, conclusions to the IPC in March 1990. freezers, payload video system, a Integration of the Eureca flight unit at vacuum pump and a general purpose MBB/ERNO in Bremen is progessing The ESA Columbus Preliminary workbench) are being initiated for well. Full pressure testing and leak Requirements Review (PRR) Board completion at the end of Phase 1 of the verification of the cold gas reaction convened in June to review the results of Columbus Programme. control system and the hydrazine orbital the 'delta' PRR 1 reviews completed in transfer system has been completed the early part of this year (a 'delta', or successfully. Emphasis is now on initial follow-on, review is held to verify that the Ariane integration and function testing of 1he recommendations of the original review electronic subsystems, with the exception have been carried out). The Board ELA-3 site status of the attitude-control subsystem which concluded that, with completion of the Civil engineering works on the Ariane-5 will not be available until early next year. delta reviews, all Columbus PRR 1 launch complex, ELA-3, at Kourou, Of the fifteen instruments to be objectives had been met. Having French Guiana, have progressed despite integrated for the first mission, seven are received the technical documentation, as a particularly wet season earlier this year.

87 ~ bulletin 60 autonome Columbus. Une revue PRR Ariane Les travaux de construction du Mtiment complementaire doit avoit lieu vers la fin d'assemblage final (BAF) commenceront de i'annee, lorsque que la Revue de Site ELA-3 en 1990. Les fondations du centre de conception preliminaire de i'avion spatial En Guyane, les travaux de genie civil se lancement (COL) et de i'aire de Hermes aura ete achevee. sont deroulees, en debut d 'annee, dans lancement sont terminees (zone avant). un climat particulierement humide. La Debut juillet, la NASA a fait savoir cl structure en beton, d'une hauteur de La fabrication en Europe de la structure i'ESA qu'elle avait entame une revue 55 m, du Mtiment d'integration metallique de la table de lancement a interne et critique de la Station spatiale propulseurs (BIP) a ete achevee et peut debute en aoOt et se poursuivra juSqu 'cl internationale (Freedom) en prevision des main tenant accueillir les equipements la fin de i'annee; i'expedition et reductions budgetaires attendues pour secondaires (plates-formes , installation i'installation des systemes fluides et les prochaines annees. Debut aoOt, la d 'air conditionne, etc.). electriques pourront donc avoir lieu NASA a informe les partenaires debut 1990. internationaux qu'il y aurait une reduction La structure du Mtiment d 'integration substantielle des ressources de la Station lanceur (BIL), qui est en cours de Les travaux sur le banc d 'essais P230 spatiale internationale (Freedom), tout du construction, doit etre achevee d'ici la fin ont bien avance, et la pyramide de moins pendant les premieres annees de de i'annee pour que I'on puisse soutien en beton est presque achevee. son exploitation. L 'ESA a fait part de sa proceder cl i'assemblage des structures L 'assemblage des structures mMalliques preoccupation cl la NASA et des mMalliques et des equipements au debut devrait egalement commencer debut consultations sont en cours afin de de 1990. 1990. resoudre ces problemes.

Une etude d'utilisation multi/aterale realisee avec le concours de tous les partenaires de la Station spatiale internationale sera achevee en septembre. L 'equipe d'etude a dresse une liste detaillee des charges utiles candidates pour tous les modules de la Station spatiale., dans laquelle figurent des renseignements sur les besoins en matiere de ressources. Ces renseignements ont permis cl i'equipe d'etude d 'analyser i'integration et i'exploitation de cette charge utile.

Un contrat a ete passe avec i'industrie pour la realisation d 'un ensemble de mesure de microgravite qui doit tout d 'abord etre embarque sur le Spacelab 0 -2 puis, apres d 'autres travaux de developpement, etre utilise dans le Laboratoire raccorde et dans le Laboratoire autonome. On entame des etudes de phase A portant sur des equipements supplementaires communs aux deux laboratoires (par exemple, refrigerateurs, congelateurs, systeme video de charge utile, pompe cl vide et etabli polyvalent), qui seront achevees cl la fin de la phase 1 du Programme Columbus.

ELA-3 Booster Integration Building (BIP) under construction (May 1989) Le Batiment d 'integration propulseurs de I'ELA-3 en cours de construction (mai 1989)

ELA-3 P230 Test Stand under construction (August 1989)

Le banc d'essai P230 de I'ELA-3 en cours de construction (aoDt 1989)

88 programmes & operations

The 55 m high Booster Integration The Liquid Gauging Technology Hermes Building (BIP) concrete structure has experiment development contract will been completed and is now ready to start in September and will last 18 Since the last Bulletin two major Hermes receive the secondary equipment months. reviews have been held. Although (platforms, air conditioning, etc.) Industry's involvement was limited to the Common Support Subsystems spaceplane main contractor and Avion The Launcher Integration Building (BIL) Development of the Payload Control Unit Marcel Dassault (AM D) , these reviews structure is under way, with completion has been delayed and is now scheduled will have a strong impact on the rest of scheduled for the end of the year in for completion by the end of this year. the Phase 1 activities. order to start assembly of the metallic The first operational unit of the structures and equipment in early Hitchhiker-G simulator has been The objective of the first review, the 1990. manufactured. Preliminary Requirements Review (PRR), was to prepare the Hermes The Final Payload Assembly Building ESAlNASA Cooperative Experiments requirements' baseline at top system (BAF) works will start in 1990. Regarding the In-Flight Contamination level for space, crew and ground Foundations have been completed for Experiment (IFCE) the NASA Phase-B segments. With the Hermes System the Control Centre (COL) and the launch was completed in July (the ESA Phase-B Requirements Document as reference, a pad (forward area). having been completed earlier). number of key documents were Discussions on Phase CID are examined in detail. The PRR Board Manufacture of the metal structure for awaiting the outcome of the CTM issued a number of recommendations the Table started in August in Europe decision. dealing with these documents and their and will last until the end of the year, architecture; it will formally be closed in enabling shipment and installation of fluid The NASA Phase-B for the Solar Array October. and electrical systems to take place in Module Plasma Interaction Experiment early 1990. (SAMPlE) will be completed in The second review, the Preliminary September. ESA is again awaiting the Spaceplane Definition Review (RDP-A), The P230 teststand is well under CTM decision. was organised by CNES and way, with the concrete support pyramid Aerospatiale and started at the end of near completion. Assembly of the metal Flight opportunities June. Its main objective was to assess structures is also scheduled to start in With regard to the Hitchhiker the spaceplane 'Stage 0' configuration early 1990. experiments, the Altitude Sensor against the requirements cleared at the Package is now manifested on STS-49, PRR. It also aimed to approve the on 30 September 1991, the Collapsible 'level l' documentation, including Tube Mast with the IFCE on 22 February Aerospatiale's space plane specifications, 1993 (STS 64). the space plane development plan and TOP the general specifications which will form The final safety review cycle for the Solid the basis of the future industrial Experiments State Microaccelerometer will be development phase. The Review Board For the Gallium Arsenide Solar Array completed by the end of this year. It is and the six review panels, made up (GaAs) experiment the flight unit panel expected to be launched in 1990 (Shuttle largely of independent external experts, and the experimental patch have been Get-Away Special G21). participated in two weeks of intensive manufactured and tested, and the Flight discussion at Aerospatiale in Blagnac, Acceptance Review was held in August. UoSAT-E will be launched on during which over 4000 pages of The experiment will be integrated aboard 9 November on an Ariane 4 as piggy­ documentation were reviewed. A number UoSAT-E in September. Phase-2, back to Spot-2. The TOP experiments on of presentations were made by focussing on 2 x 4 cm cells with welded board are the Transputer and Single Aerospatiale and AMD, as well as by the interconnectors, has been initiated. Event Upset and the Gallium Arsenide Technology Panels appointed by CNES Solar Panel with an experimental patch. and ESA. The Solid State Microaccelerometer flight The final choice of carrier for the Gallium unit has successfully completed Arsenide Panel with larger cells (Phase Over 100 recommendations were made, environmental testing and the Flight 2) is in progress. dealing with major issues such as crew Acceptance Review is scheduled for safety and the use of the ejectable cabin, September. The Transputer and Single TDP Next Phase Preparation the space plane mass budget, critical Event Upset flight unit completed its In the framework of the preparatory technology and aerodynamics, the Flight Acceptance Review in August and activities for Phase 2 of the Technology qualification plan, and the Ariane-5 will also be integrated on UoSAT-E in Demonstration Programme (TOP), the interfaces. They will be submitted to a September. preliminary evaluation of proposals Steering Board in mid-September and, received in reply to the Announcement once approved, will enter into force in In July Phase-B activities for the of Opportunity has been completed and October. G Collapsible Tube Mast (CTM) were the detailed evaluation should be completed. The decision as to whether to completed by the end of this year. proceed to Phase CID will be taken in October.

89 • bulletin 60

TOP I'ensemble de detection d'orientation est La deuxieme revue, la Revue de inscrit au manifeste de vol de la Navette definition preliminaire de I'avion spatial Experiences pour le 30 septembre 1991 (STS-49) et (RDP-A), organisee par le CNES et Pour I'experience de generateur solaire a le mat a tube enroulable avec I'IFCE I'Aerospatiale, a commence fin juin. Elle I'arseniure de gallium (GaAs), la pour le 22 fevrier 1993 (STS 64). visa it essentiellement a evaluer la fabrication et les essais du panneau du configuration de 'stade 0' de I'avion modele de vol et des plaquettes Le cycle de la Revue finale de securite spatial, compte tenu des exigences experimentales sont termines et la Revue pour le microaccelerometre a I'etat solide approuvees lors de la PRR. Elle portait d 'acceptation au vol s'est tenue en aout. sera acheve a la fin de I'annee. Le egalement sur I'approbation des L 'experience sera integree a bard lancement doit avoir lieu en 1990 (Get­ documents de 'niveau 1 ', notamment les d 'UoSAT-E en septembre. La phase-2, Away Special G21 sur la Navette). specifications de l'Aerospatiale pour qui parte principalement sur des piles de I'avion spatial, le plan de realisation de 2 cm x 4 cm avec interconnecteurs UoSA T-E sera lance le 9 novembre 1989 I'avion spatial et les specifications soudes, a ete engagee. sur Ariane-4 en tandem avec SPOT-2. 11 generales qui constitueront la base de la emportera les experiences future phase de developpement L 'unite de vol du microaccelerometre a transordinateur et pertubations sous industriel. Le Comite de la revue et les I'etat solide a satisfait aux essais I'effet de particules elementaires et six groupes d'etudes, constitues en d'ambiance. La Revue d'acceptation au panneau solaire a I'arseniure de gallium grande partie d 'experts exterieurs vol est prevue pour septembre. L 'unite avec des plaquettes de photopiles independants, ant participe a une de vol de I'experience transordinateur et experimentales. On procede au choix session d 'etude intensive de deux pertubations sous I'effet de particules definitif du satellite qui emportera le semaines a I'Aerospatiale, a Biagnac, au elementaires a deja passe cette revue en panneau a I'arseniure de gallium avec cours de laquelle ils ant examine plus de aout et sera elle aussi integree a UoSA T­ des photopiles de plus grandes quatre mille pages de documentation. E en septembre. dimensions (phase 2) . Des presentations ont ete faites par I'Aerospatiale et AMD, ainsi que par les En juillet, les activites de phase B portant La prochaine tranche du TOP groupes technologiques des ignes par le sur le mat a tube enroulable (CTM) ont Dans le cadre des activites preparatoires CNES et I'ESA. ete menees a bonne fin . On decidera en de la phase-2 du Programme de octobre s'il convient de passer a la demonstration technologique, on a Plus de cent recommandations ont ete phase CID. acheve I'evaluation preliminaire des formulees, traitant de questions propositions rer;;ues en reponse a I'avis essentielles telles que la securite de Le contrat de developpement de d 'offres de participation et I'evaluation I'equipage et I'utilisation de la cabine I'experience de technologie de jaugeage detaillee devrait etre terminee d 'ici la fin ejectable, le bilan de masse de I'avion des liquides demarrera en septembre et de I'annee. spatial, les technologies critiques et durera dix-huit mois. I'aerodynamique, le plan de qualification et les interfaces d 'Ariane-5. Elles seront Sous-systemes de sQutien communs soumises a un Comite directeur a la mi­ La realisation de I'unite de commande septembre et, si elles sont approuvees, de la charge utile, qui a ete retardee, Hermes entreront en vigueur en octobre. • devrait etre achevee d 'ici la fin de I'annee. La premiere unite operationnelle Depuis la parution du dernier bulletin, du simulateur Hitchhiker-G a ete deux revues importantes ont ete tenues. fabriquee. Bien que la participation de I'industrie soit limitee au contractant principal de Experiences en cooperation ESNNASA I'avion spatial et aux Avions Marcel En ce qui concerne I'experience de Dassault (A MD), ces revues auront de contamination en vol (IFCE), les travaux fortes repercussions sur le reste des de la NASA sur la phase B se sont activites de la phase 1. acheves en juillet (Ies travaux correspondants de I'ESA sont deja . La premiere revue, la Revue des termines). On attend pour reprendre les exigences preliminaires (PRR), avait pour discussions relatives a la phase CID de objet de dresser le catalogue de connaitre la decision du CTM. reference des exigences d'Hermes au plus haut du niveau systeme pour les La NASA achevera en septembre ses secteurs spatial, terrien et des travaux sur la phase B de I'experience equipages. Le document 'exigences du d'interactions entre le module de systeme Hermes ' a servi de reference a generateur solaire et le plasma (SAMPlE) . I'examen detaille de bon nombre de La encore, I'ESA attend une decision du documents cles. Le Comite de la PRR a CTM. fait un certain nombre de recommandations au sujet de ces Occasions de vol documents et de leur structure; la revue Pour les experiences Hitchhiker, sera officiellement cl6turee en octobre.

90 advertisement

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German Aerospace Research Establishment (DLR) is University of Stuttgart Aerospace Faculty invites seeking a scientist for the position of applications for a Director Professorship of its Institute for Chemical Propulsion and for Chemical Spacecraft Propulsion. Chemical Engineering. The Institute, located at Lampoldshausen near Stuttgart The appointment will at the same time include leave to and currently having about 70 members including 20 hold the DLR position, while involving reduced teaching scientists, is concerned with mainly experimental re­ duties. Research and teaching activities at the Univer­ search in the areas of chemical rocket and ramjet en­ sity of Stuttgart will be supported by a new Working gines as well as related energy, chemical engineering Group to be established. Emphasis will be placed on and combustion technology. The Institute is expected novel propulsion systems for hypersonic vehicles. to provide significant contributions to enhance future propulsion technology in close cooperation with other disciplines of DLR and Stuttgart University such as aero- dynamics, fluid mechanics, combustion, and structural mechanics. Future activities will be focused on super- sonic and high-pressure combustion, simulation of com- bustion chamber processes, and advanced diagnostic methods for combustion processes. For these responsibilities) DLR and the University of Stuttgart are seeking in a joint search procedure a highly qualified personality with demonstrated expertise in above areas. Applications, in duplicate, should be sent as soon as possible to the Chairman of the DLR Executive Board, Prof. Dr. W. Kroll, Under Hohe, D-5000 Koln 90, or to the Dean of the Aerospace Faculty of the University of Stuttgart, Prof. Dr.-Ing. J. Algermissen, Pfaffenwaldring 27, D-7000 Stuttgart 80.

91 • bulletin 60

* HIGH BURY COLLEGE OF TECHNOLOGY REGIONAL ELECTRONICS CENTRE AND ESA APPROVED SCHOOL

Highbury College has recognised the need for overcoming skill shortages in the Space Industry, particularly when related to electronic assembly techniques. To assist the industry in this respect the centre has expanded its course programme for 1990. Highbury is also pleased to announce that in future these courses will be marketed throughout Europe by Spur Training Services Limited. The following courses will be held at Highbury between January 1st and April 31st , 1990.

HCT 1. HAND SOLDERING COURSE TO ESA STANDARD PSS-Ol-70B. January 22-26: February 12-16: March 12-16: April 23-27. HCT 2. INSPECTOR TRAINING COURSE TO ESA STANDARD PSS-Ol-70B. January 22-26: February 12-16: March 12-16: April 23-27. HCT 3. THE PREPARATION AND SOLDER TERMINATION OF SEMI-RIGID CABLE ASSEMBLIES TO ESA SPECIFICATION PSS-Ol-71B. March 26-2B.

The above 3 courses are ESA APPROVED.

HCT 4. ELECTRONIC ASSEMBLY TECHNOLOGY: REWORK AND REPAIR. February 19-23. HCT 5. SURFACE MOUNT TECHNOLOGY. March 5-7.

The above 2 courses are currently under consideration for ESA approval.

Further details of the courses can be obtained from :-

Station House, North Street, Havant, Spur Training Hants. P09 mu, United Kingdom. • Services Ltd. Tel: (0705) 455564 Fax : (0705) 470874 advertisement

publications

Publications Available from ESA Publications Division

Publication Number of Scope/Contenta AwllebUlly Source I.. u e. per yeer

Periodicals ESA Bulletin 4 ESA's magazine Free of charge ESA Publications Division, ESTEC, ESA Journal 4 ESA's learned journal 2200 AG Noordwijk, The Netherlands Earth Observation Quarterly 4 Remote sensing newspaper (English or French) Columbus Logbook 4 Space Station/Columbus newspaper

News & Views 6 ESA Information ESRIN, Via Galileo Galilei, Retrieval Service's newspaper CP64, 00044 Frascati, Italy

Monographs Code Conference Proceedings (SP-xxx) Volumes on specific Conference subjects Prices below ESA Publications Division, ESTEC, ScientificlTechnical Monographs (SP-xxxx) Specific/detailed information on 2200 AG Noordwijk. The Netherlands graduate-level subjects ESA Brochures (BR-xxx) Summary of less than 50 pages on a specific subject ESA Folders (F-xxx) 'Folders' giving short description of a Free of charge ESA Publications Division, ESTEC, subject for the space-interested layman 2200 AG Noordwijk, The Netherlands Scientific & Technical Reports (STR-xxx) Graduate level - reflecting ESA's Prices below position on a given subject Scientific & Technical Memoranda (STM-xxx) Graduate level - latest but not finalised th inking on a given subject Procedures, Standards & Specifications (PSS-xxx) Definitive requirements in support of contracts

Other Publications Contractor Reports (CR-xxx) Study reports from contractors: Prices below ESA Publications Division, ESTEC CR(P) given unlimited distribution 2200 AG Noordwijk, The Netherlands CR(X) confined to certain ESA Member States Technical Translations (TT-xxx) Translations of national space-related Prices from ESRIN ESRIN , Via Galileo Galilei, documents - (Microfiche or CP64, 00044 Frascati, Italy, photocopy only) or ESAIIRS Office, 8-10 Mario Nikis 75738 Paris 15, France

Public-relation. material General literature, posters ESA Public Relations Service photographs, films, etc. 8-10 rue Mario-Nikis 75738 Paris 15, France

Charge. for printed documenta EO E1 E2 E3 E4 Number of pages in document: 1-50 51-100 101-200 201-400 401 - 600 Price (Dutch Guilders) 20 30 40 60 80

1. Cheques to be made payable to: ESA Publications Division 2. Prices subject to change without prior notice 3. Postal charges (non Member States only): Australia DfI . 25; Other Countries Oft. 15.

95 • bulletin 60

Order Form for ESA Publications

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