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Speakers Contreras Briess Sweeting Teston Eide Desobeau Tilmans Alminde Hardy Schilling Skullestad Foing Pedersen

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An educational process, being either of formal orpractical nature, always has as its goal to help thestudent to gain a maximum of independence andcompetitiveness in the chosen field of studies.During the acquisition of knowledge the student isgradually given greater responsibility and obtains inexchange more freedom in the decision making pro-cess.

The universities in charge of formal education givethe students an excellent background of theoreticaltools, but usually very little practical experience.Individuals are kept in an artificial "glass-house"during their university years constantly confrontedwith the outside world but freed from its responsibi-lities and guided, in the necessity of any decisionmaking, by their professors. After graduation transi-tion into industry is often accompanied by a longand costly training phase.

One goal of the Space Technology EducationConference is to offer a starting point for the discus-sion that will hopefully lead in the future to an inter-national cooperation in space education betweenuniversities, industry, space agencies and the SSETIAssociation. This cooperation structure should becapable of introducing students to space relatedactivities by offering them supplementary educationthrough hands-on experiences, and give them thepossibility to step out of their "glass-house" andassume a reasonable amount of freedom andresponsibility aside from, but in harmony with, theirformal academic progress.

Education is essentially the passing on of the tea-cher's personal experience, but as the student slowlymatures this unidirectional process becomes bidi-rectional and knowledge and experience are nomore taught but shared. A second goal of the confe-rence is to support this exchange of knowledge bygiving the possibility to experienced space experts,young engineers and students, having made theirfirst steps in the fields of space exploration andtechnology, to exchange ideas and share their expe-riences. This booklet forms the first step; it containsabstracts outlining the presentations and an over-view of the work done by student groups in variousEuropean universities. Its lecture will hopefullytrigger your interest and help to initiate many con-structive and interesting discussions.

In the name of the SSETI Association and the EPFLSpace Centre, I would like to thank all the contribu-tors to this booklet, experts and students alike, tohave given us some insights into their work. I wouldfurther like to thank the ESA Education Office andthe Swiss Space Office for their enormous supportand sponsorship during the preparation of this con-ference.

Finally to you, dear reader, I wish an excellent stayin Lausanne and hope you will enjoy your participa-tion at STEC.

Renato KrpounEPFL Student &SSETI Association Vice-President

f o r e w o r d

SpaceTechnology Education Conference

STEC 2004 - Space Technology Education Conference 1

SSETI Student Space Exploration andTechnology Initiative

InitiativeThe objective of the Space Exploration and TechnologyInitiative is to create a network of students, educationalinstitutions and organisations facilitating the distributeddesign, construction and launch of (micro)-satellites.Aiming to create a talented workforce for the 21st cen-tury the initiative seeks to enhance scientific and techni-cal literacy in Europe and develop strong relationshipswith both industry and the educational communities.This is achieved by involving a large number of youngEuropeans and increasing their interest in space techno-logy and science by involving them in real space pro-jects and providing an unequalled learning and motiva-tional experience through hands-on experience. Morethan 20 teams from different European countries aredesigning the first European Student Satellite. The pro-ject was launched in 2000 and has been supported byESA since then.

AssociationThe initiative was launched in the year 2000 byESA's Office for Educational Project OutreachActivities and was given a legal fundament and avision for the future in 2003 when it became theSSETI Association. The SSETI association hasbeen formed to support and develop the networkof students created within the SSETI project, togive a legal structure to the project and to impro-ve interactions between ESA, universities, sup-porting the designing team, national entities andindustries.Thus the SSETI Association is a body of studentparticipants independent of ESA. It was formedin June 2003 in order to offer the students thebenefits associated with being a legal entity, andalso to favour a high degree of student autonomyin the SSETI project.Members of the associations are the teams invol-ved in the SSETI project that cooperate to reach the goals stated in the programme. To guide thework of each team there is a coordinator, chosenby and among the students, who, as full memberof the association, has voting rights during gene-ral assemblies. The president of the associationand the other positions on the executive board arestudents elected by the other members.

Programme & MissionsSSETI is a long-term programme composed of differentprojects. There are at the moment two missions underpreparation and a third one should be started soon. Thefirst short-term mission, called SSETI Express, is basedon knowledge gained so far and existing equipment.The mid-term goal of having a modular and flexiblesatellite bus will be achieved when the second mission,the European Student Earth Orbiter (ESEO), is laun-ched. And finally, a long term mission to leave ourEarth and reach for the Moon, should start in September2004 and is called the European Student Moon Orbiter(ESMO).

for more information : www.sseti.net

o r g a n

ESEO - European Student Earth Orbiter

2 STEC 2004 - Space Technology Education Conference

EPFL École Polytechnique Fédérale deLausanneSituated in the heart of Europe, the ÉcolePolytechnique Fédérale de Lausanne (EPFL) is one ofthe two Swiss Federal Institute of Technology. EPFLdelivers courses in all leading fields of modern techno-logy, with a particular focus on inter-disciplinarity -one of the greatest sources of innovation. Within this

broad context, EPFL has identified space technologiesas one of its priorities.At the intersection of mechanics, electrical enginee-ring, micro-technology, and material science, theSchool of Engineering (Science et Techniques del'Ingénieur) has the responsibility to drive this effortand to foster collaborations across the entire campusand with additional national and international academicinstitutions. From 2004 onwards, space-related educa-tion and research activities will increase with the nomi-nation of new faculty, the strong involvement of Swissastronaut Claude Nicollier - already an EPFL Professor- and the creation of the EPFL Space Center. TheCenter, made possible by the support and partnership ofRUAG AG, already involves the University ofNeuchâtel and will seek strong collaborations with theSwiss Space Office (SSO), the European Space Agency(ESA) and the Swiss Space Industry.

Current space-related projects at EPFL and its partnerinstitutions, benefit from previous experience gained ina wide range of fields including: space robotics, solarcells and antennas, atomic force microscope scanners(institute of microtechnique of neuchâtel), aerodyna-mic studies, actuators, materials and structures. Currentnew projects include: i) the development of advancedtechnology to enable the integration of solar cells andantennas onto one same surface, called ASOLANT; ii)

space robotics, with new locomotion concepts andnavigation systems for planetary exploration, includingrovers from a few grams to ten kilograms; iii) theincreased study of navigation principles for theMercury Robotic Payload (MRP-ESA) and finally iv)an autonomous, solar-powered airplane for Mars explo-ration, the Sky Sailor project.The support and follow-up of student projects and asso-ciations is also an important aspect of the space activi-ties at EPFL. Numerous students participate in spacerelated projects, including most recently the PreMARSteam that has won the first Aurora student design con-test in the category "new enabling technologies". Theyproposed a mission consisting in growing a plant onMars using the resources available on the surface. Theconcept was found interesting by ESA who gave the

students the opportunity to participate in a concretemission study. Furthermore three EPFL teams havebeen selected for the 7th Student Parabolic FlightCampaign in 2004. The various experiments being per-formed during this zero-g flight will consist in a flyingrobot, the analysis of the motion of a robotic arm invariable gravity and the placement and soldering ofSMD components in microgravity.The EPFL Space Center will harbor and support selec-ted academic projects but it should also develop into anenabling platform to integrate teaching, research andtechnology transfer activities. The latter will be done inclose collaboration with the Swiss Space industry, inorder to promote global R&D for space applications inSwitzerland. EPFL has a strong tradition to organize public eventsduring which the general public is able to attend talks,exhibitions and courses linked to space technology.One of the highlights of this year is the presentSTEC'04 conference with which the EPFL would liketo support the efforts of the SSETI Association to sparkthe interest of students all across Europe towards inter-disciplinary space projects.

Prof. Roland Siegwart - Prof. Stefan Catsicas

i s e r s

Startiger III (Sky-sailor project)

Ecole Polytechnique Fédérale de Lausanne1015 Lausanne SwitzerlandTel : +41216931111www.epfl.ch


ESAEuropean Space Agency

ESA Education Office

ESA has recently made Education its fifth priority andfield of activity. The two main objectives of our officeare:

1. To reach a significant number of young people andmotivate them to enhance their literacy in science ingeneral Space in particular.

2. To stimulate talented youngsters to dedicate theircareer to Space favouring a highly skilled workforce forthe 21st century.

These objectives are met by addressing youngEuropeans, aged from 6 to 28,through different projects and infor-ming them about various activitiesdesigned for their specific agegroup. This large number of educa-tional projects is coordinated by avery dynamic group of young pro-fessionals in the Education officeand is organised around three mainaxes : Hands- On Projects, Primaryand Secondary Education andHigher Education.

Here are some of the main activitiesof the office relative to students :

1. "Physics on Stage" : A festival forteachers. Each year several hundredsof teachers are invited to attend thefestival and the fair. Teachers areselected by national steering com-mittees and join together to shareideas and practices on how to educa-te sciences at school increasing theinterest of students. Three successfuleditions already took place, the nextone should be in April 2005 inFrance and with a broader interest :"Sciences on Stage".

2. Parabolic Flight Campaigns for EuropeanStudents. Each year 120 European Students get achance to experiment weightlessness and to deve-lop their own experiment to perform in 0 gravity.The experiments are flown on board novespaceA300 and students get 30 times 20secondes ofmicro-gravity to perform their tests. Experimentscan be physics as well as life science or educatio-nal.

3. SSETI The Student Space Exploration andTechnology Initiative gives opportunity to students allover Europe to work on real space missions. At themoment more than 200 students from 12 EuropeanCountries are involved in SSETI and building the firstpan-European student satellites. More information onthis programme can be found under www.sseti.net.

4. IAF and student participation programme. To favourinteractions between students and professionals and to

enhance a sort of generation handover,opportunity is given every year to stu-dents to attend the InternationAstronautical Congress. Hundreds ofstudents have already successfullyparticipated in this programme that isnow being extended to other conferen-ces like COSPAR or workshops inESTEC.

5. YES 2 Young Engineer Satellite 2 isa project co-managed by Delta-Utec(Space Research and Consultancy).The project will demonstrate SpaceMail, the return of small re-entry cap-sule from space to Earth, using newtechnology; the deployment of a tetherin space. It is a promising alternativefor the de-orbiting of payloads. Thecapsule is inherently safe meaning thatit is planned to land as soft as a featherbut if the inflation system fails, thecapsule will burn during the re-entry. Primary and Secondary EducationMany efforts are also put on these agegroups. Tools for teachers and schoolsas well as web sites and games forchildren are developed and availableon the net.

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Medley of Education Office projects

Education Office, ADM-AE ESA - ESTEC Postbus 299 2200AG Noordwijk The Netherlands Fax : +31715655590 [email protected]


SSOSwiss Space Office

Our Mission

Under the direct authority of the State Secretary forScience and Research and in cooperation with otheroffices and organisations involved in space matters, theSSO is the administrative unit charged with planningand implementing Swiss space policy, as defined by theFederal Council. For this purpose, the SSO is the exe-cutive body of the Federal Space Affairs Commission(CFAS) and chairs the Interdepartmental Committeefor Space Affairs (IKAR). The secretariat of both ofthese groups is located at the SSO.

The SSO has prime responsibility for Swiss participa-tion in ESA programmes and activities and oversees thebudget. The SSO looks after Swiss interests withinESA, in the political, institutional, legal, financial,industrial, sciences, applications and infrastructure pro-grammes. Under the SSO's guidance, the FederalOffice for Professional Training and Technology(OFFT), the Federal Finance Administration (AFF) andthe Foreign Ministry's Political Division III (DPIII/DFAE) give their support on technological, finan-cial and political aspects, respectively.

The SSO leads the Swiss Delegation to ESA and chairsthe Delegation's coordination meetings.

The SSO assures that Swiss space policy is consistentin international operational satellite utilisation organi-sations such as EUTELSAT, INTELSAT, IMSO andEUMETSAT as well as in the respective bodies of theUnited Nations and the European Union whereSwitzerland is represented.

Based at the Swiss Embassy in Paris, the PermanentDelegate to ESA, who represents Switzerland in theadvisory bodies and administrative authorities of ESA,is part of the SSO. He especially assures consistencywith and consideration of Switzerland's positions andinterests within these groups.

s o r s

Swiss Space OfficeHallwylstrasse 4 CH-3003 Bernee-mail : [email protected]


Professor Claude Nicollier

The conference opening address will be held byProfessor Claude Nicollier who has been chosen in1978 as a member of the first group of Europeanastronauts and was selected in 1980 for astronauttraining by NASA. Veteran of four Space Shuttleflights he has logged more than 1000 hours inspace. Appointed to his four flights as a missionspecialist he has operated the shuttles robotic armduring his three first missions, while during his lastflight, STS-103, he conducted repairs on the HubbleSpace Telescope during his first space walk.

Prof Nicollier has been appointed professor at theSwiss Federal Institute of Technology in November1994 and will hold his first course at EPFL this spring entitled "Space Technology and Operations".

o p e n i n g a d d r e s s

Claude Nicollier working on the Hubble Space telescope duringthe Space Shuttle mission STS-103 in 1999.


s p e a k e r s

Lessons learned from 20 yearsof small satellites at CNES, is a student satellite possible?Pierre-Louis Contreras, CNES

The presentation will begin with a very short recall ofthe history of small sats at CNES and of today activi-ties. We practice small satellites since the beginning ofCNES mainly for scientific missions, today it has beenraised as a major priority for the missions themselvesand their costs but also for maintaining in house techni-cal abilities. The Myriade microsatellite project is onthe way and six satellites are under construction. Thefirst launch is planned for this summer. Some technicalfigures will follow to identify the different categories.

Some examples of activities made with the students willbe given. We had long projects (about 8 years) with stu-dents, universities and CNES with good or bad results.Some French schools made quite alone one satellite, itworked and it had no follow-up. We had short projectsstopped because the team was not strong enough.

Some other projects have been resized even to balloonprojects which provide also a good "space like" practi-ce. We will try to understand the reasons of these suc-cesses and failures.

Finally, we will explain what we feel as the key pro-blems to success. Sometimes technical problems slowthe work, but it is probably not the major concernbecause in most of the case students have the support ofprofessionals (if they find time) who are able to redirectthe project.

In other cases it is due to the way to build and realizethe hardware too lightly. Other main problems canoccur in term of organisation of the work of the teams.Documentation as technical memory provides troublesbecause generally there are several generation of stu-dents working on the same project, the new team has tolearn from the previous one and information is lost, the

duration of the project increases this effect. What thestudents really do in the project is also a parameter. Toend it is pointed out that generally when the studentsatellite project begins, the launcher is not clearly iden-tified. So the launch technical constraints are not stron-gly considered and many projects die in vibrations...But the conclusion remains optimistic if the projectstays simple and quick.

A short discussion with the audience will conclude thepresentation.

Artist impression of the CNES built Demeter satellite,part of the Myriad micro-satellite project.

Pierre-Louis ContrerasCNES, Communication et Education

18, avenue Edouard Belin31401 Toulouse cedex 4 -FRANCE

E-mail: [email protected]


The micro satellite mission BIRD of the GermanAerospace Centre, DLR, is dedicated to fire evaluationfrom space by means of new technologies. The missionwas established in a cooperational framework with theFraunhofer/FIRST research centre in Berlin and severalsmall and medium sized companies.

Beside this also ca. 20 students are temporarily involvedin the project team in Berlin solving different tasks. Evenca. 4 pupils have contributed to the preparation of theBIRD mission as part of the team for several weeks.

In this project the Technical University Berlin is animportant cooperation partner with special experience inmicro satellite projects and space education. For 15years students are involved in micro- and nano-satelliteprojects of the Technical University Berlin. 6 Satellitesare implemented in orbit successfully.

This excellent experience in space education combinedwith special BIRD know how will be continued duringthe next years in designing, building, testing and opera-ting cubesats primarily with students. The lecture cour-ses will give the theoreti-cal knowledge and back-ground. Working in anintegration lab, in a recei-ving station, at differentplaces with structure testfacilities and exercises inmission control will deve-lop the practical experien-ce, skills and know-how ofthe students in space edu-cation.

The presentation coversthe different aspects ofspace education at the TUBerlin in the past, todayand in the future.

Space Technology

Education at TU Berlin

Klaus Briess, Hakan Kayal

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BIRD ready for a vacuum-chamber test

Institut für Luft- und RaumfahrtMarchstraße 12-14D-10587 Berlinwww.ilr.tu-berlin.de/


k e r s

In a similar manner whereby the Personal Computer hasbrought access to modern information technologies andworldwide communications within the everyday grasp ofthe general public, small satellites have brought directparticipation and access to space within the reach of stu-dents worldwide.

Starting out as a group of PhD students with a wild ambi-tion in 1979, the University of Surrey has pioneered thedevelopment of modern, increasingly capable microsa-tellites, minisatellites and even nanosatellites. By 2004,this small team has now grown to 225 academics,postgraduate students and commercial staff at the SurreySpace Centre & SSTL.

Over 500 undergraduate and postgraduate students haveexperienced direct involvement in Surrey's satellite acti-vities through projects and, occasionally, through the

construction of research payloadsonboard some of the 23 small satellitesbuilt, launched and operated in lowEarth orbit by Surrey.

The unique configuration and symbio-sis that has been established at Surreybetween the academic research and

teaching activities of the Surrey Space Centre and thecommercial satellite missions undertaken by SSTL hasprovided powerful educational opportunities and expo-sure to the realities of 'commercial space' - indeed notjust for Surrey students but also for trainee engineersfrom 12 developing countries who have acquired in-depth hands-on satellite know-how through collaborati-ve microsatellite programmes and, in many cases, havesince returned to their countries to establish nationalspace agencies.

However, small satellites are now not simply educatio-nal, research or demonstrational tools but, within the lastfew years, their capabilities have grown to begin to rivalconventional large satellites for certain applications andthis has brought about a major change in both civil andmilitary space thinking.

Surrey Space CentreGuildfordSurrey GU2 7XHEnglandemail: [email protected]

Space educationthrough direct participation 25 years of pioneering small satellites at Surrey

Sir Martin Sweeting


PROBA (Project for On Board Autonomy) is a techno-logy demonstration mission of the European SpaceAgency's General Support Technology Programme.

PROBA was launched on October, 22nd, 2001 on aLEO Sun-synchronous 681x561 km orbit.

The spacecraft mass is 94 kg, with 25 kg dedicated toscientific and Earth observation instruments, in additionto the technology demonstration payloads.

PROBA, an ESA technology

demonstration missionF. Teston

European Space Agency/ESTECTOS -ELPO box 299, 2200 AG NoordwijkThe Netherlands

PROBA principal objectives are in-orbit evaluation ofnew spacecraft technologies. PROBA, however, wasalso the first satellite for Belgium and for the PrimeContactor as well as for several companies involved inthe development. Two universities participated also tothe development and several key engineers in industrywere having their first experience with this project.ESA was involved in this project as final customer andtechnical expertise.

PROBA onboard automatic functions include all paylo-ad operations scheduling and execution, target fly-byprediction and control of cameras pointing and scan-ning from raw inputs from users (target latitude, longi-tude and altitude). The point and stare requirements ofthe High Resolution Camera (HRC), as well as the mul-tiple images scan requirement to support Bi-directionalReflectance Distribution Function (BRDF) measure-ments with the Compact High Resolution ImagingSpectrometer (CHRIS) are satisfied with the specifiedaccuracy, by this small and agile gyro-less platform,whose attitude determination is based on autonomousstar trackers only.PROBA main Earth imaging payload, CHRIS, wei-ghting only 14 kg, is used to measure directional spec-tral reflectance. HRC is instead a black and white came-ra with a miniaturised Cassegrain telescope providing 5m geometrical resolution images. PROBA users to dateinclude more than 60 Earth observation PrincipalInvestigators from scientific Institutes within Europe.

Two additional Earth environment instruments areflown. SREM a radiation monitor and DEBIE an instru-ment to detect sub-millimeters debris.The expose will describe the spacecraft technical featu-res, the in orbit results and the programmatic set-up ofthe project.

Pictures taken from the PROBA spacecraft

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NCUBEThe Norwegian StudentSatellite ProjectEgil Eide

The Norwegian student satellite, NCUBE, is an experi-mental spacecraft that is developed and built by studentsfrom four Norwegian universities in the time period2001 - 2004. The project was initiated and funded by theNorwegian Space Centre with support from AndøyaRocket Range, Norway.

The main mission of the satellite is to demonstrate shiptraffic surveillance from a satellite using the maritimeAutomatic Identification System (AIS) recently introdu-ced by the International Maritime Organization (IMO).The AIS system is based on VHF transponders locatedonboard ships who broadcast the position, speed, hea-ding and other relevant information from the ships atregular time intervals. Another objective of the satelliteproject is to demonstrate reindeer herd monitoring fromspace by equipping a reindeer with an AIS transponderduring a limited experimental period. This part of theproject is conducted by the Norwegian AgricultureUniversity. A third objective is to demonstrate efficientattitude control using a combination of passive gravitygradient stabilization and active magnetic torquers.The project is organised with student workgroups at eachuniversity. The project management is done by theNorwegian Space Centre while the technical coordinatorhas the role as systems manager. In the initial phase, atotal of 63 students were involved in the project. Thedesign phase involved 16 masters degree students, whilethe implementation and test phase is performed by 10students and 6 supervisors. The launch is organized byCalifornia Polytechnic State University and will takeplace from Kazakhstan between September 1, 2004 andNovember 30, 2004.The communications system is based on using amateurradio frequencies in the VHF and UHF frequency bandsusing the AX.25 protocol with either 1200 bps or 9600bps data rate.. Figure 1 shows a block diagram of thesatellite system architecture. The Terminal NodeController serves as the communications interface to theVHF receiver and the UHF and S-band transmitters. Alltelecommands are validated by the Telecommand

Decoder who forwards the instructions to each subsy-stem using the I2C Telecommand Bus. The main subsy-stems are the AIS receiver payload, the ADCS systemand the Power Management Unit. The Data Selector isused to connect the different subsystems to the TNCduring transmission down to the ground station. By using this architecture, it is possible to test and veri-fy each subsystem independently during the implemen-tation phase. For attitude stabilization, the satellite con-tains a 1.5 meter long deployable gravity gradient boomconsisting of steel measuring tape and a counterweightof 40 grams at the outer end. The gravity gradient boomalso serves as a VHF antenna for the payload. Themechanical structure is manufactured by the Universityof Oslo.Five of the satellite satellite's six surfaces will be cove-red by monocrystaline solar cells that are manufacturedby Institute for Energy Technology (IFE), Norway. Thepower subsystem operates within the voltage range of atypical Lithium-Ion cell, 3.7 to 4.2 volts, and all periphe-ral equipment is interfaced with a set of DC/DC conver-ters adapting to the voltage demand. The power supplysystem was designed by students from Narvik UniversityCollege. An important activity in the project has been todesign two different ground stations for the satellite. Onestation is located in Narvik and the other is currentlybeing assembled at Svalbad.

k e r s

Norwegian University of Science and Technology

O.S. Bragstads Plass 2B, N-7491 Trondheim, Norway

Email: [email protected]

NCUBE prototype mechanical structure.


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As early as 1980, theAriane launch vehiclesbegan to provide occa-sional launch opportu-nities to radio-amateurs and scientists. During the earlygenerations of Ariane 1, 2 and 3 three auxiliary paylo-ads were launched: 2 for AMSAT and one for theSwedish Space Centre.But since no specific system was defined, the payloadswere treated on a case-by-case basis, hence making theirdesign completely specific, their launch configurationunique and the whole process long and difficult.With the arrival of the Ariane 4 launch vehicle series,Arianespace decided to provide more frequent andeasier launch opportunities to space agencies, scientists,radio-amateurs, universities etc… To this aimArianespace decided to develop a carrying structure cal-led ASAP4 (Ariane Structure for Auxiliary Payloads)for mounting and deploying satellites. In 18 years, bymostly using this ASAP4 system, 26 auxiliary payloadswere successfully deployed on orbit by using Ariane 4missions designed for the larger Arianespace MainPassenger(s).In the legacy of what had been successfully implemen-ted on the previous Ariane 4 versions, the Ariane-5launch vehicles continue to provide launch opportuni-ties to space agencies, scientists, radio-amateurs, uni-versities and other organisations. These opportunitiesare offered either on the Arianespace developed structu-re called ASAP5 (Ariane Structure for AuxiliaryPayloads) or thanks to some other innovative solutions,

On ground, it's useless.Space is its place! But ... how to get there?Jean-Michel Desobeau

but always giving the auxiliary payload a dedicatedinterface. Like on Ariane 4, the Ariane 5 auxiliary pay-loads are launched on-board missions designed for theMain Passenger(s).The Ariane 5 being much larger and more powerful thanAriane 4, it naturally provides much larger mass andvolume envelopes to auxiliary payloads than the ASAP4on Ariane 4.Auxiliary Payloads are flown to the orbit defined by theMain Passenger(s); for Ariane 5, these orbits are chieflyGeostationary Transfer Orbit (GTO) but also SunSynchronous Orbit (SSO) or else (LEO, MEO, etc). Atypical Ariane 5 GTO mission is 200 - 300 km x 35'786- 45'000 km and 4° - 7° inclination. For the microsats onAriane 5, the separation system is provided byArianespace and provides an adjustable distancing velo-city between 1 and 3 meters per second. All specificinterface information is available in the ASAP5 User'sManual.

After successful completion of its in-flight qualifica-tion, the Ariane 5 is now fully operational. This vehiclehas already performed 14 commercial flights, succes-sfully and accurately delivering on their required orbits22 main passengers and 5 auxiliary payloads. To allowrealistic budget preparation, Arianespace has publiclyreleased "cataloque" prices for providing standardlaunch services within standard conditions:* for one microsat (120 kg max.):3.0 MEuros* for one minisat (600 kg max.):10.0 MEurosThese all-inclusive prices include delivery of adapter &connector hardware, the ASAP5 or other adaptersystem, all Arianespace technical assistance, the mis-sion analysis studies and the flightworthiness work withthe auxiliary passenger team as well as the necessarysupport during the preparation campaign for the launchin Kourou, French Guiana. The forthcoming addition ofthe Soyuz and Vega systems to the Arianespace vehiclesfamily will also open new opportunities to the AuxiliaryPassengers.

An Ariane 5 sets off intospace from its launch pad atthe Guiana Space Centre,Europe's space port

Jean-Michel Desobeau, ArianespaceBoulevard de l'Europe, 91006 Evry Cedex - [email protected]


PROBA stands for PRoject for OnBoardAutonomy. It is the first ESA technologicaland demonstration mini satellite. Apart fromthe experimental aspect, it fulfils also a scien-tific mission, which is now extended beyondthe original 2 years lifetime. The project deve-lopment time until the launch was short, from1998 to October 2001. The operation environ-ment developed for PROBA-1 was kept"light" but with a high degree of automation inorder to support fully automated satellite pas-ses without manning. It provides to the ESAProject, the Industry support, the end-user andthe Principal investigator a Web access toretrieve the satellite and the payload datamade available shortly after the satellite pass.

European Space Agency/ESTECThe PROBA spacecraft was launched by theIndian PSLV Launcher on the 22nd Octoberof 2001 on a Sun Synchronous Orbit. It is a 3-axis stabilized satellite with a high platformmanoeuvring capability. The advanced avio-nics of the satellite confers a high degree ofautonomy and required robustness which are a drivingfactor on the way to conduct the operations. The mainpayloads are two imagers (Compact High-ResolutionImaging Spectrometer and High Resolution Camera)and two space environment instruments (StandardRadiation Environment Monitor and DEBris In orbitEvaluator). The mission is included in the ESA EarthObservation Programme but it serves also general inte-rest users and it is intended to play a role in the frameof the International Charter on Space and MajorDisasters.The EduPROBA Belgian initiative was aninvitation to the secondary schools under the form of acompetition to submit proposals to utilize the satellitepayload. That concerns mainly the imagers and the pic-tures acquisition is still ongoing.

The main elements of the ground segment are a fullysteerable S-band antenna of 2.4 m., a baseband equip-ment, a control system based on the ESA SCOS IIsystem used also during the ground test and integrationphase, a planning system and a data server. A uniquescript language allows to interface with the telemetryand the telecommand server of the control system andto control all the pass activities from the preparation tothe post-processing phase and most of the ground seg-

ment units. It is the key element of the automation ofthe ground segment tasks progressively put in placealong the mission. It allows also the automatic emailgeneration in case of any warning message. It is com-pleted by the automated pass template tool which sche-dules the pass activities and provides a graphical inter-face of the activities statuses. The NORAD Two LinesElements automatically retrieved from the Web, areused to predict with a COTS software the ground sta-tion visibilities. The antenna pointing angles are alsoderived from the TLEs.

The success of the mission is due to a series of factors,the main ones being: a small coherent and motivatedProject and Industry team, the use of modern softwaretechnology, an innovative and robust satellite designmaking the operations more simple and less critical andfinally an easy programmable operations environment.Although the presentation will give more details aboutthe Mission characteristics, the ground infrastructure,the EduPROBA initiative and the mission results, it willalso highlight the mission elements which impact posi-tively the operations: the satellite autonomy and robu-stness, and the ground segment automation.

The Redu ground station in Belgium

k e r s

Agence Spatiale EuropéenneStation de REDU, B-6890 Redu

Belgium [email protected]

ThePROBAGround Infrastructure and Mission Operations.Etienne Tilmans


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AAU-cubesat: a successfull student satellite

Lars Alminde

In the summer of 2001 it was decided to initiate theAAU-Cubesat project at Aalborg University inDenmark. This project was made possible due to thecubesat concept, which has been developed at StanfordUniversity and California polytechnic institute lead byprofessor Bob Twiggs. This concept allows a satellite ofdimensions 10x10x10cm and mass 1kg to be launchedinto low Earth Orbit at a total launch cost of about40,000USD.

The motivation was to let engineering students fromvarious departments cooperate in the completion of avery large project and thereby give them a unique chan-ce to participate in a project that not only needs goodengineering skills, but also the skills to solve problemsthat are inter-disciplinary of nature.

In the initial period of the project it was decided by thestudents that the scientific mission of the project shouldbe Earth Observation and many ideas were studied, butthey were all found to be to technical challenging toimplement on a platform as small as the cubesat. Aftermany meetings it was finally decided to fly a camerawithout a specific scientific purpose for it, but rather usethe satellite as an technology evaluation mission prepa-ring the ground for future scientific missions using thecubesat concept.

The satellite was completed in April 2003 and was tran-sported to Canada, together with three students, toundergo environmental qualification tests together withthe other satellites to be deployed from the same deploy-ment mechanism. From Canada it was transported toPlesetsk in Russia, where it was functionally tested andthe batteries were conditioned before the launch on the30th of June 2003. In the first daysfollowing launchit took a lot ofcoordinated effortof all the involvedoperation teams,

together with the NORAD tracking radars, to locate andidentify all the satellites separated from the launch vehi-cle.

For the first 24 hours no distinct signal was heard fromAAU-cubesat, but hereafter the operation team was ableto detect the beacon signal with increasing confidence.After about 4 days it was clear that the satellite had beensuccessfully located, but the transmitted signal strengthwas far below expected. Therefore the ground stationwas relocated 200km to make use of an 8m dish anten-na.

When the new ground station was finally fitted for ope-rations in the correct frequency (1 month after launch)signal was received with enough strength to decodesome of them, but at this point the beacon intervals andthe decoded signals started to indicate massive loss ofbattery capacity leading to frequent returns to the contin-gency charge mode of operation, which does not supplypower to the OBC.

Unfortunately the degraded battery condition made itimpossible to establish a real datalink connection anddownload extensive house keeping data, but simple two-way communication was established (pinging) demon-strating that the complete data path from ground stationto OBC and back was functional.

Aalborg University, [email protected]

AAU Cubesat flight model radio test in the anechoic chamber


What Is A 'Small satellite'And Who Cares Anyway?David Hardy - ESA

The standards and norms we are indoctrinated with atschool and university today are not absolute - theychange and evolve over time. The students of today takecomputers, mobile phones and the internet for granted -and wouldn't know where to turn without them. Givethem a slide rule and most would not know what to dowith it. Technology's rise over the last 150 years has beenexplosive - it took thousands of years before man couldtravel faster than a galloping horse, but it took only 66years to go from the first ever powered flight of a fewmetres (at around 200 Km/hour) to landing on the moon(necessitating a flight at around 8 Km/second). Butthere are pitfalls in accepting all this technologywithout question and losing sight of how we got to ourpresent state.

It is still less than 50 years since the first ever man-made object orbited the Earth. Back then the conceptsof Solar wind; Van Allen belts and the shape and extentof the Earth's magnetic field were all theoretical ideaswhich only became 'real' in the 1960's. The effects ofmicrogravity on the human body and its functions wereunknown until the 1970's and the long-term effects, notonly for humans but also for plants and animals, are stillto be unravelled.

European Space Agency/ESTEC

This presentation, drawing on personal experiences ofmore than 35 years in the space industry, attempts to putin perspective the phenomenal changes which havetaken place over those years and the relevance they stillhave. So many projects, following a successful launchand early orbit phase have done a few weeks of soul-searching to write up a 'lessons learned' document,which has promptly been filed in an archive and forgot-ten about. A few years later, new people on a new pro-

ject make many of the same mistakes over again, partlybecause of not taking the trouble to find out what hasgone before and partly through the 'arrogance of inex-perience' in much the same way as the average teenagerthinks their parents are retarded morons and it takesthem until middle-age to realise that those parentsactually knew a thing or two.

Powerful processors and sophisticated software nowallow fully autonomous spacecraft such as Proba-1 andthe Martian landers to achieve what was science fictiononly twenty years ago. Proba achieved this with 30% ofits mass dedicated to the payload, but the farther you gofrom Earth the more mass you need for propulsion andpowerful communications, and 'small' spacecraft ceaseto be practical - Smart-1 had a launch mass of 350 Kg

with only 5% as payload - and the more autonomy youneed due to the long transmission loop delays and shor-ter contact periods. Despite all the advances, we'vebarely scratched the surface of all there is to know anddo and the present student community has to carry theachievements forward for the following generations.The technology we need to send people into space forlong periods and to distant planets does not exist yet. So the message is clear - don't waste time re-inventingthe wheel; learn from our mistakes; have fun makingyour own and fulfil your destiny to 'carry forward anever-advancing civilisation'.

Teamsat - ESA's 'student satellite' beingintegrated in Kourou

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ESA-ESTEC, TOS-EDD, Postbus 299, 2200 AG Noordwijk, The Netherlands,

[email protected]


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CubeSatsStudents Design andRealise Pico-Satellites

Klaus Schilling

Satellites offer excellent opportunities to learn at a moti-vating example interdisciplinary system design and inte-gration. In order to comply with the limited time frameof a study curriculum by Bob Twiggs (StanfordUniversity) a sequence of hands-on projects of increa-sing complexity has been outlined and realized leadingto implementation of a fully functional pico-satellite,called CubeSat. A CubeSat is a cube-shaped spacecraftwith side length of 10 cm and a mass of 1 kg. The struc-ture is standardized for launcher adaptation. The studentsusually design in about 1 academic year the spacecraftaccording to mission and payload requirements. Thecomplete satellite life cycle from feasibility analyses todesign, implementation, launch, in orbit operations, datacollection and interpretation is to be covered by the stu-dent teams.In interdisciplinary teams, the students have to analysethe orbit properties and related implications on differentsatellite subsystems, such as on board data handling,power, telecommunications, attitude determination andcontrol, thermal control, structure. In this context skillsin mechanical, electrical and software engineering haveto be applied in order to perform implementation and testof the satellite.

In more detail the specific activities performed at theUniversity Würzburg will be addressed as example:

1. UWE-1, the University Würzburg's Experimentalsatellite will be used to test adaptations of internet proto-cols to the space environment, characterized by signifi-cant signal propagation delays due to the large distancesand much higher noise levels compared to terrestriallinks.

2. Establishment of a satellite ground control station,which is integrated into an infrastructure of world-wideinternet linked stations.

This presentation will address details of the educationalapproach and lessons learned in this satellite implemen-tation effort. The specific experience from UWE-1 willbe combined with the overall programmatic perspecti-ves: As currently more than 40 international universitiesadopted that approach, a world-wide cooperation net-work has been set up in order to exchange experiences,procure satellite components and to organize sharedlaunches.

Bayerische Julius-Maximilians-Universität Würzburg [email protected]

1. The UWE-structural model equipped with highly effi-cient GaAs-solar cells2. The ground control station at FH Ravensburg-Weingarten with Yagi and disc antenna

1

2


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Attitude control of

microsatellites

Aage Skullestad

This paper describes attitude control, i.e., 3-axes stabili-sation and pointing, of a microsatellite. The intention ofthe original study was to find an inexpensive attitudecontrol system with sufficient high accuracy allowingmaritime surveillance from a low Earth orbit microsatel-lite.

Firstly, the satellite was furnished with a gravity boom.Satellite stabilisation from a gravity boom alone yieldsinadequate stability, and magnetic coils mounted in thex, y and z facets of the satellite were added to improveattitude control. Different control strategies, such as LQcontrol, Fuzzy Logic control and H8 control, are presen-ted.

Satellite control using gravity gradient stabilisation andmagnetic coils is inexpensive and allows low-powersolutions.

LQ control achieved attitude angular accuracies in therange 1 - 2 °, using a first order dipole model for the geo-magnetic field of the earth. Fuzzy logic control achievedattitude angular accuracies < 1 °, but at the cost of slowsatellite response. The angular accuracy of the abovecontrollers were regarded as highly dependant of thesensor accuracy, sensor noise, internal satellite noise,solar pressure, inertia distribution of the satellite, availa-ble coil current, and thermal stability of the satellite andthe gravity boom.

An H8 controller with theoretically better robustness anddisturbance rejection properties than the above control-lers was proposed.

The controller based on anH8 design results in a fastand accurate control system,with excellent disturbancerejection properties. A pro-blem with this controllerwas the demand for highwheel torques.

The required control torques can be reduced, but at thecost of less robustness and reduced disturbance rejectionproperties. Magnetic coils result in a slow control action.The magnetic coils were replaced by reaction wheels.

Actuators like reaction wheels, momentum wheels, thru-sters or control moment gyros, that all have the potentialof larger control torques than the magnetic coils, do notneed the extra stability torque resulting from the furni-shed gravity boom. Thus the gravity boom becomesredundant. A LQ controller, using reaction wheelswithout gravity boom, gave fast and accurate attitudecontrol.

Combining different actuators may in some situations bethe best solution trading accuracy, power consumptionand cost.Wheels used for attitude control will soon or later satu-rate, and the magnetic coils are shown to be handy formomentum dumping.

Chapter 1 and 2 provide a brief description of actual sen-sors and actuators. Chapter 3 describes reference framesand attitude angle representation. Mathematical modelsnecessary for building a complete mathematical modelof the satellite, using different control actuators and con-trol strategies, are presented in Chapter 4.Simulations are shown in Chapter 5.Chapter 6 shows moment dumping using magnetic coils.

Aage Skullestad Kongsberg Defense & Aerospace AS PO Box NO 3601 Kongsberg Norway [email protected]


ESA's SMART-1Mission to the Moon:share the experienceBernard H. Foing

SMART-1 is the first of Small Missions for AdvancedResearch and Technology as part of ESA science pro-gramme "Cosmic Vision". Its objective is to demonstra-te Solar Electric Primary Propulsion (SEP) for futureCornerstones (such as Bepi-Colombo) and to test new

technologies forspacecraft andinstruments. Thespacecraft hasbeen launchedon 27 sept. 2003,as an Ariane-5auxiliary passen-ger. SMART-1orbit pericenteris now outsidethe inner radia-tion belt. Thecurrent status of SMART-1 will be given at the sympo-sium. After a 15 month cruise with primary SEP, theSMART-1 mission is to orbit the Moon for a nominalperiod of six months, with possible extension. The spa-cecraft will carry out a complete programme of scienti-fic observations during the cruise and in lunar orbit.

SMART-1's science payload, with a total mass of some19 kg, features many innovative instruments and advan-ced technologies. A miniaturised high-resolution camera(AMIE) for lunar surface imaging, a near-infrared point-spectrometer (SIR) for lunar mineralogy investigation,and a very compact X-ray spectrometer (D-CIXS) with anew type of detector and micro-collimator which willprovide fluorescence spectroscopy and imagery of theMoon's surface elemental composition. The payload alsoincludes an experiment (KaTE) aimed at demonstratingdeep-space telemetry and telecommand communicationsin the X and Ka-bands, a radio-science experiment(RSIS), a deep space optical link (Laser-LinkExperiment), using the ESA Optical Ground station inTenerife, and the validation of a system of autonomousnavigation (OBAN) based on image processing. SMART-1 lunar science investigations include studies ofthe chemical composition of the Moon, of geophysicalprocesses (volcanism, tectonics, cratering, erosion,deposition of ices and volatiles) for comparative plane-tology, and high resolution studies in preparation forfuture steps of lunar exploration. The mission couldaddress several topics such as the accretional processesthat led to the formation of rocky planets, and the originand evolution of the Earth-Moon system.

The SMART-1 observations will be coordinated withJapanese missions Lunar-A and SELENE. The scientificresults of these missions should be integrated with pre-vious lunar datasets (Apollo, Luna, Clementine,Prospector) to answer open questions about comparativeplanetology, the origin of the Earth -Moon system, theearly evolution of life, the planetary environment and theexistence of in-situ resources necessary to supporthuman presence (e.g. water, oxygen). With their scienceand technology results, these missions can be consideredas preparatory missions for future robotic and humanexploration of the solar system.

s p e a

Artist's impression of SMART-1

Chief Scientist ESA RSSD & SMART-1 Project ScientistESTEC/SCI-SR, Postbus 299, NL-2200 AG Noordwijk,Email: [email protected]: http://sci.esa.int/smart-1/ILEWG: http://sci.esa.int/ilewg/Lunar Explorers Society: http://lunarexplorer.org


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The Arctic Archipelago of Svalbard loca-ted at almost 80° N is ideally located fora ground station providing services rela-ted to data reception and control of polarorbiting satellites. A ground station atSvalbard provides efficient and cost effi-cient services because its possible tomake contact with a satellite in polar orbiton all 14 of its orbits per day from onesingle ground station, whilst two or morestations would be required at lower latitu-des. Kongsberg Satellite Services(KSAT) and the Norwegian Space Centre(NSC) therefore have established theSvalbard Satellite Station (SvalSat).

Established in 1997, Svalbard has currently 6 largeapertures at the site.

The extreme location of the station, together withmodular, generic equipment that reduces the need formission specific adaptation and special operational ser-vices are the main causes for the successful growth forKSAT. Today KSAT serves customers like ESA,NASA, IPO and Eumetsat.KSAT operates 3 of the antennae from the control cen-ter in Tromsø (TNOC). Through the interface at TNOC,the clients will be able to receive TT&C services and in

near-real time receive processed products or raw data. In January 2004, the new Gigabit fiber highway becameoperational. The fiber has increased the communication reliability by decades, giving the opportunity to sendlarge amount of data in near-real time to customers bothin Europe and the US.

The new fiber enabled KSAT to connect the stations tothe European GÉANT network.That network is the backbone for high-speed data tran-sfer to EO centers and other research institutes inEurope. By exploring the benefits that the GÉANT networkholds, the possible support from SvalSat to SSETI-EXPRESS should be feasible.

The Svalbard Station

Kongsberg Satellite ServicesSvalbard Satellite StationBørre Pedersen

KONGSBERG SATELLITE SERVICES ASPostboks 6180 NO-9291Tromsø, Norway Office: Prestvannveien 38 E-mail: [email protected] [email protected]: www.ksat.no


ESEO is progressing well and is wellinto the latter stages of its designphase (phase B), and entering thetesting phase soon (phase C). Most ofthe AIV work will be concentrated inthe testing phase, which has alreadycommenced in a few sub-systems,i.e. propulsion and mechanism. Dueto the proposed launch of SSETIExpress, we will be able to learnfrom that experience and apply iteither directly or indirectly to ESEO. Our past work has been sortingthrough paper work and familiarizingourselves with the verification andhardware matrix as well as thevarious subsystems and their fun-ctions. The Hardware Matrix lists allthe components each subsystem hasand the models that they are to build,and the Verification Matrix lists thespecific requirements that each com-ponent should meet. Each sub-system will have access to a copy ofthis matrix and we will be workingclosely together to ensure propertesting procedures and test reportingis carried out.

Should the sub-system not be able tocarry out testing in their respectiveuniversities, we shall endeavour to

arrange alternative facilities. Oncethis is done, the AIV team will com-bine the sub-systems to form thevarious systems and finally

integrating the satellite to do furthertesting to ensure ESEO will be fun-ctional in space and achieve the aimsand objectives of ESEO.

s s e t i

Our major responsibility is the AIV part of theESEO. Our main role is to coordinate the testingon singular components of ESEO and proceed onto perform testing of the subsystems and systemsforming the satellite to verify that they meet therequirements set out in the ECSS-10 manual andcomply to Ariane-5 standards.

AIV - Assembly, Integration and Verification ESEO

Imperial CollegeLondon

Views of a few tests that all spacecrafts have to undergo before flight. For Express and ESEO most of these tests will be conducted at ESTEC


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Team ResponsibilitiesThe Attitude and Orbit ControlSystem must be able to fulfill theESEO requirements, namely mano-euvers and pointing requirements.The team has proposed and is nowresponsible for the development ofattitude sensors, actuators and flightsoftware, including attitude determi-nation and control algorithms. Thework is based on the development,integration and test of the requiredequipment and software, fully quali-fied for a space application.In detail, the AOCS consists of threedifferent attitude sensors. It includesa sun sensor, an earth horizon sensorand a magnetometer. These sensors,with the appropriate resolution willpermit the ESEO spacecraft attitudedetermination. The different types ofsensors are necessary for the missionorbit range but also enable sensordata fusion, for better accuracy.All data from sensors are gathered bythe flight software, with proper CANprotocol communication channels(nominal and redundant), and thecontrol algorithms shall determinethe necessary actions to be perfor-

med by the two types of attitudeactuators available in the spacecraft.These are the attitude control thru-sters and a one-axis reaction wheel toaccount for earth gravity gradienttorques.

Design StatusThe AOCS design is currently on thepreliminary design phase, and it ispreviewed that the team enters theproduction phase in mid 2004.The AOCS architecture was designedto be simple and reliable, assuringthat mission real-time restrictions aremet.

The several sensors designs is simi-lar, consisting of the measurementmodule, with adjacent signal condi-tioning electronics, and controlled byan embedded microcontroller withintegrated CAN protocol modules,thus having digital outputs connectedto the ESEO nominal and redundantCAN buses.

The reaction wheel design is based inthe mission requirements, especiallybecause its capability is intended to

damp the earth gravity gradient tor-ques. It allows saving cold-gas fuel,extending the ESEO mission time asmuch as possible.

The attitude determination and con-trol algorithms, developed as part ofthe flight software pack, are beingdesigned for maximum robustness.All algorithms are tested against thecustom-made AOCS simulator, allo-wing a detailed knowledge of systemresponse for the developed algo-rithms.

Future WorkFinish the design and enter produc-tion phase!

The responsibility of the Lisbon team is to develop acomplete AOCS system, consisting on the developmentfrom scratch of attitude sensors and actuators, as well asflight software for attitude and orbit control. The teamwas created in mid 2000 and relies on almost fifteenstudents from different courses, enabling a multidisci-plinary work. It is represented as a student associationnamed Lusastro.

AOCS - Attitude and Orbit Control SystemESEO

Instituto Superior TecnicoLisbon

Earth Horizon Sensor


Communication ESEO, SSETI-Express

University oftechnology

Wroclaw

1. To keep the costs low we concen-trated on uses of unconventionalsolutions in the SSETI micro-satelli-tes, which rely on a vast use of com-mercially available devices featuringexcellent performance (even though

they have not undergone airborne orspace approval procedures).2. We try to go far in reduction ofstructure weight and dimensions;thus lift-off costs are minimal.3. A short duration of the mission(possible due to time-efficientaccomplishment of the mission goals- must be regarded as one of themajor factors maintaining overallcosts low.

The SSETI-Expresswill use only beacontransmitter which wewill develop (2400MHz band). A fullyoperational S-bandcommunication subsy-stem will operate at thefollow up micro-satelli-te, ESEO. The com-munication system

comprises of the Ground and Spacesegments. The Ground segmentincludes an operation subsystem andthe Ground Station.

One of four our main areas of rese-arch are Low Gain Antennas (LGA)for T&C applications. The antennasare designed and manufactured inultra low weight technology. Themodel of our planar LGA antenna isshown in Figure 1. The main featuresof the antenna are a lightweightstructure and a high degree of inte-gration of antenna elements and fee-ding circuits (Circular Polarization).To analyze the properties of antennasplaced onboard the micro-satellite anumerical analysis based on theMethods of Moments is used. Thestudies aim at optimization of anten-nas placement on the micro-satellitesSSETIExpress and ESEO.

s s e t i

Participation in the SSETI Project of a team of WroclawUniversity of Technology (WUT) is influenced by specific featu-res of Central European country. In terms of technical infrastruc-ture, our computer resources and internet access are generallygood. We have advanced CAD software for electromagnetic andmicrowave uses. Our team primarily suffers from disadvantageswhich are related to poorer laboratory infrastructure and a lack oflocal industry involved in space technology. Wroclaw is a large university center with 130 thousands of stu-dents enrolled at all levels of academic studies. The ElectricalEngineering and Information Technology is primary area of stu-dies at four Engineering Departments of WUT. More than 10thousands students are enrolled into these Faculties. Such bignumber means that a pool of talented students is significant.

1. Model of the LGA fed with a slot coupled line (f0 = 2.425 GHz)


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StructureThe first task of Configurations teamwas to create a light, low cost struc-ture that verified all the requirementsimposed by the ESA's and Ariane5standars. In order to make this possi-ble, we had to investigate the possibi-lities of the different constructionmaterials, in order to develop a struc-ture that satisfied our needs.At this moment, we have reached thepoint of freezing the structure'sdesign and start the production andtesting process. This will include theuse of a complete shaking system fora complete frequency analysis.

Satellite's configurationThe second part of our work relies onthe configuration of the satellite'ssubsystems. There are a lot of restric-tions and factors to take care of, asthermal distribution, radiation, andmass of the components, the inertiamatrix or the space distribution of thesubsystems. This means that we haveto be in contact with all the groups,as a change in one of the subsystemsusually affects the rest of the confi-guration.

The responsibility of the CONF team of Bilbao isdivided between two vital parts of the satellite,the configuration of the subsystems and thedesign of the structure. Since 2000 many designsand structures have been created, due to the con-tinuous evolution of the satellite, with the entran-ce and exit of some subsystems.

Configurations - ESEOEscuela Superior de Ingegnieros Bilbao

1. Structure model2. Satellite's Configuration

1

2


Electrical Power Sub-systems

ESEO, SSETI Express

Università degliStudi "Federico II"

Napoli

Subsystem designTaking into account that SSETI shallpromote multiple missions a modularphilosophy design has been conside-red to develop all parts of the EPS.The electronics for the managementof the power onboard is in fact thesame for both ESEO and SSETIExpress mission and only minorchanges to the software of the PICcontroller shall be adopted to satisfythe different management needs ofthe two satellites. Using COTS com-ponents for the electronics ensureshighly lower costs and higher effi-ciencies although the use of them inthe radiation environment shall beevaluated carefully.

Even the batteries are completelymodular since the number of cellseries is chosen according the powerbudget, being changed only the hou-sing of the pack. A single six cellserie Li-ion battery has been adoptedas a single module guaranteeingcapacity up to 90Wh and 5A as peakcurrent. Modules can simply beparallel connected since they aremanaged by the same electronics.Solar panels shall be based uponTriple Junction cell technology allo-wing, with an efficiency of almost23 %, either to obtain high value ofpower (up to 180 W with 2 sun-trac-king solar panels) if required or toreduce the array dimensions(600x250 mm2) with respect to thesatellite when a low budget is nee-ded.

Power ManagementThe main difference in the powermanagement onboard the two satelli-tes (ESEO and SSETI Express) isdue basically on the orbit typologyand mission requirements. Since the ESEO mission is basedupon an almost equatorial GTO andthe satellite is 3 axis stabilised, thechoice of sun-tracking solar panelsensure a slightly constant powerlevel to the system leaving to the bat-teries the task of supplying the onbo-ard sub-systems during the eclipsesand power peak requests.SSETI Express is a satellite mostlybased on simplicity of design and itflies on a SSO simply basing its atti-tude upon Earth magnetic field lines.For this reason the main purpose ofthe body mounted solar panels isrecharging the battery as fast as pos-sible, leaving it the function of fee-ding the system until the 85 % of theDOD including a safety margin forthe EPS control unit: this device hasthe purpose, in this case, of switchingoff all the systems until the batteryare completely recharged.

s s e t i

The EPS developed byUniversità degli Studi diNapoli "Federico II", andSeconda università degli Studidi Napoli within the SSETIproject (for ESEO and SSETIExpress ) although fundamen-tal for the survival of the mis-sions has been designed accor-ding experimental and newtechnological choices. For thisreason the telemetry datareferring the on-orbit perfor-mances shall contribute to bet-ter understand the consequen-ces of the use of Li-ion batterycells, Triple junction solarcells and COTS (commercialoff the shelf) electronic com-ponents in the space applica-tions.

Battery pack-CATIA drawing


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Work DistributionThe work has been distributed intotwo sets, therefore creating twosmaller teams: the data and powerteam, each with its important task.The groups are composed of threeand two members respectively.

WorkTwo conceptual sketches have beencreated by the teams, one for powerand one for data. These visuals mustbe updated, detailed and errorsshould be corrected for the succes-sful continuation of the working pro-cess. The following stage will becomposed of learning and resear-ching about the environments thatESEO will have to work under.These environments are in space andinside Ariane 5. Van Allen Belts willhave to be considered in depth,though they are a minor part of thecourse they are greater in radiation.Due to the vibrations caused by takeoff, this too will need to be studied indepth.

HardwareHardware must be researched for theconditions mentioned previously. Itis already known to the teams thatthe majority of the connectors will becovered in gold in order to preventdamage from gases. The teams weregreatly helped by Mr. EricTrottemant, from ESA EducationOffice. The data team learned how toavoid using heavy and voluminousconnectors by manually gluing thepins or by using a cap.

The Harness team hasreceived the task ofcable management forthe ESEO mission, this,includes both data andpower wiring. After thecreation of the team inOctober 2003, the desi-gning phase started inJanuary 2004.

Harness - ESEO

Universitat Politècnica de CatalunyaBarcelona

25-pin gold-covered connector


Solar Array MechanismThe work done so far on the SPDPMcan be divided into three major deve-lopment steps. The first one has beenthe design and construction of a sim-ple breadboard model of the deploy-ment mechanism, allowing the team,having initially no experience inmechanism design, to demonstratethe feasibility of a simple spring loa-ded mechanism and to identify criti-cal design points.In a second appro-ach, much work has been done toidentify the many requirementsimposed on the mechanism in orderto assure its correct functioning inthe environment of outer space. Currently the whole system is beingrevised and optimized based on theknowledge gained during the mecha-nism specification phase, in particu-lar the pointing mechanism, using abrushless DC motor is being addedand fitted within the structure ofthe ESEO spacecraft.

Mechanism controllerThe subsystem developed inhouse, is based on two commer-cial off-the-shelf digital signalprocessors providing coldredundancy to the system. Anon-chip CAN controller provi-des the data interface to the datahandling system. The controllercontains a driver circuit capable

to drive two brushless DC motorsand four pyro-technical devices.A first breadboard model and anengineering qualification model ofthe electronics have been built in col-laboration with the IntegratedActuators Laboratory at EPFL, pro-viding the team the with expertise ofDC brushless motor drive design andthe infrastructures necessary to buildand test the electronics. Currently software is being develo-ped and a simulator to verify the cor-rect functional operation of the devi-ce in a virtual space environment.

Future WorkThe team's future work will consistof the conclusion of the mechanismdesign and the qualification of thedeveloped system.

s s e t i

Major responsibility of theSSETI chapter in Lausanne isthe design of a Solar PanelDeployment and PointingMechanism (SPDPM) for theESEO mission. The design workhas begun in the year 2001 andhas concluded so far in the deve-lopment of a breadboard of thedeployment mechanism and anelectronic controller capable ofdriving and deploying two solararrays.

Mechanisms - ESEO

Swiss Federal Institute of Technology

Lausanne

The double hinged system will be capableof supporting solar panel having a size of50 x 60 cm and a mass of approximately1.5 kg.

The controller provides functionali-ty to drive two solar arrays and toactivate the pyro release system.


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Mission Analysis workSince October 2000, the MissionAnalysis group has analysed theorbital state of the spacecraft, as wellas its perturbations and evolution,selecting and optimizing the mano-euvres, interacting with the differentsubsystem developing studies aboutground and communication covera-ge, eclipses, environment, …The orbit for ESEO mission will be ageostationary transfer orbit (GTO).However, the injection parametersand the launch date are not alreadydefined by Arianespace. Therefore,diverse cases of insertion have beenanalyzed.One objective of ESEO is performmanoeuvres to suffer a natural de-orbit, so that the spacecraft will beburned down in the atmosphere inthe next 5 years.

Different Manoeuvres Plans havebeen elaborated taking into accountperturbations and the propulsion and

ground segment constrains. Once theinsertion parameters are provided, itwill be possible to select the bestmanoeuvre strategy.

This strategy is directed to get theburned before five years. However,the study of the time in which thenatural de-orbit is fulfilled is in gene-ral very complex since it depends onthe atmospheric drag, solar activityand other perturbations.

On the other hand, software is alsobeing developed. The ESEOMission Analysis Program (EMAP),specific for the Sseti project, provi-des results adjusted to the ESEOmission in all Mission Analysistasks. The results are contrastedwith other industrial programs likeIMAT, STK,... The EMAP code is C, and it can beintegrated in EuroSim to simulate theorbital state of the satellite.

Future WorkThe Mission Analysis future workconsists on completing the EMAPsoftware, as well as obtaining moreaccurate results when other subsy-stems concretise definitively theirdata.

The Mission Analysis team in the SSETI project is responsiblefor the detailed analysis of the orbital evolution, the state of thespacecraft in its orbit, the optimization of the manoeuvres andthe de-orbit process. Since October 2000, this group has beenworking with the support of the Space Mechanical Group of theUniversity of Zaragoza.

Mission Analysis - ESEO, SSETI Express

University of Zaragoza Zaragoza

This figure comes from the EMAPsoftware developed by Mission Analysis


ObjectivesThe objective of the narrow anglecamera payload is to make picturesthat will show places on earth inorder to make the public more intere-sted in space activities. The largestarea covered in one picture will be aslarge as the size of Europe.

Camera factsThe pictures will be acquired by animaging sensor chip called STAR1000. STAR 1000 use CMOS APStechnology instead of the more com-mon CCD technology, this simplifiesthe construction compared to anequivalent CCD construction andreduces the cost.The sensor chip has 1024x1024pixels, which will take greyscale pic-tures with 10 bit sensitivity. Sincethis is a narrow angle camera thefield of view is set to no larger than8.4° by the special made lens.

The camera will not be an "off theshelf" product, instead it will bedeveloped and constructed from

scratch by the team. The layout of theconstruction is showed in the picturewere it can be seen that the camera will alsohave a memory, this memory is to belarge enough to store at least one pic-ture, in case the picture can't be tran-smitted at once.

Current StatusThe NAC is currently in phase B, buta prototype camera has been builtand is about to be tested on astratosphere balloon were it willreach space and hopefully takepictures of it.

s s e t i

We are a team from Sweden that are working onthe narrow angle camera. The team consists ofseven persons, all of us space engineering stu-dents at the department for space physics inKiruna at Umeå University in Sweden. Ourteam has been with SSETI since the end of2002.

Narrow Angle Camera (NAC)ESEO

Umeå UniversityKiruna

Block diagram for the camera.


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Launch PhaseThe satellite is launched with anAriane 5. The launch phase endswhen separation from ASAP(Ariane5 Structure for AuxiliaryPayload) is achieved.

LEOP(launch early operation phase)Critical during LEOP will be theacquisition of the satellite. Once thishas been achieved satellite operatorscan start perform satellite stabilisa-tion, instrument test and calibrationpreparing ESEO for regular payloadoperations. The LEOP phase beginswhen the satellite is separated fromthe ASAP. The phase ends onceinstruments are calibrated and areworking nominally.

GTO(geostationary transfer orbitphase) During this phase nominal satelliteoperations are performed they inclu-de tasks such as radiation measure-ment, when the spacecraft crosses theVan Allen belts, or pictures of Earthand the Moon.

Manoeuvre PhaseOnce objectives not including theorbital control system have been ful-filled a manoeuvre phase is startedduring which the satellites orbit ischanged to a 12 hour orbit. Theachievement of the manoeuvre phasewill conclude regular SSETI opera-tions.

Extended Phase If the vital systems of the spacecraftare still in functional state after theend of the mission an extensionmight be decided. The extendedphase allows for further experimentswith the spacecraft's payload.Objectives, still to be defined, couldinclude an increase of satellite auto-nomy or an amelioration of the poin-ting precision.

The mission operations concept, developed duringthe satellites design phase, describes how the mis-sion objectives are carried out. The determination ofmission phases, the identification of the operationssupporting architecture and its performance require-ments represent steps to be taken during missionpreparation. Hereafter the mission phases for theESEO spacecraft will be presented.

Mission Operations ConceptsESEO, SSETI - Express

University of TechnologyWarsaw


Propulsion DesignThe design work in Stuttgart began in2000 with trade studies of differentpropulsion systems and their arran-gements. Based on functionality,simplicity and feasibility the teamdecided on a cold-gas unit, which canbe developed, assembled and testedby the students themselves while itfulfils all the requirements to achievethe ESEO mission.The modular design of the systemincludes three propulsive elementswhich allows re-usability of thesystem or system elements in futureSSETI missions:1. Attitude Control System (ACS),providing active attitude controlthroughout the mission phase.2. Orbit Control System (OCS), themain thruster used for orbit changesand de-orbit.3. Reaction Control System (RCS),compensating thrust vector misali-gnment and deviation torques, alsoredundancy system to ACS.

Propulsion ComponentsLow cost COTS hardware from non-space applications are used wherepossible to minimize the system cost,the necessary testing and verification

of the components will then be doneby the propulsion team. This includeslight, carbon fibre-reinforced oxygentanks used by fire-fighters and minia-ture valves from medical applica-tions. Space-qualified hardware isonly used for the master valve andthe fill/drain valves due to safety rea-sons.The system includes five high pres-sure tanks, 14 valves, 9 thruster noz-zles, three pressure regulators andfour pressure transducers.The different nozzles and the tubingare designed by the propulsion team.An additional feature of the proposedsystem is the thrust vector control(TVC) unit which will allow a re-orientation of the OCS thrust vectorin order to minimize perturbation tor-ques.

Future WorkFirst stationary thrust tests of theACS and RCS thrust levels havebeen performed and yielded theexpected results. In the upcomingmonths an extensive test and verifi-cation plan will be realised in orderto qualify all components and to veri-fy their function within the system.

s s e t i

The SSETI chapter in Stuttgart isassigned to the design and deve-lopment of propulsion systemsfor the upcoming SSETI mis-sions. Today about 30 students ofAerospace Engineering are acti-vely involved in the design, con-struction and verification pro-cess. The current work focuseson a cold-gas propulsion unit forthe ESEO satellite using gaseousnitrogen as propellant and capa-ble of providing three-axis attitu-de control (with AOCS) as wellas orbit manoeuvres and de-orbit.

ACS/RCS Thrust Test ModelFirst test model of the ACS/RCS cluster with two thrusters (up) andassembly inside the test stand at the Universität Stuttgart (down).

Propulsion - ESEO, SSETI Express

Stuttgart UniversityStuttgard


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OBDH NodeThe OBDH Nodes started out asdistributed parts of the satellites maincomputer to take care of AD conver-sion as close to the sensors as possi-ble. Since then they have evolvedinto a separate subsystem. The nodeshandle data collection for theThermal, Power and RadFET subsy-stems. They also control the valvesand actuators of the Propulsionsystem as well as the heater forThermal.Each node consists of three cards:Two cold redundant controller cardsand a common interface card. Due tothe restricted budget all electronicsare commercial off-the-shelf (COTS)components. Two different micro-controllers (one on each controllercard) are used to increase redundan-cy and to test their performance inspace for future projects. The nodesalso have built in circuitry to protect

against radiation effects.The CAN bus was originallydeveloped for the automoti-ve industry, but it has inrecent years also been usedin space applications such asthe Swedish built SMART-1. A dual CAN bus is used toincrease redundancy and toavoid an error known as"babbling idiot", where afaulty node renders the bususeless by transmitting allthe time.

The controller cards of each node arecold redundant (only one of the twois powered at any given time), andboth cards can communicate on bothCAN buses. The active controller ischosen through power switching.

To protect the controller cards and toreduce the number of componentseach node has one interface card,which contains input buffers andcontrol circuitry for valves andactuators (these use a higher voltagethan the controller cards).

RadFETThe RadFET payload will measurethe total ionising dose (TID) that thesatellite is subjected to. This isimportant to know when evaluatingthe performance of other electronicson board since radiation breaks downthe electronic components.

RadFET's are a special type of fieldeffect transistor developed by theIrish research institute NMRC foruse as radiation sensors, and they areoften used in space applications. The6 RadFET sensors on ESEO will behighly integrated in the OBDH Nodedesign.

Future WorkThe group is right now working tofinish the electronics design andmove on to qualification and manu-facture of the flight model.

The Luleå team has been a part of SSETI since 2001and is responsible for the RadFET payload and thethree OBDH (On-Board Data Handling) Nodes used tointerface other subsystems to the satellites internalcommunication system, a redundant dual CAN bus.

OBDH Node / RadFET - ESEO

University of Technology Luleå

Node design overview


Risk ManagementOur Risk Management plan has beendeveloped in compliance with ESAstandards, with particular attention towhat is stated and required by ECSS-M-00-03A.Of course, ESA standards and requi-rements had to be tailored for ESEOproject, in order to satisfy particularneeds regarding the peculiar featuresof the project and of the structure ofteams.

Risk AssessmentDuring all these years of work, anextensive Risk Assessment phase hasbeen implemented, in order to identi-fy, describe and store as more riskscenarios as possible. This work hasbeen brought on with the precioushelp of all SSETI teams (which pro-vided data and ideas for many scena-rios), ESA experts (who helped uswith their opinions) and RISK teamown expert, Mr. Luca Paita (whoprovided us the expertise and know-how about what really RiskManagement is, along with thou-sands of useful suggestions).The result of Risk Assessment workis a database, in which all risk scena-rios assessed so far are saved for thepurposes of storage, analysis andrating; those data are of course not to

be considered definitive, as RiskAssessment is supposed to be conti-nued during all phases of the project.

Risk AnalysisIn order to improve Risk Analysiswork and data communication bet-ween RISK team and the relevantteam(s), we have developed a RiskRegister, following the templatespublished in ECSS-M-00-03Aappendix and given us by our expert,Mr. Paita. Each assessed scenario isstored in a register, and all its fieldare filled in order to provide animmediate and effective overlookupon characteristics and figuresregarding a scenario.Risk Analysis data are used to findsolutions and to help subsystems'decisions, in order to reduce severityof consequences and likelihood ofoccurance of each scenario, andfinally discuss and approve theiracceptance.

Risk CommunicationBeing one of the most critical aspectsof Risk Management, in ESEO pro-ject Risk Communication is madeeven more crucial by the fact thatSSETI teams are spread all overEurope. Anyway, communicationbetween RISK team and ESEO

teams and management is the live-liest, thanks to the great number ofcommunications media adoptable(newsgroups, chat sessions, email,teleconference) and to the veryimportant occasion of workshops.All the relevant data from RISK teamare of course at hand of each memberof ESEO teams and management, asRISK team dedicated folder onSSETI ftp is constantly updated, andconsultable by each SSETI member.

Future workThe perspective of work for RISKteam is going on in applying RiskManagement Plan during each phaseof ESEO project, until its very com-pletion. In this work, all the steps ofRisk Management plan presentedhere will be implemented more andmore deeply and finely, as long assystem complexity increases, toge-ther with our comprehension of it. Inparticular, much emphasis will be putinto bringing Risk Assessment phaseto a deeper level of complexity, ana-lysing risk scenarios to find betterand more effective solution to them,and implementing those solution inorder to obtain acceptance and closu-re for a bigger and bigger number ofscenarios.

s s e t i

The responsibility of RISK team within ESEO project is develo-ping and applying an extensive Risk Management policy duringall phases of the project, in order to provide an aid in designingand decision-making to the best extent possible, both to individualteams and to the project as a whole. Our work began in October2000, and it has brought us through the development of a RiskManagement plan and the implementation of an extensive RiskAssessment and Analysis phase.

Risk Management - ESEO

University of PisaPisa


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As the "real life" projects, ESEOmust be checked before it is finished.The difference between a space pro-ject and other industrial areas is thata real test cannot be made because ofthe cost of each launch. Therefore thesimulation is essential in our project.If we want to know how good ourdesign is, we need to check how eachsubsystem will run and whether theywill work together. The creation of avirtual environment is very useful tosolve design problems without buil-ding the real subsystem.

For all of these reasons, the simula-tion is one of the most importanttools in this project. LaunchingESEO without making simulations islike taking a plane that you do notknow whether it will fly or not.

For the whole simulation of the satel-lite we plan to use a program calledEurosim which is published byDutch Space. Eurosim is primary areal-time controller; its task is to exe-cute a list of periodical tasks (it holdsthe list in what it calls the"Schedule"), tasks that are coded inC or Fortran in subprograms that

represent every subsystem of a satel-lite (or other hardware).

One of the advantages is thatEurosim cares of all the timing andsynchronisation assuring that thesimulation runs in real-time withouthaving to code all that routines in thecode of simulation.

It also offers a high modularizationof the simulations making possiblethat different groups work in diffe-rent parts and later assembly all inone simulator. And last but no lessimportant, it is used in the ESA, sowe had access to some examples tolearn how to use it in a real environ-ment.

Our work until now has consisted ofasking the other teams about theirsimulation. We have prepared a"how to simulate" guideline in orderto prevent possible incompatibilitieswith Eurosim software. This guide-line should be followed by allgroups to avoid language problems(the use of different names for thesame variable, type of the sharedvariables…). We are helping teams

with their simulation, how to start,what is needed to be simulated…

Concerning our main future objecti-ves, they are basically three:1. Continue helping other teams withtheir subsystems simulation.Although all teams have to simulatetheir own subsystem some of themhaven't got enough time, or they mayfind some troubles we try to solve.2. Integrate all subsystems simula-tions using Eurosim. As told before,we are using Eurosim to integrate allsubsystems simulations in one.3. Make the ESEO simulation. Whenwe have all subsystems in Eurosim,we can make the ESEO simulation.

Simulation team is responsible of the coordination, review andrectification, and has to join all the simulations of the subsystemsof the micro satellite in an only simulation. Eight students aremembers of this team. We study in the Universidad Politécnicade Madrid (UPM), one telecommunications engineering and therest aeronautical engineering. We joined this project at the end ofthe year 2002.

Simulations - ESEO

Escuela Técnica Superior de Ingenieros Aeronáuticos Madrid

Eurosim


Structures-CalculationsESEO, SSETI Express

Faculty ofEngineering

Porto

The Faculty of Engineering of theUniversity of Porto, Portugal wasofficially accepted as member ofSSETI in April 2001. The subsystemassigned to the Porto team was struc-tures/calculations. This means theteam was responsible for developingfinite element models as required by

the program in order to verify stiff-ness requirements, compute loadsand stresses. This should be done inclose cooperation with the structuraldesign and configurations team loca-ted in Bilbao, Spain.The definition of subsystem require-ments was the first technical task thathad to be performed. Here the teamwas helped by ESA published stan-dards called European Cooperationfor Space Standardisation (ECSS).The next technical task for the Portoteam was the development of finiteelement models of the satellite toasses its natural frequencies. Therequirements document established aminimum stiffness that had to beverified by analysis and tests.The basis for the work was the confi-guration model which was done bythe Spanish team using CATIA.Upon that, a mesh was developedusing FEMAP 8.0 as pre-processorand ABAQUS 6.3 as processor.During the development phases, a lotof different finite element (FE)models were developed. They are allbased on shell/composite, beam,rigid and contact elements. Also, atrade study was performed to evalua-te the efficiency of using shell/com-posite elements to simulate the beha-viour of sandwich panels that the pri-mary structure is made of. The use ofcarbon fibre reinforced plastics(CFRP) as the honeycomb face she-ets was also considered and compa-red versus traditional aluminiumskins. Aluminium skins were ultima-

tely chosen because of the qualifica-tion needed to fly CFRP panels.More recently, the issue of interfacesbetween structure and subsystems'components rose. The connectionshave to be made using potted insertsthat transfer loads from the compo-nents to the honeycomb facing she-ets. The use of polymeric insertsinstead of typical metallic inserts wasconsidered. The behaviour anddesign of metallic inserts is well esta-blished and documented in ESA'sInsert Design Handbook (IDH). Inorder to provide insight about thebehaviour of polymeric inserts, itwas recommended by the reviewboard to conduct a short test cam-paign. Determination of the inserts'pull-out strength and failure modesof the joint under traction was thegoal.

Current and future activitiesCurrently, work on ESEO is ongoingwith new and improved modelsbeing developed. These provide bet-ter results and will be confrontedwith experimental results later in theacademic year.A new challenge that has come outrecently is the SSETI Express initia-tive. The team from Porto has theadded responsibility of the configu-rations subsystem for SSETIExpress. This will, in principle,decrease design time as both designand analysis teams are in the sameplace.

s s e t i

Major responsibility of the SSETI chapter in Porto, Portugal is the veri-fication of the satellite's structural design through FE analysis. Theteam joined SSETI in 2001 and, together with Configurations Team inBilbao, has produced a number of models that follow the design itera-tion process. For SSETI Express, this team has accumulated the task ofdeveloping the satellite's configuration, too.

1. Latest FE model2. Inserts' pull-out test

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Lierni Arana

System engineering,what is it and whydo we need it?ESA-ESTEC

A spacecraft is divided into a set offunctional elements or subsystems. Aspacecraft itself however is only partof the whole scenario. A groundsystem is needed to communicatewith the spacecraft and a launcher tolaunch it into space. The systemengineering team needs to ensurethat the user requirements will be ful-filled and the system will work as aunit once it is in orbit.The system engineering team mustbalance many conflicting require-ments in order to propose a solution.These requirements may includecost, mass, reliability or any othercombination of competing require-ments.

System engineering focuses ondefining customer needs andrequired functionality early inthe development cycle, docu-menting requirements, thenproceeding with design synthe-sis and system validation whileconsidering the complete pro-blem:

Operations Performance Test Manufacturing Cost & Schedule Training & Support Disposal

System engineering monitors theprogress of the project by participa-ting in technical reviews, performingrisk management, data managementas well as configuration, verification,interface management and tests. The design decisions are based onstudies, trade-offs and analyses,models, simulations and develop-ment activities. System Engineering joins all the dif-ferent disciplines into a team endea-vour, which effectively becomes an

ordered and controlled developmentprocess from concept to developmentand operation.

System engineering together withmanagement act as the big brother ofthe project making sure that when thetime arrives for placing all piecestogether, they will all fit togetherwith the minimum of problems andthe final system will perform asrequired by the customer.

System Engineering is an art where the ove-rall tasks and possible risks need controllingso that at the end of the project, the customeris pleased with the working product. It invol-ves a close control of all technical aspects ofthe system and decision making based ontrade offs, analysis and models.

Artist’s impression for ESEO


Attitude Control andDetermination on a BudgetDuring the SSETI-Express feasibilitydiscussion in December 2003 it wasfound that no near-flight-readyAttitude Control and DeterminationSystem (ACDS) existed that could beadopted for the Express mission.Therefore a specific ACDS groupswas formed to supply the missionwith such a system.

The challenge in this endeavour isfirst and foremost to complete thedesign and construction within aschedule budget of less than sixmonths. A normal micro-satelliteusually spends about ten man yearson the same task. Further, the solu-tion is also constrained severely bythe need to have minimum impact onthe other space-craft budgets, speci-fically the power budget and on-board computation budget. Finally,

the system is not allowed to infer anymajor configuration changes to thealready set baseline configuration.

The approach in terms of control is touse passive magnets to make thesatellite track the ambient Earth fieldand the approach thus ensures thatthe camera payload and antennas willbe roughly Nadir pointing in the nor-thern hemisphere. However, in orderto reach this state of attitude evolu-tion then the excess energy of satelli-te must be dissipated. To this end twoelectro-magnetic coils are usedmounted perpendicular to the perma-nent field (and each other).Essentially the scheme only stabili-zes two axes, and the rotation aroundthe longitudinal axis remains uncon-trolled. The coils are designed to pro-vide a current path if the system isnot powered and will thus work as anEddy-current damper, and thus theattitude control will be effective evenif the Power Control Unit fails.

The attitude determination system isbasically needed to evaluate thepropulsion payload. The primarysensor is a three-axis magnetometersupplemented with data from expe-rimental sun-sensors. All sensordata is stored on-board the satelliteand then downlinked for off-lineanalysis. This analysis is performedusing continuous filtering and tem-

poral sensor fusion techniques. Datawill be processed both forwards andbackwards in time in order to gain asmuch information as possible fromthe data. A performance comparisonbetween the Extended Kalman Filterand the Unscented Kalman Filter willbe performed as academic work.

Following successful commissioningof the satellite it is hoped that it willbe possible to perform advancedopen-loop manoeuvres in order tosupport the camera mission further,and to explore the interesting rela-tionship between the off-line modeland the real spacecraft behaviour.

As of the 20th of February thesystem has been specified and orderson main hardware components havebeen placed. Next step is the detaileddesign and analysis of the controlpart of the system, which then is tobe followed by the same process forthe determination part.

s s e t i

The ADCS group atAalborg University isresponsible for the designand construction of theSSETI Express AttitudeControl and DeterminationSystem. The design chosenincludes a stabilisation andattitude detection schemeusing passive magnets, sunsensors and magnetome-ters.

Attitude Determination and Control System SSETI Express

Aalborg UniversityAalborg


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The On-board ComputerIt is a major time consuming taskdesigning a custom On BoardComputer (OBC) every time a smallsatellite, like the Cubesat or SSETI-express, is developed. To ease theburden of constructing such satelli-tes, a flexible standard computerplatform is designed which can beapplied to most micro-satellites. Therationale is to minimise the problemsduring integration of the parts in asatellite, thus lowering the overallconstruction time while boostingoperation reliability. This is achievedby developing a generic frameworkthat strictly defines the communica-tion interfaces between onboard sub-systems.The result of the research is a frame-work consisting of an OBC subsy-stem and a protocol description forfurther development of the newAAUSAT-II satellite. A solution forthe internal subsystem communica-tion was developed and dubbedINSANE - short for INternal SatelliteArea NEtwork. A protocol specifica-tion for INSANE was created for useby future subsystem developers.INSANE is a network concept thatprovides a generic communicationinterface to any subsystem regardlessof the residence of the subsystem.Specifically, software applications

on the OBC usethe same API( A p p l i c a t i o nP r o g r a m m e r sInterface) for com-munication as anapplication residingon an externalmicro controllerdoes, which adds alayer of abstractionto the developers of subsystems.In order to fit the OBC for SSETI-express an interface card is suppliedto adapt a variety of interfaces toINSANE, thus making the OBCcomply with even the most intricateinterfaces.

Flying a camera the Express wayThe SSETI-Express camera groupwas formed as a response to the star-ting discussion about an Expressmission. The idea is to fly the AAU-cubesat flight spare camera unit. TheAAU-cubesat was launched in June2003, but unfortunately various plat-form problems made it impossible tooperate the camera that was the mainpayload. The SSETI-Express wastherefore a perfect opportunity togive this student built payload ano-ther chance, and it was included in

the mission as the tertiary payload.The camera is based around a KodakCMOS image sensor that provides aresolution of 1280x1024 pixels in24bit colors. The lens systems for thecamera has been custom built for thisproject and it will provide an onground resolution of approximately150x120 meter from a 900~km orbit.On the SSETI-Express the camerawill be mounted on the top-plate ofthe satellite and will therefore, due tothe primitive attitude control systemon SSETI-Express, only be able totake pictures of the Earth when thesatellite is at northern latitudes.However, it will also be interesting totake pictures when the satellite pointsout in space - these pictures can forexample be used to evaluate the fea-sibility of using the camera system asa star tracker on future missions.

Since the year 2001, students at AalborgUniversity have been involved in designingand building small satellites. Already, oneCubesat has been successfully launched intoorbit and the next generation Cubesat, AAU-SAT-II, is now being developed to serve as aframework for future Cubesats at AalborgUniversity. The versatility of this frameworkallows the On Board Computer of AAUSAT-IIto be implemented into other satellites inclu-ding ESA's SSETI-express, further the teamwill provide the camera for this mission.

On-board computer and camera SSETI Express

Aalborg UniversityAalborg


Case study of ESEOThe ESMO ADCS team started theirwork in January 2004, as the firstESMO team. More ESMO teamswill be recruited for fall 2004. Thisspring, the team is working on a casestudy of ESEO. The main objectivesare mathematical modeling of thesatellite and its actuators (thrustersand reaction wheel), stability analy-sis, orbital maneuvering and attitudecontrol. The latter includes severalcontrol schemes, including linear andnonlinear control, as well as modelpredictive control (i.e. design of con-trol laws to minimize power and fuelconsumption). Finally, the closed-loop system will be extensivelysimulated in MATLAB andSimulink.

Some of this work has alreadybeen completed by the ESEOAOCS team. This way, theESMO ADCS team can learnfrom them, and in return helpthem in areas where the ESEOAOCS team may have problems.

Future workWhen the case study is finished,the ESMO ADCS team will startto work on the ADCS for ESMO.

s s e t i t e a m s

This SSETI chapter is based in Trondheim and Narvik inNorway.

It is responsible for the Attitude Determination and ControlSystem (ADCS) for the European Student Moon Orbiter(ESMO). This work starts with a case study of the European StudentEarth Orbiter (ESEO), in order to investigate to what extentthe ADCS can be reused for the ESMO. Focus will also be on stability analysis of the ADCS.

Attitude Determination and Control System - ESMONorwegian University of Science and Technology (NTNU)

and Narvik University College (HiN)Trondheim, Narvik

The Moon


Phase 0 : DesignIn early 2000 the SSET Initiative waspresented through a web site (seeFig. 1) which was located on theweb-server of the ESA OutreachOffice at the ESA/ESTEC. Besidesstatic HTML pages describing SSETIand the mission, the chance fordiscussions was offered by linking toan dedicated bulletin board system. During the mission definition phasethe major needs for the infrastructurewere identified and implemented inprototypes. Some trade-offs werediscussed 'on-the-fly' and severalimplementation decisions had to berevised or were overruled by theusers' acceptance.

Phase A/B : PrototypeThe prototype that was implementedto fulfill the requirements consists ofa set of web-pages (WWW) and -scripts and a set of native Internetservices. For the web-scripts the"PHP Hypertext Processor" (PHP) isutilized. The user interaction is per-formed over the well-known World-Wide-Web (WWW) (see Fig.2).The following list shows the majorrequirements and their implementa-tion components that turned out to bepowerful and important for the

design infrastructure:1.Near real-time communication(delay in range of seconds): imple-mented through a dedicated "InternetRelay Chat" (IRC) system.2.Low-delay communication (delayin range of minutes/hours): imple-mented through a dedicated UltimateBulletin Board (UBB) system.3.Document / data exchange (ran-dom access): implemented through adedicated File Transfer server (FTP).4.Member / team data storage: imple-mented through a MySQL databaseaccessible through web-scripts.5.Easy and continuous access: imple-mented through the registration ofthe Internet domain 'sseti.net' and theinstallation of dedicated servers forSSETI.

Phase C : OutlookOne of the changes compared to theinitial concept is the changeoverfrom the UBB to a dedicated InternetNetwork News (INN) system due toadministration and styling problemswith the UBB.The redundancy and backup strategyshould be improved by the plannedimplementation of two synchronizedservers and WWW front-ends for the

native services. In addition, the safe-ty, permissions and administrationmanagement shall be re-structuredto minimize the number of accountsneeded per team.Furthermore, the separation betwe-en content and formatting should beimproved to allow a dynamic stylingof the tools by the SSETI PR Team.

AcknowledgmentsThe WSW development was startedin the beginning of the year 2000 byEd C. Chester and was supported bycomments and evaluation by EricTrottemant.

The student satellite design project 'SSETI' is based on distributed workthat is coordinated over the Internet. Therefore, the infrastructuresdiscipline of SSETI has the main objective to provide the necessary ser-vices, clients and interfaces to facilitate the desired design strategy.After starting from scratch the needs and requirements were identifiedthrough the implementation and application of a prototype called 'theWorkshop-Web' (WSW).

Infrastructures Design for a Distributed Satellite Design ProjectJörg Schaefer, University of StuttgartLars Mehnen, University of Technology Vienna

1. first SSETI Web-Pagethe 2. Workshop-Web Prototype (WSW1)

s u p p o r t t e a m s

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SSETI Legal Team

UniverstiéParis XI

Faculté JeanMonnet

Paris

The current legal team is formed oftwo members, Guilhem Brouard andJulien Mariez, students in the Master(D.E.S.S.) of Space andTelecommunications Law, a mostunique formation in Europe, sponso-red by ESA for 2003-2004, at thelegal department (Faculté JeanMonnet) of the University Paris XI.They are also members of IDEST(Institute of Space andTelecommunications Law), an inter-national law research centre. The for-mer members were Delphine Gomesde Sousa and Sylvie Constante, for-mer students (2002-2003) of themaster, and still members of IDEST.

During their term, the legal teamdrafted the statutes of the SSETIAssociation, the first agreementswith ESA and worked on the issuesof intellectual and industrial propertyrights. Currently it is going on withthis work and draft the general agree-ment with ESA for Express andESEO. The Legal Team is as well incharge of the common proceduresrelated to the construction, launch,and operation of SSETI satelli-tes, such as the frequenciessummons at the InternationalTelecommunications Union (ITU)and the satellite registration at theUnited Nations.

The team endorsing professor, M.Philippe Achilleas, is the founder andthe director of both the master andIDEST. As a consequence the legalteam benefits of the infrastructureand resources provided by the insti-tute. The team has its seat in Sceaux,at the Faculté Jean Monnet, in afavourable environment for spacelawyers with the proximity of majornational (CNES) and European(ESA) institutions as well as impor-tant companies (Alcatel Space,Astrium, and EADS...).

s u p p o r


t t e a m s

Public relations

Accademiadi Belle Arti diBreraMilano

SSETI Public Relations Team"Communicate a project that jointechnological research with the pas-sion of a network of european uni-versities and students, supported byan institution caring on formation:respectively SSETI and ESA". Thisis one of the main PR Team objecti-ves. The team is made up of studentsfrom the "Accademia di Belle Arti diBrera" in Milan. The students, whoare assisted by university professors,have all the necessary skills to mana-ge all communication aspects of theSSETI project.

Main GoalsObjectives to be reached are focusedin a communication plan that ismainly targeted on: primary schools,universities, institutions and indu-stries. The need to speak to a largeand educationally differing audiencerequires different languages/approa-

ches for every target: cartoon stylefor primary formation, hi-tech fortechnical schools, a direct languagefor the university, concrete and reali-stic for economic and research insti-tution. Therefore, our communica-tion instruments should be different:the institutional internet site willbecome didactic format and act as alearning whilst playing situation, aninformative point for university stu-dents and a resource for press andsponsors. We are producing editorialinstruments such as a general bro-chure, a school presentation pack, awelcome kit and posters. Objectivesthat are still being planned will inclu-de a video documentary and anadvertising spot. Considering achie-ved goals, there is sure the produc-tion of all the STEC 2004 materials.

Instruments and methodologiesThe capability to plan a trajectory tobe supported with our resources is areality for our work, thanks to ourcommunication plan that underlinesmethods and objectives. The need

to discuss and share it should jointhe capability to get a professionaland realistic project that matchesSSETI objectives optimizing teammembers' capacity. In particular, theachievement of our objectives is clo-sely connected to five single wor-

king phases: ideas, planning, review,realization and distribution. Thesephases correspond to the needs tooffer professional materials with animportant visual component, to plantimes and resources for every aspectof the production, to grow for bettersupporting the SSETI project, to begood listeners to SSETI members, tobe real spokespersons and to be ableto use all the available media for dif-ferentiating and optimising commu-nication.

The growing of each team member is connected to the pos-sibility to be involved in a stable and original project likethe SSETI.Personal capacity, motivation and resources are the ele-ments required by each individual involved to ensure thesuccess of this project: Let's launch the dream….

1. Graphic project for communication in schools

2. Sseti website ( www.sseti.net )

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IntroductionThe DOBSON SPACE TELESCO-PE Projects is a student initiative atthe TU-Berlin. It is our aim to deve-lop foldable optics for micro satelliteapplication. The Idea is to overcomethe volume limits of hitchhiker pay-loads by disassembling the telescopeduring transport and reassemble itfor observation. This technology willenable university satellites to carryoptic systems needed to make them afavourable science tool. Our Projectis part of the micro satellites activi-ties at our university (the TUB-Satfamily). It is supervised by Prof.Briess the former project manager ofthe DLR BIRD mission. The core group consist of 3 masterstudents from the TU-Berlin. Due tothe high complexity of the topic wetried to acquire external expert kno-wledge from the beginning. With thehelp of nearly a dozen externalexperts of various fields we formed awell known science network.

TechnologyThe idea of avoiding volume limitsby disassembling the telescopeduring transport was derived from atechnology invented the amateurastronomers. It is called truss DOB-

SON design. The DST team wants toadapt this technology for spaceapplication.

Applications for foldable telesco-pesAlthough the Dobson SpaceTelescope is designed as a microsatellite for earth observation andNEO survey the technology of fol-dable telescope design offers advan-tages for other satellites classes andmissions, too. Even pico-satellitesmay benefit from this technologybut the real bargain lies in apertureslarger than 12inch.

Unfolding and collimationThe telescope will be unfolded withthe deployment of the booms. Afterthis the secondary mirror is about1,5m depart from the main mirrorbut not exactly in the right position.Secondly micro actuators will fineadjust the position of the secondarymirror and thereby collimate thetelescope. The fine adjustment canbe seen as a mediator between therequirements of the optical systemand the abilities of the booms.

Current status and OutlookWe are at the end of the paper stu-dies. In late 2003 we have construc-ted our first telescope. With the helpof this mock-up we acquired fundingfor a lab model containing a 12inchmain mirror. It will be built during2004.

The DOBSON SPACE TELESCOPE Project (DST) at the TechnicalUniversity of Berlin (TU-Berlin) believes that the challenging task formicro-sat remote sensing is to overcome the lack of an appropriateinstrument. In order to break the limits for optical payloads on smallsatellites the DST team develops an optical telescope with deployablestructures. The telescope is compressed during launch and it will unfoldafter being deployed in orbit.

The Dobson Space TelescopeTechnical University of Berlin

Dobson Space Telescope Mock-up

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ConferenceCoordination Board

The board has been formed to coordinate the organi-sation of the conference and is composed of membersof ESA, SSO, EPFL and the SSETI Association

Lierni AranaESA Education Office

Marie De CockESA Education Office

Renato KrpounEPFL, SSETI Association

Neil MelvilleESA Education Office

Stéphane MichaudEPFL Space Centre

Daniel NeuenschwanderSwiss Space Office

Vincenzo PulcinoSSETI Association

Phillipe VollichardEPFL Space Centre

Philipe WillekensESA Education Office

The CCB is backed by a local organisation committeeat the EPFL composed of the following members:

Enterprise and public relationsVincent Schaller

Speaker and participants relationsConstantin Niemeyer

Logistics & CateringAlexandre HermannAndres Müller

IT InfrastructureLionel Clavien

FinancesMarc Tosetti


STEC Pages

Documents

van allen belts

facult jean monnet

narrow angle camera

norwegian space centre

european space agency

swiss space office

swiss federal institute

board data handling