N 34-97 - Paris, 21 October 1997

TEAMSAT, a "passenger" for ARIANE 502

One of the "passengers" to be flown on the ARIANE 502 flight is an ESA project involving young graduate trainees and executed at ESA's R&D establishment, ESTEC, in The Netherlands. TEAMSAT (Technology, science andEducation experiments Added to Maqsat) is an initiative of the Automation and Informatics Department at ESTEC, a response to the opportunity afforded by the Ariane 5 qualification launch (A502). The satellite was produced in only seven months from start (December 1996) to readiness (July 1997).

Costs were kept to a bare minimum (less than one million ECU) through the use of existing flight equipment and generous support from various ESA departments. And the launch is being provided free of charge.

Five experiments, already in the final stages of completion and flight readiness, were integrated into an octagonal aluminium "box". Two identical "boxes" were produced; one "dummy" and one flight model. The dummy is a representative structural model used for mechanical qualification of TEAMSAT and the MAQSAT-H (*)/TEAMSAT composite.

After the qualification programme it was available for use in flight, should the flight model not be completed by the launch date. ESTEC was responsible for the design and manufacture of the "boxes", the power system, the data handling and communication systems. ESOC, ESA's Space Operations Centre in Darmstadt, Germany, is providing the necessary ground support and satellite flight control services from a control centre located in Kourou. To allow as many students as possible to participate, experiment control will be performed remotely from ESTEC at an "Experiment Control Centre", re-using computers and software used in the spacecraft testing.

The five experiments comprising the 350kg TEAMSAT payload are:

• Orbiting Debris Device(ODD) - Automation & Informatics Department, ESTEC. The MAQSAT-H satellite is painted with contrasting patterns (75% white and 25% black) to support testing and calibration of ground-based optical and radar stations in Europe. The contrasting paint should also allow detection of the rotation or tumbling of MAQSAT-H. Additionally, surface paint degradation will be studied.
• Autonomous Vision System (AVS) - Technical University of Denmark. AVS is a camera which automatically recognises and tracks stars or non-stellar objects (such as satellites). AVS can be used to identify specific stars, determine the attitude of satellites for navigation purposes and acquire images.
• Visual Telemetry System (VTS) - MMS Bristol (UK) / IMEC and OIP (Belgium). VTS is an imaging system to monitor spacecraft activities such as the operations of critical mechanisms. TEAMSAT hosts a system of three cameras and a master unit to provide compressed image sequences of the fairing opening and satellite separations.
• Flux Probe Experiment (FIPEX) - University of Stuttgart. FIPEX will measure the concentration of atomic oxygen at altitudes up to 1000 kilometres. Atomic oxygen is known for its erosion effect and degradation of optical surfaces and lenses.
• Young Engineers' Satellite (YES)- Delft University of Technology. YES is a sub-satellite developed to be deployed on a 35km tether, to study the dynamics of tethered satellites. It was designed, assembled and integrated in record time by young graduates and students at ESTEC. A GPS receiver is installed to evaluate the use of GPS for navigation, especially above the GPS satellite constellation. YES also contains technology validation experiments which will measure radiation, the solar angle and acceleration in autonomous mode, after separation from MAQSAT-H. Unfortunately, the afternoon launch window requirement could not be accommodated, resulting in the tether posing too high a collision and debris risk. Consequently the tether will no longer be deployed but the sub-satellite will be separated from TEAMSAT.

The project has enabled Young Graduate Trainees (YGTs) and Spanish Trainees to gain valuable experience in designing, building and integrating a satellite and its payload. YGTs come to ESA (mainly to the Technical Departments in ESTEC) for a period of one year to be involved in the everyday work of the Agency. Under an agreement with Spain, ESTEC also hosts a small number of Spanish Trainees for a period of two years to gain work experience and knowledge to take back with them to Spanish industry. Some 43 young engineers on these schemes and from the Delft University of Technology were involved at some stage of the project. The project has also been invaluable experience for ESA staff, providing a flight opportunity for several technologies developed in-house and under industrial contracts.

The names of all the project participants, engraved on a side panel of TEAMSAT, will be in space for the lifetime of its geostationary transfer orbit around the earth.

Since the project was a last-minute flight opportunity for which there was no cover in any budgets, there was little money available for parts and equipment. So some very creative scavenging for unused or spare equipment had to be done; among the items collected from earlier projects were batteries from ECS and transponders from the Olympus and Eureca satellites.

Inexperience in the design and construction of satellites meant that considerable spare-time effort was required from ESTEC and ESOC staff to guide the young engineers and students. The mechanical design and fabrication were carried out in the ESTEC workshop, relying heavily on the years of experience and workmanship of the technicians and engineers - several of whom, being already retired, volunteered to return to their old place of work to pass on "tips and tricks" to the younger generation. Newly developed data-handling systems employing ESA's packetised data standards were adapted for TEAMSAT and the YES sub-satellite. ESTEC facilities were used to test the satellite, in particular the "shaker", which exposed the satellite to conditions similar to the demanding launch environment. To simplify the design of the spacecraft no attitude control, power generation or thermal control was incorporated.

The flight operations would have been impossible to perform without the contribution of ESOC, which is providing access to its ground stations, network infrastructure and vast experience of satellite operations. A flight control system for both TEAMSAT and YES was configured from the new generation control system (SCOS2) in record time, tested at ESTEC and installed at Kourou.

The satellite was shipped to Kourou on 11 July to commence the launch campaign. Additional information, including photographs taken by the on-board cameras can be found after launch on the TEAMSAT web site at http://www.estec.esa.nl/teamsat/

(*) MAQSAT-H is one of the two instrument platforms that will constitute the main ARIANE 502 payload, the other being MAQSAT-B. The two platforms, with a mass of 2300 kg and 1400 kg respectively, simulate large satellites and are equipped with instruments and sensors that will measure the actual environment to be encountered by future ARIANE 5 payloads during flight.

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