In view of shrinking budgets, reliable satellites, which enable affordable missions in the areas of science, Earth observation and climate research, are in greater and greater demand. The Flexbus concept allowed the successful entry of Astrium into the area of development and manufacture of "low cost" satellites. Important contracts were won on the basis of Flexbus.

Following the launch of the Champ satellites, the two spacecraft for the Grace gravimetry mission will be prepared for NASA. Additionally, keen interest has been voiced worldwide in using the Flexbus concept, with its intelligent and affordable component solutions, for commercial missions. Compared to a conventional design, the Flexbus concept of Champ resulted in a cost reduction by more than half.

The use of a mature basic architecture for the spacecraft bus and the combination of commercial, proven components with mission-specific, new components make Flexbus a satellite "of building blocks" which optimally adapts to individual mission and payload requirements. For this reason, satellites developed and built on the basis of Flexbus can be placed into orbit already two to three years after receipt of order. In addition to development and testing for a mission, this concept also facilitates satellite operation.

Champ (Challenging Minisatellite Payload) will provide data on the composition, structure and dynamics of the solid planet, its oceans and atmosphere as well as the surrounding envelope of charged particles and magnetic fields. On its orbital track, Champ will orbit the Earth every 93 minutes. The route will be exactly over the poles. Similar to a globe on an axis, the Earth will rotate below its orbit, thus enabling a precise measurement.

One of the mission objectives is to further develop the existing gravity model of the Earth. This enables exact measurements of the mass changes on the Earth's surface -- for instance, by assumed polar ice melting. Exact magnetic field measurement also gives an insight into the Earth's interior.

Thus, geophysicists hope for a more in-depth investigation of the driving force of continental drifts. The research satellite Champ is a project of the geophysical research center in Potsdam (GFZ) and the German aerospace center (DLR). Jena Optronik GmbH, a subsidiary of Europe's new aerospace company Astrium, was responsible for building the satellite.

Owned by the Italian space agency (ASI) and developed by Carlo Gavazzi with contributions from many other Italian companies, MITA has two tasks to perform: in a circular orbit at 450 km altitude, the mini satellite will carry a cosmic particle detector, while its platform will be tested for the first time as a vehicle for future scientific missions.

MITA also carries the MTS-AOMS payload (MicroTechSensor for Attitude and Orbit Measurement System), developed by Astrium in the framework of ESA's Technology Flight Opportunity trial programme.

With the Technology Flight Opportunity scheme, funded by its General Studies Programme, ESA intends to provide access to space for European industry's technology products needing in-orbit demonstration to enhance their competitiveness on the space market.

This new form of support to the European space industry ties in with ESA's strategy for fostering the competitiveness of European-made technology for eventual commercialisation. In-orbit demonstration is essential if new technologies are to compete on level terms on non-European markets. It thus consolidates strategic investments made by the space industry.

The MTS-AOMS is a highly integrated sensor for autonomous attitude and orbit control systems. It combines three functions in one unit: Earth sensing, star sensing and magnetic field sensing. The equipment incorporates an active pixel array sensor and a 2-D fluxgate magnetometer.

The aims of the flight are to verify in situ the payload's inherent functions and performance, which cannot be done on the ground, and to assess the behaviour of this type of technology when exposed to the space environment.

The Technology Flight Opportunity rule is that ESA funds the launch and integration costs, industry the development and operating costs. According to present planning, two further in-orbit demonstrations funded by this scheme will be carried out between now and January 2001.