FIRST LOOK · Fast initial in-orbit identification of scientific satellites

Final Activity Report Summary - FIRST LOOK (Fast initial in-orbit identification of scientific satellites)

The main goal of this project was the development of technologies for an improved understanding of satellite dynamics. Sophisticated scientific satellites are used today to measure extremely small effects of gravity and relativity or execute highly precise measurements of the positions of the stars. Because the scientific instruments on-board of these spacecrafts are very sensitive to any disturbance or wrong calibration, the system of each spacecraft must be very precisely known. It must be known how it reacts to external forces, like the residual earth atmosphere, micro meteorites or the earth magnetic field. As most satellites have a unique attitude and orbit control system, the influence of these items must also be taken into consideration. FIRST LOOK technologies provided a set of methods and modules to simulate the dynamic behaviour of a satellite in orbit down to a very precise level. Therefore, many effects that might be observed in the instrument measurements were predictable by the undertaken simulation. The spacecraft operators and measurement data analysts would then be able to check what kind of filters was appropriate to separate real measurements from spacecraft induced effects. Besides the pre-launch operations for a mission, a post-launch analysis was also possible. Because of the very sensitive instruments of such a scientific spacecraft it was very difficult, or even impossible, to calibrate the systems. The main reason for that fact was the overall gravity influence of 1 g, whereas the operational environment was weightless, i.e. corresponded to zero g. Thus the first real measurements could only be obtained once the satellite was already in orbit. With a very good knowledge on the spacecraft dynamics and a detailed simulation, it was possible to fit the first real measurements with the spacecraft model and obtain valid calibration data for the instruments. Furthermore, it was feasible to detect errors in the spacecraft operations when they left traces in the instrument data.

Data: CORDIS, © European Union