DIMAC data arrived: the tether had its swing!

The long awaited DIMAC data sheds new light on YES2 and the workings and influence of the Foton attitude thruster. It is now confirmed that the tether deployment stopped at 8625 s, as suspected earlier. New is that it is now certain that the tether REMAINED attached when deployment completed and a swing back to the vertical was started! At the proper time the tether was cut. It also seems that Fotino was released at the right moment and deorbited into Kazakhstan. Features such as the stepper driver/barberpole activity can be clearly recognized, as well as the hold phase (gravity gradient tension), including longitudinal tether oscillations. During the swing, jerks such as those predicted are visible (see separate article below).

Above picture compares the YES2 measured tension after ejection to that derived from DIMAC Foton accelerometer data. An amazing fit!

The DIMAC data shows a clear tension component that indicates significant deviations (up to 30 degrees) of Foton attitude from the vertical. From this it could be understood what was the Foton attitude control algorithm, which turns out to be quite different from the one expected. The new understanding resolves some apparent contradictions in our earlier analysis (see also below).