AFF Completion of experiments
SSC (Swedish Space Corporation) performed a remarkable autonomous close approached to bring MANGO and TANGO to a distance of less than 15 m. The maneuvers needed for that approach were computed by their autonomous formation flying (AFF) software on-board of MANGO. During an experiment of 8 days duration SSC performed numerous formation keeping and formation configuration maneuvers to verify the handling of different formation scenarios.
Earlier SSC already performed the AFF (Autonomous Formation Flying) Early Harvest experiment (see http://www.prismasatellites.se/aff-early-harvest.aspx). The previously gained experience was now used to improve the performance for the completion of the AFF experiments performed on April 06 – 13.
Starting from a safe formation with a maximum horizontal distance (z-component) of 100 m and a maximum vertical distance of 100 m (y-component) MANGO’s approach towards TANGO was introduced. First a reduction under less than 50 m took placed in horizontal as well as vertical distance, while the mean along-track distance stayed almost unchanged close to 0 m (see Fig. 1).
Fig. 1: Along-track (x:=blue), vertical (y:=green) and horizontal (z:=red) distances during one day of AFF-completion
After several little changes and successful formation keeping maneuvers over some days, demonstrating the flexibility of the system (e.g. see Fig.2) finally on the 12th of April the cross-track and radial components (y and z) were reduced until completely gone, thus a highly unstable and dangerous formation was acquired while the along-track distance was further reduced down to 15m (see Fig. 3).
Fig. 2: Keeping of the formation until 09:00, reconfiguration & back-reconfiguration (09:00-13:30), and keeping again until 16:00.
Fig. 3: Close approach down to 15 m 3D-distance.
After reaching the required close formation of less than 15 m 3D-distance in the early morning hours of April 13 quickly a stable formation was established and SSC was happy about the successful completion of their AFF experiment.