1. SkySails GmbH; Luisenweg 40 20537 Hamburg Germany
2. Systems Control and Optimization Laboratory; Department of Microsystems Engineering (IMTEK), University of Freiburg; Georges-Köhler-Allee 102 79110 Freiburg Germany
3. Department ESAT (STADIUS/OPTEC); KU Leuven University; Kasteelpark Arenberg 10 3001 Leuven Belgium