Unconventional thinker, visionary and pioneer for sustainability – these are just some of the terms that describe Wubbo Ockels, our former chair holder and colleague at Delft University of Technology. In 1985, he became the first Dutch astronaut in space flying for the European Space Agency on the Space Shuttle Challenger. In 1992, he started an academic career that would lead him to inspire and shape generations of students in Delft, creating an awareness for sustainability. One of his most prominent visionary initiatives was the Laddermill, the characteristic cable loop reaching far into the sky, with kites attached to tap into the kinetic energy potential of the jet stream. In 1997, Wubbo patented this idea and explored its potential in the years to come. In 2004 he assembled a dedicated research group which by 2010 had advanced to regular tests of the mobile 20 kW kite power system that is still used as research and development platform today. Yet, this was only one of the many strands of his scientific interests.

We experienced him as a truly inspiring teacher and colleague as well as a relentless activist for a sustainable environment. During lunch breaks at the faculty he would often pose daring engineering questions to staff and students to subsequently work out a solution together at the white board. These brainstorming sessions were indeed moments for developing great ideas. Wubbo was also an important facilitator for research and development. He effectively employed his broad network of personal-professional relations and was often central in triggering the interest and support of politicians and industrial decision makers, both on national and on international level. But most remarkable was the passion with which he pursued all these activities.

We would probably not be where we are today if it wouldn't be for his dedication and passion. We were fortunate to have the opportunity to know him and work with him. We will miss him.

The active and alumni members of the kite power research group and supporters: Roland Schmehl, Uwe Fechner, Rolf van der Vlugt, Nana Saaneh, Joris Melkert, Aart de Wachter, Barend Lubbers, Jeroen Breukels, John van den Heuvel, Robin van Kappel, Claudius Jehle, Marien Ruppert, Stefan Haug, Joost Schwoll, Joost Kirkenier, Edwin Terink, Stefan de Groot, Filip H. Saad and Henriette Bier.