ESTCube-1 in-orbit experience and lessons learned

In this article, we report on the in-orbit experience - an overview of ESTCube-1 operations from the launch until the experiment, as well as on lessons learned from five years of development and almost two years of operations. Lessons are identified from the point of view of system engineering, electrical engineering, mechanical engineering, software engineering, testing and measurements, payload, and management. Detailed flight results of ESTCube-1 will be provided in dedicated articles. We hope that other teams can benefit from our experience.